Fix the loss of JSON types when using multipart/form-data

To pass a binary blob in a POST request, browser sets the header
'Content-Type: multipart/form-data', which in turn causes all form
fields' values to be passed as strings. Circumvent this by storing
original field values as a JSON string on client-side and decoding it
on server-side. As a result the setting HORIZON_IMAGES_UPLOAD_MODE =
'legacy' will start working together with Glance V2.

Closes-Bug: #1613703
Change-Id: I53a8fbba15e4c3c6c17d6ef1ffe701634efda149

horizon/static/framework/util/http/http.js

@@ -57,6 +57,9 @@ limitations under the License.
         for (var key in config.data) {
           if (config.data.hasOwnProperty(key) && uploadService.isFile(config.data[key])) {
             backend = uploadService.upload;
+            // NOTE(tsufiev): keeping the original JSON to not lose value types
+            // after sending them all as strings via multipart/form-data
+            config.data.$$originalJSON = JSON.stringify(config.data);
             break;
           }
         }

horizon/static/framework/util/http/http.spec.js

@@ -128,7 +128,10 @@
       it('upload() is used when there is a File() blob inside data', function () {
         api.post('/good', {first: file, second: 'the data'});
         expect(Upload.upload).toHaveBeenCalled();
-        expect(called.config.data).toEqual({first: file, second: 'the data'});
+
+        var expected = {first: file, second: 'the data'};
+        expected.$$originalJSON = JSON.stringify(expected);
+        expect(called.config.data).toEqual(expected);
       });
 
       it('upload() is NOT used when a File() blob is passed as data', function () {

openstack_dashboard/api/rest/glance.py

@@ -170,14 +170,15 @@ class Images(generic.View):
 
     # note: not an AJAX request - the body will be raw file content mixed with
     # metadata
+    @rest_utils.post2data
     @csrf_exempt
     def post(self, request):
-        form = UploadObjectForm(request.POST, request.FILES)
+        form = UploadObjectForm(request.DATA, request.FILES)
         if not form.is_valid():
             raise rest_utils.AjaxError(500, 'Invalid request')
 
         data = form.clean()
-        meta = create_image_metadata(request.POST)
+        meta = create_image_metadata(request.DATA)
         meta['data'] = data['data']
 
         image = api.glance.image_create(request, **meta)

openstack_dashboard/api/rest/utils.py

@@ -163,3 +163,20 @@ def parse_filters_kwargs(request, client_keywords=None):
         else:
             filters[param] = request.GET[param]
     return filters, kwargs
+
+
+def post2data(func):
+    """The sole purpose of this decorator is to restore original form values
+    along with their types stored on client-side under key $$originalJSON.
+    This in turn prevents the loss of field types when they are passed with
+    header 'Content-Type: multipart/form-data', which is needed to pass a
+    binary blob as a part of POST request.
+    """
+    def wrapper(self, request):
+        request.DATA = request.POST
+        if '$$originalJSON' in request.POST:
+            request.DATA = json.loads(request.POST['$$originalJSON'])
+
+        return func(self, request)
+
+    return wrapper