Add cache to attachment urls

src/articles/migrations/0034_replace_attachment_urls.py

@@ -0,0 +1,59 @@
+# Generated by Django 4.1.1 on 2022-10-01 06:55
+from django.apps.registry import Apps
+from django.db import migrations
+from django.db.backends.base.schema import BaseDatabaseSchemaEditor
+from django.urls import reverse
+
+
+def replace_with_wrapper_url(
+    apps: Apps, schema_editor: BaseDatabaseSchemaEditor
+) -> None:
+    Attachment = apps.get_model("attachments", "Attachment")
+    Article = apps.get_model("articles", "Article")
+    db_alias = schema_editor.connection.alias
+    attachments = Attachment.objects.using(db_alias).all()
+    modified = []
+    for article in Article.objects.using(db_alias).all():
+        for attachment in attachments:
+            article.content = article.content.replace(
+                attachment.original_file.url,
+                reverse("attachments:original", kwargs={"pk": attachment.pk}),
+            )
+            if attachment.processed_file:
+                article.content = article.content.replace(
+                    attachment.processed_file.url,
+                    reverse("attachments:processed", kwargs={"pk": attachment.pk}),
+                )
+        modified.append(article)
+    Article.objects.using(db_alias).bulk_update(modified, ["content"])
+
+
+def replace_with_file_url(apps: Apps, schema_editor: BaseDatabaseSchemaEditor) -> None:
+    Attachment = apps.get_model("attachments", "Attachment")
+    Article = apps.get_model("articles", "Article")
+    db_alias = schema_editor.connection.alias
+    attachments = Attachment.objects.using(db_alias).all()
+    modified = []
+    for article in Article.objects.using(db_alias).all():
+        for attachment in attachments:
+            article.content = article.content.replace(
+                reverse("attachments:original", kwargs={"pk": attachment.pk}),
+                attachment.original_file.url,
+            )
+            if attachment.processed_file:
+                article.content = article.content.replace(
+                    reverse("attachments:processed", kwargs={"pk": attachment.pk}),
+                    attachment.processed_file.url,
+                )
+        modified.append(article)
+    Article.objects.using(db_alias).bulk_update(modified, ["content"])
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("articles", "0033_alter_article_options"),
+        ("attachments", "0008_attachment_updated_at"),
+    ]
+
+    operations = [migrations.RunPython(replace_with_wrapper_url, replace_with_file_url)]

src/attachments/admin.py

@@ -43,18 +43,16 @@ class AttachmentAdmin(admin.ModelAdmin):
     def processed_file_url(self, instance: Attachment) -> str:
         if instance.processed_file:
             return format_html(
-                '{0} <a class="copy-button" data-to-copy="{1}" href="#">&#128203;</a>',
-                instance.processed_file.url,
-                instance.processed_file.url,
+                '{0} <a class="copy-button" data-to-copy="{0}" href="#">&#128203;</a>',
+                instance.processed_file_url,
             )
         return ""
 
     def original_file_url(self, instance: Attachment) -> str:
         if instance.original_file:
             return format_html(
-                '{0} <a class="copy-button" data-to-copy="{1}" href="#">&#128203;</a>',
-                instance.original_file.url,
-                instance.original_file.url,
+                '{0} <a class="copy-button" data-to-copy="{0}" href="#">&#128203;</a>',
+                instance.original_file_url,
             )
         return ""
 

src/attachments/migrations/0008_attachment_updated_at.py

@@ -0,0 +1,18 @@
+# Generated by Django 4.1.1 on 2022-10-01 06:13
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ("attachments", "0007_auto_20201201_1917"),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name="attachment",
+            name="updated_at",
+            field=models.DateTimeField(auto_now=True),
+        ),
+    ]

src/attachments/models.py

@@ -11,6 +11,7 @@ from django.core.files import File
 from django.core.handlers.wsgi import WSGIRequest
 from django.db import models
 from django.db.models.fields.files import FieldFile
+from django.urls import reverse
 from PIL import Image
 
 from articles.utils import build_full_absolute_url
@@ -35,6 +36,7 @@ class Attachment(models.Model):
     original_file = AbsoluteUrlFileField()
     processed_file = AbsoluteUrlFileField(blank=True, null=True)
     open_graph_image = models.BooleanField(blank=True, default=False)
+    updated_at = models.DateTimeField(auto_now=True)
 
     objects = AttachmentManager()
 
@@ -48,6 +50,16 @@ class Attachment(models.Model):
         self.processed_file = None  # type: ignore
         self.save()
 
+    @property
+    def original_file_url(self) -> str:
+        return reverse("attachments:original", kwargs={"pk": self.pk})
+
+    @property
+    def processed_file_url(self) -> str | None:
+        if self.processed_file:
+            return reverse("attachments:processed", kwargs={"pk": self.pk})
+        return None
+
     def save(self, *args: Any, **kwargs: Any) -> None:
         super().save(*args, **kwargs)
 

src/attachments/tests/test_views.py

@@ -0,0 +1,45 @@
+from pathlib import Path
+
+import pytest
+from django.core.files import File
+from django.test.client import Client
+from django.urls import reverse
+
+from attachments.models import Attachment
+
+
+@pytest.mark.block_network()
+@pytest.fixture()
+def attachment(db: None) -> Attachment:
+    # This path manipulation is required to make the test run from this directory
+    # or from upper in the hierarchy (e.g.: settings.BASE_DIR)
+    original_path = Path(__file__).parent / "resources" / "image.png"
+    original_path = original_path.relative_to(Path.cwd())
+    processed_path = Path(__file__).parent / "resources" / "docker-logo.png"
+    processed_path = processed_path.relative_to(Path.cwd())
+    with original_path.open("rb") as of, processed_path.open("rb") as pf:
+        original_file = File(of)
+        processed_file = File(pf)
+        attachment = Attachment.objects.create(
+            description="Docker logo",
+            original_file=original_file,
+            processed_file=processed_file,
+        )
+        attachment.save()
+    return attachment
+
+
+def test_view_original(attachment: Attachment, client: Client) -> None:
+    url = reverse("attachments:original", kwargs={"pk": attachment.pk})
+    res = client.get(url)
+    assert res.status_code == 302
+    assert res.url == attachment.original_file.url
+    assert "Last-Modified" in res.headers
+
+
+def test_view_processed(attachment: Attachment, client: Client) -> None:
+    url = reverse("attachments:processed", kwargs={"pk": attachment.pk})
+    res = client.get(url)
+    assert res.status_code == 302
+    assert res.url == attachment.processed_file.url
+    assert "Last-Modified" in res.headers

src/attachments/urls.py

@@ -0,0 +1,10 @@
+from django.urls import path
+
+from attachments import views
+
+app_name = "attachments"
+
+urlpatterns = [
+    path("<int:pk>/original/", views.get_original, name="original"),
+    path("<int:pk>/processed/", views.get_processed, name="processed"),
+]

src/attachments/views.py

@@ -0,0 +1,25 @@
+import datetime
+
+from django.core.handlers.wsgi import WSGIRequest
+from django.http import HttpResponse, HttpResponseRedirect
+from django.shortcuts import get_object_or_404
+from django.views.decorators.http import last_modified
+
+from attachments.models import Attachment
+
+
+def get_updated_at(request: WSGIRequest, pk: int) -> datetime.datetime:
+    attachment = get_object_or_404(Attachment, pk=pk)
+    return attachment.updated_at
+
+
+@last_modified(get_updated_at)
+def get_original(request: WSGIRequest, pk: int) -> HttpResponse:
+    attachment = get_object_or_404(Attachment, pk=pk)
+    return HttpResponseRedirect(attachment.original_file.url)
+
+
+@last_modified(get_updated_at)
+def get_processed(request: WSGIRequest, pk: int) -> HttpResponse:
+    attachment = get_object_or_404(Attachment, pk=pk)
+    return HttpResponseRedirect(attachment.processed_file.url)

src/blog/urls.py

@@ -32,6 +32,7 @@ urlpatterns = [
     ),
     path("admin/", admin.site.urls),
     path("", include("articles.urls")),
+    path("attachments/", include("attachments.urls")),
 ]
 
 if settings.DEBUG: