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