hanging POST requests

[joeyAghion]

Hi,
I'm using express and trying to proxy certain requests to a different server, as follows (simplified):

var httpProxy = require('http-proxy');
var apiProxy = new httpProxy.RoutingProxy();
...
app.all('/api/*', function(req, res){
  apiProxy.proxyRequest(req, res, {host: 'example.com', port: 9000});
});

...but POST requests to my server appear to just hang, and never arrive at the target server.

I'm working on a stripped-down-but-working example of this but thought I'd ask first. Has anyone seen this behavior, or are there good examples of node-http-proxy coexisting with express?
Thanks!

[AvianFlu]

I believe your issue may be solved by using the buffer method. A very good explanation can be found here.

[joeyAghion]

@AvianFlu: Thanks for the buffer pointer, but this ended up being caused by express's body-parsing.

Instead of declaring the API route (for proxying) within express routes, I configured it as middleware and used it before express.bodyParser().

Some coffeescript of the solution:

httpProxy = require 'http-proxy'
routingProxy = new httpProxy.RoutingProxy()
apiProxy = (pattern, host, port) ->
  (req, res, next) ->
    if req.url.match(pattern)
      routingProxy.proxyRequest req, res, host: host, port: port
    else
      next()

app.configure ->
  @set 'views', 'app/templates'
  # ...
  @use apiProxy /\/api\/.*/, 'localhost', 3000
  @use express.bodyParser()
  # ...

[AvianFlu]

You're correct - express's body parsing turns the request stream into a regular object. The solution is either to buffer it, as I was suggesting, or to deal with the request before the parsing, as you ended up doing. Glad you figured it out!

[coldfire22x]

I ran into this problem too .. http-proxy@0.8.0, express@2.5.8, connect@1.8.5.

In my case, it turns out that http-proxy's buffer doesn't play well with connect's bodyParser middleware. The buffer is adding listeners for the 'data' and 'end' events to the request object so that it can re-emit them later (on a call to proxyRequest, e.g.). The bodyParser middleware is also adding listeners for the 'data' and 'end' events to the request object but they are never removed. So when re-emitted by the buffer, they're picked up a second time by the bodyParser.

This can result in JSON parse errors and "Can't render headers after they are sent to the client" exceptions (and probably other errors).

[eethann]

For those having issues with this, I found that this information seemed a bit out of date or difficult to implement (too much so for me, at least), compared to using connect-restreamer. That approach is outlined in the middleware example for using the bodyParser: https://github.com/nodejitsu/node-http-proxy/blob/master/examples/middleware/bodyDecoder-middleware.js

[ijse]

So, How to solve this problem?

[cesutherland]

connect-restreamer worked for me. The last thing in my middle-ware is:

app.use(require('connect-restreamer')());

Then I have a can do the proxy request normally:

var httpProxy = require('http-proxy');
var routingProxy = new httpProxy.RoutingProxy();

app.get('/proxy/', function (req, res) {
  routingProxy.proxyRequest(req, res, {
    host : host,
    port : port
  });
});

Configuring the proxy as part of middleware before bodyParser (if this is an option for you) also worked for me.

I did not attempt the buffer solution.

[xixixao]

Also, simply not using the bodyParser also works (for anyone's future reference).

[renatoargh]

This thread has helped me. Thanks everyone.

[nicolazj]

Helpful, Thanks!