Simple pub/sub messaging for the web

Browser client

Network errors

As explained in the architecture documentation, the Faye client does not talk to the network directly but uses a ‘transport’ object based on WebSocket, XMLHttpRequest, and other network APIs.

The client exposes an abstract interface for checking the status of whichever connection type is in use, which is useful for giving the user feedback about the connection, or making your application deal with being offline. You can listen to the transport:up and transport:down events to be notified that the client is online or offline.

client.on('transport:down', function() {
  // the client is offline

client.on('transport:up', function() {
  // the client is online

Note that these events do not reflect the status of the client’s session, or whether there is literally a network connection active. For example, you are not told that the transport is down just because a long-polling request just completed. The transport is only considered down if a request or WebSocket connection explicitly fails, or times out, indicating the server is unreachable.

Also remember that Faye deals with buffering and re-sending messages for you, so you don’t need to deal with that. These events are simply for providing feedback on the health of the connection.