Pass positional arguments to attachment render functions

This allows handling `{attachment slug link}` as a synonym for
`{attachment slug link=self}`.

pillar/shortcodes.py

@@ -194,7 +194,7 @@ class Attachment:
         except self.NotSupported as ex:
             return html_module.escape('{attachment %s}' % ex)
 
-        return self.render(file_doc, kwargs)
+        return self.render(file_doc, pargs, kwargs)
 
     def sdk_file(self, slug: str, node_properties: dict) -> pillarsdk.File:
         """Return the file document for the attachment with this slug."""
@@ -222,7 +222,9 @@ class Attachment:
         sdk_file = pillarsdk.File.find(object_id, api=api)
         return sdk_file
 
-    def render(self, sdk_file: pillarsdk.File, tag_args: dict) -> str:
+    def render(self, sdk_file: pillarsdk.File,
+               pargs: typing.List[str],
+               kwargs: typing.Dict[str, str]) -> str:
         file_renderers = {
             'image': self.render_image,
             'video': self.render_video,
@@ -230,21 +232,29 @@ class Attachment:
 
         mime_type_cat, _ = sdk_file.content_type.split('/', 1)
         renderer = file_renderers.get(mime_type_cat, self.render_generic)
-        return renderer(sdk_file, tag_args)
+        return renderer(sdk_file, pargs, kwargs)
 
-    def render_generic(self, sdk_file, tag_args):
+    def render_generic(self, sdk_file,
+                       pargs: typing.List[str],
+                       kwargs: typing.Dict[str, str]):
         import flask
         return flask.render_template('nodes/attachments/file_generic.html',
-                                     file=sdk_file, tag_args=tag_args)
+                                     file=sdk_file, tag_args=kwargs)
 
-    def render_image(self, sdk_file, tag_args):
+    def render_image(self, sdk_file,
+                     pargs: typing.List[str],
+                     kwargs: typing.Dict[str, str]):
         """Renders an image file."""
         import flask
+        if 'link' in pargs:
+            kwargs['link'] = 'self'
         variations = {var.size: var for var in sdk_file.variations}
         return flask.render_template('nodes/attachments/file_image.html',
-                                     file=sdk_file, vars=variations, tag_args=tag_args)
+                                     file=sdk_file, vars=variations, tag_args=kwargs)
 
-    def render_video(self, sdk_file, tag_args):
+    def render_video(self, sdk_file,
+                     pargs: typing.List[str],
+                     kwargs: typing.Dict[str, str]):
         """Renders a video file."""
         import flask
         try:
@@ -255,7 +265,7 @@ class Attachment:
             return flask.render_template('nodes/attachments/file_generic.html', file=sdk_file)
 
         return flask.render_template('nodes/attachments/file_video.html',
-                                     file=sdk_file, var=default_variation, tag_args=tag_args)
+                                     file=sdk_file, var=default_variation, tag_args=kwargs)
 
 
 def _get_parser() -> typing.Tuple[shortcodes.Parser, shortcodes.Parser]:

tests/test_shortcodes.py

@@ -155,3 +155,52 @@ class IFrameTest(AbstractPillarTest):
         with self.app.app_context():
             self.login_api_as(uid, roles=roles)
             self.assertEqual(expect, render(md))
+
+
+class AttachmentTest(AbstractPillarTest):
+    def test_image(self):
+        from pillar.shortcodes import render
+
+        oid, _ = self.ensure_file_exists(file_overrides={
+            'variations': [
+                {'format': 'jpg', 'height': 2048, 'width': 2048, 'length': 819569,
+                 'link': 'https://i.imgur.com/FmbuPNe.jpg',
+                 'content_type': 'image/jpeg',
+                 'md5': '--',
+                 'file_path': 'c2a5c897769ce1ef0eb10f8fa1c472bcb8e2d5a4-h.jpg',
+                 'size': 'l'},
+            ],
+            'filename': 'cute_kitten.jpg',
+        })
+        node_props = {
+            'attachments': {
+                'img': {'oid': oid},
+            }
+        }
+
+        # We have to get the file document again, because retrieving it via the
+        # API (which is what the shortcode rendering is doing) will change its
+        # link URL.
+        db_file = self.get(f'/api/files/{oid}').json()
+        link = db_file['variations'][0]['link']
+
+        with self.app.test_request_context():
+            self.assertEqual(
+                f'<a href="{link}"><img src="{link}" alt="cute_kitten.jpg"/></a>',
+                render('{attachment img link}', context=node_props).strip()
+            )
+            self.assertEqual(
+                f'<a href="{link}"><img src="{link}" alt="cute_kitten.jpg"/></a>',
+                render('{attachment img link=self}', context=node_props).strip()
+            )
+            self.assertEqual(
+                f'<img src="{link}" alt="cute_kitten.jpg"/>',
+                render('{attachment img}', context=node_props).strip()
+            )
+
+            tag_link = 'https://i.imgur.com/FmbuPNe.jpg'
+            self.assertEqual(
+                f'<a href="{tag_link}" target="_blank">'
+                f'<img src="{link}" alt="cute_kitten.jpg"/></a>',
+                render('{attachment img link=%r}' % tag_link, context=node_props).strip()
+            )