How do you get default headers in a urllib2 Request?

Question

I have a Python web client that uses urllib2. It is easy enough to add HTTP headers to my outgoing requests. I just create a dictionary of the headers I want to add, and pa

Answer 1

A other solution, witch used the idea from How do you get default headers in a urllib2 Request? But doesn't copy code from std-lib:

class HTTPConnection2(httplib.HTTPConnection):
    """
    Like httplib.HTTPConnection but stores the request headers.
    Used in HTTPConnection3(), see below.
    """
    def __init__(self, *args, **kwargs):
        httplib.HTTPConnection.__init__(self, *args, **kwargs)
        self.request_headers = []
        self.request_header = ""

    def putheader(self, header, value):
        self.request_headers.append((header, value))
        httplib.HTTPConnection.putheader(self, header, value)

    def send(self, s):
        self.request_header = s
        httplib.HTTPConnection.send(self, s)


class HTTPConnection3(object):
    """
    Wrapper around HTTPConnection2
    Used in HTTPHandler2(), see below.
    """
    def __call__(self, *args, **kwargs):
        """
        instance made in urllib2.HTTPHandler.do_open()
        """
        self._conn = HTTPConnection2(*args, **kwargs)
        self.request_headers = self._conn.request_headers
        self.request_header = self._conn.request_header
        return self

    def __getattribute__(self, name):
        """
        Redirect attribute access to the local HTTPConnection() instance.
        """
        if name == "_conn":
            return object.__getattribute__(self, name)
        else:
            return getattr(self._conn, name)


class HTTPHandler2(urllib2.HTTPHandler):
    """
    A HTTPHandler which stores the request headers.
    Used HTTPConnection3, see above.

    >>> opener = urllib2.build_opener(HTTPHandler2)
    >>> opener.addheaders = [("User-agent", "Python test")]
    >>> response = opener.open('http://www.python.org/')

    Get the request headers as a list build with HTTPConnection.putheader():
    >>> response.request_headers
    [('Accept-Encoding', 'identity'), ('Host', 'www.python.org'), ('Connection', 'close'), ('User-Agent', 'Python test')]

    >>> response.request_header
    'GET / HTTP/1.1\\r\\nAccept-Encoding: identity\\r\\nHost: www.python.org\\r\\nConnection: close\\r\\nUser-Agent: Python test\\r\\n\\r\\n'
    """
    def http_open(self, req):
        conn_instance = HTTPConnection3()
        response = self.do_open(conn_instance, req)
        response.request_headers = conn_instance.request_headers
        response.request_header = conn_instance.request_header
        return response

EDIT: Update the source