Defensive file access in news.html

Prevent a 500 error when the image of a news article cannot be opened

Fix assertion for pipeline test

can_open_file templatetag condition changes

itou/templates/announcements/news.html

@@ -1,4 +1,5 @@
 {% extends "layout/base.html" %}
+{% load file_access %}
 {% load theme_inclusion %}
 
 {% block title %}Nouveautés {{ block.super }}{% endblock %}
@@ -32,7 +33,7 @@
                             {% for news_item in month_news.items.all %}
                                 <div class="row mb-3">
                                     <div class="col-12 col-md-4{% if news_item.image %} mb-3{% else %} d-none d-md-inline{% endif %}">
-                                        {% if news_item.image %}
+                                        {% if news_item.image|can_open_file %}
                                             <img src="{{ news_item.image.url }}"
                                                  alt="{{ news_item.image_alt_text }}"
                                                  {% if not news_item.image_alt_text %}aria-hidden="true"{% endif %}

itou/utils/templatetags/file_access.py

@@ -0,0 +1,17 @@
+from django import template
+from sentry_sdk.api import capture_exception
+
+
+register = template.Library()
+
+
+@register.filter
+def can_open_file(file):
+    if not file:
+        return False
+    try:
+        with file.open():
+            return True
+    except FileNotFoundError as e:
+        capture_exception(e)
+        return False

tests/www/announcements/test_views.py

@@ -1,6 +1,10 @@
+import re
+from unittest.mock import patch
+
 import pytest
+from django.core.files.storage import storages
 from django.urls import reverse
-from pytest_django.asserts import assertContains
+from pytest_django.asserts import assertContains, assertNotContains
 
 from itou.users.enums import UserKind
 from tests.communications.factories import AnnouncementCampaignFactory, AnnouncementItemFactory
@@ -107,3 +111,17 @@ def assert_content_matches_snapshot(response):
         AnnouncementItemFactory(user_kind_tags=[UserKind.PRESCRIBER])
         client.force_login(JobSeekerFactory())
         assert_content_matches_snapshot(client.get(url))
+
+    def test_rendering_invalid_file_does_not_crash(self, client):
+        user = JobSeekerFactory()
+        item = AnnouncementItemFactory(with_image=True, user_kind_tags=[user.kind])
+
+        with patch.object(storages["public"], "_open", side_effect=FileNotFoundError("File does not exist")):
+            response = client.get(reverse("announcements:news"))
+
+            self._assert_all_items_rendered(response, item.campaign)
+
+            # Contains placeholder image
+            assertNotContains(response, item.image.url)
+            pattern = re.compile(r"ico-bicro-important\.?[a-zA-Z0-9_]*\.?svg")
+            assert pattern.search(str(parse_response_to_soup(response, "#news-1 img.img-muted"))) is not None