reland "rebaseline_server: download actual-results.json files from GCS instead of SVN"

tools/pyutils/url_utils.py

Index: tools/pyutils/url_utils.py
diff --git a/tools/pyutils/url_utils.py b/tools/pyutils/url_utils.py
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+#!/usr/bin/python
+
+"""
+Copyright 2014 Google Inc.
+
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file.
+
+Utilities for working with URLs.
+
+TODO(epoger): move this into tools/utils for broader use?
+"""
+
+# System-level imports
+import contextlib
+import os
+import shutil
+import urllib
+import urlparse
+
+
+def create_filepath_url(filepath):
+  """ Returns a file:/// URL pointing at the given filepath on local disk.
+
+  Args:
+    filepath: string; path to a file on local disk (may be absolute or relative,
+        and the file does not need to exist)
+
+  Returns:
+    A file:/// URL pointing at the file.  Regardless of whether filepath was
+        specified as a relative or absolute path, the URL will contain an
+        absolute path to the file.
+
+  Raises:
+    An Exception, if filepath is already a URL.
+  """
+  if urlparse.urlparse(filepath).scheme:
+    raise Exception('"%s" is already a URL' % filepath)
+  return urlparse.urljoin(
+      'file:', urllib.pathname2url(os.path.abspath(filepath)))
+
+
+def copy_contents(source_url, dest_path, create_subdirs_if_needed=False):
+  """ Copies the full contents of the URL 'source_url' into
+  filepath 'dest_path'.
+
+  Args:
+    source_url: string; complete URL to read from
+    dest_path: string; complete filepath to write to (may be absolute or
+        relative)
+    create_subdirs_if_needed: boolean; whether to create subdirectories as
+        needed to create dest_path
+
+  Raises:
+    Some subclass of Exception if unable to read source_url or write dest_path.
+  """
+  if create_subdirs_if_needed:
+    dest_dir = os.path.dirname(dest_path)
+    if not os.path.exists(dest_dir):
+      os.makedirs(dest_dir)
+  with contextlib.closing(urllib.urlopen(source_url)) as source_handle:
+    with open(dest_path, 'wb') as dest_handle:
+      shutil.copyfileobj(fsrc=source_handle, fdst=dest_handle)