/diag.ashx · public API

Append-only diagnostic log endpoint used by the conference client. Captures per-call WebRTC observability data (ICE candidates, transition timelines, RTP byte counters) so operators can later reconstruct why a particular session failed.

POST `/diag.ashx` #

Append client-side diagnostic entries. Used by the conference page’s WebRTC instrumentation to record ICE candidates, connection-state transitions and RTP byte counters. Entries are buffered server-side for the admin diagnostic UI.

Request

application/json body:

{
  "entries": [
    { "t": "2026-06-02T19:33:37.388Z",
      "s": "<session-id>",
      "u": "<user-context>",
      "m": "ice-conn state=connected" }
  ]
}

Up to 100 entries per POST.

Response

{ "appended": N } where N is the count actually stored.

Errors

Malformed JSON is silently dropped (returns {appended:0}) so a buggy logger never breaks the page. 500 is the only error you might see, from disk I/O.

Example (verified 2026-06-05)

$ curl -X POST https://phone.codeb.io/diag.ashx \
    -H "Content-Type: application/json" \
    -d '{"entries":[{"t":"2026-06-05T11:00:00Z","s":"room-abc","u":"alex","m":"ice-conn state=connected"}]}'
{"appended":1}

Recommended JavaScript usage from the conference client itself (kept here for completeness):

navigator.sendBeacon('/diag.ashx',
  new Blob([JSON.stringify({entries: queuedEntries})],
           {type: 'application/json'}));

The GET tail of this endpoint is admin-gated via the X-CodeB-Admin-Signature HMAC header and is therefore not part of the public API — admins read entries back through the IIS web-logs admin page.