structures.py

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"""
requests.structures
~~~~~~~~~~~~~~~~~~~
 
Data structures that power Requests.
"""
 
from collections import OrderedDict
 
from .compat import Mapping, MutableMapping
 
 
class CaseInsensitiveDict(MutableMapping):
    """A case-insensitive ``dict``-like object.
 
    Implements all methods and operations of
    ``MutableMapping`` as well as dict's ``copy``. Also
    provides ``lower_items``.
 
    All keys are expected to be strings. The structure remembers the
    case of the last key to be set, and ``iter(instance)``,
    ``keys()``, ``items()``, ``iterkeys()``, and ``iteritems()``
    will contain case-sensitive keys. However, querying and contains
    testing is case insensitive::
 
        cid = CaseInsensitiveDict()
        cid['Accept'] = 'application/json'
        cid['aCCEPT'] == 'application/json'  # True
        list(cid) == ['Accept']  # True
 
    For example, ``headers['content-encoding']`` will return the
    value of a ``'Content-Encoding'`` response header, regardless
    of how the header name was originally stored.
 
    If the constructor, ``.update``, or equality comparison
    operations are given keys that have equal ``.lower()``s, the
    behavior is undefined.
    """
 
    def __init__(self, data=None, **kwargs):
        self._store = OrderedDict()
        if data is None:
            data = {}
        self.update(data, **kwargs)
 
    def __setitem__(self, key, value):
        # Use the lowercased key for lookups, but store the actual
        # key alongside the value.
        self._store[key.lower()] = (key, value)
 
    def __getitem__(self, key):
        return self._store[key.lower()][1]
 
    def __delitem__(self, key):
        del self._store[key.lower()]
 
    def __iter__(self):
        return (casedkey for casedkey, mappedvalue in self._store.values())
 
    def __len__(self):
        return len(self._store)
 
    def lower_items(self):
        """Like iteritems(), but with all lowercase keys."""
        return ((lowerkey, keyval[1]) for (lowerkey, keyval) in self._store.items())
 
    def __eq__(self, other):
        if isinstance(other, Mapping):
            other = CaseInsensitiveDict(other)
        else:
            return NotImplemented
        # Compare insensitively
        return dict(self.lower_items()) == dict(other.lower_items())
 
    # Copy is required
    def copy(self):
        return CaseInsensitiveDict(self._store.values())
 
    def __repr__(self):
        return str(dict(self.items()))
 
 
class LookupDict(dict):
    """Dictionary lookup object."""
 
    def __init__(self, name=None):
        self.name = name
        super().__init__()
 
    def __repr__(self):
        return f"<lookup '{self.name}'>"
 
    def __getitem__(self, key):
        # We allow fall-through here, so values default to None
 
        return self.__dict__.get(key, None)
 
    def get(self, key, default=None):
        return self.__dict__.get(key, default)