chrome/common/extensions/docs/server2/render_servlet.py

   1 # Copyright 2013 The Chromium Authors. All rights reserved.
   2 # Use of this source code is governed by a BSD-style license that can be
   3 # found in the LICENSE file.
   4
   5 import logging
   6 import posixpath
   7 import traceback
   8
   9 from environment import IsPreviewServer
  10 from file_system import FileNotFoundError
  11 from redirector import Redirector
  12 from servlet import Servlet, Response
  13 from third_party.handlebar import Handlebar
  14
  15
  16 def _MakeHeaders(content_type):
  17   return {
  18     'X-Frame-Options': 'sameorigin',
  19     'Content-Type': content_type,
  20     'Cache-Control': 'max-age=300',
  21   }
  22
  23
  24 class RenderServlet(Servlet):
  25   '''Servlet which renders templates.
  26   '''
  27
  28   class Delegate(object):
  29     def CreateServerInstance(self):
  30       raise NotImplementedError(self.__class__)
  31
  32   def __init__(self, request, delegate):
  33     Servlet.__init__(self, request)
  34     self._delegate = delegate
  35
  36   def Get(self):
  37     ''' Render the page for a request.
  38     '''
  39     # TODO(kalman): a consistent path syntax (even a Path class?) so that we
  40     # can stop being so conservative with stripping and adding back the '/'s.
  41     path = self._request.path.lstrip('/')
  42     server_instance = self._delegate.CreateServerInstance()
  43
  44     try:
  45       return self._GetSuccessResponse(path, server_instance)
  46     except FileNotFoundError:
  47       if IsPreviewServer():
  48         logging.error(traceback.format_exc())
  49       # Maybe it didn't find the file because its canonical location is
  50       # somewhere else; this is distinct from "redirects", which are typically
  51       # explicit. This is implicit.
  52       canonical_result = server_instance.path_canonicalizer.Canonicalize(path)
  53       redirect = canonical_result.path.lstrip('/')
  54       if path != redirect:
  55         return Response.Redirect('/' + redirect,
  56                                  permanent=canonical_result.permanent)
  57
  58       # Not found for reals. Find the closest 404.html file and serve that;
  59       # e.g. if the path is extensions/manifest/typo.html then first look for
  60       # extensions/manifest/404.html, then extensions/404.html, then 404.html.
  61       #
  62       # Failing that just print 'Not Found' but that should preferrably never
  63       # happen, because it would look really bad.
  64       path_components = path.split('/')
  65       for i in xrange(len(path_components) - 1, -1, -1):
  66         try:
  67           path_404 = posixpath.join(*(path_components[0:i] + ['404.html']))
  68           response = self._GetSuccessResponse(path_404, server_instance)
  69           return Response.NotFound(response.content.ToString(),
  70                                    headers=response.headers)
  71         except FileNotFoundError: continue
  72       logging.warning('No 404.html found in %s' % path)
  73       return Response.NotFound('Not Found', headers=_MakeHeaders('text/plain'))
  74
  75   def _GetSuccessResponse(self, path, server_instance):
  76     '''Returns the Response from trying to render |path| with
  77     |server_instance|.  If |path| isn't found then a FileNotFoundError will be
  78     raised, such that the only responses that will be returned from this method
  79     are Ok and Redirect.
  80     '''
  81     content_provider, path = (
  82         server_instance.content_providers.GetByServeFrom(path))
  83     assert content_provider, 'No ContentProvider found for %s' % path
  84
  85     redirect = Redirector(
  86         server_instance.compiled_fs_factory,
  87         content_provider.file_system).Redirect(self._request.host, path)
  88     if redirect is not None:
  89       return Response.Redirect(redirect, permanent=False)
  90
  91     content_and_type = content_provider.GetContentAndType(path).Get()
  92     if not content_and_type.content:
  93       logging.error('%s had empty content' % path)
  94
  95     content = content_and_type.content
  96     if isinstance(content, Handlebar):
  97       template_content, template_warnings = (
  98           server_instance.template_renderer.Render(content, self._request))
  99       # HACK: the Google ID thing (google2ed...) doesn't have a title.
 100       content, doc_warnings = server_instance.document_renderer.Render(
 101           template_content,
 102           render_title=path != 'google2ed1af765c529f57.html')
 103       warnings = template_warnings + doc_warnings
 104       if warnings:
 105         sep = '\n - '
 106         logging.warning('Rendering %s:%s%s' % (path, sep, sep.join(warnings)))
 107
 108     content_type = content_and_type.content_type
 109     if isinstance(content, unicode):
 110       content = content.encode('utf-8')
 111       content_type += '; charset=utf-8'
 112
 113     return Response.Ok(content, headers=_MakeHeaders(content_type))