Edit File: _collections.py
from __future__ import absolute_import try: from collections.abc import Mapping, MutableMapping except ImportError: from collections import Mapping, MutableMapping try: from threading import RLock except ImportError: # Platform-specific: No threads available class RLock: def __enter__(self): pass def __exit__(self, exc_type, exc_value, traceback): pass from collections import OrderedDict from .exceptions import InvalidHeader from .packages.six import iterkeys, itervalues, PY3 __all__ = ['RecentlyUsedContainer', 'HTTPHeaderDict'] _Null = object() class RecentlyUsedContainer(MutableMapping): """ Provides a thread-safe dict-like container which maintains up to ``maxsize`` keys while throwing away the least-recently-used keys beyond ``maxsize``. :param maxsize: Maximum number of recent elements to retain. :param dispose_func: Every time an item is evicted from the container, ``dispose_func(value)`` is called. Callback which will get called """ ContainerCls = OrderedDict def __init__(self, maxsize=10, dispose_func=None): self._maxsize = maxsize self.dispose_func = dispose_func self._container = self.ContainerCls() self.lock = RLock() def __getitem__(self, key): # Re-insert the item, moving it to the end of the eviction line. with self.lock: item = self._container.pop(key) self._container[key] = item return item def __setitem__(self, key, value): evicted_value = _Null with self.lock: # Possibly evict the existing value of 'key' evicted_value = self._container.get(key, _Null) self._container[key] = value # If we didn't evict an existing value, we might have to evict the # least recently used item from the beginning of the container. if len(self._container) > self._maxsize: _key, evicted_value = self._container.popitem(last=False) if self.dispose_func and evicted_value is not _Null: self.dispose_func(evicted_value) def __delitem__(self, key): with self.lock: value = self._container.pop(key) if self.dispose_func: self.dispose_func(value) def __len__(self): with self.lock: return len(self._container) def __iter__(self): raise NotImplementedError('Iteration over this class is unlikely to be threadsafe.') def clear(self): with self.lock: # Copy pointers to all values, then wipe the mapping values = list(itervalues(self._container)) self._container.clear() if self.dispose_func: for value in values: self.dispose_func(value) def keys(self): with self.lock: return list(iterkeys(self._container)) class HTTPHeaderDict(MutableMapping): """ :param headers: An iterable of field-value pairs. Must not contain multiple field names when compared case-insensitively. :param kwargs: Additional field-value pairs to pass in to ``dict.update``. A ``dict`` like container for storing HTTP Headers. Field names are stored and compared case-insensitively in compliance with RFC 7230. Iteration provides the first case-sensitive key seen for each case-insensitive pair. Using ``__setitem__`` syntax overwrites fields that compare equal case-insensitively in order to maintain ``dict``'s api. For fields that compare equal, instead create a new ``HTTPHeaderDict`` and use ``.add`` in a loop. If multiple fields that are equal case-insensitively are passed to the constructor or ``.update``, the behavior is undefined and some will be lost. >>> headers = HTTPHeaderDict() >>> headers.add('Set-Cookie', 'foo=bar') >>> headers.add('set-cookie', 'baz=quxx') >>> headers['content-length'] = '7' >>> headers['SET-cookie'] 'foo=bar, baz=quxx' >>> headers['Content-Length'] '7' """ def __init__(self, headers=None, **kwargs): super(HTTPHeaderDict, self).__init__() self._container = OrderedDict() if headers is not None: if isinstance(headers, HTTPHeaderDict): self._copy_from(headers) else: self.extend(headers) if kwargs: self.extend(kwargs) def __setitem__(self, key, val): self._container[key.lower()] = [key, val] return self._container[key.lower()] def __getitem__(self, key): val = self._container[key.lower()] return ', '.join(val[1:]) def __delitem__(self, key): del self._container[key.lower()] def __contains__(self, key): return key.lower() in self._container def __eq__(self, other): if not isinstance(other, Mapping) and not hasattr(other, 'keys'): return False if not isinstance(other, type(self)): other = type(self)(other) return (dict((k.lower(), v) for k, v in self.itermerged()) == dict((k.lower(), v) for k, v in other.itermerged())) def __ne__(self, other): return not self.__eq__(other) if not PY3: # Python 2 iterkeys = MutableMapping.iterkeys itervalues = MutableMapping.itervalues __marker = object() def __len__(self): return len(self._container) def __iter__(self): # Only provide the originally cased names for vals in self._container.values(): yield vals[0] def pop(self, key, default=__marker): '''D.pop(k[,d]) -> v, remove specified key and return the corresponding value. If key is not found, d is returned if given, otherwise KeyError is raised. ''' # Using the MutableMapping function directly fails due to the private marker. # Using ordinary dict.pop would expose the internal structures. # So let's reinvent the wheel. try: value = self[key] except KeyError: if default is self.__marker: raise return default else: del self[key] return value def discard(self, key): try: del self[key] except KeyError: pass def add(self, key, val): """Adds a (name, value) pair, doesn't overwrite the value if it already exists. >>> headers = HTTPHeaderDict(foo='bar') >>> headers.add('Foo', 'baz') >>> headers['foo'] 'bar, baz' """ key_lower = key.lower() new_vals = [key, val] # Keep the common case aka no item present as fast as possible vals = self._container.setdefault(key_lower, new_vals) if new_vals is not vals: vals.append(val) def extend(self, *args, **kwargs): """Generic import function for any type of header-like object. Adapted version of MutableMapping.update in order to insert items with self.add instead of self.__setitem__ """ if len(args) > 1: raise TypeError("extend() takes at most 1 positional " "arguments ({0} given)".format(len(args))) other = args[0] if len(args) >= 1 else () if isinstance(other, HTTPHeaderDict): for key, val in other.iteritems(): self.add(key, val) elif isinstance(other, Mapping): for key in other: self.add(key, other[key]) elif hasattr(other, "keys"): for key in other.keys(): self.add(key, other[key]) else: for key, value in other: self.add(key, value) for key, value in kwargs.items(): self.add(key, value) def getlist(self, key, default=__marker): """Returns a list of all the values for the named field. Returns an empty list if the key doesn't exist.""" try: vals = self._container[key.lower()] except KeyError: if default is self.__marker: return [] return default else: return vals[1:] def _prepare_for_method_change(self): """ Remove content-specific header fields before changing the request method to GET or HEAD according to RFC 9110, Section 15.4. """ content_specific_headers = [ "Content-Encoding", "Content-Language", "Content-Location", "Content-Type", "Content-Length", "Digest", "Last-Modified", ] for header in content_specific_headers: self.discard(header) return self # Backwards compatibility for httplib getheaders = getlist getallmatchingheaders = getlist iget = getlist # Backwards compatibility for http.cookiejar get_all = getlist def __repr__(self): return "%s(%s)" % (type(self).__name__, dict(self.itermerged())) def _copy_from(self, other): for key in other: val = other.getlist(key) if isinstance(val, list): # Don't need to convert tuples val = list(val) self._container[key.lower()] = [key] + val def copy(self): clone = type(self)() clone._copy_from(self) return clone def iteritems(self): """Iterate over all header lines, including duplicate ones.""" for key in self: vals = self._container[key.lower()] for val in vals[1:]: yield vals[0], val def itermerged(self): """Iterate over all headers, merging duplicate ones together.""" for key in self: val = self._container[key.lower()] yield val[0], ', '.join(val[1:]) def items(self): return list(self.iteritems()) @classmethod def from_httplib(cls, message): # Python 2 """Read headers from a Python 2 httplib message object.""" # python2.7 does not expose a proper API for exporting multiheaders # efficiently. This function re-reads raw lines from the message # object and extracts the multiheaders properly. obs_fold_continued_leaders = (' ', '\t') headers = [] for line in message.headers: if line.startswith(obs_fold_continued_leaders): if not headers: # We received a header line that starts with OWS as described # in RFC-7230 S3.2.4. This indicates a multiline header, but # there exists no previous header to which we can attach it. raise InvalidHeader( 'Header continuation with no previous header: %s' % line ) else: key, value = headers[-1] headers[-1] = (key, value + ' ' + line.strip()) continue key, value = line.split(':', 1) headers.append((key, value.strip())) return cls(headers)
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