I implemented a proxy and Express middleware for Node.js

[marella]

@grpc-web/proxy

This is a standalone proxy server created using @grpc-web/middleware (see below), connect and cors packages. It passes the interop tests and can be run directly from the command line:

npx @grpc-web/proxy --target http://localhost:9090 --listen 8080

or used as a library:

const proxy = require('@grpc-web/proxy');

proxy({ target: 'http://localhost:9090' }).listen(8080);

It can be run in the same process as the gRPC server:

// Proxy server
proxy({ target: 'http://localhost:9090' }).listen(8080);

// gRPC server
const server = new grpc.Server();
server.addProtoService(service, implementation);
server.bind('0.0.0.0:9090', credentials);
server.start();

For more details, please see README.

@grpc-web/middleware

This middleware can be used with existing Express and Connect applications. Here is a full working example of a proxy server created using express and cors packages:

const express = require('express');
const cors = require('cors');
const grpcWeb = require('@grpc-web/middleware');

const app = express();
app.use(cors({ exposedHeaders: ['grpc-status', 'grpc-message'] }));
app.use(grpcWeb('http://localhost:9090'));
app.listen(8080);

It only handles gRPC Web requests and ignores normal HTTP requests, so it can be used together with normal web applications:

app.use(grpcWeb('http://localhost:9090'));

app.get('/', (req, res) => {
  res.send('Hello World');
});

For more details, please see README.

[sampajano]

Very cool.. such a simple solution.. Thanks very much for sharing.. :)

[fawzibazari]

Hello,

is it possible to use the package for server-side-streaming in a browser ?

can i use the @grpc-web/middleware to replace envoy proxy ?

i did saw the http2 option, it will send http2 requests through express ?

Thanks

[fawzibazari]

Hello,
I forgot to write sooner i did use the package and it replace the Envoy server part but we have to use the grpc-web package and call the express proxy instead of the gRPC server

Thanks !

[sampajano]

Thanks for sharing your experience! 😃