add support for pymongo 4.x

docs/index.rst

@@ -182,7 +182,7 @@ History and Contributors
 
 Changes:
 
-- 2.4.0: Unreleased
+- 3.0.0: Unreleased
 
   - `#125 <https://github.com/dcrosta/flask-pymongo/pull/125>`_ Drop
     MongoDB 3.2 support.
@@ -191,8 +191,12 @@ Changes:
   - `#62 <https://github.com/dcrosta/flask-pymongo/issues/62>`_ Add
     support for :func:`~flask.json.jsonify()`.
   - `#131 <https://github.com/dcrosta/flask-pymongo/pulls/131>`_ Drop
-    support for Flask 0.11 and Python 3.4; Add support for MongoDB 4.2,
-    PyMongo 3.9, and Flask 1.1.
+    support for Flask 0.11 and Python < 3.8; Change test matrix to test
+    latest MongoDB 4.x, 5.x, 6.x series
+  - Support conditional GET with explicit ETag value passed in to
+    ``save_file``; MongoDB has dropped support for automatic MD5 generation
+    in GridFS
+
 
 - 2.3.0: April 24, 2019
 

flask_pymongo/__init__.py

@@ -118,12 +118,15 @@ def init_app(self, app, uri=None, *args, **kwargs):
         app.json_encoder = self._json_encoder
 
     # view helpers
-    def send_file(self, filename, base="fs", version=-1, cache_for=31536000):
+    def send_file(self, filename, base="fs", version=-1, cache_for=31536000):  # noqa: C901, E501
         """Respond with a file from GridFS.
 
         Returns an instance of the :attr:`~flask.Flask.response_class`
         containing the named file, and implement conditional GET semantics
         (using :meth:`~werkzeug.wrappers.ETagResponseMixin.make_conditional`).
+        Conditional GET with ``If-Match`` is supported using the ``etag`` key
+        of the grid file's ``metadata`` dict, or the file's ``md5`` attribute,
+        if present.
 
         .. code-block:: python
 
@@ -163,13 +166,24 @@ def get_upload(filename):
         )
         response.content_length = fileobj.length
         response.last_modified = fileobj.upload_date
-        response.set_etag(fileobj.md5)
+        if fileobj.metadata and fileobj.metadata.get("etag"):
+            response.set_etag(fileobj.metadata["etag"])
+        elif fileobj.md5:
+            response.set_etag(fileobj.md5)
         response.cache_control.max_age = cache_for
         response.cache_control.public = True
         response.make_conditional(request)
         return response
 
-    def save_file(self, filename, fileobj, base="fs", content_type=None, **kwargs):
+    def save_file(
+        self,
+        filename,
+        fileobj,
+        base="fs",
+        content_type=None,
+        etag=None,
+        **kwargs,
+    ):
         """Save a file-like object to GridFS using the given filename.
 
         .. code-block:: python
@@ -185,6 +199,9 @@ def save_upload(filename):
         :param str content_type: the MIME content-type of the file. If
            ``None``, the content-type is guessed from the filename using
            :func:`~mimetypes.guess_type`
+        :param str etag: value to be used for HTTP entity tags in support
+            of conditional ``GET``. See `ETag on MDN
+            <https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/ETag>`_.
         :param kwargs: extra attributes to be stored in the file's document,
            passed directly to :meth:`gridfs.GridFS.put`
         """
@@ -196,6 +213,10 @@ def save_upload(filename):
         if content_type is None:
             content_type, _ = guess_type(filename)
 
+        if etag:
+            kwargs.setdefault("metadata", {})
+            kwargs["metadata"]["etag"] = etag
+
         storage = GridFS(self.db, base)
         id = storage.put(fileobj, filename=filename, content_type=content_type, **kwargs)
         return id

flask_pymongo/tests/test_gridfs.py

@@ -63,7 +63,8 @@ def setUp(self):
 
         # make it bigger than 1 gridfs chunk
         self.myfile = BytesIO(b"a" * 500 * 1024)
-        self.mongo.save_file("myfile.txt", self.myfile)
+        self.etag = md5(self.myfile.getvalue()).hexdigest()
+        self.mongo.save_file("myfile.txt", self.myfile, etag=self.etag)
 
     def test_it_404s_for_missing_files(self):
         with pytest.raises(NotFound):
@@ -77,19 +78,36 @@ def test_it_sets_content_length(self):
         resp = self.mongo.send_file("myfile.txt")
         assert resp.content_length == len(self.myfile.getvalue())
 
-    def test_it_sets_supports_conditional_gets(self):
+    def test_it_sets_supports_conditional_gets_from_etag(self):
         # a basic conditional GET
         environ_args = {
             "method": "GET",
             "headers": {
-                "If-None-Match": md5(self.myfile.getvalue()).hexdigest(),
+                "If-None-Match": self.etag,
             },
         }
 
         with self.app.test_request_context(**environ_args):
             resp = self.mongo.send_file("myfile.txt")
             assert resp.status_code == 304
 
+    def test_it_sets_supports_conditional_gets_from_md5(self):
+        myfile = BytesIO(b"hello world")
+        etag = md5(myfile.getvalue()).hexdigest()
+        self.mongo.save_file("myfile-md5.txt", myfile, md5=etag)
+
+        # a basic conditional GET
+        environ_args = {
+            "method": "GET",
+            "headers": {
+                "If-None-Match": etag,
+            },
+        }
+
+        with self.app.test_request_context(**environ_args):
+            resp = self.mongo.send_file("myfile-md5.txt")
+            assert resp.status_code == 304
+
     def test_it_sets_cache_headers(self):
         resp = self.mongo.send_file("myfile.txt", cache_for=60)
         assert resp.cache_control.max_age == 60

tox.ini

@@ -1,8 +1,7 @@
 [tox]
 
-; pymongo{311,312,40,41,42,43}-mongo{4x,5x,6x}-flask{10,11,2x}, style
 envlist=
-    pymongo{311,312}-mongo{4x,5x,6x}-flask{10,11,2x}, style
+    pymongo{311,312,40,41,42,43}-mongo{4x,5x,6x}-flask{10,11,2x}, style
 
 [testenv]
 docker =
@@ -28,7 +27,7 @@ deps =
     flask2x:   flask>=2.0,<3.0
 
 commands =
-    {envbindir}/py.test --tb=native {toxinidir}
+    py.test --tb=native {toxinidir}/flask_pymongo {posargs}
 
 [testenv:style]
 skipsdist = true