MCP
H3 MCP related utils.
defineJsonRpcHandler()
Creates an H3 event handler that implements the JSON-RPC 2.0 specification.
Example:
app.post(
"/rpc",
defineJsonRpcHandler({
methods: {
echo: ({ params }, event) => {
return `Received \`${params}\` on path \`${event.url.pathname}\``;
},
sum: ({ params }, event) => {
return params.a + params.b;
},
},
}),
);
defineJsonRpcWebSocketHandler()
Creates an H3 event handler that implements JSON-RPC 2.0 over WebSocket.
This is an opt-in feature that allows JSON-RPC communication over WebSocket connections for bi-directional messaging. Each incoming WebSocket text message is processed as a JSON-RPC request, and responses are sent back to the peer.
Example:
app.get(
"/rpc/ws",
defineJsonRpcWebSocketHandler({
methods: {
echo: ({ params }) => {
return `Received: ${Array.isArray(params) ? params[0] : params?.message}`;
},
sum: ({ params }) => {
return params.a + params.b;
},
},
}),
);
Example:
// With additional WebSocket hooks
app.get(
"/rpc/ws",
defineJsonRpcWebSocketHandler({
methods: {
greet: ({ params }) => `Hello, ${params.name}!`,
},
hooks: {
open(peer) {
console.log(`Peer connected: ${peer.id}`);
},
close(peer, details) {
console.log(`Peer disconnected: ${peer.id}`, details);
},
},
}),
);