node, rpc: add JWT auth support in client (#24911)

This adds a generic mechanism for 'dial options' in the RPC client,
and also implements a specific dial option for the JWT authentication
mechanism used by the engine API. Some real tests for the server-side
authentication handling are also added.

Co-authored-by: Joshua Gutow <jgutow@optimism.io>
Co-authored-by: Felix Lange <fjl@twurst.com>

node/node.go

@@ -668,6 +668,19 @@ func (n *Node) WSEndpoint() string {
 	return "ws://" + n.ws.listenAddr() + n.ws.wsConfig.prefix
 }
 
+// HTTPAuthEndpoint returns the URL of the authenticated HTTP server.
+func (n *Node) HTTPAuthEndpoint() string {
+	return "http://" + n.httpAuth.listenAddr()
+}
+
+// WSAuthEndpoint returns the current authenticated JSON-RPC over WebSocket endpoint.
+func (n *Node) WSAuthEndpoint() string {
+	if n.httpAuth.wsAllowed() {
+		return "ws://" + n.httpAuth.listenAddr() + n.httpAuth.wsConfig.prefix
+	}
+	return "ws://" + n.wsAuth.listenAddr() + n.wsAuth.wsConfig.prefix
+}
+
 // EventMux retrieves the event multiplexer used by all the network services in
 // the current protocol stack.
 func (n *Node) EventMux() *event.TypeMux {