Apache-dubbo-express NPM

apache-dubbo-express

Dubbo is a family of libraries for building and consuming APIs on different languages and platforms, and apache-dubbo brings type-safe APIs with Protobuf to TypeScript.

apache-dubbo-express provides a middleware for Express, the fast, unopinionated, minimalist web framework for Node.js

expressDubboMiddleware()

Adds your Dubbo RPCs to an Express server.

// connect.ts
import { DubboRouter } from "apache-dubbo";

export default function(router: DubboRouter) {
  // implement rpc Say(SayRequest) returns (SayResponse)
  router.rpc(ElizaService, ElizaService.methods.say, async (req) => ({
    sentence: `you said: ${req.sentence}`,
  }));
}

// server.ts
import http from "http";
import express from "express";
+ import routes from "dubbo";
+ import { expressDubboMiddleware } from "apache-dubbo-express";

const app = express();

+ app.use(expressDubboMiddleware({ 
+  routes 
+ }));

http.createServer(app).listen(8080);

With that server running, you can make requests with any gRPC-web or Dubbo client.

curl with the Dubbo protocol:

curl \
    --header "Content-Type: application/json" \
    --data '{"sentence": "I feel happy."}' \
    http://localhost:8080/buf.connect.demo.eliza.v1.ElizaService/Say

Node.js with the gRPC-web protocol (using a transport from apache-dubbo-node):

import { createPromiseClient } from "apache-dubbo";
import { createGrpcWebTransport } from "apache-dubbo-node";
import { ElizaService } from "./gen/eliza_dubbo.js";

const transport = createGrpcWebTransport({
  baseUrl: "http://localhost:8080",
  httpVersion: "1.1",
});

const client = createPromiseClient(ElizaService, transport);
const { sentence } = await client.say({ sentence: "I feel happy." });
console.log(sentence) // you said: I feel happy.

A client for the web browser actually looks identical to this example - it would simply use createDubboTransport from apache-dubbo-web instead.

Note that support for gRPC is limited, since many gRPC clients require HTTP/2, and Express does not support the Node.js http2 module.