fetchers.py 文件源码

def fetch(self, url, body=None, headers=None):
        """Perform an HTTP request

        @raises Exception: Any exception that can be raised by httplib2

        @see: C{L{HTTPFetcher.fetch}}
        """
        if body:
            method = 'POST'
        else:
            method = 'GET'

        if headers is None:
            headers = {}

        # httplib2 doesn't check to make sure that the URL's scheme is
        # 'http' so we do it here.
        if not (url.startswith('http://') or url.startswith('https://')):
            raise ValueError('URL is not a HTTP URL: %r' % (url,))

        httplib2_response, content = self.httplib2.request(
            url, method, body=body, headers=headers)

        # Translate the httplib2 response to our HTTP response abstraction

        # When a 400 is returned, there is no "content-location"
        # header set. This seems like a bug to me. I can't think of a
        # case where we really care about the final URL when it is an
        # error response, but being careful about it can't hurt.
        try:
            final_url = httplib2_response['content-location']
        except KeyError:
            # We're assuming that no redirects occurred
            assert not httplib2_response.previous

            # And this should never happen for a successful response
            assert httplib2_response.status != 200
            final_url = url

        return HTTPResponse(
            body=content,
            final_url=final_url,
            headers=dict(httplib2_response.items()),
            status=httplib2_response.status,
            )