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| """Manage HTTP Response Headers | |
| Much of this module is red-handedly pilfered from email.message in the stdlib, | |
| so portions are Copyright (C) 2001,2002 Python Software Foundation, and were | |
| written by Barry Warsaw. | |
| """ | |
| # Regular expression that matches `special' characters in parameters, the | |
| # existence of which force quoting of the parameter value. | |
| import re | |
| tspecials = re.compile(r'[ \(\)<>@,;:\\"/\[\]\?=]') | |
| def _formatparam(param, value=None, quote=1): | |
| """Convenience function to format and return a key=value pair. | |
| This will quote the value if needed or if quote is true. | |
| """ | |
| if value is not None and len(value) > 0: | |
| if quote or tspecials.search(value): | |
| value = value.replace('\\', '\\\\').replace('"', r'\"') | |
| return '%s="%s"' % (param, value) | |
| else: | |
| return '%s=%s' % (param, value) | |
| else: | |
| return param | |
| class Headers: | |
| """Manage a collection of HTTP response headers""" | |
| def __init__(self, headers=None): | |
| headers = headers if headers is not None else [] | |
| if type(headers) is not list: | |
| raise TypeError("Headers must be a list of name/value tuples") | |
| self._headers = headers | |
| if __debug__: | |
| for k, v in headers: | |
| self._convert_string_type(k) | |
| self._convert_string_type(v) | |
| def _convert_string_type(self, value): | |
| """Convert/check value type.""" | |
| if type(value) is str: | |
| return value | |
| raise AssertionError("Header names/values must be" | |
| " of type str (got {0})".format(repr(value))) | |
| def __len__(self): | |
| """Return the total number of headers, including duplicates.""" | |
| return len(self._headers) | |
| def __setitem__(self, name, val): | |
| """Set the value of a header.""" | |
| del self[name] | |
| self._headers.append( | |
| (self._convert_string_type(name), self._convert_string_type(val))) | |
| def __delitem__(self,name): | |
| """Delete all occurrences of a header, if present. | |
| Does *not* raise an exception if the header is missing. | |
| """ | |
| name = self._convert_string_type(name.lower()) | |
| self._headers[:] = [kv for kv in self._headers if kv[0].lower() != name] | |
| def __getitem__(self,name): | |
| """Get the first header value for 'name' | |
| Return None if the header is missing instead of raising an exception. | |
| Note that if the header appeared multiple times, the first exactly which | |
| occurrence gets returned is undefined. Use getall() to get all | |
| the values matching a header field name. | |
| """ | |
| return self.get(name) | |
| def __contains__(self, name): | |
| """Return true if the message contains the header.""" | |
| return self.get(name) is not None | |
| def get_all(self, name): | |
| """Return a list of all the values for the named field. | |
| These will be sorted in the order they appeared in the original header | |
| list or were added to this instance, and may contain duplicates. Any | |
| fields deleted and re-inserted are always appended to the header list. | |
| If no fields exist with the given name, returns an empty list. | |
| """ | |
| name = self._convert_string_type(name.lower()) | |
| return [kv[1] for kv in self._headers if kv[0].lower()==name] | |
| def get(self,name,default=None): | |
| """Get the first header value for 'name', or return 'default'""" | |
| name = self._convert_string_type(name.lower()) | |
| for k,v in self._headers: | |
| if k.lower()==name: | |
| return v | |
| return default | |
| def keys(self): | |
| """Return a list of all the header field names. | |
| These will be sorted in the order they appeared in the original header | |
| list, or were added to this instance, and may contain duplicates. | |
| Any fields deleted and re-inserted are always appended to the header | |
| list. | |
| """ | |
| return [k for k, v in self._headers] | |
| def values(self): | |
| """Return a list of all header values. | |
| These will be sorted in the order they appeared in the original header | |
| list, or were added to this instance, and may contain duplicates. | |
| Any fields deleted and re-inserted are always appended to the header | |
| list. | |
| """ | |
| return [v for k, v in self._headers] | |
| def items(self): | |
| """Get all the header fields and values. | |
| These will be sorted in the order they were in the original header | |
| list, or were added to this instance, and may contain duplicates. | |
| Any fields deleted and re-inserted are always appended to the header | |
| list. | |
| """ | |
| return self._headers[:] | |
| def __repr__(self): | |
| return "%s(%r)" % (self.__class__.__name__, self._headers) | |
| def __str__(self): | |
| """str() returns the formatted headers, complete with end line, | |
| suitable for direct HTTP transmission.""" | |
| return '\r\n'.join(["%s: %s" % kv for kv in self._headers]+['','']) | |
| def __bytes__(self): | |
| return str(self).encode('iso-8859-1') | |
| def setdefault(self,name,value): | |
| """Return first matching header value for 'name', or 'value' | |
| If there is no header named 'name', add a new header with name 'name' | |
| and value 'value'.""" | |
| result = self.get(name) | |
| if result is None: | |
| self._headers.append((self._convert_string_type(name), | |
| self._convert_string_type(value))) | |
| return value | |
| else: | |
| return result | |
| def add_header(self, _name, _value, **_params): | |
| """Extended header setting. | |
| _name is the header field to add. keyword arguments can be used to set | |
| additional parameters for the header field, with underscores converted | |
| to dashes. Normally the parameter will be added as key="value" unless | |
| value is None, in which case only the key will be added. | |
| Example: | |
| h.add_header('content-disposition', 'attachment', filename='bud.gif') | |
| Note that unlike the corresponding 'email.message' method, this does | |
| *not* handle '(charset, language, value)' tuples: all values must be | |
| strings or None. | |
| """ | |
| parts = [] | |
| if _value is not None: | |
| _value = self._convert_string_type(_value) | |
| parts.append(_value) | |
| for k, v in _params.items(): | |
| k = self._convert_string_type(k) | |
| if v is None: | |
| parts.append(k.replace('_', '-')) | |
| else: | |
| v = self._convert_string_type(v) | |
| parts.append(_formatparam(k.replace('_', '-'), v)) | |
| self._headers.append((self._convert_string_type(_name), "; ".join(parts))) | |