Docserver: Implement the content providers infrastructure, where a

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

+# Copyright 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.
+
+from HTMLParser import HTMLParser
+import mimetypes
+import logging
+import os
+
+from compiled_file_system import SingleFile
+from directory_zipper import DirectoryZipper
+from file_system import ToUnicode
+from future import Gettable, Future
+from third_party.handlebar import Handlebar
+
+
+class ContentInfo(object):

[Jeffrey Yasskin, 2013/11/04 21:21:18]

"TypedContent"? This isn't "Info" because it also includes the content.

[not at google - send to devlin, 2013/11/04 23:34:49]

Info can't include the content? I'd need to rename GetContentInfo.
GetTypedContent would be a weird name for that. GetContentAndType? So this could
be ContentAndType?

[Jeffrey Yasskin, 2013/11/04 23:45:21]

ContentAndType would be fine with me.

+  '''Return value from ContentProvider.GetContentInfo.
+  '''
+
+  def __init__(self, content, content_type):
+    self.content = content
+    self.content_type = content_type
+
+
+class ContentProvider(object):
+  '''Provides correctly typed content: templates for HTML, text for CSS, binary

[Jeffrey Yasskin, 2013/11/04 21:21:18]

"Provides" is too vague: through what interface does it provide stuff? What are
the actual types callers should expect? You're breaking static type discipline
here, so you need to document this really clearly.

Also mention how it knows the content type of the files (filename, I think).

[not at google - send to devlin, 2013/11/04 23:34:49]

Done.

+  for images, and so on.
+  '''
+
+  def __init__(self,
+               name,
+               compiled_fs_factory,
+               file_system,

[Jeffrey Yasskin, 2013/11/04 21:21:18]

Document the difference between file_system and host_file_system.

[not at google - send to devlin, 2013/11/04 23:34:49]

Good point. It's only used by the template cache though; I'll delete it for now,
then add a comment in the follow-up which uses template cache.

+               host_file_system,
+               supports_templates=False,
+               supports_zip=False):
+    # Public.
+    self.name = name
+    self.file_system = file_system
+    # Private.
+    self._template_cache = compiled_fs_factory.ForTemplates(host_file_system)

[Jeffrey Yasskin, 2013/11/04 21:21:18]

This isn't used.

[not at google - send to devlin, 2013/11/04 23:34:49]

Done.

+    self._content_cache = compiled_fs_factory.Create(file_system,
+                                                     self._CompileContent,
+                                                     ContentProvider)
+    self._supports_templates = supports_templates
+    if supports_zip:
+      self._directory_zipper = DirectoryZipper(compiled_fs_factory, file_system)
+    else:
+      self._directory_zipper = None
+
+  @SingleFile
+  def _CompileContent(self, path, text):
+    assert text is not None, path
+    mimetype = mimetypes.guess_type(path)[0]
+    if mimetype is None:
+      content = text
+      mimetype = 'text/plain'
+    elif mimetype == 'text/html':
+      content = ToUnicode(text)
+      if self._supports_templates:
+        content = Handlebar(content)
+    elif (mimetype.startswith('text/') or
+          mimetype in ('application/javascript', 'application/json')):
+      content = ToUnicode(text)
+    else:
+      content = text
+    return ContentInfo(content, mimetype)
+
+  def GetContentInfo(self, host, path):
+    path = path.lstrip('/')
+    base, ext = os.path.splitext(path)
+
+    # Check for a zip file first, if zip is enabled.
+    if self._directory_zipper and ext == '.zip':
+      zip_future = self._directory_zipper.Zip(base)
+      return Future(delegate=Gettable(
+          lambda: ContentInfo(zip_future.Get(), 'application/zip')))
+
+    return self._content_cache.GetFromFile(path, binary=True)
+
+  def Cron(self):
+    # TODO(kalman): Implement.
+    pass