Source code for wsgidav.request_resolver

# -*- coding: utf-8 -*-
# (c) 2009-2022 Martin Wendt and contributors; see WsgiDAV
# Original PyFileServer (c) 2005 Ho Chun Wei.
# Licensed under the MIT license:
WSGI middleware that finds the registered mapped DAV-Provider, creates a new
RequestServer instance, and dispatches the request.

.. warning::
   The following documentation was taken over from PyFileServer and is outdated.

WsgiDAV file sharing

WsgiDAV allows the user to specify in wsgidav.conf a number of
realms, and a number of users for each realm.

   Each realm corresponds to a filestructure on disk to be stored,
   for example::


   would allow the users to access using WebDAV the directory/file
   structure at /home/public/share from the url

   The realm name is set as '/pubshare'

   e.g. /home/public/share/WsgiDAV/LICENSE becomes accessible as

   A number of user_name/password pairs can be set for each realm::

      adduser('pubshare', 'user_name', 'password', 'description/unused')

   would add a user_name/password pair to realm /pubshare.

Note: if developers wish to maintain a separate users database, you can
write your own domain controller for the HTTPAuthenticator. See and for more details.

Request Resolver

WSGI middleware for resolving Realm and Paths for the WsgiDAV

   It *must* be configured as the last item on `middleware_stack` list.

   from wsgidav.request_resolver import RequestResolver
   config = {
        'middleware_stack': [

The RequestResolver resolves the requested URL to the following values
placed in the environ dictionary. First it resolves the corresponding

   url: http://<servername:port>/<approot>/pubshare/WsgiDAV/LICENSE
   environ['wsgidav.mappedrealm'] = /pubshare

Based on the configuration given, the resource abstraction layer for the
realm is determined. if no configured abstraction layer is found, the
default abstraction layer fileabstractionlayer.FilesystemAbstractionLayer()
is used::

   environ['wsgidav.resourceAL'] = fileabstractionlayer.MyOwnFilesystemAbstractionLayer()

The path identifiers for the requested url are then resolved using the
resource abstraction layer::

   environ['wsgidav.mappedpath'] = /home/public/share/WsgiDAV/LICENSE
   environ['wsgidav.mappedURI'] = /pubshare/WsgiDAV/LICENSE

in this case, FilesystemAbstractionLayer resolves any relative paths
to its canonical absolute path

The RequestResolver also resolves any value in the Destination request
header, if present, to::

   Destination: http://<servername:port>/<approot>/pubshare/WsgiDAV/LICENSE-dest
   environ['wsgidav.destrealm'] = /pubshare
   environ['wsgidav.destpath'] = /home/public/share/WsgiDAV/LICENSE-dest
   environ['wsgidav.destURI'] = /pubshare/WsgiDAV/LICENSE
   environ['wsgidav.destresourceAL'] = fileabstractionlayer.MyOwnFilesystemAbstractionLayer()

from wsgidav import util
from wsgidav.dav_error import HTTP_NOT_FOUND, DAVError
from import BaseMiddleware
from wsgidav.request_server import RequestServer

__docformat__ = "reStructuredText"

_logger = util.get_module_logger(__name__)

# NOTE (Martin Wendt, 2009-05):
# The following remarks were made by Ian Bicking when reviewing PyFileServer in 2005.
# I leave them here after my refactoring for reference.
# Remarks:
# @@: If this were just generalized URL mapping, you'd map it like:
#    Incoming:
#        SCRIPT_NAME=<approot>; PATH_INFO=/pubshare/PyFileServer/LICENSE
#    After transforamtion:
#        SCRIPT_NAME=<approot>/pubshare; PATH_INFO=/PyFileServer/LICENSE
#    Then you dispatch to the application that serves '/home/public/share/'
#    This uses SCRIPT_NAME and PATH_INFO exactly how they are intended to be
#    used -- they give context about where you are (SCRIPT_NAME) and what you
#    still have to handle (PATH_INFO)
#    An example of an dispatcher that does this is paste.urlmap, and you use it
#    like:
#      urlmap = paste.urlmap.URLMap()
#      # urlmap is a WSGI application
#      urlmap['/pubshare'] = PyFileServerForPath('/home/public/share')
#    Now, that requires that you have a server that is easily
#    instantiated, but that's kind of a separate concern -- what you
#    really want is to do more general configuration at another level.  E.g.,
#    you might have::
#      app = config(urlmap, config_file)
#    Which adds the configuration from that file to the request, and
#    PyFileServerForPath then fetches that configuration.  paste.deploy
#    has another way of doing that at instantiation-time; either way
#    though you want to inherit configuration you can still use more general
#    dispatching.
#    Incidentally some WebDAV servers do redirection based on the user
#    agent (Zope most notably).  This is because of how WebDAV reuses
#    GET in an obnxious way, so that if you want to use WebDAV on pages
#    that also include dynamic content you have to mount the whole
#    thing at another point in the URL space, so you can GET the
#    content without rendering the dynamic parts.  I don't actually
#    like using user agents -- I'd rather mount the same resources at
#    two different URLs -- but it's just an example of another kind of
#    dispatching that can be done at a higher level.

# ========================================================================
# RequestResolver
# ========================================================================

[docs]class RequestResolver(BaseMiddleware): def __init__(self, wsgidav_app, next_app, config): super().__init__(wsgidav_app, next_app, config)
[docs] def __call__(self, environ, start_response): path = environ["PATH_INFO"] # We want to answer OPTIONS(*), even if no handler was registered for # the top-level realm (e.g. required to map drive letters). provider = environ["wsgidav.provider"] config = environ["wsgidav.config"] hotfixes = util.get_dict_value(config, "hotfixes", as_dict=True) is_asterisk_options = environ["REQUEST_METHOD"] == "OPTIONS" and path == "*" if path == "/": # Hotfix for WinXP / Vista: accept '/' for a '*' treat_as_asterisk = hotfixes.get("treat_root_options_as_asterisk") if treat_as_asterisk: is_asterisk_options = True else:"Got OPTIONS '/' request") if is_asterisk_options: # Answer HTTP 'OPTIONS' method on server-level. # From RFC 2616: # If the Request-URI is an asterisk ("*"), the OPTIONS request is # intended to apply to the server in general rather than to a specific # resource. Since a server's communication options typically depend on # the resource, the "*" request is only useful as a "ping" or "no-op" # type of method; it does nothing beyond allowing the client to test the # capabilities of the server. For example, this can be used to test a # proxy for HTTP/1.1 compliance (or lack thereof). dav_compliance_level = "1,2" if ( provider is None or provider.is_readonly() or provider.lock_manager is None ): dav_compliance_level = "1" headers = [ ("Content-Type", "text/html; charset=utf-8"), ("Content-Length", "0"), ("DAV", dav_compliance_level), ("Date", util.get_rfc1123_time()), ] if environ["wsgidav.config"].get("add_header_MS_Author_Via", False): headers.append(("MS-Author-Via", "DAV")) start_response("200 OK", headers) yield b"" return if provider is None: raise DAVError( HTTP_NOT_FOUND, f"Could not find resource provider for {path!r}" ) # Let the appropriate resource provider for the realm handle the # request app = RequestServer(provider) app_iter = app(environ, start_response) for v in app_iter: yield v if hasattr(app_iter, "close"): app_iter.close() return