Action Cable payload size limit

[Cezinha (Cezinha - ASSEINFO)]

Hi!

Is there a size limit for a message sent by an Action Cable?

[dennyluan (denny)]

Hello! I am also wondering the same thing.

[bensheldon (Ben Sheldon [he/him])]

I don’t believe that ActionCable has a payload size limit, but the adapter does.

I can speak from experience using the Postgres ActionCable Adapter. The limit is 8kb. Calling ActionCable.server.broadcast with a larger payload will raise PG::InvalidParameterValue: ERROR: payload string too long.

[samsaffron]

Note, my recommended pattern here for large payloads would be

1. Send a message saying there is new data, with a CDN url

2. Have client retrieve data from the CDN

If the data is secret then use the same pattern but without CDN