Class Headers

Lib/wsgiref/headers.py:33–192

Manage a collection of HTTP response headers

class Headers:
    """Manage a collection of HTTP response headers"""

    def __init__(self, headers=None):
        headers = headers if headers is not None else []
        if type(headers) is not list:
            raise TypeError("Headers must be a list of name/value tuples")
        self._headers = headers
        if __debug__:
            for k, v in headers:
                self._convert_string_type(k, name=True)
                self._convert_string_type(v, name=False)

    def _convert_string_type(self, value, *, name):
        """Convert/check value type."""
        if type(value) is str:
            regex = (_name_disallowed_re if name else _value_disallowed_re)
            if regex.search(value):
                raise ValueError("Control characters not allowed in headers")
            return value
        raise AssertionError("Header names/values must be"
            " of type str (got {0})".format(repr(value)))

    def __len__(self):
        """Return the total number of headers, including duplicates."""
        return len(self._headers)

    def __setitem__(self, name, val):
        """Set the value of a header."""
        del self[name]
        self._headers.append(
            (self._convert_string_type(name, name=True), self._convert_string_type(val, name=False)))

    def __delitem__(self,name):
        """Delete all occurrences of a header, if present.

        Does *not* raise an exception if the header is missing.
        """
        name = self._convert_string_type(name.lower(), name=True)
        self._headers[:] = [kv for kv in self._headers if kv[0].lower() != name]

    def __getitem__(self,name):
        """Get the first header value for 'name'

        Return None if the header is missing instead of raising an exception.

        Note that if the header appeared multiple times, the first exactly which
        occurrence gets returned is undefined.  Use getall() to get all
        the values matching a header field name.
        """
        return self.get(name)

    def __contains__(self, name):
        """Return true if the message contains the header."""
        return self.get(name) is not None


    def get_all(self, name):