@a2alite/sdk/dist/esm/server/http/hono/hono.js

A Modular SDK (Server & Client) for Agent to Agent (A2A) protocol, with easy task lifecycle management

import { Hono } from "hono";
import { jsonRpcBodyParser } from "../../jsonRPC/jsonRpcBodyParser.js";
import { isJSONRPCError } from "../../../types/types.js";
import { internalError } from "../../../utils/errors.js";
import { streamSSE } from "hono/streaming";
/**
 * Creates a Hono HTTP application configured for A2A protocol communication
 *
 * This function sets up the necessary HTTP endpoints for the A2A protocol:
 * - POST /a2a - Main JSON-RPC endpoint for agent communication
 * - GET /.well-known/agent.json - Agent discovery endpoint
 *
 * The application handles both synchronous and streaming responses using Server-Sent Events.
 *
 * @param params - Configuration object
 * @param params.a2aServer - The A2A server instance to handle requests
 * @returns Promise resolving to a configured Hono application instance
 */
async function createHonoApp({ a2aServer }) {
    const app = new Hono();
    // Start the a2a server
    await a2aServer.start();
    // JSON-RPC endpoint
    app.post("/a2a", async (c) => {
        try {
            const bodyText = await c.req.text();
            const parsed = await jsonRpcBodyParser(bodyText);
            // If parser returns a JSONRPCError (has code/message), send JSON-RPC error response
            if (isJSONRPCError(parsed)) {
                return c.json({
                    jsonrpc: "2.0",
                    id: null,
                    error: parsed,
                });
            }
            // Handle request
            const result = await a2aServer.handleRequest(parsed);
            if (result.response) {
                return c.json(result.response);
            }
            else if (result.stream) {
                const stream = result.stream;
                // Use Hono's StreamSSE helper for SSE
                return streamSSE(c, async (sse) => {
                    for await (const jsonRpcResponse of stream) {
                        await sse.writeSSE({ data: JSON.stringify(jsonRpcResponse) });
                    }
                });
            }
            else {
                // Unexpected result
                return c.json({
                    jsonrpc: "2.0",
                    id: parsed?.id || null,
                    error: internalError(),
                });
            }
        }
        catch (err) {
            console.error(err);
            return c.json({
                jsonrpc: "2.0",
                id: null,
                error: internalError(),
            });
        }
    });
    // Agent card handler
    app.get("/.well-known/agent.json", async (c) => {
        return c.json(a2aServer.agentCard);
    });
    return app;
}
export { createHonoApp };