invalid content length error when used chunked transfer

[lixiv]

Bug report:

when harbor repo use chunked as transfer-encoding, pull image failed with error "invalid content length "

Expected behavior:

pull image success without the error

How to reproduce it:

1. containerd use http_proxy (mirror also have same error)

  /etc/systemd/system/containerd.service.d/http-proxy.conf
  [Service]
  Environment="HTTP_PROXY=http://127.0.0.1:4001/"
  Environment="HTTPS_PROXY=http://127.0.0.1:4001/"

2. use curl to confirm chuncked

curl -k -vv -H "Authorization: Basic x" https://xx.com/v2/keda/prometheus/blobs/sha256:a683da7699127231b140f7dbd7d60e9741d51543ba91c656bf3287860a39428f
< Content-Type: text/plain; charset=utf-8
< Connection: close
< Transfer-Encoding: chunked

3. crictl pull or nerdctl -n k8s.io pull

crictl pull xx.com/keda/prometheus:v3.7.0

4. the dfdaemon logs show errors:

  2026-01-20T10:34:26.483499170+00:00 ERROR  download started failed: invalid content length
    at dragonfly-client/src/grpc/dfdaemon_download.rs:312
    in download_task with host_id: "ip-cluster-worker-s547t", task_id: "2eaddecde4a9a7f0823350f6b7f16d35973bf0e829cadd874d4a31b28c8d9925", peer_id: "ip-cluster-worker-s547t-a59949bf-7fe0-458d-9ea7-629625091b21", url: "http://xxx.com/v2/keda/prometheus/blobs/sha256:a683da7699127231b140f7dbd7d60e9741d51543ba91c656bf3287860a39428f"

  2026-01-20T10:34:26.483646474+00:00 ERROR  download task failed: status: Internal, message: "invalid content length", details: [], metadata: MetadataMap { headers: {"content-type": "application/grpc", "date": "Tue, 20 Jan 2026 10:34:26 GMT", "content-length": "0"} }
    at dragonfly-client/src/proxy/mod.rs:672
    in proxy_via_dfdaemon
    in http_handler
    in handler with uri: "http://xxx.com/v2/keda/prometheus/blobs/sha256:a683da7699127231b140f7dbd7d60e9741d51543ba91c656bf3287860a39428f", method: "GET"

5. related issues: ERROR download task failed: status: Internal, messagge: "invalid content length" #4366 (comment)
6. cherry-pick this pr feat: add Range header to ensure Content-Length is returned in response headers client#1263 ,not work

Environment:

• Dragonfly version: dfdaemon: v0.2.36; manager: v2.2.2

[gaius-qi]

@lixiv Dragonfly first needs to get the Content-Length to calculate the piece length. Since it needs to support object storage downloads via HTTP protocol, it uses a GET request to receive the Content-Length. However, your server supports Transfer-Encoding: chunked, so if the GET request doesn't return a Content-Length, I will use a HEAD request to get the Content-Length.

Note: Dragonfly requires the server to support Range requests for piece-level downloads.