add file_document param to GridOut to initialize from existing file doc PYTHON-117

Author: Mike Dirolf

gridfs/grid_file.py

@@ -293,30 +293,38 @@ def __exit__(self, exc_type, exc_val, exc_tb):
 class GridOut(object):
  """Class to read data out of GridFS.
  """
- def __init__(self, root_collection, file_id):
+ def __init__(self, root_collection, file_id=None, file_document=None):
  """Read a file from GridFS
 
  Application developers should generally not need to
  instantiate this class directly - instead see the methods
  provided by :class:`~gridfs.GridFS`.
 
- Raises :class:`TypeError` if `root_collection` is not an instance of
+ Either `file_id` or `file_document` must be specified,
+ `file_document` will be given priority if present. Raises
+ :class:`TypeError` if `root_collection` is not an instance of
  :class:`~pymongo.collection.Collection`.
 
  :Parameters:
  - `root_collection`: root collection to read from
  - `file_id`: value of ``"_id"`` for the file to read
+ - `file_document`: file document from `root_collection.files`
+
+ .. versionadded:: 1.8.1+
+ The `file_document` parameter.
  """
  if not isinstance(root_collection, Collection):
  raise TypeError("root_collection must be an "
  "instance of Collection")
 
  self.__chunks = root_collection.chunks
- self._file = root_collection.files.find_one({"_id": file_id})
+
+ files = root_collection.files
+ self._file = file_document or files.find_one({"_id": file_id})
 
  if not self._file:
  raise NoFile("no file in gridfs collection %r with _id %r" %
- (root_collection, file_id))
+ (files, file_id))
 
  self.__buffer = ""
  self.__position = 0

test/test_grid_file.py

@@ -226,6 +226,19 @@ def test_grid_out_custom_opts(self):
  "upload_date", "aliases", "metadata", "md5"]:
  self.assertRaises(AttributeError, setattr, b, attr, 5)
 
+ def test_grid_out_file_document(self):
+ a = GridIn(self.db.fs)
+ a.write("foo bar")
+ a.close()
+
+ b = GridOut(self.db.fs, file_document=self.db.fs.files.find_one())
+ self.assertEqual("foo bar", b.read())
+
+ c = GridOut(self.db.fs, 5, file_document=self.db.fs.files.find_one())
+ self.assertEqual("foo bar", c.read())
+
+ self.assertRaises(NoFile, GridOut, self.db.fs, file_document={})
+
  def test_write_file_like(self):
  a = GridIn(self.db.fs)
  a.write("hello world")