Node-http-proxy: POST requests to my server appear to just hang, and never arrive at the target server

[xingxinglail]

I'm using the node-http-proxy library to create a forward proxy server. I eventually plan to use some middleware to modify the html code on the fly. This is how my proxy server code looks like

fastify v3.2.1
http-proxy v1.18.1

const fastify = require('fastify')();
const httpProxy = require('http-proxy');

const proxy = httpProxy.createProxyServer();

fastify.post('/', (request, reply) => {
    proxy.web(request.raw, reply.raw,
        {
            target: 'http://127.0.0.1:8084/a-node/demo',
            ignorePath: true
        },
        (err) => {
            if (err) {
                reply.raw.statusCode = 500;
                reply.raw.end('Error');
            }
        });
});

fastify.listen(9103);

[jaredjensen]

I had this problem with a PUT request and was able to get it working with:

proxy.on('proxyReq', (proxyReq, req, res, options) => {
  if (req.body) {
    const bodyData = JSON.stringify(req.body);
    proxyReq.setHeader('content-type', 'application/json');
    proxyReq.setHeader('content-length', Buffer.byteLength(bodyData));
    proxyReq.write(bodyData);
  }
});

I feel like I'm doing something wrong, though, and this shouldn't be necessary.

[alex88]

Thanks @jaredjensen! That fixed it for me as well!

[alex88]

In my case I had to change it to

if (req.body && ['POST', 'PATCH', 'PUT'].includes(req.method)) {
          const bodyData = JSON.stringify(req.body);
          proxyReq.setHeader('content-type', 'application/json');
          proxyReq.setHeader('content-length', Buffer.byteLength(bodyData));
          proxyReq.write(bodyData);
}

because for get requests req.body was {} and the backend service was having issues with it

[alex88]

Does anyone have an idea on how to use this for e.g. multipart requests? In my case req.body is {} (maybe because I'm using nestjs and the middleware order messes up the request object?)

Update: this has been solved after making sure that the middleware using the proxy is the first one

[verkyyi]

        let bufferStream = new Stream.PassThrough
        /**
         * Must using rawBody instead of qs.stringify because array value stringify error.
         */
        bufferStream.end(Buffer.from(ctx.request.rawBody))
        ctx.respond = false
        proxy.web(ctx.req, ctx.res, { buffer: bufferStream }, next)

Hope this can help.

[cameronbraid]

same issue - FYI I discovered it started to happen when I added koa-body middleware