gzipServer

Web server that receives gzip'd POST requests and saves them uncompressed locally

To force Firefox to send a Telemetry payload to this server:

1. Start the server: ./gzipServer.py (you may need to install simplejson Python module)
2. In about:config, change the preference "toolkit.telemetry.server" to "http://localhost"
3. Restart Firefox to have Telemetry pick up the above pref change
4. Open about:telemetry (it has some Telemetry namespaces nicely set up) and open the DevTools console
5. Paste the following into the console:
   Cu.import("resource://gre/modules/TelemetrySession.jsm");
TelemetrySession.testPing();
6. The script will save the request it receives to report1.json in the script's working directory

Note: The procedure above will create a "test ping", which is equivalent to a regular Telemetry "saved-session" ping.

Alternatives:

1. If you just need to see the Telemetry measurements from the current session, you can see them directly on the about:telemetry page in Firefox.
2. If you need to see what the full ping looks like, but you don't need to send it to a server, simply exit Firefox and restart. In about:telemetry select the last "main" ping from the archived ping data. You can switch to the raw ping data to see the full raw contents.
3. You can also get the full ping from the DevTools console by opening the about:telemetry page and running the commands:
   Cu.import("resource://gre/modules/TelemetrySession.jsm");
ping = TelemetrySession.getPayload()