Class HTTPHeaders

tornado/httputil.py:145–384

A dictionary that maintains ``Http-Header-Case`` for all keys. Supports multiple values per key via a pair of new methods, `add()` and `get_list()`. The regular dictionary interface returns a single value per key, with multiple values joined by a comma. >>> h = HTTPHeaders({"c

class HTTPHeaders(StrMutableMapping):
    """A dictionary that maintains ``Http-Header-Case`` for all keys.

    Supports multiple values per key via a pair of new methods,
    `add()` and `get_list()`.  The regular dictionary interface
    returns a single value per key, with multiple values joined by a
    comma.

    >>> h = HTTPHeaders({"content-type": "text/html"})
    >>> list(h.keys())
    ['Content-Type']
    >>> h["Content-Type"]
    'text/html'

    >>> h.add("Set-Cookie", "A=B")
    >>> h.add("Set-Cookie", "C=D")
    >>> h["set-cookie"]
    'A=B,C=D'
    >>> h.get_list("set-cookie")
    ['A=B', 'C=D']

    >>> for (k,v) in sorted(h.get_all()):
    ...    print('%s: %s' % (k,v))
    ...
    Content-Type: text/html
    Set-Cookie: A=B
    Set-Cookie: C=D
    """

    @typing.overload
    def __init__(self, __arg: Mapping[str, List[str]]) -> None:
        pass

    @typing.overload  # noqa: F811
    def __init__(self, __arg: Mapping[str, str]) -> None:
        pass

    @typing.overload  # noqa: F811
    def __init__(self, *args: Tuple[str, str]) -> None:
        pass

    @typing.overload  # noqa: F811
    def __init__(self, **kwargs: str) -> None:
        pass

    def __init__(self, *args: typing.Any, **kwargs: str) -> None:  # noqa: F811
        # Formally, HTTP headers are a mapping from a field name to a "combined field value",
        # which may be constructed from multiple field lines by joining them with commas.
        # In practice, however, some headers (notably Set-Cookie) do not follow this convention,
        # so we maintain a mapping from field name to a list of field lines in self._as_list.
        # self._combined_cache is a cache of the combined field values derived from self._as_list
        # on demand (and cleared whenever the list is modified).
        self._as_list: dict[str, list[str]] = {}
        self._combined_cache: dict[str, str] = {}
        self._last_key = None  # type: Optional[str]
        if len(args) == 1 and len(kwargs) == 0 and isinstance(args[0], HTTPHeaders):
            # Copy constructor
            for k, v in args[0].get_all():