From 045238995178d1eacc4e8438028f44d0aa5e6115 Mon Sep 17 00:00:00 2001
From: Lorenz Padberg <lorenz.padberg@iterativ.ch>
Date: Tue, 30 Apr 2024 13:55:32 +0200
Subject: [PATCH] Refactor Wagtail Images to srcset

---
 .../components/content-blocks/ImageBlock.vue  |  3 +-
 .../content-blocks/ImageUrlBlock.vue          |  2 +-
 client/src/components/modules/Module.vue      |  3 +
 .../src/components/modules/ModuleTeaser.vue   |  1 +
 client/src/components/ui/WagtailImage.vue     | 59 ++++++++++---------
 .../gql/fragments/wagtailImageParts.gql       |  1 +
 server/api/graphene_wagtail.py                |  8 ++-
 server/books/schema/nodes/wagtail_image.py    | 23 ++++++--
 server/core/urls.py                           |  6 +-
 server/core/views.py                          | 49 +--------------
 10 files changed, 65 insertions(+), 90 deletions(-)

diff --git a/client/src/components/content-blocks/ImageBlock.vue b/client/src/components/content-blocks/ImageBlock.vue
index 59683de4..df9d59ff 100644
--- a/client/src/components/content-blocks/ImageBlock.vue
+++ b/client/src/components/content-blocks/ImageBlock.vue
@@ -1,6 +1,7 @@
 <template>
   <wagtail-image
     :src="value.src"
+    :srcset="value.srcset"
     alt=""
     :original-height="value.height"
     :original-width="value.width"
@@ -17,7 +18,7 @@ export default {
   components: { WagtailImage },
   methods: {
     openFullscreen() {
-      this.$store.dispatch('showFullscreenImage', this.value.url);
+      this.$store.dispatch('showFullscreenImage', this.value.src);
     },
   },
 };
diff --git a/client/src/components/content-blocks/ImageUrlBlock.vue b/client/src/components/content-blocks/ImageUrlBlock.vue
index c53afdd8..6dd6e37d 100644
--- a/client/src/components/content-blocks/ImageUrlBlock.vue
+++ b/client/src/components/content-blocks/ImageUrlBlock.vue
@@ -20,7 +20,7 @@ export default {
           '-/resize/800/ 800w,'
         );
       }
-      return '';
+      return this.value.url;
     },
   },
   methods: {
diff --git a/client/src/components/modules/Module.vue b/client/src/components/modules/Module.vue
index 7f97b2b8..581ac3c1 100644
--- a/client/src/components/modules/Module.vue
+++ b/client/src/components/modules/Module.vue
@@ -31,9 +31,12 @@
       <wagtail-image
         class="module__hero-image"
         :src="module.heroImage.src"
+        :srcset="module.heroImage.srcset"
         :original-width="module.heroImage.width"
         :original-height="module.heroImage.height"
       ></wagtail-image>
+
+
       <h5
         class="module__hero-source"
         v-if="module.heroSource"
diff --git a/client/src/components/modules/ModuleTeaser.vue b/client/src/components/modules/ModuleTeaser.vue
index d130a944..03b2bc40 100644
--- a/client/src/components/modules/ModuleTeaser.vue
+++ b/client/src/components/modules/ModuleTeaser.vue
@@ -6,6 +6,7 @@
     <wagtail-image
       class="module-teaser__image"
       :src="heroImage.src"
+      :srcset="heroImage.srcset"
       :original-height="heroImage.height"
       :original-width="heroImage.width"
     ></wagtail-image>
diff --git a/client/src/components/ui/WagtailImage.vue b/client/src/components/ui/WagtailImage.vue
index 6f68da4a..3d77a43e 100644
--- a/client/src/components/ui/WagtailImage.vue
+++ b/client/src/components/ui/WagtailImage.vue
@@ -1,9 +1,11 @@
 <template>
   <div class="wagtail-image">
     <img
-      :src="modifiedUrl"
+      :src="props.src"
+      :srcset="props.srcset"
       :alt="alt"
       :class="['wagtail-image__image', { loaded: loaded }]"
+      :sizes="computedSizes"
       loading="eager"
       v-show="loaded"
       ref="imgElement"
@@ -16,15 +18,15 @@
     ></div>
   </div>
 </template>
-
 <script setup>
-import { ref, computed, onMounted } from 'vue';
+import { ref, computed, onMounted, onBeforeUnmount } from 'vue';
 
 const props = defineProps({
   src: String,
   alt: String(''),
   originalWidth: Number,
   originalHeight: Number,
+  srcset: String,
 });
 
 const imgElement = ref(null);
@@ -32,19 +34,6 @@ const width = ref(0);
 const height = ref(0);
 const loaded = ref(false);
 
-const modifiedUrl = computed(() => {
-  const density = isHighDensity() ? 2 : 1;
-
-  if (width.value) {
-    return props.src.replace('original', 'width-' + width.value * density);
-  }
-  if (height.value) {
-    return props.src.replace('original', 'height-' + height.value * density);
-  }
-
-  return props.src;
-});
-
 const updateDimensions = () => {
   if (imgElement.value && imgElement.value.parentElement) {
     const { clientWidth, clientHeight } = imgElement.value.parentElement;
@@ -57,6 +46,23 @@ const handleLoad = () => {
   loaded.value = true; // Set loaded to true when the image loads
 };
 
+const computedSizes = computed(() => {
+  // the default set of image sizes is [160px, 320px, 800px, 1600px]
+  let size;
+
+  if (width.value <= 300) {
+    size = '160px';
+  } else if (300 < width.value && width.value <= 600) {
+    size = '320px';
+  } else if (600 < width.value && width.value <= 1200) {
+    size = '800px';
+  } else {
+    size = '100vw';
+  }
+  console.log(size, width.value);
+  return size;
+});
+
 const placeholderStyle = computed(() => {
   const styles = {
     width: '100%',
@@ -77,20 +83,15 @@ const placeholderStyle = computed(() => {
   return styles;
 });
 
-const isHighDensity = () => {
-  return (
-    (window.matchMedia &&
-      (window.matchMedia(
-        'only screen and (min-resolution: 124dpi), only screen and (min-resolution: 1.3dppx), only screen and (min-resolution: 48.8dpcm)'
-      ).matches ||
-        window.matchMedia(
-          'only screen and (-webkit-min-device-pixel-ratio: 1.3), only screen and (-o-min-device-pixel-ratio: 2.6/2), only screen and (min--moz-device-pixel-ratio: 1.3), only screen and (min-device-pixel-ratio: 1.3)'
-        ).matches)) ||
-    (window.devicePixelRatio && window.devicePixelRatio > 1.3)
-  );
-};
+onMounted(() => {
+  console.log('src set', props.srcset);
+  updateDimensions();
+  window.addEventListener('resize', updateDimensions);
+});
 
-onMounted(updateDimensions);
+onBeforeUnmount(() => {
+  window.removeEventListener('resize', updateDimensions);
+});
 </script>
 
 <style scoped lang="scss">
diff --git a/client/src/graphql/gql/fragments/wagtailImageParts.gql b/client/src/graphql/gql/fragments/wagtailImageParts.gql
index 2895fe0e..f171ad49 100644
--- a/client/src/graphql/gql/fragments/wagtailImageParts.gql
+++ b/client/src/graphql/gql/fragments/wagtailImageParts.gql
@@ -5,4 +5,5 @@ fragment WagtailImageParts on WagtailImageNode {
     width
     height
     title
+    srcset
   }
diff --git a/server/api/graphene_wagtail.py b/server/api/graphene_wagtail.py
index b39a152c..11a92f2b 100644
--- a/server/api/graphene_wagtail.py
+++ b/server/api/graphene_wagtail.py
@@ -6,7 +6,6 @@ from graphene.types import Scalar
 from graphene_django.converter import convert_django_field
 from graphql_relay import to_global_id
 from wagtail.fields import StreamField
-from wagtail.documents.models import Document
 from wagtail.images.models import Image
 
 from assignments.models import Assignment
@@ -14,6 +13,7 @@ from basicknowledge.models import BasicKnowledge
 from books.models import CustomDocument
 from surveys.models import Survey
 
+
 logger = logging.getLogger(__name__)
 
 
@@ -43,17 +43,19 @@ def get_document_json(document_id):
 
 
 def get_wagtail_image_dict(image_id: int) -> dict | None:
-    """"""
+    from books.schema.nodes import get_srcset, get_src
+
     try:
         image = Image.objects.get(id=image_id)
         value = {
             'value': image_id,
             'id': image.id,
-            'src': generate_image_url(image, 'original'),
+            'src': get_src(image),
             'alt': image.title,
             'title': image.title,
             'width': image.width,
             'height': image.height,
+            'srcset': get_srcset(image),
         }
         return value
     except Image.DoesNotExist:
diff --git a/server/books/schema/nodes/wagtail_image.py b/server/books/schema/nodes/wagtail_image.py
index 9f3802e6..bc53ed79 100644
--- a/server/books/schema/nodes/wagtail_image.py
+++ b/server/books/schema/nodes/wagtail_image.py
@@ -7,8 +7,20 @@ from wagtail.images.models import Image
 from wagtail.images.views.serve import generate_image_url
 
 
-class WagtailImageNode(DjangoObjectType):
+def get_srcset(image: Image) -> str:
+    return (
+        f"{generate_image_url(image, 'width-160')} 160w, "
+        f"{generate_image_url(image, 'width-320')} 320w, "
+        f"{generate_image_url(image, 'width-800')} 1280w, "
+        f"{generate_image_url(image, 'width-1600')} 2560w"
+    )
 
+
+def get_src(image: Image) -> str:
+    return generate_image_url(image, f'width-{min(3840, image.width)}')
+
+
+class WagtailImageNode(DjangoObjectType):
     class Meta:
         model = Image
         fields = [
@@ -20,10 +32,13 @@ class WagtailImageNode(DjangoObjectType):
 
     src = graphene.String()
     alt = graphene.String()
-
+    srcset = graphene.String()
 
     def resolve_src(self, info):
-        return generate_image_url(self, 'original')
+        return get_src(self)
 
     def resolve_alt(self, info):
-        return ""
+        return self.title
+
+    def resolve_srcset(self, info):
+        return get_srcset(self)
diff --git a/server/core/urls.py b/server/core/urls.py
index c4a8ab2d..e0c0ede0 100644
--- a/server/core/urls.py
+++ b/server/core/urls.py
@@ -6,8 +6,7 @@ from django.views.generic import RedirectView
 from wagtail.admin import urls as wagtailadmin_urls
 from wagtail import urls as wagtail_urls
 from wagtail.documents import urls as wagtaildocs_urls
-#from wagtail.images import urls as wagtailimages_urls
-from core.views import CustomImageServeView
+from wagtail.images.views.serve import ServeView
 
 from wagtailautocomplete.urls.admin import urlpatterns as autocomplete_admin_urls
 
@@ -19,14 +18,13 @@ urlpatterns = [
     re_path(r"^guru/", admin.site.urls),
     re_path(r"^statistics/", include("statistics.urls", namespace="statistics")),
     # wagtail
-    re_path(r'^api/images/([^/]*)/(\d*)/([^/]*)/[^/]*$', CustomImageServeView.as_view(action='redirect'), name='wagtailimages_serve'),
+    re_path(r'^api/images/([^/]*)/(\d*)/([^/]*)/[^/]*$', ServeView.as_view(action='redirect'), name='wagtailimages_serve'),
 
     re_path(r"^cms/autocomplete/", include(autocomplete_admin_urls)),
     re_path(r"^cms/pages/(\d+)/$", override_wagtailadmin_explore_default_ordering),
     re_path(r"^cms/", include(wagtailadmin_urls)),
     re_path(r"^documents/", include(wagtaildocs_urls)),
 
-    #re_path(r"^images/", include(wagtailimages_urls)),
 
     # graphql backend
     re_path(r"^api/", include("api.urls", namespace="api")),
diff --git a/server/core/views.py b/server/core/views.py
index e489c49c..8c16abdf 100644
--- a/server/core/views.py
+++ b/server/core/views.py
@@ -1,29 +1,15 @@
-import imghdr
-from wsgiref.util import FileWrapper
-
 import requests
 from django.conf import settings
-from django.contrib.auth.decorators import login_required
 from django.contrib.auth.mixins import LoginRequiredMixin
-from django.core.exceptions import PermissionDenied
-from django.http import HttpResponse, StreamingHttpResponse
+from django.http import HttpResponse
 from django.http.request import HttpRequest
 from django.http.response import HttpResponseRedirect
-from django.shortcuts import get_object_or_404
 from django.shortcuts import render
-from django.utils.decorators import method_decorator
-from django.views.decorators.cache import cache_control
 from django.views.decorators.csrf import ensure_csrf_cookie
 from graphene_django.views import GraphQLView
 from graphql import get_operation_ast, parse
 from sentry_sdk.api import start_transaction
 from wagtail.admin.views.pages import listing
-from wagtail.images import get_image_model
-from wagtail.images.exceptions import InvalidFilterSpecError
-from wagtail.images.models import Image
-from wagtail.images.models import SourceImageIOError
-from wagtail.images.utils import verify_signature
-from wagtail.images.views.serve import ServeView
 
 from core.logger import get_logger
 
@@ -85,36 +71,3 @@ def override_wagtailadmin_explore_default_ordering(request, parent_page_id):
 
     return listing.IndexView.as_view()(request, parent_page_id)
 
-class CustomImageServeView(ServeView):
-    ''' Taken from wagtail.images.views.serve.ServeView the only change is that we use original for the filter_spec_for_signature'''
-    model = get_image_model()
-    action = "serve"
-    key = None
-
-    @method_decorator(cache_control(max_age=3600, public=True))
-    def get(self, request, signature, image_id, filter_spec, filename=None):
-        # This variable is the only change to the wagtail implementation
-        filter_spec_for_signature = 'original'
-
-        if not verify_signature(
-            signature.encode(), image_id, filter_spec_for_signature, key=self.key
-        ):
-            raise PermissionDenied
-
-        image = get_object_or_404(self.model, id=image_id)
-
-        # Get/generate the rendition
-        try:
-            rendition = image.get_rendition(filter_spec)
-        except SourceImageIOError:
-            return HttpResponse(
-                "Source image file not found", content_type="text/plain", status=410
-            )
-        except InvalidFilterSpecError:
-            return HttpResponse(
-                "Invalid filter spec: " + filter_spec,
-                content_type="text/plain",
-                status=400,
-            )
-
-        return getattr(self, self.action)(rendition)