vcs middleware: Fix up TODO note

Add more context to the existing TODO note.

rhodecode/lib/middleware/vcs.py

@@ -1,197 +1,198 b''
 # -*- coding: utf-8 -*-
 
 # Copyright (C) 2010-2016  RhodeCode GmbH
 #
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU Affero General Public License, version 3
 # (only), as published by the Free Software Foundation.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU Affero General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 #
 # This program is dual-licensed. If you wish to learn more about the
 # RhodeCode Enterprise Edition, including its added features, Support services,
 # and proprietary license terms, please see https://rhodecode.com/licenses/
 
 import gzip
 import shutil
 import logging
 import tempfile
 import urlparse
 
 from webob.exc import HTTPNotFound
 
 import rhodecode
 from rhodecode.lib.middleware.appenlight import wrap_in_appenlight_if_enabled
 from rhodecode.lib.middleware.simplegit import SimpleGit, GIT_PROTO_PAT
 from rhodecode.lib.middleware.simplehg import SimpleHg
 from rhodecode.lib.middleware.simplesvn import SimpleSvn
 from rhodecode.model.settings import VcsSettingsModel
 
 log = logging.getLogger(__name__)
 
 
 def is_git(environ):
     """
     Returns True if requests should be handled by GIT wsgi middleware
     """
     is_git_path = GIT_PROTO_PAT.match(environ['PATH_INFO'])
     log.debug(
         'request path: `%s` detected as GIT PROTOCOL %s', environ['PATH_INFO'],
         is_git_path is not None)
 
     return is_git_path
 
 
 def is_hg(environ):
     """
     Returns True if requests target is mercurial server - header
     ``HTTP_ACCEPT`` of such request would start with ``application/mercurial``.
     """
     is_hg_path = False
 
     http_accept = environ.get('HTTP_ACCEPT')
 
     if http_accept and http_accept.startswith('application/mercurial'):
         query = urlparse.parse_qs(environ['QUERY_STRING'])
         if 'cmd' in query:
             is_hg_path = True
 
     log.debug(
         'request path: `%s` detected as HG PROTOCOL %s', environ['PATH_INFO'],
         is_hg_path)
 
     return is_hg_path
 
 
 def is_svn(environ):
     """
     Returns True if requests target is Subversion server
     """
     http_dav = environ.get('HTTP_DAV', '')
     magic_path_segment = rhodecode.CONFIG.get(
         'rhodecode_subversion_magic_path', '/!svn')
     is_svn_path = (
         'subversion' in http_dav or
         magic_path_segment in environ['PATH_INFO'])
     log.debug(
         'request path: `%s` detected as SVN PROTOCOL %s', environ['PATH_INFO'],
         is_svn_path)
 
     return is_svn_path
 
 
 class GunzipMiddleware(object):
     """
     WSGI middleware that unzips gzip-encoded requests before
     passing on to the underlying application.
     """
 
     def __init__(self, application):
         self.app = application
 
     def __call__(self, environ, start_response):
         accepts_encoding_header = environ.get('HTTP_CONTENT_ENCODING', b'')
 
         if b'gzip' in accepts_encoding_header:
             log.debug('gzip detected, now running gunzip wrapper')
             wsgi_input = environ['wsgi.input']
 
             if not hasattr(environ['wsgi.input'], 'seek'):
                 # The gzip implementation in the standard library of Python 2.x
                 # requires the '.seek()' and '.tell()' methods to be available
                 # on the input stream.  Read the data into a temporary file to
                 # work around this limitation.
 
                 wsgi_input = tempfile.SpooledTemporaryFile(64 * 1024 * 1024)
                 shutil.copyfileobj(environ['wsgi.input'], wsgi_input)
                 wsgi_input.seek(0)
 
             environ['wsgi.input'] = gzip.GzipFile(fileobj=wsgi_input, mode='r')
             # since we "Ungzipped" the content we say now it's no longer gzip
             # content encoding
             del environ['HTTP_CONTENT_ENCODING']
 
             # content length has changes ? or i'm not sure
             if 'CONTENT_LENGTH' in environ:
                 del environ['CONTENT_LENGTH']
         else:
             log.debug('content not gzipped, gzipMiddleware passing '
                       'request further')
         return self.app(environ, start_response)
 
 
 class VCSMiddleware(object):
 
     def __init__(self, app, config, appenlight_client, registry):
         self.application = app
         self.config = config
         self.appenlight_client = appenlight_client
         self.registry = registry
         self.use_gzip = True
         # order in which we check the middlewares, based on vcs.backends config
         self.check_middlewares = config['vcs.backends']
         self.checks = {
             'hg': (is_hg, SimpleHg),
             'git': (is_git, SimpleGit),
             'svn': (is_svn, SimpleSvn),
         }
 
     def vcs_config(self, repo_name=None):
         """
         returns serialized VcsSettings
         """
         return VcsSettingsModel(repo=repo_name).get_ui_settings_as_config_obj()
 
     def wrap_in_gzip_if_enabled(self, app, config):
         if self.use_gzip:
             app = GunzipMiddleware(app)
         return app
 
     def _get_handler_app(self, environ):
         app = None
         log.debug('Checking vcs types in order: %r', self.check_middlewares)
         for vcs_type in self.check_middlewares:
             vcs_check, handler = self.checks[vcs_type]
             if vcs_check(environ):
                 log.debug(
                     'Found VCS Middleware to handle the request %s', handler)
                 app = handler(self.application, self.config, self.registry)
                 break
 
         return app
 
     def __call__(self, environ, start_response):
         # check if we handle one of interesting protocols, optionally extract
         # specific vcsSettings and allow changes of how things are wrapped
         vcs_handler = self._get_handler_app(environ)
         if vcs_handler:
             # translate the _REPO_ID into real repo NAME for usage
             # in middleware
             environ['PATH_INFO'] = vcs_handler._get_by_id(environ['PATH_INFO'])
             repo_name = vcs_handler._get_repository_name(environ)
 
             # check for type, presence in database and on filesystem
             if not vcs_handler.is_valid_and_existing_repo(
                     repo_name, vcs_handler.basepath, vcs_handler.SCM):
                 return HTTPNotFound()(environ, start_response)
 
-            # TODO(marcink): this is probably not needed anymore
+            # TODO: johbo: Needed for the Pyro4 backend and Mercurial only.
+            # Remove once we fully switched to the HTTP backend.
             environ['REPO_NAME'] = repo_name
 
             # register repo_name and it's config back to the handler
             vcs_handler.repo_name = repo_name
             vcs_handler.repo_vcs_config = self.vcs_config(repo_name)
 
             vcs_handler = self.wrap_in_gzip_if_enabled(
                 vcs_handler, self.config)
             vcs_handler, _ = wrap_in_appenlight_if_enabled(
                 vcs_handler, self.config, self.appenlight_client)
             return vcs_handler(environ, start_response)
 
         return self.application(environ, start_response)