Extensions Docs Server: Apps samples page

chrome/common/extensions/docs/server2/github_file_system.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 json
+import os
+
+import appengine_blobstore as blobstore
+import appengine_memcache as memcache
+import file_system
+from io import BytesIO
+from future import Future
+from zipfile import ZipFile
+
+ZIP_KEY = 'zipball'
+
+def _MakeKey(version):
+  return ZIP_KEY + '.' + str(version)
+
+class _AsyncFetchFutureZip(object):
+  def __init__(self, fetcher, blobstore, new_version, old_version):
+    self._fetch = fetcher.FetchAsync(ZIP_KEY)
+    self._blobstore = blobstore
+    self._new_version = new_version
+    self._old_version = old_version
+
+  def Get(self):
+    blob = self._fetch.Get().content
+    self._blobstore.Set(_MakeKey(self._new_version),
+                        blob,
+                        blobstore.BLOBSTORE_GITHUB)
+    self._blobstore.Delete(_MakeKey(self._old_version),
+                           blobstore.BLOBSTORE_GITHUB)
+    return ZipFile(BytesIO(blob))
+
+class GithubFileSystem(file_system.FileSystem):
+  """FileSystem implementation which fetches resources from github.
+  """
+  def __init__(self, fetcher, memcache, blobstore):
+    self._fetcher = fetcher
+    self._memcache = memcache
+    self._blobstore = blobstore
+    self._version = self.Stat(ZIP_KEY).version
+    self._GetZip(self._version)
+
+  def _GetZip(self, version):
+    blob = self._blobstore.Get(_MakeKey(version), blobstore.BLOBSTORE_GITHUB)
+    if blob is not None:
+      self._zip_file = Future(value=ZipFile(BytesIO(blob)))
+    else:
+      self._zip_file = Future(delegate=_AsyncFetchFutureZip(self._fetcher,
+                                                            self._blobstore,
+                                                            version,
+                                                            self._version))
+    self._version = version
+
+  def _ReadFile(self, path):
+    zip_file = self._zip_file.Get()
+    prefix = zip_file.namelist()[0][:-1]
+    return zip_file.read(prefix + path)
+
+  def _ListDir(self, path):
+    filenames = self._zip_file.Get().namelist()
+    # Take out parent directory name (GoogleChrome-chrome-app-samples-c78a30f)
+    filenames = [f[len(filenames[0]) - 1:] for f in filenames]
+    # Remove the path of the directory we're listing from the filenames.
+    filenames = [f[len(path):] for f in filenames
+                 if f != path and f.startswith(path)]
+    # Remove all files not directly in this directory.
+    return [f for f in filenames if f[:-1].count('/') == 0]
+
+  def Read(self, paths, binary=False):
+    version = self.Stat(ZIP_KEY).version
+    if version != self._version:
+      self._GetZip(version)
+    result = {}
+    for path in paths:
+      if path.endswith('/'):
+        result[path] = self._ListDir(path)
+      else:
+        result[path] = self._ReadFile(path)
+    return Future(value=result)
+
+  def Stat(self, path):
+    version = self._memcache.Get(path, memcache.MEMCACHE_GITHUB_STAT)
+    if version is not None:
+      return self.StatInfo(version)
+    version = json.loads(
+        self._fetcher.Fetch('commits/HEAD').content)['commit']['tree']['sha']
+    self._memcache.Set(path, version, memcache.MEMCACHE_GITHUB_STAT)
+    return self.StatInfo(version)