__init__.py 文件源码

def _authenticate_with_backend(backend, backend_path, request, credentials):
    args = (request,)
    # Does the backend accept a request argument?
    try:
        inspect.getcallargs(backend.authenticate, request, **credentials)
    except TypeError:
        args = ()
        credentials.pop('request', None)
        # Does the backend accept a request keyword argument?
        try:
            inspect.getcallargs(backend.authenticate, request=request, **credentials)
        except TypeError:
            # Does the backend accept credentials without request?
            try:
                inspect.getcallargs(backend.authenticate, **credentials)
            except TypeError:
                # This backend doesn't accept these credentials as arguments. Try the next one.
                return None
            else:
                warnings.warn(
                    "Update %s.authenticate() to accept a positional "
                    "`request` argument." % backend_path,
                    RemovedInDjango21Warning
                )
        else:
            credentials['request'] = request
            warnings.warn(
                "In %s.authenticate(), move the `request` keyword argument "
                "to the first positional argument." % backend_path,
                RemovedInDjango21Warning
            )
    return backend.authenticate(*args, **credentials)