Add thumbnail endpoint (#2468)

- Add /thumbnail collections endpoint to serve the thumbnail as an image for public
collections.
- Also fix uploading thumbnail images to use correct mime, if available.

backend/btrixcloud/colls.py

@@ -11,6 +11,7 @@ import os
 
 import asyncio
 import pymongo
+import aiohttp
 from pymongo.collation import Collation
 from fastapi import Depends, HTTPException, Response
 from fastapi.responses import StreamingResponse
@@ -407,6 +408,34 @@ class CollectionOps:
 
         return PublicCollOut.from_dict(result)
 
+    async def get_public_thumbnail(
+        self, slug: str, org: Organization
+    ) -> StreamingResponse:
+        """return thumbnail of public collection, if any"""
+        result = await self.get_collection_raw_by_slug(
+            slug, public_or_unlisted_only=True
+        )
+
+        thumbnail = result.get("thumbnail")
+        if not thumbnail:
+            raise HTTPException(status_code=404, detail="thumbnail_not_found")
+
+        image_file = ImageFile(**thumbnail)
+        image_file_out = await image_file.get_public_image_file_out(
+            org, self.storage_ops
+        )
+
+        path = self.storage_ops.resolve_internal_access_path(image_file_out.path)
+
+        async def reader():
+            async with aiohttp.ClientSession() as session:
+                async with session.get(path) as resp:
+                    async for chunk in resp.content.iter_chunked(4096):
+                        yield chunk
+
+        headers = {"Cache-Control": "max-age=3600, stale-while-revalidate=86400"}
+        return StreamingResponse(reader(), media_type=image_file.mime, headers=headers)
+
     async def list_collections(
         self,
         org: Organization,
@@ -852,6 +881,7 @@ class CollectionOps:
             file_prep.upload_name,
             stream_iter(),
             MIN_UPLOAD_PART_SIZE,
+            mime=file_prep.mime,
         ):
             print("Collection thumbnail stream upload failed", flush=True)
             raise HTTPException(status_code=400, detail="upload_failed")
@@ -1175,6 +1205,24 @@ def init_collections_api(
 
         return await colls.download_collection(coll.id, org)
 
+    @app.get(
+        "/public/orgs/{org_slug}/collections/{coll_slug}/thumbnail",
+        tags=["collections", "public"],
+        response_class=StreamingResponse,
+    )
+    async def get_public_thumbnail(
+        org_slug: str,
+        coll_slug: str,
+    ):
+        try:
+            org = await colls.orgs.get_org_by_slug(org_slug)
+        # pylint: disable=broad-exception-caught
+        except Exception:
+            # pylint: disable=raise-missing-from
+            raise HTTPException(status_code=404, detail="collection_not_found")
+
+        return await colls.get_public_thumbnail(coll_slug, org)
+
     @app.post(
         "/orgs/{oid}/collections/{coll_id}/home-url",
         tags=["collections"],

backend/btrixcloud/storages.py

@@ -382,6 +382,7 @@ class StorageOps:
         filename: str,
         file_: AsyncIterator,
         min_size: int,
+        mime: Optional[str] = None,
     ) -> bool:
         """do upload to specified key using multipart chunking"""
         s3storage = self.get_org_primary_storage(org)
@@ -405,7 +406,10 @@ class StorageOps:
             key += filename
 
             mup_resp = await client.create_multipart_upload(
-                ACL="bucket-owner-full-control", Bucket=bucket, Key=key
+                ACL="bucket-owner-full-control",
+                Bucket=bucket,
+                Key=key,
+                ContentType=mime or "",
             )
 
             upload_id = mup_resp["UploadId"]