Merge pull request #49 from plone/preview-image-link

Added preview image link.

CHANGES.rst

@@ -80,6 +80,7 @@ Bug fixes:
 - Fix deprecated import of isDefaultPage
   [pbauer]
 
+
 4.0.0a3 (2022-02-04)
 --------------------
 

Makefile

@@ -75,6 +75,7 @@ black: bin/black ## Format codebase
 isort: bin/isort ## Format imports in the codebase
 	bin/isort $(CHECK_PATH)
 
+.PHONY: zpretty
 zpretty: bin/zpretty ## Format xml and zcml with zpretty
 	find "${PACKAGE_PATH}" -name '*.xml' | xargs bin/zpretty -x -i
 	find "${PACKAGE_PATH}" -name '*.zcml' | xargs bin/zpretty -z -i

README.rst

@@ -173,13 +173,13 @@ Plone). This will be fixed in core in upcoming sprints.
 Preview Image Behavior
 ----------------------
 
-The preview image behavior makes content types provide a preview_image field that can store a preview image that Volto views can pick up.
+The preview image behavior makes content types provide a ``preview_image`` field that can store a preview image that Volto views can pick up.
 This is especially userful for listings (e.g. listing block customizations) and teaser elements (e.g. teaser blocks such as [volto-blocks-grid](https://github.com/kitconcept/volto-blocks-grid)).
 
-The "volto.preview_image behavior can be enabled in the generic setup XML definition of a content type (e.g. "/profiles/default/types/MyContentType.xml")::
+The ``volto.preview_image`` behavior can be enabled in the generic setup XML definition of a content type (e.g. ``/profiles/default/types/MyContentType.xml``)::
 
    <?xml version="1.0" encoding="UTF-8" ?>
-   <object i18n:domain="fzj.internet" meta_type="Dexterity FTI" name="MyContentType"
+   <object i18n:domain="my.project" meta_type="Dexterity FTI" name="MyContentType"
      xmlns:i18n="http://xml.zope.org/namespaces/i18n">
 
      ...
@@ -192,6 +192,8 @@ The "volto.preview_image behavior can be enabled in the generic setup XML defini
      ...
    </object>
 
+There is also another variation of the preview image behavior called ``volto.preview_image_link``.
+This one stores preview images using a relation to an Image content type, rather than in an image field. This might be preferable if many content items use the same preview image.
 
 Navigation Title Behavior
 -------------------------

news/49.feature

@@ -0,0 +1,2 @@
+- Added preview image link behavior (Plone 6+ only)
+  [robgietema]

src/plone/volto/behaviors/configure.zcml

@@ -1,6 +1,7 @@
 <configure
     xmlns="http://namespaces.zope.org/zope"
     xmlns:plone="http://namespaces.plone.org/plone"
+    xmlns:zcml="http://namespaces.zope.org/zcml"
     i18n_domain="plone.volto"
     >
 
@@ -16,6 +17,16 @@
       provides=".preview.IPreview"
       />
 
+  <configure zcml:condition="have plone-60">
+    <plone:behavior
+        name="volto.preview_image_link"
+        title="Preview Image Link"
+        description="Preview image for listings based on links"
+        provides=".preview_link.IPreviewLink"
+        />
+    <adapter factory=".preview_link.PreviewImageScalesFieldAdapter" />
+  </configure>
+
   <plone:behavior
       name="volto.navtitle"
       title="Navigation title"

src/plone/volto/behaviors/preview_link.py

@@ -0,0 +1,71 @@
+# -*- coding: utf-8 -*-
+from plone import api
+from plone.app.z3cform.widget import RelatedItemsFieldWidget
+from plone.autoform import directives
+from plone.autoform.interfaces import IFormFieldProvider
+from plone.base.interfaces import IImageScalesFieldAdapter
+from plone.rfc822.interfaces import IPrimaryFieldInfo
+from plone.supermodel import model
+from plone.volto import _
+from z3c.form.util import getSpecification
+from z3c.relationfield.schema import RelationChoice
+from zope.component import adapter
+from zope.component import queryMultiAdapter
+from zope.interface import implementer
+from zope.interface import Interface
+from zope.interface import provider
+from zope.schema import TextLine
+
+
+@provider(IFormFieldProvider)
+class IPreviewLink(model.Schema):
+
+    preview_image_link = RelationChoice(
+        title=_("label_previewimage", default="Preview image"),
+        description=_(
+            "help_previewimage",
+            default="Select an image that will be used in listing and teaser blocks.",
+        ),
+        vocabulary="plone.app.vocabularies.Catalog",
+        required=False,
+    )
+
+    directives.widget(
+        "preview_image_link",
+        RelatedItemsFieldWidget,
+        frontendOptions={
+            "widget": "object_browser",
+            "widgetProps": {"mode": "image", "return": "single"},
+        },
+    )
+
+    preview_caption_link = TextLine(
+        title=_("Preview image caption"), description="", required=False
+    )
+
+
+@adapter(getSpecification(IPreviewLink["preview_image_link"]), Interface, Interface)
+@implementer(IImageScalesFieldAdapter)
+class PreviewImageScalesFieldAdapter:
+    """Get the image_scales for the preview_image_link field"""
+
+    def __init__(self, field, context, request):
+        self.field = field
+        self.context = context
+        self.request = request
+
+    def __call__(self):
+        value = self.field.get(self.context)
+        linked_image = value.to_object
+        primary_field = IPrimaryFieldInfo(linked_image).field
+        serializer = queryMultiAdapter(
+            (primary_field, linked_image, self.request), IImageScalesFieldAdapter
+        )
+        if serializer is not None:
+            values = serializer()
+            if values:
+                portal_url = api.portal.get().absolute_url()
+                base_path = linked_image.absolute_url().replace(portal_url, "")
+                for value in values:
+                    value["base_path"] = base_path
+            return values

src/plone/volto/indexers.py

@@ -10,7 +10,7 @@ def hasPreviewImage(obj):
     Indexer for knowing in a catalog search if a content with the IPreview behavior has
     a preview_image
     """
-    if obj.aq_base.preview_image:
+    if obj.aq_base.preview_image or obj.aq_base.preview_image_link:
         return True
     return False
 
@@ -23,6 +23,8 @@ def image_field_indexer(obj):
     image_field = ""
     if getattr(base_obj, "preview_image", False):
         image_field = "preview_image"
+    elif getattr(base_obj, "preview_image_link", False):
+        image_field = "preview_image_link"
     elif getattr(base_obj, "image", False):
         image_field = "image"
     return image_field

src/plone/volto/testing.py

@@ -17,6 +17,16 @@
 import plone.volto.coresandbox
 
 
+try:
+    from Products.CMFPlone.factory import PLONE60MARKER
+
+    PLONE60MARKER  # pyflakes
+except ImportError:
+    PLONE_6 = False
+else:
+    PLONE_6 = True
+
+
 class PloneVoltoCoreLayer(PloneSandboxLayer):
 
     defaultBases = (PLONE_APP_CONTENTTYPES_FIXTURE,)

src/plone/volto/tests/test_migrate_to_volto.py

@@ -6,6 +6,7 @@
 from plone.volto.content import FolderishDocument
 from plone.volto.content import FolderishEvent
 from plone.volto.content import FolderishNewsItem
+from plone.volto.testing import PLONE_6
 from plone.volto.testing import PLONE_VOLTO_MIGRATION_FUNCTIONAL_TESTING
 from Products.CMFPlone.utils import get_installer
 
@@ -14,16 +15,6 @@
 import unittest
 
 
-try:
-    from Products.CMFPlone.factory import PLONE60MARKER
-
-    PLONE60MARKER  # pyflakes
-except ImportError:
-    PLONE_6 = False
-else:
-    PLONE_6 = True
-
-
 @unittest.skipIf(
     not PLONE_6,
     "This test is only intended to run for Plone 6",

src/plone/volto/tests/test_preview_link_behavior.py

@@ -0,0 +1,50 @@
+# -*- coding: utf-8 -*-
+
+from plone.namedfile.file import NamedBlobImage
+from plone.restapi.interfaces import ISerializeToJsonSummary
+from plone.volto.testing import PLONE_6
+from plone.volto.testing import PLONE_VOLTO_CORE_INTEGRATION_TESTING
+from z3c.form.interfaces import IDataManager
+from zope.component import getMultiAdapter
+
+import unittest
+
+
+TEST_GIF = (
+    b"GIF89a\x01\x00\x01\x00\x00\xff\x00,\x00\x00\x00\x00\x01\x00\x01\x00\x00\x02\x00;"
+)
+
+
+@unittest.skipIf(
+    not PLONE_6,
+    "This test is only intended to run for Plone 6",
+)
+class TestPreviewLinkBehavior(unittest.TestCase):
+    layer = PLONE_VOLTO_CORE_INTEGRATION_TESTING
+
+    def setUp(self):
+        from plone.volto.behaviors.preview_link import IPreviewLink
+
+        self.app = self.layer["app"]
+        self.portal = self.layer["portal"]
+        self.request = self.layer["request"]
+        self.catalog = self.portal.portal_catalog
+
+        fti = self.portal.portal_types.Document
+        fti.behaviors += ("volto.preview_image_link",)
+
+        self.doc = self.portal[self.portal.invokeFactory("Document", id="doc1")]
+        self.image = self.portal[
+            self.portal.invokeFactory("Image", id="image-1", title="Target image")
+        ]
+        self.image.image = NamedBlobImage(data=TEST_GIF, filename="test.gif")
+        dm = getMultiAdapter(
+            (self.doc, IPreviewLink["preview_image_link"]), IDataManager
+        )
+        dm.set(self.image)
+        self.doc.reindexObject()
+
+    def test_image_scales_includes_preview_image_link(self):
+        brain = self.catalog(UID=self.doc.UID())[0]
+        summary = getMultiAdapter((brain, self.request), ISerializeToJsonSummary)()
+        self.assertIn("preview_image_link", summary["image_scales"])