catch errors on non existing images

CHANGELOG.txt

@@ -38,6 +38,7 @@ Changelog
  * Fix: `MenuItem` `url` parameter can now take a lazy URL (Adon Metcalfe, rayrayndwiga)
  * Fix: Added missing translation tag to InlinePanel 'Add' button (jnns)
  * Fix: Restored correct highlighting behaviour of rich text toolbar buttons
+ * Fix: Rendering a missing image through ImageChooserBlock no longer breaks the whole page (Christian Peters)
 
 1.2 (12.11.2015)
 ~~~~~~~~~~~~~~~~

docs/releases/1.3.rst

@@ -88,6 +88,7 @@ Bug fixes
  * ``MenuItem`` ``url`` parameter can now take a lazy URL (Adon Metcalfe, rayrayndwiga)
  * Added missing translation tag to InlinePanel 'Add' button (jnns)
  * Restored correct highlighting behaviour of rich text toolbar buttons
+ * Rendering a missing image through ImageChooserBlock no longer breaks the whole page (Christian Peters)
 
 
 Upgrade considerations

wagtail/wagtailimages/blocks.py

@@ -1,6 +1,7 @@
 from django.utils.functional import cached_property
 
 from wagtail.wagtailcore.blocks import ChooserBlock
+from .shortcuts import get_rendition_or_not_found
 
 
 class ImageChooserBlock(ChooserBlock):
@@ -16,6 +17,6 @@ class ImageChooserBlock(ChooserBlock):
 
     def render_basic(self, value):
         if value:
-            return value.get_rendition('original').img_tag()
+            return get_rendition_or_not_found(value, 'original').img_tag()
         else:
             return ''

wagtail/wagtailimages/formats.py

@@ -1,7 +1,7 @@
 from django.utils.html import escape
 
 from wagtail.utils.apps import get_app_submodules
-from wagtail.wagtailimages.models import SourceImageIOError
+from .shortcuts import get_rendition_or_not_found
 
 
 class Format(object):
@@ -26,15 +26,7 @@ class Format(object):
         )
 
     def image_to_html(self, image, alt_text, extra_attributes=''):
-        try:
-            rendition = image.get_rendition(self.filter_spec)
-        except SourceImageIOError:
-            # Image file is (probably) missing from /media/original_images - generate a dummy
-            # rendition so that we just output a broken image, rather than crashing out completely
-            # during rendering
-            Rendition = image.renditions.model  # pick up any custom Image / Rendition classes that may be in use
-            rendition = Rendition(image=image, width=0, height=0)
-            rendition.file.name = 'not-found'
+        rendition = get_rendition_or_not_found(image, self.filter_spec)
 
         if self.classnames:
             class_attr = 'class="%s" ' % escape(self.classnames)

wagtail/wagtailimages/jinja2tags.py

@@ -2,25 +2,14 @@ from __future__ import absolute_import
 
 from jinja2.ext import Extension
 
-from wagtail.wagtailimages.models import SourceImageIOError
+from .shortcuts import get_rendition_or_not_found
 
 
 def image(image, filterspec, **attrs):
     if not image:
         return ''
 
-    try:
-        rendition = image.get_rendition(filterspec)
-    except SourceImageIOError:
-        # It's fairly routine for people to pull down remote databases to their
-        # local dev versions without retrieving the corresponding image files.
-        # In such a case, we would get a SourceImageIOError at the point where we try to
-        # create the resized version of a non-existent image. Since this is a
-        # bit catastrophic for a missing image, we'll substitute a dummy
-        # Rendition object so that we just output a broken link instead.
-        Rendition = image.renditions.model  # pick up any custom Image / Rendition classes that may be in use
-        rendition = Rendition(image=image, width=0, height=0)
-        rendition.file.name = 'not-found'
+    rendition = get_rendition_or_not_found(image, filterspec)
 
     if attrs:
         return rendition.img_tag(attrs)

wagtail/wagtailimages/shortcuts.py

@@ -0,0 +1,22 @@
+# coding=utf-8
+from wagtail.wagtailimages.models import SourceImageIOError
+
+
+def get_rendition_or_not_found(image, specs):
+    """
+    Tries to get / create the rendition for the image or renders a not-found image if it does not exist.
+
+    :param image: AbstractImage
+    :param specs: str or Filter
+    :return: Rendition
+    """
+    try:
+        return image.get_rendition(specs)
+    except SourceImageIOError:
+        # Image file is (probably) missing from /media/original_images - generate a dummy
+        # rendition so that we just output a broken image, rather than crashing out completely
+        # during rendering.
+        Rendition = image.renditions.model  # pick up any custom Image / Rendition classes that may be in use
+        rendition = Rendition(image=image, width=0, height=0)
+        rendition.file.name = 'not-found'
+        return rendition

wagtail/wagtailimages/templatetags/wagtailimages_tags.py

@@ -1,7 +1,8 @@
 from django import template
 from django.utils.functional import cached_property
 
-from wagtail.wagtailimages.models import Filter, SourceImageIOError
+from wagtail.wagtailimages.models import Filter
+from wagtail.wagtailimages.shortcuts import get_rendition_or_not_found
 
 register = template.Library()
 
@@ -54,18 +55,7 @@ class ImageNode(template.Node):
         if not image:
             return ''
 
-        try:
-            rendition = image.get_rendition(self.filter)
-        except SourceImageIOError:
-            # It's fairly routine for people to pull down remote databases to their
-            # local dev versions without retrieving the corresponding image files.
-            # In such a case, we would get a SourceImageIOError at the point where we try to
-            # create the resized version of a non-existent image. Since this is a
-            # bit catastrophic for a missing image, we'll substitute a dummy
-            # Rendition object so that we just output a broken link instead.
-            Rendition = image.renditions.model  # pick up any custom Image / Rendition classes that may be in use
-            rendition = Rendition(image=image, width=0, height=0)
-            rendition.file.name = 'not-found'
+        rendition = get_rendition_or_not_found(image, self.filter)
 
         if self.output_var_name:
             # return the rendition object in the given variable

wagtail/wagtailimages/tests/test_blocks.py

@@ -0,0 +1,57 @@
+# -*- coding: utf-8 -*
+from __future__ import unicode_literals
+
+import os
+
+from django.test import TestCase
+from django.core import serializers
+from django.conf import settings
+
+from wagtail.wagtailimages.blocks import ImageChooserBlock
+
+from .utils import get_test_image_file, Image
+
+
+class TestImageChooserBlock(TestCase):
+    def setUp(self):
+        self.image = Image.objects.create(
+            title="Test image",
+            file=get_test_image_file(),
+        )
+
+        # Create an image with a missing file, by deserializing fom a python object
+        # (which bypasses FileField's attempt to read the file)
+        self.bad_image = list(serializers.deserialize('python', [{
+            'fields': {
+                'title': 'missing image',
+                'height': 100,
+                'file': 'original_images/missing-image.jpg',
+                'width': 100,
+            },
+            'model': 'wagtailimages.image'
+        }]))[0].object
+        self.bad_image.save()
+
+    def get_image_filename(self, image, filterspec):
+        """
+        Get the generated filename for a resized image
+        """
+        name, ext = os.path.splitext(os.path.basename(image.file.name))
+        return '{}images/{}.{}{}'.format(
+            settings.MEDIA_URL, name, filterspec, ext)
+
+    def test_render(self):
+        block = ImageChooserBlock()
+        html = block.render(self.image)
+        expected_html = '<img alt="Test image" src="{}" width="640" height="480">'.format(
+            self.get_image_filename(self.image, "original")
+        )
+
+        self.assertHTMLEqual(html, expected_html)
+
+    def test_render_missing(self):
+        block = ImageChooserBlock()
+        html = block.render(self.bad_image)
+        expected_html = '<img alt="missing image" src="/media/not-found" width="0" height="0">'
+
+        self.assertHTMLEqual(html, expected_html)

wagtail/wagtailimages/tests/test_jinja2.py

@@ -5,6 +5,7 @@ import unittest
 
 import django
 from django.conf import settings
+from django.core import serializers
 from django.test import TestCase
 
 from wagtail.wagtailcore.models import Site
@@ -25,6 +26,19 @@ class TestImagesJinja(TestCase):
             file=get_test_image_file(),
         )
 
+        # Create an image with a missing file, by deserializing fom a python object
+        # (which bypasses FileField's attempt to read the file)
+        self.bad_image = list(serializers.deserialize('python', [{
+            'fields': {
+                'title': 'missing image',
+                'height': 100,
+                'file': 'original_images/missing-image.jpg',
+                'width': 100,
+            },
+            'model': 'wagtailimages.image'
+        }]))[0].object
+        self.bad_image.save()
+
     def render(self, string, context=None, request_context=True):
         if context is None:
             context = {}
@@ -64,3 +78,9 @@ class TestImagesJinja(TestCase):
                     'width: {{ background.width }}, url: {{ background.url }}')
         output = ('width: 200, url: ' + self.get_image_filename(self.image, "width-200"))
         self.assertHTMLEqual(self.render(template, {'myimage': self.image}), output)
+
+    def test_missing_image(self):
+        self.assertHTMLEqual(
+            self.render('{{ image(myimage, "width-200") }}', {'myimage': self.bad_image}),
+            '<img alt="missing image" src="/media/not-found" width="0" height="0">'
+        )

wagtail/wagtailimages/tests/test_shortcuts.py

@@ -0,0 +1,22 @@
+# coding=utf-8
+from django.test import TestCase
+from wagtail.wagtailimages.shortcuts import get_rendition_or_not_found
+from .utils import Image, get_test_image_file
+
+
+class TestShortcuts(TestCase):
+
+    fixtures = ['test.json']
+
+    def test_fallback_to_not_found(self):
+        bad_image = Image.objects.get(id=1)
+        good_image = Image.objects.create(
+            title="Test image",
+            file=get_test_image_file(),
+        )
+
+        rendition = get_rendition_or_not_found(good_image, 'width-400')
+        self.assertEqual(rendition.width, 400)
+
+        rendition = get_rendition_or_not_found(bad_image, 'width-400')
+        self.assertEqual(rendition.file.name, 'not-found')