fix(storage): fall back to range GET when proxy strips Content-Length

src/lib/storage/s3.test.ts

@@ -149,6 +149,80 @@ describe("S3StorageClient", () => {
     });
   });
 
+  test("getObjectInfo falls back to a range GET when HEAD omits Content-Length", async () => {
+    mockSend
+      .mockResolvedValueOnce({
+        // HEAD: no ContentLength (proxy stripped it)
+        ContentType: "text/html",
+        ETag: '"abc"',
+        LastModified: new Date("2026-04-10"),
+        Metadata: {},
+      })
+      .mockResolvedValueOnce({
+        // Range GET: Content-Range tells us the real size
+        ContentRange: "bytes 0-0/5032",
+        Body: Readable.from([Buffer.from("x")]),
+      });
+    const client = new S3StorageClient({ endpoint: "https://data.source.coop" });
+    const result = await client.getObjectInfo({
+      account_id: "acct",
+      product_id: "prod",
+      object_path: "dir/index.html",
+    });
+
+    const calls = mockSend.mock.calls.map((c) => c[0]);
+    expect(calls[0]).toBeInstanceOf(HeadObjectCommand);
+    expect(calls[1]).toBeInstanceOf(GetObjectCommand);
+    expect(calls[1].input).toMatchObject({
+      Bucket: "acct",
+      Key: "prod/dir/index.html",
+      Range: "bytes=0-0",
+    });
+    expect(result?.size).toBe(5032);
+  });
+
+  test("getObjectInfo falls back to a range GET when ContentLength is 0", async () => {
+    mockSend
+      .mockResolvedValueOnce({
+        ContentLength: 0,
+        ContentType: "text/html",
+        ETag: '"abc"',
+        LastModified: new Date("2026-04-10"),
+        Metadata: {},
+      })
+      .mockResolvedValueOnce({
+        ContentRange: "bytes 0-0/5032",
+        Body: Readable.from([Buffer.from("x")]),
+      });
+    const client = new S3StorageClient({ endpoint: "https://data.source.coop" });
+    const result = await client.getObjectInfo({
+      account_id: "acct",
+      product_id: "prod",
+      object_path: "dir/index.html",
+    });
+
+    expect(result?.size).toBe(5032);
+  });
+
+  test("getObjectInfo keeps size as 0 when range GET also fails", async () => {
+    mockSend
+      .mockResolvedValueOnce({
+        ContentType: "text/html",
+        ETag: '"abc"',
+        LastModified: new Date("2026-04-10"),
+        Metadata: {},
+      })
+      .mockRejectedValueOnce(new Error("range not supported"));
+    const client = new S3StorageClient({ endpoint: "https://data.source.coop" });
+    const result = await client.getObjectInfo({
+      account_id: "acct",
+      product_id: "prod",
+      object_path: "dir/index.html",
+    });
+
+    expect(result?.size).toBe(0);
+  });
+
   test("getObjectInfo returns null on a NotFound S3ServiceException", async () => {
     const actual = jest.requireActual("@aws-sdk/client-s3");
     const notFound = new actual.S3ServiceException({

src/lib/storage/s3.ts

@@ -188,11 +188,40 @@ export class S3StorageClient {
           VersionId: params.versionId,
         }),
       );
+
+      let size = response.ContentLength ?? 0;
+
+      // Some proxies omit Content-Length from HEAD responses. Fall back to a
+      // range GET to read the actual size from Content-Range.
+      if (!size) {
+        try {
+          const rangeResponse = await this.client.send(
+            new GetObjectCommand({
+              Bucket: params.account_id,
+              Key: keyFor(params),
+              VersionId: params.versionId,
+              Range: "bytes=0-0",
+            }),
+          );
+          // Content-Range format: "bytes 0-0/TOTAL_SIZE". That header is all
+          // we need, so destroy the body instead of reading it — a proxy that
+          // ignores Range and returns the full object shouldn't be downloaded
+          // just to size it.
+          const match = rangeResponse.ContentRange?.match(/\/(\d+)$/);
+          if (match) {
+            size = parseInt(match[1], 10);
+          }
+          (rangeResponse.Body as Readable | undefined)?.destroy();
+        } catch {
+          // range request failed; keep size as 0
+        }
+      }
+
       return {
         id: params.object_path,
         product_id: params.product_id,
         path: params.object_path,
-        size: response.ContentLength ?? 0,
+        size,
         mime_type: response.ContentType ?? "",
         type: "file",
         created_at: