Source code: Lib/urllib/request.py
The urllib.request module defines functions and classes which help in opening URLs (mostly HTTP) in a complex world — basic and digest authentication, redirections, cookies and more.
See also
The Requests package is recommended for a higher-level HTTP client interface.
The urllib.request module defines the following functions:
Open the URL url, which can be either a string or a Request object.
data must be an object specifying additional data to be sent to the server, or None if no such data is needed. See Request for details.
urllib.request module uses HTTP/1.1 and includes Connection:close header in its HTTP requests.
The optional timeout parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used). This actually only works for HTTP, HTTPS and FTP connections.
If context is specified, it must be a ssl.SSLContext instance describing the various SSL options. See HTTPSConnection for more details.
The optional cafile and capath parameters specify a set of trusted CA certificates for HTTPS requests. cafile should point to a single file containing a bundle of CA certificates, whereas capath should point to a directory of hashed certificate files. More information can be found in ssl.SSLContext.load_verify_locations().
The cadefault parameter is ignored.
This function always returns an object which can work as a context manager and has the properties url, headers, and status. See urllib.response.addinfourl for more detail on these properties.
For HTTP and HTTPS URLs, this function returns a http.client.HTTPResponse object slightly modified. In addition to the three new methods above, the msg attribute contains the same information as the reason attribute — the reason phrase returned by server — instead of the response headers as it is specified in the documentation for HTTPResponse.
For FTP, file, and data URLs and requests explicitly handled by legacy URLopener and FancyURLopener classes, this function returns a urllib.response.addinfourl object.
Raises URLError on protocol errors.
Note that None may be returned if no handler handles the request (though the default installed global OpenerDirector uses UnknownHandler to ensure this never happens).
In addition, if proxy settings are detected (for example, when a *_proxy environment variable like http_proxy is set), ProxyHandler is default installed and makes sure the requests are handled through the proxy.
The legacy urllib.urlopen function from Python 2.6 and earlier has been discontinued; urllib.request.urlopen() corresponds to the old urllib2.urlopen. Proxy handling, which was done by passing a dictionary parameter to urllib.urlopen, can be obtained by using ProxyHandler objects.
The default opener raises an auditing event urllib.Request with arguments fullurl, data, headers, method taken from the request object.
Changed in version 3.2: cafile and capath were added.
Changed in version 3.2: HTTPS virtual hosts are now supported if possible (that is, if ssl.HAS_SNI is true).
New in version 3.2: data can be an iterable object.
Changed in version 3.3: cadefault was added.
Changed in version 3.4.3: context was added.
Deprecated since version 3.6: cafile, capath and cadefault are deprecated in favor of context. Please use ssl.SSLContext.load_cert_chain() instead, or let ssl.create_default_context() select the system’s trusted CA certificates for you.
Install an OpenerDirector instance as the default global opener. Installing an opener is only necessary if you want urlopen to use that opener; otherwise, simply call OpenerDirector.open() instead of urlopen(). The code does not check for a real OpenerDirector, and any class with the appropriate interface will work.
Return an OpenerDirector instance, which chains the handlers in the order given. handlers can be either instances of BaseHandler, or subclasses of BaseHandler (in which case it must be possible to call the constructor without any parameters). Instances of the following classes will be in front of the handlers, unless the handlers contain them, instances of them or subclasses of them: ProxyHandler (if proxy settings are detected), UnknownHandler, HTTPHandler, HTTPDefaultErrorHandler, HTTPRedirectHandler, FTPHandler, FileHandler, HTTPErrorProcessor.
If the Python installation has SSL support (i.e., if the ssl module can be imported), HTTPSHandler will also be added.
A BaseHandler subclass may also change its handler_order attribute to modify its position in the handlers list.
Convert the pathname path from the local syntax for a path to the form used in the path component of a URL. This does not produce a complete URL. The return value will already be quoted using the quote() function.
Convert the path component path from a percent-encoded URL to the local syntax for a path. This does not accept a complete URL. This function uses unquote() to decode path.
This helper function returns a dictionary of scheme to proxy server URL mappings. It scans the environment for variables named <scheme>_proxy, in a case insensitive approach, for all operating systems first, and when it cannot find it, looks for proxy information from Mac OSX System Configuration for Mac OS X and Windows Systems Registry for Windows. If both lowercase and uppercase environment variables exist (and disagree), lowercase is preferred.
Note
If the environment variable REQUEST_METHOD is set, which usually indicates your script is running in a CGI environment, the environment variable HTTP_PROXY (uppercase _PROXY) will be ignored. This is because that variable can be injected by a client using the “Proxy:” HTTP header. If you need to use an HTTP proxy in a CGI environment, either use ProxyHandler explicitly, or make sure the variable name is in lowercase (or at least the _proxy suffix).
The following classes are provided:
This class is an abstraction of a URL request.
url should be a string containing a valid URL.
data must be an object specifying additional data to send to the server, or None if no such data is needed. Currently HTTP requests are the only ones that use data. The supported object types include bytes, file-like objects, and iterables of bytes-like objects. If no Content-Length nor Transfer-Encoding header field has been provided, HTTPHandler will set these headers according to the type of data. Content-Length will be used to send bytes objects, while Transfer-Encoding: chunked as specified in RFC 7230, Section 3.3.1 will be used to send files and other iterables.
For an HTTP POST request method, data should be a buffer in the standard application/x-www-form-urlencoded format. The urllib.parse.urlencode() function takes a mapping or sequence of 2-tuples and returns an ASCII string in this format. It should be encoded to bytes before being used as the data parameter.
headers should be a dictionary, and will be treated as if add_header() was called with each key and value as arguments. This is often used to “spoof” the User-Agent header value, which is used by a browser to identify itself – some HTTP servers only allow requests coming from common browsers as opposed to scripts. For example, Mozilla Firefox may identify itself as "Mozilla/5.0
(X11; U; Linux i686) Gecko/20071127 Firefox/2.0.0.11", while urllib’s default user agent string is "Python-urllib/2.6" (on Python 2.6).
An appropriate Content-Type header should be included if the data argument is present. If this header has not been provided and data is not None, Content-Type: application/x-www-form-urlencoded will be added as a default.
The next two arguments are only of interest for correct handling of third-party HTTP cookies:
origin_req_host should be the request-host of the origin transaction, as defined by RFC 2965. It defaults to http.cookiejar.request_host(self). This is the host name or IP address of the original request that was initiated by the user. For example, if the request is for an image in an HTML document, this should be the request-host of the request for the page containing the image.
unverifiable should indicate whether the request is unverifiable, as defined by RFC 2965. It defaults to False. An unverifiable request is one whose URL the user did not have the option to approve. For example, if the request is for an image in an HTML document, and the user had no option to approve the automatic fetching of the image, this should be true.
method should be a string that indicates the HTTP request method that will be used (e.g. 'HEAD'). If provided, its value is stored in the method attribute and is used by get_method(). The default is 'GET' if data is None or 'POST' otherwise. Subclasses may indicate a different default method by setting the method attribute in the class itself.
Note
The request will not work as expected if the data object is unable to deliver its content more than once (e.g. a file or an iterable that can produce the content only once) and the request is retried for HTTP redirects or authentication. The data is sent to the HTTP server right away after the headers. There is no support for a 100-continue expectation in the library.
Changed in version 3.3: Request.method argument is added to the Request class.
Changed in version 3.4: Default Request.method may be indicated at the class level.
Changed in version 3.6: Do not raise an error if the Content-Length has not been provided and data is neither None nor a bytes object. Fall back to use chunked transfer encoding instead.
The OpenerDirector class opens URLs via BaseHandlers chained together. It manages the chaining of handlers, and recovery from errors.
This is the base class for all registered handlers — and handles only the simple mechanics of registration.
A class which defines a default handler for HTTP error responses; all responses are turned into HTTPError exceptions.
A class to handle redirections.
A class to handle HTTP Cookies.
Cause requests to go through a proxy. If proxies is given, it must be a dictionary mapping protocol names to URLs of proxies. The default is to read the list of proxies from the environment variables <protocol>_proxy. If no proxy environment variables are set, then in a Windows environment proxy settings are obtained from the registry’s Internet Settings section, and in a Mac OS X environment proxy information is retrieved from the OS X System Configuration Framework.
To disable autodetected proxy pass an empty dictionary.
The no_proxy environment variable can be used to specify hosts which shouldn’t be reached via proxy; if set, it should be a comma-separated list of hostname suffixes, optionally with :port appended, for example cern.ch,ncsa.uiuc.edu,some.host:8080.
Note
HTTP_PROXY will be ignored if a variable REQUEST_METHOD is set; see the documentation on getproxies().
Keep a database of (realm, uri) -> (user, password) mappings.
Keep a database of (realm, uri) -> (user, password) mappings. A realm of None is considered a catch-all realm, which is searched if no other realm fits.
A variant of HTTPPasswordMgrWithDefaultRealm that also has a database of uri -> is_authenticated mappings. Can be used by a BasicAuth handler to determine when to send authentication credentials immediately instead of waiting for a 401 response first.
New in version 3.5.
This is a mixin class that helps with HTTP authentication, both to the remote host and to a proxy. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported. If passwd_mgr also provides is_authenticated and update_authenticated methods (see HTTPPasswordMgrWithPriorAuth Objects), then the handler will use the is_authenticated result for a given URI to determine whether or not to send authentication credentials with the request. If is_authenticated returns True for the URI, credentials are sent. If is_authenticated is False, credentials are not sent, and then if a 401 response is received the request is re-sent with the authentication credentials. If authentication succeeds, update_authenticated is called to set is_authenticated True for the URI, so that subsequent requests to the URI or any of its super-URIs will automatically include the authentication credentials.
New in version 3.5: Added is_authenticated support.
Handle authentication with the remote host. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported. HTTPBasicAuthHandler will raise a ValueError when presented with a wrong Authentication scheme.
Handle authentication with the proxy. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported.
This is a mixin class that helps with HTTP authentication, both to the remote host and to a proxy. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported.
Handle authentication with the remote host. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported. When both Digest Authentication Handler and Basic Authentication Handler are both added, Digest Authentication is always tried first. If the Digest Authentication returns a 40x response again, it is sent to Basic Authentication handler to Handle. This Handler method will raise a ValueError when presented with an authentication scheme other than Digest or Basic.
Changed in version 3.3: Raise ValueError on unsupported Authentication Scheme.
Handle authentication with the proxy. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported.
A class to handle opening of HTTP URLs.
A class to handle opening of HTTPS URLs. context and check_hostname have the same meaning as in http.client.HTTPSConnection.
Changed in version 3.2: context and check_hostname were added.
Open local files.
Open data URLs.
New in version 3.4.
Open FTP URLs.
Open FTP URLs, keeping a cache of open FTP connections to minimize delays.
A catch-all class to handle unknown URLs.
Process HTTP error responses.
The following methods describe Request’s public interface, and so all may be overridden in subclasses. It also defines several public attributes that can be used by clients to inspect the parsed request.
The original URL passed to the constructor.
Changed in version 3.4.
Request.full_url is a property with setter, getter and a deleter. Getting full_url returns the original request URL with the fragment, if it was present.
The URI scheme.
The URI authority, typically a host, but may also contain a port separated by a colon.
The original host for the request, without port.
The URI path. If the Request uses a proxy, then selector will be the full URL that is passed to the proxy.
The entity body for the request, or None if not specified.
Changed in version 3.4: Changing value of Request.data now deletes “Content-Length” header if it was previously set or calculated.
boolean, indicates whether the request is unverifiable as defined by RFC 2965.
The HTTP request method to use. By default its value is None, which means that get_method() will do its normal computation of the method to be used. Its value can be set (thus overriding the default computation in get_method()) either by providing a default value by setting it at the class level in a Request subclass, or by passing a value in to the Request constructor via the method argument.
New in version 3.3.
Changed in version 3.4: A default value can now be set in subclasses; previously it could only be set via the constructor argument.
Return a string indicating the HTTP request method. If Request.method is not None, return its value, otherwise return 'GET' if Request.data is None, or 'POST' if it’s not. This is only meaningful for HTTP requests.
Changed in version 3.3: get_method now looks at the value of Request.method.
Add another header to the request. Headers are currently ignored by all handlers except HTTP handlers, where they are added to the list of headers sent to the server. Note that there cannot be more than one header with the same name, and later calls will overwrite previous calls in case the key collides. Currently, this is no loss of HTTP functionality, since all headers which have meaning when used more than once have a (header-specific) way of gaining the same functionality using only one header.
Add a header that will not be added to a redirected request.
Return whether the instance has the named header (checks both regular and unredirected).
Remove named header from the request instance (both from regular and unredirected headers).
New in version 3.4.
Return the URL given in the constructor.
Changed in version 3.4.
Returns Request.full_url
Prepare the request by connecting to a proxy server. The host and type will replace those of the instance, and the instance’s selector will be the original URL given in the constructor.
Return the value of the given header. If the header is not present, return the default value.
Return a list of tuples (header_name, header_value) of the Request headers.
Changed in version 3.4: The request methods add_data, has_data, get_data, get_type, get_host, get_selector, get_origin_req_host and is_unverifiable that were deprecated since 3.3 have been removed.
OpenerDirector instances have the following methods:
handler should be an instance of BaseHandler. The following methods are searched, and added to the possible chains (note that HTTP errors are a special case). Note that, in the following, protocol should be replaced with the actual protocol to handle, for example http_response() would be the HTTP protocol response handler. Also type should be replaced with the actual HTTP code, for example http_error_404() would handle HTTP 404 errors.
<protocol>_open() — signal that the handler knows how to open protocol URLs.
See BaseHandler.<protocol>_open() for more information.
http_error_<type>() — signal that the handler knows how to handle HTTP errors with HTTP error code type.
See BaseHandler.http_error_<nnn>() for more information.
<protocol>_request() — signal that the handler knows how to pre-process protocol requests.
See BaseHandler.<protocol>_request() for more information.
<protocol>_response() — signal that the handler knows how to post-process protocol responses.
See BaseHandler.<protocol>_response() for more information.
Open the given url (which can be a request object or a string), optionally passing the given data. Arguments, return values and exceptions raised are the same as those of urlopen() (which simply calls the open() method on the currently installed global OpenerDirector). The optional timeout parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used). The timeout feature actually works only for HTTP, HTTPS and FTP connections).
Handle an error of the given protocol. This will call the registered error handlers for the given protocol with the given arguments (which are protocol specific). The HTTP protocol is a special case which uses the HTTP response code to determine the specific error handler; refer to the http_error_<type>() methods of the handler classes.
Return values and exceptions raised are the same as those of urlopen().
OpenerDirector objects open URLs in three stages:
The order in which these methods are called within each stage is determined by sorting the handler instances.
Handlers with a method named like <protocol>_open() are called to handle the request. This stage ends when a handler either returns a non-None value (ie. a response), or raises an exception (usually URLError). Exceptions are allowed to propagate.
In fact, the above algorithm is first tried for methods named default_open(). If all such methods return None, the algorithm is repeated for methods named like <protocol>_open(). If all such methods return None, the algorithm is repeated for methods named unknown_open().
Note that the implementation of these methods may involve calls of the parent OpenerDirector instance’s open() and error() methods.
BaseHandler objects provide a couple of methods that are directly useful, and others that are meant to be used by derived classes. These are intended for direct use:
Add a director as parent.
Remove any parents.
The following attribute and methods should only be used by classes derived from BaseHandler.
Note
The convention has been adopted that subclasses defining <protocol>_request() or <protocol>_response() methods are named *Processor; all others are named *Handler.
A valid OpenerDirector, which can be used to open using a different protocol, or handle errors.
This method is not defined in BaseHandler, but subclasses should define it if they want to catch all URLs.
This method, if implemented, will be called by the parent OpenerDirector. It should return a file-like object as described in the return value of the open() of OpenerDirector, or None. It should raise URLError, unless a truly exceptional thing happens (for example, MemoryError should not be mapped to URLError).
This method will be called before any protocol-specific open method.
This method is not defined in BaseHandler, but subclasses should define it if they want to handle URLs with the given protocol.
This method, if defined, will be called by the parent OpenerDirector. Return values should be the same as for default_open().
This method is not defined in BaseHandler, but subclasses should define it if they want to catch all URLs with no specific registered handler to open it.
This method, if implemented, will be called by the parent OpenerDirector. Return values should be the same as for default_open().
This method is not defined in BaseHandler, but subclasses should override it if they intend to provide a catch-all for otherwise unhandled HTTP errors. It will be called automatically by the OpenerDirector getting the error, and should not normally be called in other circumstances.
req will be a Request object, fp will be a file-like object with the HTTP error body, code will be the three-digit code of the error, msg will be the user-visible explanation of the code and hdrs will be a mapping object with the headers of the error.
Return values and exceptions raised should be the same as those of urlopen().
nnn should be a three-digit HTTP error code. This method is also not defined in BaseHandler, but will be called, if it exists, on an instance of a subclass, when an HTTP error with code nnn occurs.
Subclasses should override this method to handle specific HTTP errors.
Arguments, return values and exceptions raised should be the same as for http_error_default().
This method is not defined in BaseHandler, but subclasses should define it if they want to pre-process requests of the given protocol.
This method, if defined, will be called by the parent OpenerDirector. req will be a Request object. The return value should be a Request object.
This method is not defined in BaseHandler, but subclasses should define it if they want to post-process responses of the given protocol.
This method, if defined, will be called by the parent OpenerDirector. req will be a Request object. response will be an object implementing the same interface as the return value of urlopen(). The return value should implement the same interface as the return value of urlopen().
Note
Some HTTP redirections require action from this module’s client code. If this is the case, HTTPError is raised. See RFC 2616 for details of the precise meanings of the various redirection codes.
An HTTPError exception raised as a security consideration if the HTTPRedirectHandler is presented with a redirected URL which is not an HTTP, HTTPS or FTP URL.
Return a Request or None in response to a redirect. This is called by the default implementations of the http_error_30*() methods when a redirection is received from the server. If a redirection should take place, return a new Request to allow http_error_30*() to perform the redirect to newurl. Otherwise, raise HTTPError if no other handler should try to handle this URL, or return None if you can’t but another handler might.
Note
The default implementation of this method does not strictly follow RFC 2616, which says that 301 and 302 responses to POST requests must not be automatically redirected without confirmation by the user. In reality, browsers do allow automatic redirection of these responses, changing the POST to a GET, and the default implementation reproduces this behavior.
Redirect to the Location: or URI: URL. This method is called by the parent OpenerDirector when getting an HTTP ‘moved permanently’ response.
The same as http_error_301(), but called for the ‘found’ response.
The same as http_error_301(), but called for the ‘see other’ response.
The same as http_error_301(), but called for the ‘temporary redirect’ response.
HTTPCookieProcessor instances have one attribute:
The http.cookiejar.CookieJar in which cookies are stored.
The ProxyHandler will have a method <protocol>_open() for every protocol which has a proxy in the proxies dictionary given in the constructor. The method will modify requests to go through the proxy, by calling request.set_proxy(), and call the next handler in the chain to actually execute the protocol.
These methods are available on HTTPPasswordMgr and HTTPPasswordMgrWithDefaultRealm objects.
uri can be either a single URI, or a sequence of URIs. realm, user and passwd must be strings. This causes (user, passwd) to be used as authentication tokens when authentication for realm and a super-URI of any of the given URIs is given.
Get user/password for given realm and URI, if any. This method will return (None, None) if there is no matching user/password.
For HTTPPasswordMgrWithDefaultRealm objects, the realm None will be searched if the given realm has no matching user/password.
This password manager extends HTTPPasswordMgrWithDefaultRealm to support tracking URIs for which authentication credentials should always be sent.
realm, uri, user, passwd are as for HTTPPasswordMgr.add_password(). is_authenticated sets the initial value of the is_authenticated flag for the given URI or list of URIs. If is_authenticated is specified as True, realm is ignored.
Same as for HTTPPasswordMgrWithDefaultRealm objects
Update the is_authenticated flag for the given uri or list of URIs.
Returns the current state of the is_authenticated flag for the given URI.
Handle an authentication request by getting a user/password pair, and re-trying the request. authreq should be the name of the header where the information about the realm is included in the request, host specifies the URL and path to authenticate for, req should be the (failed) Request object, and headers should be the error headers.
host is either an authority (e.g. "python.org") or a URL containing an authority component (e.g. "http://python.org/"). In either case, the authority must not contain a userinfo component (so, "python.org" and "python.org:80" are fine, "joe:password@python.org" is not).
Retry the request with authentication information, if available.
Retry the request with authentication information, if available.
authreq should be the name of the header where the information about the realm is included in the request, host should be the host to authenticate to, req should be the (failed) Request object, and headers should be the error headers.
Retry the request with authentication information, if available.
Retry the request with authentication information, if available.
Send an HTTP request, which can be either GET or POST, depending on req.has_data().
Send an HTTPS request, which can be either GET or POST, depending on req.has_data().
Open the file locally, if there is no host name, or the host name is 'localhost'.
Changed in version 3.2: This method is applicable only for local hostnames. When a remote hostname is given, an URLError is raised.
Read a data URL. This kind of URL contains the content encoded in the URL itself. The data URL syntax is specified in RFC 2397. This implementation ignores white spaces in base64 encoded data URLs so the URL may be wrapped in whatever source file it comes from. But even though some browsers don’t mind about a missing padding at the end of a base64 encoded data URL, this implementation will raise an ValueError in that case.
Open the FTP file indicated by req. The login is always done with empty username and password.
CacheFTPHandler objects are FTPHandler objects with the following additional methods:
Set timeout of connections to t seconds.
Set maximum number of cached connections to m.
Raise a URLError exception.
Process HTTP error responses.
For 200 error codes, the response object is returned immediately.
For non-200 error codes, this simply passes the job on to the http_error_<type>() handler methods, via OpenerDirector.error(). Eventually, HTTPDefaultErrorHandler will raise an HTTPError if no other handler handles the error.
Process HTTPS error responses.
The behavior is same as http_response().
In addition to the examples below, more examples are given in HOWTO Fetch Internet Resources Using The urllib Package.
This example gets the python.org main page and displays the first 300 bytes of it.
Note that urlopen returns a bytes object. This is because there is no way for urlopen to automatically determine the encoding of the byte stream it receives from the HTTP server. In general, a program will decode the returned bytes object to string once it determines or guesses the appropriate encoding.
The following W3C document, https://www.w3.org/International/O-charset, lists the various ways in which an (X)HTML or an XML document could have specified its encoding information.
As the python.org website uses utf-8 encoding as specified in its meta tag, we will use the same for decoding the bytes object.
It is also possible to achieve the same result without using the context manager approach.
In the following example, we are sending a data-stream to the stdin of a CGI and reading the data it returns to us. Note that this example will only work when the Python installation supports SSL.
The code for the sample CGI used in the above example is:
Here is an example of doing a PUT request using Request:
Use of Basic HTTP Authentication:
build_opener() provides many handlers by default, including a ProxyHandler. By default, ProxyHandler uses the environment variables named <scheme>_proxy, where <scheme> is the URL scheme involved. For example, the http_proxy environment variable is read to obtain the HTTP proxy’s URL.
This example replaces the default ProxyHandler with one that uses programmatically-supplied proxy URLs, and adds proxy authorization support with ProxyBasicAuthHandler.
Adding HTTP headers:
Use the headers argument to the Request constructor, or:
OpenerDirector automatically adds a User-Agent header to every Request. To change this:
Also, remember that a few standard headers (Content-Length, Content-Type and Host) are added when the Request is passed to urlopen() (or OpenerDirector.open()).
Here is an example session that uses the GET method to retrieve a URL containing parameters:
The following example uses the POST method instead. Note that params output from urlencode is encoded to bytes before it is sent to urlopen as data:
The following example uses an explicitly specified HTTP proxy, overriding environment settings:
The following example uses no proxies at all, overriding environment settings:
The following functions and classes are ported from the Python 2 module urllib (as opposed to urllib2). They might become deprecated at some point in the future.
Copy a network object denoted by a URL to a local file. If the URL points to a local file, the object will not be copied unless filename is supplied. Return a tuple (filename, headers) where filename is the local file name under which the object can be found, and headers is whatever the info() method of the object returned by urlopen() returned (for a remote object). Exceptions are the same as for urlopen().
The second argument, if present, specifies the file location to copy to (if absent, the location will be a tempfile with a generated name). The third argument, if present, is a callable that will be called once on establishment of the network connection and once after each block read thereafter. The callable will be passed three arguments; a count of blocks transferred so far, a block size in bytes, and the total size of the file. The third argument may be -1 on older FTP servers which do not return a file size in response to a retrieval request.
The following example illustrates the most common usage scenario:
If the url uses the http: scheme identifier, the optional data argument may be given to specify a POST request (normally the request type is GET). The data argument must be a bytes object in standard application/x-www-form-urlencoded format; see the urllib.parse.urlencode() function.
urlretrieve() will raise ContentTooShortError when it detects that the amount of data available was less than the expected amount (which is the size reported by a Content-Length header). This can occur, for example, when the download is interrupted.
The Content-Length is treated as a lower bound: if there’s more data to read, urlretrieve reads more data, but if less data is available, it raises the exception.
You can still retrieve the downloaded data in this case, it is stored in the content attribute of the exception instance.
If no Content-Length header was supplied, urlretrieve can not check the size of the data it has downloaded, and just returns it. In this case you just have to assume that the download was successful.
Cleans up temporary files that may have been left behind by previous calls to urlretrieve().
Deprecated since version 3.3.
Base class for opening and reading URLs. Unless you need to support opening objects using schemes other than http:, ftp:, or file:, you probably want to use FancyURLopener.
By default, the URLopener class sends a User-Agent header of urllib/VVV, where VVV is the urllib version number. Applications can define their own User-Agent header by subclassing URLopener or FancyURLopener and setting the class attribute version to an appropriate string value in the subclass definition.
The optional proxies parameter should be a dictionary mapping scheme names to proxy URLs, where an empty dictionary turns proxies off completely. Its default value is None, in which case environmental proxy settings will be used if present, as discussed in the definition of urlopen(), above.
Additional keyword parameters, collected in x509, may be used for authentication of the client when using the https: scheme. The keywords key_file and cert_file are supported to provide an SSL key and certificate; both are needed to support client authentication.
URLopener objects will raise an OSError exception if the server returns an error code.
Open fullurl using the appropriate protocol. This method sets up cache and proxy information, then calls the appropriate open method with its input arguments. If the scheme is not recognized, open_unknown() is called. The data argument has the same meaning as the data argument of urlopen().
This method always quotes fullurl using quote().
Overridable interface to open unknown URL types.
Retrieves the contents of url and places it in filename. The return value is a tuple consisting of a local filename and either an email.message.Message object containing the response headers (for remote URLs) or None (for local URLs). The caller must then open and read the contents of filename. If filename is not given and the URL refers to a local file, the input filename is returned. If the URL is non-local and filename is not given, the filename is the output of tempfile.mktemp() with a suffix that matches the suffix of the last path component of the input URL. If reporthook is given, it must be a function accepting three numeric parameters: A chunk number, the maximum size chunks are read in and the total size of the download (-1 if unknown). It will be called once at the start and after each chunk of data is read from the network. reporthook is ignored for local URLs.
If the url uses the http: scheme identifier, the optional data argument may be given to specify a POST request (normally the request type is GET). The data argument must in standard application/x-www-form-urlencoded format; see the urllib.parse.urlencode() function.
Variable that specifies the user agent of the opener object. To get urllib to tell servers that it is a particular user agent, set this in a subclass as a class variable or in the constructor before calling the base constructor.
Deprecated since version 3.3.
FancyURLopener subclasses URLopener providing default handling for the following HTTP response codes: 301, 302, 303, 307 and 401. For the 30x response codes listed above, the Location header is used to fetch the actual URL. For 401 response codes (authentication required), basic HTTP authentication is performed. For the 30x response codes, recursion is bounded by the value of the maxtries attribute, which defaults to 10.
For all other response codes, the method http_error_default() is called which you can override in subclasses to handle the error appropriately.
Note
According to the letter of RFC 2616, 301 and 302 responses to POST requests must not be automatically redirected without confirmation by the user. In reality, browsers do allow automatic redirection of these responses, changing the POST to a GET, and urllib reproduces this behaviour.
The parameters to the constructor are the same as those for URLopener.
Note
When performing basic authentication, a FancyURLopener instance calls its prompt_user_passwd() method. The default implementation asks the users for the required information on the controlling terminal. A subclass may override this method to support more appropriate behavior if needed.
The FancyURLopener class offers one additional method that should be overloaded to provide the appropriate behavior:
Return information needed to authenticate the user at the given host in the specified security realm. The return value should be a tuple, (user,
password), which can be used for basic authentication.
The implementation prompts for this information on the terminal; an application should override this method to use an appropriate interaction model in the local environment.
Currently, only the following protocols are supported: HTTP (versions 0.9 and 1.0), FTP, local files, and data URLs.
Changed in version 3.4: Added support for data URLs.
The urllib.response module defines functions and classes which define a minimal file-like interface, including read() and readline(). Functions defined by this module are used internally by the urllib.request module. The typical response object is a urllib.response.addinfourl instance:
URL of the resource retrieved, commonly used to determine if a redirect was followed.
Returns the headers of the response in the form of an EmailMessage instance.
New in version 3.9.
Status code returned by server.
Deprecated since version 3.9: Deprecated in favor of url.
Deprecated since version 3.9: Deprecated in favor of headers.
Deprecated since version 3.9: Deprecated in favor of status.
Deprecated since version 3.9: Deprecated in favor of status.


This is a mixin class that helps with HTTP authentication, both to the remote host and to a proxy. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported. If passwd_mgr also provides is_authenticated and update_authenticated methods (see HTTPPasswordMgrWithPriorAuth Objects), then the handler will use the is_authenticated result for a given URI to determine whether or not to send authentication credentials with the request. If is_authenticated returns True for the URI, credentials are sent. If is_authenticated is False, credentials are not sent, and then if a 401 response is received the request is re-sent with the authentication credentials. If authentication succeeds, update_authenticated is called to set is_authenticated True for the URI, so that subsequent requests to the URI or any of its super-URIs will automatically include the authentication credentials.
New in version 3.5: Added is_authenticated support.


Handle an authentication request by getting a user/password pair, and re-trying the request. authreq should be the name of the header where the information about the realm is included in the request, host specifies the URL and path to authenticate for, req should be the (failed) Request object, and headers should be the error headers.
host is either an authority (e.g. "python.org") or a URL containing an authority component (e.g. "http://python.org/"). In either case, the authority must not contain a userinfo component (so, "python.org" and "python.org:80" are fine, "joe:password@python.org" is not).


This is a mixin class that helps with HTTP authentication, both to the remote host and to a proxy. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported.


authreq should be the name of the header where the information about the realm is included in the request, host should be the host to authenticate to, req should be the (failed) Request object, and headers should be the error headers.


This is the base class for all registered handlers — and handles only the simple mechanics of registration.


This method is not defined in BaseHandler, but subclasses should define it if they want to catch all URLs.
This method, if implemented, will be called by the parent OpenerDirector. It should return a file-like object as described in the return value of the open() of OpenerDirector, or None. It should raise URLError, unless a truly exceptional thing happens (for example, MemoryError should not be mapped to URLError).
This method will be called before any protocol-specific open method.


This method is not defined in BaseHandler, but subclasses should override it if they intend to provide a catch-all for otherwise unhandled HTTP errors. It will be called automatically by the OpenerDirector getting the error, and should not normally be called in other circumstances.
req will be a Request object, fp will be a file-like object with the HTTP error body, code will be the three-digit code of the error, msg will be the user-visible explanation of the code and hdrs will be a mapping object with the headers of the error.
Return values and exceptions raised should be the same as those of urlopen().


A valid OpenerDirector, which can be used to open using a different protocol, or handle errors.


This method is not defined in BaseHandler, but subclasses should define it if they want to catch all URLs with no specific registered handler to open it.
This method, if implemented, will be called by the parent OpenerDirector. Return values should be the same as for default_open().


Return an OpenerDirector instance, which chains the handlers in the order given. handlers can be either instances of BaseHandler, or subclasses of BaseHandler (in which case it must be possible to call the constructor without any parameters). Instances of the following classes will be in front of the handlers, unless the handlers contain them, instances of them or subclasses of them: ProxyHandler (if proxy settings are detected), UnknownHandler, HTTPHandler, HTTPDefaultErrorHandler, HTTPRedirectHandler, FTPHandler, FileHandler, HTTPErrorProcessor.
If the Python installation has SSL support (i.e., if the ssl module can be imported), HTTPSHandler will also be added.
A BaseHandler subclass may also change its handler_order attribute to modify its position in the handlers list.


Open FTP URLs, keeping a cache of open FTP connections to minimize delays.


Set maximum number of cached connections to m.


Set timeout of connections to t seconds.


Read a data URL. This kind of URL contains the content encoded in the URL itself. The data URL syntax is specified in RFC 2397. This implementation ignores white spaces in base64 encoded data URLs so the URL may be wrapped in whatever source file it comes from. But even though some browsers don’t mind about a missing padding at the end of a base64 encoded data URL, this implementation will raise an ValueError in that case.


Deprecated since version 3.3.
FancyURLopener subclasses URLopener providing default handling for the following HTTP response codes: 301, 302, 303, 307 and 401. For the 30x response codes listed above, the Location header is used to fetch the actual URL. For 401 response codes (authentication required), basic HTTP authentication is performed. For the 30x response codes, recursion is bounded by the value of the maxtries attribute, which defaults to 10.
For all other response codes, the method http_error_default() is called which you can override in subclasses to handle the error appropriately.
Note
According to the letter of RFC 2616, 301 and 302 responses to POST requests must not be automatically redirected without confirmation by the user. In reality, browsers do allow automatic redirection of these responses, changing the POST to a GET, and urllib reproduces this behaviour.
The parameters to the constructor are the same as those for URLopener.
Note
When performing basic authentication, a FancyURLopener instance calls its prompt_user_passwd() method. The default implementation asks the users for the required information on the controlling terminal. A subclass may override this method to support more appropriate behavior if needed.
The FancyURLopener class offers one additional method that should be overloaded to provide the appropriate behavior:
Return information needed to authenticate the user at the given host in the specified security realm. The return value should be a tuple, (user,
password), which can be used for basic authentication.
The implementation prompts for this information on the terminal; an application should override this method to use an appropriate interaction model in the local environment.


Return information needed to authenticate the user at the given host in the specified security realm. The return value should be a tuple, (user,
password), which can be used for basic authentication.
The implementation prompts for this information on the terminal; an application should override this method to use an appropriate interaction model in the local environment.


Open the file locally, if there is no host name, or the host name is 'localhost'.
Changed in version 3.2: This method is applicable only for local hostnames. When a remote hostname is given, an URLError is raised.


Open the FTP file indicated by req. The login is always done with empty username and password.


This helper function returns a dictionary of scheme to proxy server URL mappings. It scans the environment for variables named <scheme>_proxy, in a case insensitive approach, for all operating systems first, and when it cannot find it, looks for proxy information from Mac OSX System Configuration for Mac OS X and Windows Systems Registry for Windows. If both lowercase and uppercase environment variables exist (and disagree), lowercase is preferred.
Note
If the environment variable REQUEST_METHOD is set, which usually indicates your script is running in a CGI environment, the environment variable HTTP_PROXY (uppercase _PROXY) will be ignored. This is because that variable can be injected by a client using the “Proxy:” HTTP header. If you need to use an HTTP proxy in a CGI environment, either use ProxyHandler explicitly, or make sure the variable name is in lowercase (or at least the _proxy suffix).


Handle authentication with the remote host. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported. HTTPBasicAuthHandler will raise a ValueError when presented with a wrong Authentication scheme.


Retry the request with authentication information, if available.


The http.cookiejar.CookieJar in which cookies are stored.


A class which defines a default handler for HTTP error responses; all responses are turned into HTTPError exceptions.


Handle authentication with the remote host. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported. When both Digest Authentication Handler and Basic Authentication Handler are both added, Digest Authentication is always tried first. If the Digest Authentication returns a 40x response again, it is sent to Basic Authentication handler to Handle. This Handler method will raise a ValueError when presented with an authentication scheme other than Digest or Basic.
Changed in version 3.3: Raise ValueError on unsupported Authentication Scheme.


Process HTTPS error responses.
The behavior is same as http_response().


Process HTTP error responses.
For 200 error codes, the response object is returned immediately.
For non-200 error codes, this simply passes the job on to the http_error_<type>() handler methods, via OpenerDirector.error(). Eventually, HTTPDefaultErrorHandler will raise an HTTPError if no other handler handles the error.


Send an HTTP request, which can be either GET or POST, depending on req.has_data().


Keep a database of (realm, uri) -> (user, password) mappings.


uri can be either a single URI, or a sequence of URIs. realm, user and passwd must be strings. This causes (user, passwd) to be used as authentication tokens when authentication for realm and a super-URI of any of the given URIs is given.


Get user/password for given realm and URI, if any. This method will return (None, None) if there is no matching user/password.
For HTTPPasswordMgrWithDefaultRealm objects, the realm None will be searched if the given realm has no matching user/password.


Keep a database of (realm, uri) -> (user, password) mappings. A realm of None is considered a catch-all realm, which is searched if no other realm fits.


A variant of HTTPPasswordMgrWithDefaultRealm that also has a database of uri -> is_authenticated mappings. Can be used by a BasicAuth handler to determine when to send authentication credentials immediately instead of waiting for a 401 response first.
New in version 3.5.


realm, uri, user, passwd are as for HTTPPasswordMgr.add_password(). is_authenticated sets the initial value of the is_authenticated flag for the given URI or list of URIs. If is_authenticated is specified as True, realm is ignored.


Same as for HTTPPasswordMgrWithDefaultRealm objects


Returns the current state of the is_authenticated flag for the given URI.


Update the is_authenticated flag for the given uri or list of URIs.


Redirect to the Location: or URI: URL. This method is called by the parent OpenerDirector when getting an HTTP ‘moved permanently’ response.


The same as http_error_301(), but called for the ‘found’ response.


The same as http_error_301(), but called for the ‘see other’ response.


The same as http_error_301(), but called for the ‘temporary redirect’ response.


Return a Request or None in response to a redirect. This is called by the default implementations of the http_error_30*() methods when a redirection is received from the server. If a redirection should take place, return a new Request to allow http_error_30*() to perform the redirect to newurl. Otherwise, raise HTTPError if no other handler should try to handle this URL, or return None if you can’t but another handler might.
Note
The default implementation of this method does not strictly follow RFC 2616, which says that 301 and 302 responses to POST requests must not be automatically redirected without confirmation by the user. In reality, browsers do allow automatic redirection of these responses, changing the POST to a GET, and the default implementation reproduces this behavior.


A class to handle opening of HTTPS URLs. context and check_hostname have the same meaning as in http.client.HTTPSConnection.
Changed in version 3.2: context and check_hostname were added.


Send an HTTPS request, which can be either GET or POST, depending on req.has_data().


Install an OpenerDirector instance as the default global opener. Installing an opener is only necessary if you want urlopen to use that opener; otherwise, simply call OpenerDirector.open() instead of urlopen(). The code does not check for a real OpenerDirector, and any class with the appropriate interface will work.


The OpenerDirector class opens URLs via BaseHandlers chained together. It manages the chaining of handlers, and recovery from errors.


handler should be an instance of BaseHandler. The following methods are searched, and added to the possible chains (note that HTTP errors are a special case). Note that, in the following, protocol should be replaced with the actual protocol to handle, for example http_response() would be the HTTP protocol response handler. Also type should be replaced with the actual HTTP code, for example http_error_404() would handle HTTP 404 errors.
<protocol>_open() — signal that the handler knows how to open protocol URLs.
See BaseHandler.<protocol>_open() for more information.
http_error_<type>() — signal that the handler knows how to handle HTTP errors with HTTP error code type.
See BaseHandler.http_error_<nnn>() for more information.
<protocol>_request() — signal that the handler knows how to pre-process protocol requests.
See BaseHandler.<protocol>_request() for more information.
<protocol>_response() — signal that the handler knows how to post-process protocol responses.
See BaseHandler.<protocol>_response() for more information.


Handle an error of the given protocol. This will call the registered error handlers for the given protocol with the given arguments (which are protocol specific). The HTTP protocol is a special case which uses the HTTP response code to determine the specific error handler; refer to the http_error_<type>() methods of the handler classes.
Return values and exceptions raised are the same as those of urlopen().


Open the given url (which can be a request object or a string), optionally passing the given data. Arguments, return values and exceptions raised are the same as those of urlopen() (which simply calls the open() method on the currently installed global OpenerDirector). The optional timeout parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used). The timeout feature actually works only for HTTP, HTTPS and FTP connections).


Convert the pathname path from the local syntax for a path to the form used in the path component of a URL. This does not produce a complete URL. The return value will already be quoted using the quote() function.


Handle authentication with the proxy. password_mgr, if given, should be something that is compatible with HTTPPasswordMgr; refer to section HTTPPasswordMgr Objects for information on the interface that must be supported.


Retry the request with authentication information, if available.


Cause requests to go through a proxy. If proxies is given, it must be a dictionary mapping protocol names to URLs of proxies. The default is to read the list of proxies from the environment variables <protocol>_proxy. If no proxy environment variables are set, then in a Windows environment proxy settings are obtained from the registry’s Internet Settings section, and in a Mac OS X environment proxy information is retrieved from the OS X System Configuration Framework.
To disable autodetected proxy pass an empty dictionary.
The no_proxy environment variable can be used to specify hosts which shouldn’t be reached via proxy; if set, it should be a comma-separated list of hostname suffixes, optionally with :port appended, for example cern.ch,ncsa.uiuc.edu,some.host:8080.
Note
HTTP_PROXY will be ignored if a variable REQUEST_METHOD is set; see the documentation on getproxies().


This class is an abstraction of a URL request.
url should be a string containing a valid URL.
data must be an object specifying additional data to send to the server, or None if no such data is needed. Currently HTTP requests are the only ones that use data. The supported object types include bytes, file-like objects, and iterables of bytes-like objects. If no Content-Length nor Transfer-Encoding header field has been provided, HTTPHandler will set these headers according to the type of data. Content-Length will be used to send bytes objects, while Transfer-Encoding: chunked as specified in RFC 7230, Section 3.3.1 will be used to send files and other iterables.
For an HTTP POST request method, data should be a buffer in the standard application/x-www-form-urlencoded format. The urllib.parse.urlencode() function takes a mapping or sequence of 2-tuples and returns an ASCII string in this format. It should be encoded to bytes before being used as the data parameter.
headers should be a dictionary, and will be treated as if add_header() was called with each key and value as arguments. This is often used to “spoof” the User-Agent header value, which is used by a browser to identify itself – some HTTP servers only allow requests coming from common browsers as opposed to scripts. For example, Mozilla Firefox may identify itself as "Mozilla/5.0
(X11; U; Linux i686) Gecko/20071127 Firefox/2.0.0.11", while urllib’s default user agent string is "Python-urllib/2.6" (on Python 2.6).
An appropriate Content-Type header should be included if the data argument is present. If this header has not been provided and data is not None, Content-Type: application/x-www-form-urlencoded will be added as a default.
The next two arguments are only of interest for correct handling of third-party HTTP cookies:
origin_req_host should be the request-host of the origin transaction, as defined by RFC 2965. It defaults to http.cookiejar.request_host(self). This is the host name or IP address of the original request that was initiated by the user. For example, if the request is for an image in an HTML document, this should be the request-host of the request for the page containing the image.
unverifiable should indicate whether the request is unverifiable, as defined by RFC 2965. It defaults to False. An unverifiable request is one whose URL the user did not have the option to approve. For example, if the request is for an image in an HTML document, and the user had no option to approve the automatic fetching of the image, this should be true.
method should be a string that indicates the HTTP request method that will be used (e.g. 'HEAD'). If provided, its value is stored in the method attribute and is used by get_method(). The default is 'GET' if data is None or 'POST' otherwise. Subclasses may indicate a different default method by setting the method attribute in the class itself.
Note
The request will not work as expected if the data object is unable to deliver its content more than once (e.g. a file or an iterable that can produce the content only once) and the request is retried for HTTP redirects or authentication. The data is sent to the HTTP server right away after the headers. There is no support for a 100-continue expectation in the library.
Changed in version 3.3: Request.method argument is added to the Request class.
Changed in version 3.4: Default Request.method may be indicated at the class level.
Changed in version 3.6: Do not raise an error if the Content-Length has not been provided and data is neither None nor a bytes object. Fall back to use chunked transfer encoding instead.


Add another header to the request. Headers are currently ignored by all handlers except HTTP handlers, where they are added to the list of headers sent to the server. Note that there cannot be more than one header with the same name, and later calls will overwrite previous calls in case the key collides. Currently, this is no loss of HTTP functionality, since all headers which have meaning when used more than once have a (header-specific) way of gaining the same functionality using only one header.


Add a header that will not be added to a redirected request.


The entity body for the request, or None if not specified.
Changed in version 3.4: Changing value of Request.data now deletes “Content-Length” header if it was previously set or calculated.


The original URL passed to the constructor.
Changed in version 3.4.
Request.full_url is a property with setter, getter and a deleter. Getting full_url returns the original request URL with the fragment, if it was present.


Return the URL given in the constructor.
Changed in version 3.4.
Returns Request.full_url


Return the value of the given header. If the header is not present, return the default value.


Return a string indicating the HTTP request method. If Request.method is not None, return its value, otherwise return 'GET' if Request.data is None, or 'POST' if it’s not. This is only meaningful for HTTP requests.
Changed in version 3.3: get_method now looks at the value of Request.method.


Return whether the instance has the named header (checks both regular and unredirected).


Return a list of tuples (header_name, header_value) of the Request headers.


The URI authority, typically a host, but may also contain a port separated by a colon.


The HTTP request method to use. By default its value is None, which means that get_method() will do its normal computation of the method to be used. Its value can be set (thus overriding the default computation in get_method()) either by providing a default value by setting it at the class level in a Request subclass, or by passing a value in to the Request constructor via the method argument.
New in version 3.3.
Changed in version 3.4: A default value can now be set in subclasses; previously it could only be set via the constructor argument.


The original host for the request, without port.


Remove named header from the request instance (both from regular and unredirected headers).
New in version 3.4.


The URI path. If the Request uses a proxy, then selector will be the full URL that is passed to the proxy.


Prepare the request by connecting to a proxy server. The host and type will replace those of the instance, and the instance’s selector will be the original URL given in the constructor.


boolean, indicates whether the request is unverifiable as defined by RFC 2965.


A catch-all class to handle unknown URLs.


Convert the path component path from a percent-encoded URL to the local syntax for a path. This does not accept a complete URL. This function uses unquote() to decode path.


Cleans up temporary files that may have been left behind by previous calls to urlretrieve().


Open the URL url, which can be either a string or a Request object.
data must be an object specifying additional data to be sent to the server, or None if no such data is needed. See Request for details.
urllib.request module uses HTTP/1.1 and includes Connection:close header in its HTTP requests.
The optional timeout parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used). This actually only works for HTTP, HTTPS and FTP connections.
If context is specified, it must be a ssl.SSLContext instance describing the various SSL options. See HTTPSConnection for more details.
The optional cafile and capath parameters specify a set of trusted CA certificates for HTTPS requests. cafile should point to a single file containing a bundle of CA certificates, whereas capath should point to a directory of hashed certificate files. More information can be found in ssl.SSLContext.load_verify_locations().
The cadefault parameter is ignored.
This function always returns an object which can work as a context manager and has the properties url, headers, and status. See urllib.response.addinfourl for more detail on these properties.
For HTTP and HTTPS URLs, this function returns a http.client.HTTPResponse object slightly modified. In addition to the three new methods above, the msg attribute contains the same information as the reason attribute — the reason phrase returned by server — instead of the response headers as it is specified in the documentation for HTTPResponse.
For FTP, file, and data URLs and requests explicitly handled by legacy URLopener and FancyURLopener classes, this function returns a urllib.response.addinfourl object.
Raises URLError on protocol errors.
Note that None may be returned if no handler handles the request (though the default installed global OpenerDirector uses UnknownHandler to ensure this never happens).
In addition, if proxy settings are detected (for example, when a *_proxy environment variable like http_proxy is set), ProxyHandler is default installed and makes sure the requests are handled through the proxy.
The legacy urllib.urlopen function from Python 2.6 and earlier has been discontinued; urllib.request.urlopen() corresponds to the old urllib2.urlopen. Proxy handling, which was done by passing a dictionary parameter to urllib.urlopen, can be obtained by using ProxyHandler objects.
The default opener raises an auditing event urllib.Request with arguments fullurl, data, headers, method taken from the request object.
Changed in version 3.2: cafile and capath were added.
Changed in version 3.2: HTTPS virtual hosts are now supported if possible (that is, if ssl.HAS_SNI is true).
New in version 3.2: data can be an iterable object.
Changed in version 3.3: cadefault was added.
Changed in version 3.4.3: context was added.
Deprecated since version 3.6: cafile, capath and cadefault are deprecated in favor of context. Please use ssl.SSLContext.load_cert_chain() instead, or let ssl.create_default_context() select the system’s trusted CA certificates for you.


Deprecated since version 3.3.
Base class for opening and reading URLs. Unless you need to support opening objects using schemes other than http:, ftp:, or file:, you probably want to use FancyURLopener.
By default, the URLopener class sends a User-Agent header of urllib/VVV, where VVV is the urllib version number. Applications can define their own User-Agent header by subclassing URLopener or FancyURLopener and setting the class attribute version to an appropriate string value in the subclass definition.
The optional proxies parameter should be a dictionary mapping scheme names to proxy URLs, where an empty dictionary turns proxies off completely. Its default value is None, in which case environmental proxy settings will be used if present, as discussed in the definition of urlopen(), above.
Additional keyword parameters, collected in x509, may be used for authentication of the client when using the https: scheme. The keywords key_file and cert_file are supported to provide an SSL key and certificate; both are needed to support client authentication.
URLopener objects will raise an OSError exception if the server returns an error code.
Open fullurl using the appropriate protocol. This method sets up cache and proxy information, then calls the appropriate open method with its input arguments. If the scheme is not recognized, open_unknown() is called. The data argument has the same meaning as the data argument of urlopen().
This method always quotes fullurl using quote().
Overridable interface to open unknown URL types.
Retrieves the contents of url and places it in filename. The return value is a tuple consisting of a local filename and either an email.message.Message object containing the response headers (for remote URLs) or None (for local URLs). The caller must then open and read the contents of filename. If filename is not given and the URL refers to a local file, the input filename is returned. If the URL is non-local and filename is not given, the filename is the output of tempfile.mktemp() with a suffix that matches the suffix of the last path component of the input URL. If reporthook is given, it must be a function accepting three numeric parameters: A chunk number, the maximum size chunks are read in and the total size of the download (-1 if unknown). It will be called once at the start and after each chunk of data is read from the network. reporthook is ignored for local URLs.
If the url uses the http: scheme identifier, the optional data argument may be given to specify a POST request (normally the request type is GET). The data argument must in standard application/x-www-form-urlencoded format; see the urllib.parse.urlencode() function.
Variable that specifies the user agent of the opener object. To get urllib to tell servers that it is a particular user agent, set this in a subclass as a class variable or in the constructor before calling the base constructor.


Open fullurl using the appropriate protocol. This method sets up cache and proxy information, then calls the appropriate open method with its input arguments. If the scheme is not recognized, open_unknown() is called. The data argument has the same meaning as the data argument of urlopen().
This method always quotes fullurl using quote().


Overridable interface to open unknown URL types.


Retrieves the contents of url and places it in filename. The return value is a tuple consisting of a local filename and either an email.message.Message object containing the response headers (for remote URLs) or None (for local URLs). The caller must then open and read the contents of filename. If filename is not given and the URL refers to a local file, the input filename is returned. If the URL is non-local and filename is not given, the filename is the output of tempfile.mktemp() with a suffix that matches the suffix of the last path component of the input URL. If reporthook is given, it must be a function accepting three numeric parameters: A chunk number, the maximum size chunks are read in and the total size of the download (-1 if unknown). It will be called once at the start and after each chunk of data is read from the network. reporthook is ignored for local URLs.
If the url uses the http: scheme identifier, the optional data argument may be given to specify a POST request (normally the request type is GET). The data argument must in standard application/x-www-form-urlencoded format; see the urllib.parse.urlencode() function.


Variable that specifies the user agent of the opener object. To get urllib to tell servers that it is a particular user agent, set this in a subclass as a class variable or in the constructor before calling the base constructor.


Copy a network object denoted by a URL to a local file. If the URL points to a local file, the object will not be copied unless filename is supplied. Return a tuple (filename, headers) where filename is the local file name under which the object can be found, and headers is whatever the info() method of the object returned by urlopen() returned (for a remote object). Exceptions are the same as for urlopen().
The second argument, if present, specifies the file location to copy to (if absent, the location will be a tempfile with a generated name). The third argument, if present, is a callable that will be called once on establishment of the network connection and once after each block read thereafter. The callable will be passed three arguments; a count of blocks transferred so far, a block size in bytes, and the total size of the file. The third argument may be -1 on older FTP servers which do not return a file size in response to a retrieval request.
The following example illustrates the most common usage scenario:
If the url uses the http: scheme identifier, the optional data argument may be given to specify a POST request (normally the request type is GET). The data argument must be a bytes object in standard application/x-www-form-urlencoded format; see the urllib.parse.urlencode() function.
urlretrieve() will raise ContentTooShortError when it detects that the amount of data available was less than the expected amount (which is the size reported by a Content-Length header). This can occur, for example, when the download is interrupted.
The Content-Length is treated as a lower bound: if there’s more data to read, urlretrieve reads more data, but if less data is available, it raises the exception.
You can still retrieve the downloaded data in this case, it is stored in the content attribute of the exception instance.
If no Content-Length header was supplied, urlretrieve can not check the size of the data it has downloaded, and just returns it. In this case you just have to assume that the download was successful.


URL of the resource retrieved, commonly used to determine if a redirect was followed.
Returns the headers of the response in the form of an EmailMessage instance.
New in version 3.9.
Status code returned by server.
Deprecated since version 3.9: Deprecated in favor of url.
Deprecated since version 3.9: Deprecated in favor of headers.
Deprecated since version 3.9: Deprecated in favor of status.
Deprecated since version 3.9: Deprecated in favor of status.


Deprecated since version 3.9: Deprecated in favor of status.


Deprecated since version 3.9: Deprecated in favor of url.


Returns the headers of the response in the form of an EmailMessage instance.


Deprecated since version 3.9: Deprecated in favor of headers.


New in version 3.9.
Status code returned by server.


URL of the resource retrieved, commonly used to determine if a redirect was followed.


Source code: Lib/urllib/robotparser.py
This module provides a single class, RobotFileParser, which answers questions about whether or not a particular user agent can fetch a URL on the Web site that published the robots.txt file. For more details on the structure of robots.txt files, see http://www.robotstxt.org/orig.html.
This class provides methods to read, parse and answer questions about the robots.txt file at url.
Sets the URL referring to a robots.txt file.
Reads the robots.txt URL and feeds it to the parser.
Parses the lines argument.
Returns True if the useragent is allowed to fetch the url according to the rules contained in the parsed robots.txt file.
Returns the time the robots.txt file was last fetched. This is useful for long-running web spiders that need to check for new robots.txt files periodically.
Sets the time the robots.txt file was last fetched to the current time.
Returns the value of the Crawl-delay parameter from robots.txt for the useragent in question. If there is no such parameter or it doesn’t apply to the useragent specified or the robots.txt entry for this parameter has invalid syntax, return None.
New in version 3.6.
Returns the contents of the Request-rate parameter from robots.txt as a named tuple RequestRate(requests, seconds). If there is no such parameter or it doesn’t apply to the useragent specified or the robots.txt entry for this parameter has invalid syntax, return None.
New in version 3.6.
Returns the contents of the Sitemap parameter from robots.txt in the form of a list(). If there is no such parameter or the robots.txt entry for this parameter has invalid syntax, return None.
New in version 3.8.
The following example demonstrates basic use of the RobotFileParser class:


This class provides methods to read, parse and answer questions about the robots.txt file at url.
Sets the URL referring to a robots.txt file.
Reads the robots.txt URL and feeds it to the parser.
Parses the lines argument.
Returns True if the useragent is allowed to fetch the url according to the rules contained in the parsed robots.txt file.
Returns the time the robots.txt file was last fetched. This is useful for long-running web spiders that need to check for new robots.txt files periodically.
Sets the time the robots.txt file was last fetched to the current time.
Returns the value of the Crawl-delay parameter from robots.txt for the useragent in question. If there is no such parameter or it doesn’t apply to the useragent specified or the robots.txt entry for this parameter has invalid syntax, return None.
New in version 3.6.
Returns the contents of the Request-rate parameter from robots.txt as a named tuple RequestRate(requests, seconds). If there is no such parameter or it doesn’t apply to the useragent specified or the robots.txt entry for this parameter has invalid syntax, return None.
New in version 3.6.
Returns the contents of the Sitemap parameter from robots.txt in the form of a list(). If there is no such parameter or the robots.txt entry for this parameter has invalid syntax, return None.
New in version 3.8.


Returns True if the useragent is allowed to fetch the url according to the rules contained in the parsed robots.txt file.


Returns the value of the Crawl-delay parameter from robots.txt for the useragent in question. If there is no such parameter or it doesn’t apply to the useragent specified or the robots.txt entry for this parameter has invalid syntax, return None.
New in version 3.6.


Sets the time the robots.txt file was last fetched to the current time.


Returns the time the robots.txt file was last fetched. This is useful for long-running web spiders that need to check for new robots.txt files periodically.


Reads the robots.txt URL and feeds it to the parser.


Returns the contents of the Request-rate parameter from robots.txt as a named tuple RequestRate(requests, seconds). If there is no such parameter or it doesn’t apply to the useragent specified or the robots.txt entry for this parameter has invalid syntax, return None.
New in version 3.6.


Sets the URL referring to a robots.txt file.


Returns the contents of the Sitemap parameter from robots.txt in the form of a list(). If there is no such parameter or the robots.txt entry for this parameter has invalid syntax, return None.
New in version 3.8.


Base class for warnings generated by user code.


Source code: Lib/uu.py
This module encodes and decodes files in uuencode format, allowing arbitrary binary data to be transferred over ASCII-only connections. Wherever a file argument is expected, the methods accept a file-like object. For backwards compatibility, a string containing a pathname is also accepted, and the corresponding file will be opened for reading and writing; the pathname '-' is understood to mean the standard input or output. However, this interface is deprecated; it’s better for the caller to open the file itself, and be sure that, when required, the mode is 'rb' or 'wb' on Windows.
This code was contributed by Lance Ellinghouse, and modified by Jack Jansen.
The uu module defines the following functions:
Uuencode file in_file into file out_file. The uuencoded file will have the header specifying name and mode as the defaults for the results of decoding the file. The default defaults are taken from in_file, or '-' and 0o666 respectively. If backtick is true, zeros are represented by '`' instead of spaces.
Changed in version 3.7: Added the backtick parameter.
This call decodes uuencoded file in_file placing the result on file out_file. If out_file is a pathname, mode is used to set the permission bits if the file must be created. Defaults for out_file and mode are taken from the uuencode header. However, if the file specified in the header already exists, a uu.Error is raised.
decode() may print a warning to standard error if the input was produced by an incorrect uuencoder and Python could recover from that error. Setting quiet to a true value silences this warning.
Subclass of Exception, this can be raised by uu.decode() under various situations, such as described above, but also including a badly formatted header, or truncated input file.
See also
Support module containing ASCII-to-binary and binary-to-ASCII conversions.


This call decodes uuencoded file in_file placing the result on file out_file. If out_file is a pathname, mode is used to set the permission bits if the file must be created. Defaults for out_file and mode are taken from the uuencode header. However, if the file specified in the header already exists, a uu.Error is raised.
decode() may print a warning to standard error if the input was produced by an incorrect uuencoder and Python could recover from that error. Setting quiet to a true value silences this warning.


Uuencode file in_file into file out_file. The uuencoded file will have the header specifying name and mode as the defaults for the results of decoding the file. The default defaults are taken from in_file, or '-' and 0o666 respectively. If backtick is true, zeros are represented by '`' instead of spaces.
Changed in version 3.7: Added the backtick parameter.


Subclass of Exception, this can be raised by uu.decode() under various situations, such as described above, but also including a badly formatted header, or truncated input file.


Source code: Lib/uuid.py
This module provides immutable UUID objects (the UUID class) and the functions uuid1(), uuid3(), uuid4(), uuid5() for generating version 1, 3, 4, and 5 UUIDs as specified in RFC 4122.
If all you want is a unique ID, you should probably call uuid1() or uuid4(). Note that uuid1() may compromise privacy since it creates a UUID containing the computer’s network address. uuid4() creates a random UUID.
Depending on support from the underlying platform, uuid1() may or may not return a “safe” UUID. A safe UUID is one which is generated using synchronization methods that ensure no two processes can obtain the same UUID. All instances of UUID have an is_safe attribute which relays any information about the UUID’s safety, using this enumeration:
New in version 3.7.
The UUID was generated by the platform in a multiprocessing-safe way.
The UUID was not generated in a multiprocessing-safe way.
The platform does not provide information on whether the UUID was generated safely or not.
Create a UUID from either a string of 32 hexadecimal digits, a string of 16 bytes in big-endian order as the bytes argument, a string of 16 bytes in little-endian order as the bytes_le argument, a tuple of six integers (32-bit time_low, 16-bit time_mid, 16-bit time_hi_version, 8-bit clock_seq_hi_variant, 8-bit clock_seq_low, 48-bit node) as the fields argument, or a single 128-bit integer as the int argument. When a string of hex digits is given, curly braces, hyphens, and a URN prefix are all optional. For example, these expressions all yield the same UUID:
Exactly one of hex, bytes, bytes_le, fields, or int must be given. The version argument is optional; if given, the resulting UUID will have its variant and version number set according to RFC 4122, overriding bits in the given hex, bytes, bytes_le, fields, or int.
Comparison of UUID objects are made by way of comparing their UUID.int attributes. Comparison with a non-UUID object raises a TypeError.
str(uuid) returns a string in the form 12345678-1234-5678-1234-567812345678 where the 32 hexadecimal digits represent the UUID.
UUID instances have these read-only attributes:
The UUID as a 16-byte string (containing the six integer fields in big-endian byte order).
The UUID as a 16-byte string (with time_low, time_mid, and time_hi_version in little-endian byte order).
A tuple of the six integer fields of the UUID, which are also available as six individual attributes and two derived attributes:
Field
Meaning
time_low
the first 32 bits of the UUID
time_mid
the next 16 bits of the UUID
time_hi_version
the next 16 bits of the UUID
clock_seq_hi_variant
the next 8 bits of the UUID
clock_seq_low
the next 8 bits of the UUID
node
the last 48 bits of the UUID
time
the 60-bit timestamp
clock_seq
the 14-bit sequence number
The UUID as a 32-character hexadecimal string.
The UUID as a 128-bit integer.
The UUID as a URN as specified in RFC 4122.
The UUID variant, which determines the internal layout of the UUID. This will be one of the constants RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, or RESERVED_FUTURE.
The UUID version number (1 through 5, meaningful only when the variant is RFC_4122).
An enumeration of SafeUUID which indicates whether the platform generated the UUID in a multiprocessing-safe way.
New in version 3.7.
The uuid module defines the following functions:
Get the hardware address as a 48-bit positive integer. The first time this runs, it may launch a separate program, which could be quite slow. If all attempts to obtain the hardware address fail, we choose a random 48-bit number with the multicast bit (least significant bit of the first octet) set to 1 as recommended in RFC 4122. “Hardware address” means the MAC address of a network interface. On a machine with multiple network interfaces, universally administered MAC addresses (i.e. where the second least significant bit of the first octet is unset) will be preferred over locally administered MAC addresses, but with no other ordering guarantees.
Changed in version 3.7: Universally administered MAC addresses are preferred over locally administered MAC addresses, since the former are guaranteed to be globally unique, while the latter are not.
Generate a UUID from a host ID, sequence number, and the current time. If node is not given, getnode() is used to obtain the hardware address. If clock_seq is given, it is used as the sequence number; otherwise a random 14-bit sequence number is chosen.
Generate a UUID based on the MD5 hash of a namespace identifier (which is a UUID) and a name (which is a string).
Generate a random UUID.
Generate a UUID based on the SHA-1 hash of a namespace identifier (which is a UUID) and a name (which is a string).
The uuid module defines the following namespace identifiers for use with uuid3() or uuid5().
When this namespace is specified, the name string is a fully-qualified domain name.
When this namespace is specified, the name string is a URL.
When this namespace is specified, the name string is an ISO OID.
When this namespace is specified, the name string is an X.500 DN in DER or a text output format.
The uuid module defines the following constants for the possible values of the variant attribute:
Reserved for NCS compatibility.
Specifies the UUID layout given in RFC 4122.
Reserved for Microsoft compatibility.
Reserved for future definition.
See also
This specification defines a Uniform Resource Name namespace for UUIDs, the internal format of UUIDs, and methods of generating UUIDs.
Here are some examples of typical usage of the uuid module:


Get the hardware address as a 48-bit positive integer. The first time this runs, it may launch a separate program, which could be quite slow. If all attempts to obtain the hardware address fail, we choose a random 48-bit number with the multicast bit (least significant bit of the first octet) set to 1 as recommended in RFC 4122. “Hardware address” means the MAC address of a network interface. On a machine with multiple network interfaces, universally administered MAC addresses (i.e. where the second least significant bit of the first octet is unset) will be preferred over locally administered MAC addresses, but with no other ordering guarantees.
Changed in version 3.7: Universally administered MAC addresses are preferred over locally administered MAC addresses, since the former are guaranteed to be globally unique, while the latter are not.


When this namespace is specified, the name string is a fully-qualified domain name.


When this namespace is specified, the name string is an ISO OID.


When this namespace is specified, the name string is a URL.


When this namespace is specified, the name string is an X.500 DN in DER or a text output format.


Specifies the UUID layout given in RFC 4122.


New in version 3.7.
The UUID was generated by the platform in a multiprocessing-safe way.
The UUID was not generated in a multiprocessing-safe way.
The platform does not provide information on whether the UUID was generated safely or not.


The UUID was generated by the platform in a multiprocessing-safe way.


The platform does not provide information on whether the UUID was generated safely or not.


The UUID was not generated in a multiprocessing-safe way.


Create a UUID from either a string of 32 hexadecimal digits, a string of 16 bytes in big-endian order as the bytes argument, a string of 16 bytes in little-endian order as the bytes_le argument, a tuple of six integers (32-bit time_low, 16-bit time_mid, 16-bit time_hi_version, 8-bit clock_seq_hi_variant, 8-bit clock_seq_low, 48-bit node) as the fields argument, or a single 128-bit integer as the int argument. When a string of hex digits is given, curly braces, hyphens, and a URN prefix are all optional. For example, these expressions all yield the same UUID:
Exactly one of hex, bytes, bytes_le, fields, or int must be given. The version argument is optional; if given, the resulting UUID will have its variant and version number set according to RFC 4122, overriding bits in the given hex, bytes, bytes_le, fields, or int.
Comparison of UUID objects are made by way of comparing their UUID.int attributes. Comparison with a non-UUID object raises a TypeError.
str(uuid) returns a string in the form 12345678-1234-5678-1234-567812345678 where the 32 hexadecimal digits represent the UUID.


The UUID as a 16-byte string (containing the six integer fields in big-endian byte order).


The UUID as a 16-byte string (with time_low, time_mid, and time_hi_version in little-endian byte order).


A tuple of the six integer fields of the UUID, which are also available as six individual attributes and two derived attributes:
Field
Meaning
time_low
the first 32 bits of the UUID
time_mid
the next 16 bits of the UUID
time_hi_version
the next 16 bits of the UUID
clock_seq_hi_variant
the next 8 bits of the UUID
clock_seq_low
the next 8 bits of the UUID
node
the last 48 bits of the UUID
time
the 60-bit timestamp
clock_seq
the 14-bit sequence number


The UUID as a 32-character hexadecimal string.


An enumeration of SafeUUID which indicates whether the platform generated the UUID in a multiprocessing-safe way.
New in version 3.7.


The UUID as a URN as specified in RFC 4122.


The UUID variant, which determines the internal layout of the UUID. This will be one of the constants RESERVED_NCS, RFC_4122, RESERVED_MICROSOFT, or RESERVED_FUTURE.


The UUID version number (1 through 5, meaningful only when the variant is RFC_4122).


Generate a UUID from a host ID, sequence number, and the current time. If node is not given, getnode() is used to obtain the hardware address. If clock_seq is given, it is used as the sequence number; otherwise a random 14-bit sequence number is chosen.


Generate a UUID based on the MD5 hash of a namespace identifier (which is a UUID) and a name (which is a string).


Generate a UUID based on the SHA-1 hash of a namespace identifier (which is a UUID) and a name (which is a string).


Raised when an operation or function receives an argument that has the right type but an inappropriate value, and the situation is not described by a more precise exception such as IndexError.


Return the __dict__ attribute for a module, class, instance, or any other object with a __dict__ attribute.
Objects such as modules and instances have an updateable __dict__ attribute; however, other objects may have write restrictions on their __dict__ attributes (for example, classes use a types.MappingProxyType to prevent direct dictionary updates).
Without an argument, vars() acts like locals(). Note, the locals dictionary is only useful for reads since updates to the locals dictionary are ignored.
A TypeError exception is raised if an object is specified but it doesn’t have a __dict__ attribute (for example, if its class defines the __slots__ attribute).