Check what works between R and an open Cellucid viewer

The report cellucid-python's AnnDataViewer.debug_connection() gives, for a viewer of this R session: whether the server answers its routes, whether the store is read with byte ranges, and whether the viewer's channel (a WebSocket) carries a command and its answer. It is the first thing to look at when a viewer stays blank or does not react, for example behind a proxy that does not pass WebSockets.

Usage

cellucid_debug_connection(viewer, timeout = 5)

Arguments

viewer

A viewer cellucid_view() or cellucid_serve() returned.

timeout

Seconds to wait for each answer.

Value

A list: viewer_id, viewer_url, server_url, server_running, channel_connected, web_ui (the web build's folder, and whether it is served), state (the viewer's ready event and its last command_error); the server's own server_health, server_info and server_datasets documents (or server_health_error and so on); anndata_store_probe, the store's HEAD answer (status, Content-Length, Accept-Ranges, ETag) and its first byte asked with Range; and frontend_roundtrip and frontend_debug_snapshot, each list(ok, answer) or list(ok = FALSE, error): a ping answered by a pong, and the viewer's own view of its address, origin and connection.

Details

The server is asked over HTTP from this R session, through R's event loop, which is where it answers; nothing leaves the machine. Without an open channel the two frontend_ entries say so instead of waiting.

Examples

if (interactive() && requireNamespace("SeuratObject", quietly = TRUE)) {
  data("pbmc_small", package = "SeuratObject")
  viewer <- cellucid_view(SeuratObject::UpdateSeuratObject(pbmc_small))
  str(cellucid_debug_connection(viewer))
  cellucid_stop(viewer)
}