Dynamically generate a heading for Extension Docs API pages

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

+# Copyright (c) 2013 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 json
+import logging
+
+import object_store
+
+class ChromeVersionDataSource:
+  """Generates and stores API data sources corresponding to the latest branch
+  number for a given version of Chrome.
+
+  Accesses data found on omahaproxy in order to link branch numbers to version
+  numbers.
+  """
+
+  def __init__(self,
+               base_path,
+               fetcher,
+               object_store,
+               create_api_data_source_for_branch):
+    self._base_path = base_path
+    self._fetcher = fetcher
+    self._object_store = object_store
+    self._create_api_data_source_for_branch = create_api_data_source_for_branch
+
+  def _GetBranchNumberForVersion(self, version_number):
+    """Returns the most recent branch number for a given chrome version number
+    using data stored on omahaproxy (see url_constants)
+    """
+    if version_number == 'trunk':
+      return 'trunk'
+
+    branch = self._object_store.Get(
+        version_number,
+        object_store.CHROME_VERSION_DATA_SOURCE).Get()
+
+    if branch is not None:
+      return branch
+
+    try:
+      version_json = json.loads(self._fetcher.Fetch(self._base_path).content)
+    except Exception as e:
+      # If omahaproxy is having problems, report it.
+      logging.error('Could not fetch data at Omaha Proxy: %s' % (e))
+      return None
+
+    # Here, entry['title'] looks like: 'title - version#.#.branch#.#'
+    for entry in version_json['events']:
+      version_title = entry['title'].split(' - ')[1].split('.')
+      if version_title[0] == version_number:
+        self._object_store.Set(version_number,
+                               version_title[2],
+                               object_store.CHROME_VERSION_DATA_SOURCE)
+        return version_title[2]
+    return None
+
+  def GetLatestVersionNumber(self):
+    try:
+      version_json = json.loads(self._fetcher.Fetch(self._base_path).content)
+    except Exception as e:
+      logging.error('Could not fetch data at Omaha Proxy: %s' % (e))
+      return None
+
+    latest_version = 0
+    for entry in version_json['events']:
+      version_title = entry['title'].split(' - ')[1].split('.')
+      version = int(version_title[0])
+      if version > latest_version:
+        latest_version = version
+    return latest_version
+
+  def GetDataSourceForVersion(self, version_number):
+    """Returns an api data source for the most recent branch number
+    corresponding to a given version number
+    """
+    branch_number = self._GetBranchNumberForVersion(version_number)
+    branch_api_data_source = self._create_api_data_source_for_branch(
+        branch_number)
+    return branch_api_data_source