Class Headers

mitmproxy/http.py:49–176

Header class which allows both convenient access to individual headers as well as direct access to the underlying raw data. Provides a full dictionary interface. Create headers with keyword arguments: >>> h = Headers(host="example.com", content_type="application/xml") Headers

# This cannot be easily typed with mypy yet, so we just specify MultiDict without concrete types.
class Headers(multidict.MultiDict):  # type: ignore
    """
    Header class which allows both convenient access to individual headers as well as
    direct access to the underlying raw data. Provides a full dictionary interface.

    Create headers with keyword arguments:
    >>> h = Headers(host="example.com", content_type="application/xml")

    Headers mostly behave like a normal dict:
    >>> h["Host"]
    "example.com"

    Headers are case insensitive:
    >>> h["host"]
    "example.com"

    Headers can also be created from a list of raw (header_name, header_value) byte tuples:
    >>> h = Headers([
        (b"Host",b"example.com"),
        (b"Accept",b"text/html"),
        (b"accept",b"application/xml")
    ])

    Multiple headers are folded into a single header as per RFC 7230:
    >>> h["Accept"]
    "text/html, application/xml"

    Setting a header removes all existing headers with the same name:
    >>> h["Accept"] = "application/text"
    >>> h["Accept"]
    "application/text"

    `bytes(h)` returns an HTTP/1 header block:
    >>> print(bytes(h))
    Host: example.com
    Accept: application/text

    For full control, the raw header fields can be accessed:
    >>> h.fields

    Caveats:
     - For use with the "Set-Cookie" and "Cookie" headers, either use `Response.cookies` or see `Headers.get_all`.
    """

    def __init__(self, fields: Iterable[tuple[bytes, bytes]] = (), **headers):
        """
        *Args:*
         - *fields:* (optional) list of ``(name, value)`` header byte tuples,
           e.g. ``[(b"Host", b"example.com")]``. All names and values must be bytes.
         - *\\*\\*headers:* Additional headers to set. Will overwrite existing values from `fields`.
           For convenience, underscores in header names will be transformed to dashes -
           this behaviour does not extend to other methods.

        If ``**headers`` contains multiple keys that have equal ``.lower()`` representations,
        the behavior is undefined.
        """
        super().__init__(fields)