Refactor the devserver to make it easier to control caching

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

 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 import logging
 
 from branch_utility import BranchUtility
 from docs_server_utils import FormatKey
 import compiled_file_system as compiled_fs
 from file_system import FileNotFoundError
 from third_party.handlebar import Handlebar
 import url_constants
 
-# Increment this if there are changes to the data stored about templates.
-_VERSION = 2
+# Increment this if the data model changes for TemplateDataSource.
+_VERSION = 3
 
 EXTENSIONS_URL = '/chrome/extensions'
 
 def _MakeChannelDict(channel_name):
   channel_dict = {
     'channels': [{'name': name} for name in BranchUtility.GetAllBranchNames()],
     'current': channel_name
   }
   for channel in channel_dict['channels']:
     if channel['name'] == channel_name:
@@ skipping 15 matching lines @@
   class Factory(object):
     """A factory to create lightweight TemplateDataSource instances bound to
     individual Requests.
     """
     def __init__(self,
                  channel_name,
                  api_data_source_factory,
                  api_list_data_source_factory,
                  intro_data_source_factory,
                  samples_data_source_factory,
-                 known_issues_data_source,
                  sidenav_data_source_factory,
-                 cache_factory,
+                 compiled_fs_factory,
                  ref_resolver_factory,
                  public_template_path,
                  private_template_path):
       self._branch_info = _MakeChannelDict(channel_name)
       self._api_data_source_factory = api_data_source_factory
       self._api_list_data_source_factory = api_list_data_source_factory
       self._intro_data_source_factory = intro_data_source_factory
       self._samples_data_source_factory = samples_data_source_factory
-      self._known_issues_data_source = known_issues_data_source
       self._sidenav_data_source_factory = sidenav_data_source_factory
-      self._cache = cache_factory.Create(self._CreateTemplate,
-                                         compiled_fs.HANDLEBAR,
-                                         version=_VERSION)
+      self._cache = compiled_fs_factory.Create(self._CreateTemplate,
+                                               TemplateDataSource,
+                                               version=_VERSION)
       self._ref_resolver = ref_resolver_factory.Create()
       self._public_template_path = public_template_path
       self._private_template_path = private_template_path
       self._static_resources = '/%s/static' % channel_name
 
     def _CreateTemplate(self, template_name, text):
       return Handlebar(self._ref_resolver.ResolveAllLinks(text))
 
     def Create(self, request, path):
       """Returns a new TemplateDataSource bound to |request|.
       """
       return TemplateDataSource(
           self._branch_info,
           self._api_data_source_factory.Create(request),
           self._api_list_data_source_factory.Create(),
           self._intro_data_source_factory.Create(),
           self._samples_data_source_factory.Create(request),
-          self._known_issues_data_source,
           self._sidenav_data_source_factory.Create(path),
           self._cache,
           self._public_template_path,
           self._private_template_path,
-          self._static_resources,
-          request)
+          self._static_resources)
 
   def __init__(self,
                branch_info,
                api_data_source,
                api_list_data_source,
                intro_data_source,
                samples_data_source,
-               known_issues_data_source,
                sidenav_data_source,
                cache,
                public_template_path,
                private_template_path,
-               static_resources,
-               request):
+               static_resources):
     self._branch_info = branch_info
     self._api_list_data_source = api_list_data_source
     self._intro_data_source = intro_data_source
     self._samples_data_source = samples_data_source
     self._api_data_source = api_data_source
-    self._known_issues_data_source = known_issues_data_source
     self._sidenav_data_source = sidenav_data_source
     self._cache = cache
     self._public_template_path = public_template_path
     self._private_template_path = private_template_path
     self._static_resources = static_resources
-    self._request = request
 
   def Render(self, template_name):
     """This method will render a template named |template_name|, fetching all
     the partial templates needed from |self._cache|. Partials are retrieved
     from the TemplateDataSource with the |get| method.
     """
     template = self.GetTemplate(self._public_template_path, template_name)
     if not template:
       return ''
       # TODO error handling
     render_data = template.render({
       'api_list': self._api_list_data_source,
       'apis': self._api_data_source,
       'branchInfo': self._branch_info,
       'intros': self._intro_data_source,
-      'known_issues': self._known_issues_data_source,
       'sidenavs': self._sidenav_data_source,
       'partials': self,
       'samples': self._samples_data_source,
       'static': self._static_resources,
       'app': 'app',
       'extension': 'extension',
       'apps_title': 'Apps',
       'extensions_title': 'Extensions',
       'apps_samples_url': url_constants.GITHUB_BASE,
       'extensions_samples_url': url_constants.EXTENSIONS_SAMPLES,
       'true': True,
       'false': False
     })
     if render_data.errors:
       logging.error('Handlebar error(s) rendering %s:\n%s' %
           (template_name, '  \n'.join(render_data.errors)))
     return render_data.text
 
   def get(self, key):
     return self.GetTemplate(self._private_template_path, key)
 
   def GetTemplate(self, base_path, template_name):
     real_path = FormatKey(template_name)
     try:
       return self._cache.GetFromFile(base_path + '/' + real_path)
     except FileNotFoundError as e:
       logging.info(e)
       return None