Fastly Compute WebSockets starter kit for JavaScript

Learn about Fastly Compute with WebSockets using a basic starter that sends connections to a backend.

Note: The WebSockets feature handles passthrough connections only. If you want to handle WebSocket connections from clients without having to run a WebSocket backend, see the Fanout Starter Kit.

For more details about this and other starter kits for Compute, see the Fastly Documentation Hub.

Setup

The app expects a configured backend named backend that points to a WebSocket server. For example, if the WebSocket server is available at domain websockets.example.com, then you'll need to create a backend on your Compute service named backend with the destination host set to websockets.example.com and port 443. Also set 'Override Host' to the same host value.

After deploying the app and setting up the backend configuration, all connections received by the service will be passed to the backend.

Enabling WebSockets passthrough

When you create a new service from this starter kit, WebSockets passthrough is enabled automatically.

To enable WebSockets passthrough on an existing Fastly service, type:

fastly products --enable=websockets

Testing locally

If testing locally, make sure that you have a backend named backend defined in the local_server section of your fastly.toml file:

[local_server.backends]
[local_server.backends.backend]
url = "https://websockets.example.com/"
override_host = "websockets.example.com"

Compatibility

• Fastly CLI 15.2.0 or newer
• Fastly Local Development Server (Viceroy) 0.18.0 or newer

Security issues

Please see SECURITY.md for guidance on reporting security-related issues.