Add scale_info parameter to _scale_url

news/199.feature

@@ -1,2 +1,2 @@
-Extract ``_scale_url()`` method on ``ImageScale`` and ``ImageScaling`` for overridable scale URL generation. This allows custom image backends (e.g. Thumbor) to generate direct URLs by overriding a single method.
+Extract ``_scale_url()`` method on ``ImageScale`` and ``ImageScaling`` for overridable scale URL generation. Accepts an optional ``scale_info`` dict with scale metadata (width, height, mode, fieldname, mimetype, etc.) so custom image backends (e.g. Thumbor) can generate URLs with full context by overriding a single method.
 @jensens

src/plone/namedfile/scaling.py

@@ -102,10 +102,10 @@ def __init__(self, context, request, **info):
         else:
             name = info["fieldname"]
         self.__name__ = f"{name}.{extension}"
-        self.url = self._scale_url(name, extension)
+        self.url = self._scale_url(name, extension, scale_info=info)
         self.srcset = info.get("srcset", [])
 
-    def _scale_url(self, uid, extension, base_url=None):
+    def _scale_url(self, uid, extension, base_url=None, scale_info=None):
         """Build the URL for an image scale.
 
         Override this method to generate custom scale URLs, e.g. for
@@ -115,6 +115,10 @@ def _scale_url(self, uid, extension, base_url=None):
         :param extension: The file extension (e.g. "jpeg", "png").
         :param base_url: The base URL of the content object.
             Defaults to ``self.context.absolute_url()``.
+        :param scale_info: Optional dict with scale metadata (width,
+            height, mode, fieldname, mimetype, etc.).  The contents
+            depend on the call site — ``__init__`` passes the full
+            info dict, ``srcset`` passes the ``pre_scale()`` result.
         :returns: The full URL to the image scale.
         """
         if base_url is None:
@@ -128,7 +132,7 @@ def srcset_attribute(self):
         _srcset_attr = []
         extension = self.data.contentType.split("/")[-1].lower()
         for scale in self.srcset:
-            url = self._scale_url(scale["uid"], extension)
+            url = self._scale_url(scale["uid"], extension, scale_info=scale)
             _srcset_attr.append(f"{url} {scale['scale']}x")
         srcset_attr = ", ".join(_srcset_attr)
         return srcset_attr
@@ -532,7 +536,7 @@ def available_sizes(self):
     def available_sizes(self, value):
         self._sizes = value
 
-    def _scale_url(self, uid, extension, base_url=None):
+    def _scale_url(self, uid, extension, base_url=None, scale_info=None):
         """Build the URL for an image scale.
 
         Override this method to generate custom scale URLs, e.g. for
@@ -542,6 +546,10 @@ def _scale_url(self, uid, extension, base_url=None):
         :param extension: The file extension (e.g. "jpeg", "png").
         :param base_url: The base URL of the content object.
             Defaults to ``self.context.absolute_url()``.
+        :param scale_info: Optional dict with scale metadata (width,
+            height, mode, fieldname, mimetype, etc.).  The contents
+            depend on the call site — ``srcset`` passes the
+            ``pre_scale()`` result.
         :returns: The full URL to the image scale.
         """
         if base_url is None:
@@ -804,7 +812,7 @@ def srcset(
             )
             if scale:
                 extension = scale["mimetype"].split("/")[-1].lower()
-                url = self._scale_url(scale["uid"], extension)
+                url = self._scale_url(scale["uid"], extension, scale_info=scale)
                 srcset_urls.append(f"{url} {scale['width']}w")
 
         # then get the urls of the scales that are smaller than the original
@@ -814,7 +822,7 @@ def srcset(
                     fieldname=fieldname, width=width, height=height, mode="scale"
                 )
                 extension = scale["mimetype"].split("/")[-1].lower()
-                url = self._scale_url(scale["uid"], extension)
+                url = self._scale_url(scale["uid"], extension, scale_info=scale)
                 srcset_urls.append(f"{url} {scale['width']}w")
 
         attributes = {}

src/plone/namedfile/tests/test_scaling.py

@@ -840,7 +840,7 @@ def test_image_scaling_scale_url_override(self):
         """Subclasses can override _scale_url to produce custom URLs."""
 
         class CustomScaling(ImageScaling):
-            def _scale_url(self, uid, extension, base_url=None):
+            def _scale_url(self, uid, extension, base_url=None, scale_info=None):
                 return f"https://thumbor.example.com/{uid}.{extension}"
 
         scaling = CustomScaling(self.item, None)
@@ -859,7 +859,7 @@ def test_image_scale_override(self):
         """A custom ImageScale subclass can override _scale_url."""
 
         class CustomImageScale(ImageScale):
-            def _scale_url(self, uid, extension, base_url=None):
+            def _scale_url(self, uid, extension, base_url=None, scale_info=None):
                 return f"https://cdn.example.com/{uid}.{extension}"
 
         class CustomScaling(ImageScaling):
@@ -869,11 +869,32 @@ class CustomScaling(ImageScaling):
         scale = scaling.scale("image", width=100, height=100, pre=True)
         self.assertTrue(scale.url.startswith("https://cdn.example.com/"))
 
+    def test_scale_info_passed_to_scale_url(self):
+        """_scale_url receives scale_info with metadata."""
+        captured = {}
+
+        class CustomImageScale(ImageScale):
+            def _scale_url(self, uid, extension, base_url=None, scale_info=None):
+                captured["scale_info"] = scale_info
+                return super()._scale_url(uid, extension, base_url, scale_info)
+
+        class CustomScaling(ImageScaling):
+            _scale_view_class = CustomImageScale
+
+        scaling = CustomScaling(self.item, None)
+        scale = scaling.scale("image", width=100, height=100, pre=True)
+        self.assertIsNotNone(scale)
+        info = captured["scale_info"]
+        self.assertIn("uid", info)
+        self.assertIn("width", info)
+        self.assertIn("height", info)
+        self.assertIn("fieldname", info)
+
     def test_srcset_uses_scale_url(self):
         """ImageScaling.srcset should use _scale_url for srcset URLs."""
 
         class CustomScaling(ImageScaling):
-            def _scale_url(self, uid, extension, base_url=None):
+            def _scale_url(self, uid, extension, base_url=None, scale_info=None):
                 return f"https://thumbor.example.com/{uid}.{extension}"
 
         scaling = CustomScaling(self.item, None)
@@ -886,6 +907,27 @@ def _scale_url(self, uid, extension, base_url=None):
         # The srcset attribute URLs should use the custom _scale_url
         self.assertIn("https://thumbor.example.com/", tag)
 
+    def test_srcset_passes_scale_info(self):
+        """ImageScaling.srcset passes scale_info to _scale_url."""
+        captured_infos = []
+
+        class CustomScaling(ImageScaling):
+            def _scale_url(self, uid, extension, base_url=None, scale_info=None):
+                captured_infos.append(scale_info)
+                return super()._scale_url(uid, extension, base_url, scale_info)
+
+        scaling = CustomScaling(self.item, None)
+        scaling.available_sizes = {
+            "mini": (200, 65536),
+            "thumb": (128, 128),
+        }
+        scaling.srcset("image", sizes="100vw", scale_in_src="mini")
+        self.assertTrue(len(captured_infos) > 0)
+        for info in captured_infos:
+            self.assertIsNotNone(info)
+            self.assertIn("uid", info)
+            self.assertIn("width", info)
+
 
 class TestImgSrcSet(unittest.TestCase):