Add download functionality for items and images with presigned URLs

docs/PHASE_2_EMBEDDING_PIPELINE.md

@@ -493,6 +493,6 @@ All tests use Django `TestCase`. External services (LLM APIs, Neo4j) are mocked.
 - [ ] Celery tasks handle async embedding with progress tracking
 - [ ] Re-embedding works (delete old chunks, re-process)
 - [ ] Content hash prevents redundant re-embedding
-- [ ] Prometheus metrics exposed at `/metrics` for pipeline monitoring
+- [x] Prometheus metrics exposed at `/metrics` for pipeline monitoring
 - [ ] All tests pass with mocked LLM/embedding APIs
 - [ ] Bedrock embedding works via Bearer token HTTP (no boto3)

mnemosyne/library/templates/library/collection_detail.html

@@ -56,6 +56,7 @@
                 <td>{{ item.file_type|default:"-" }}</td>
                 <td>
                     <a href="{% url 'library:item-detail' uid=item.uid %}" class="btn btn-xs btn-ghost">View</a>
+                    {% if item.s3_key %}<a href="{% url 'library:item-download' uid=item.uid %}" class="btn btn-xs btn-ghost" title="Download original file">↓ Download</a>{% endif %}
                     <a href="{% url 'library:item-edit' uid=item.uid %}" class="btn btn-xs btn-ghost">Edit</a>
                 </td>
             </tr>

mnemosyne/library/templates/library/item_detail.html

@@ -15,6 +15,11 @@
         {% if item.file_type %}<div class="badge badge-ghost mt-2 ml-1">{{ item.file_type }}</div>{% endif %}
     </div>
     <div class="flex gap-2">
+        {% if item.s3_key %}
+        <a href="{% url 'library:item-download' uid=item.uid %}" class="btn btn-sm btn-outline btn-primary" title="Download original file">
+            ↓ Download
+        </a>
+        {% endif %}
         <a href="{% url 'library:item-edit' uid=item.uid %}" class="btn btn-sm btn-outline">Edit</a>
         <form method="post" action="{% url 'library:item-reembed' uid=item.uid %}" class="inline">
             {% csrf_token %}
@@ -94,15 +99,22 @@
     <h2 class="text-xl font-bold mb-3">Images ({{ images|length }})</h2>
     <div class="grid grid-cols-2 md:grid-cols-4 gap-3">
         {% for img in images %}
-        <div class="card bg-base-200">
+        <a href="{% url 'library:image-serve' uid=img.uid %}" target="_blank" rel="noopener" class="card bg-base-200 hover:shadow-lg hover:bg-base-300 transition-all cursor-pointer">
+            {% if img.s3_key %}
+            <figure class="px-3 pt-3">
+                <img src="{% url 'library:image-serve' uid=img.uid %}" alt="{{ img.description|default:'Image' }}" class="rounded-lg object-cover w-full h-32" loading="lazy" />
+            </figure>
+            {% endif %}
             <div class="card-body p-3">
                 <span class="badge badge-sm">{{ img.image_type|default:"image" }}</span>
                 {% if img.description %}
                 <p class="text-xs opacity-60 mt-1">{{ img.description|truncatewords:10 }}</p>
                 {% endif %}
-                <p class="text-xs opacity-40 mt-1">{{ img.s3_key }}</p>
-            </div>
+                <p class="text-xs opacity-40 mt-1 flex items-center gap-1">
+                    <span>🔍</span> Click to view
+                </p>
             </div>
+        </a>
         {% endfor %}
     </div>
 </div>

mnemosyne/library/urls.py

@@ -50,7 +50,10 @@ urlpatterns = [
     path("items/<str:uid>/", views.item_detail, name="item-detail"),
     path("items/<str:uid>/edit/", views.item_edit, name="item-edit"),
     path("items/<str:uid>/reembed/", views.item_reembed, name="item-reembed"),
+    path("items/<str:uid>/download/", views.item_download, name="item-download"),
     path("items/<str:uid>/delete/", views.item_delete, name="item-delete"),
+    # Image views
+    path("images/<str:uid>/view/", views.image_serve, name="image-serve"),
     # DRF API
     path("api/", include("library.api.urls")),
 ]

mnemosyne/library/views.py

@@ -14,6 +14,7 @@ from django.contrib import messages
 from django.contrib.auth.decorators import login_required
 from django.core.files.base import ContentFile
 from django.core.files.storage import default_storage
+from django.http import Http404
 from django.shortcuts import redirect, render
 
 from .content_types import get_library_type_config
@@ -485,6 +486,55 @@ def item_delete(request, uid):
     return render(request, "library/item_confirm_delete.html", {"item": item})
 
 
+@login_required
+def item_download(request, uid):
+    """Redirect to a presigned/storage URL for the item's original file."""
+    try:
+        from .models import Item
+
+        item = Item.nodes.get(uid=uid)
+    except Exception:
+        raise Http404("Item not found.")
+
+    if not item.s3_key:
+        raise Http404("No file available for this item.")
+
+    try:
+        url = default_storage.url(item.s3_key)
+    except Exception as e:
+        logger.error("Failed to generate download URL for %s: %s", item.s3_key, e)
+        raise Http404("File not accessible.")
+
+    return redirect(url)
+
+
+# ---------------------------------------------------------------------------
+# Image views
+# ---------------------------------------------------------------------------
+
+
+@login_required
+def image_serve(request, uid):
+    """Redirect to a presigned/storage URL for an image file."""
+    try:
+        from .models import Image
+
+        img = Image.nodes.get(uid=uid)
+    except Exception:
+        raise Http404("Image not found.")
+
+    if not img.s3_key:
+        raise Http404("No file available for this image.")
+
+    try:
+        url = default_storage.url(img.s3_key)
+    except Exception as e:
+        logger.error("Failed to generate image URL for %s: %s", img.s3_key, e)
+        raise Http404("Image not accessible.")
+
+    return redirect(url)
+
+
 # ---------------------------------------------------------------------------
 # Embedding Pipeline Dashboard
 # ---------------------------------------------------------------------------