I am building a cross system admin app, which will be used as an admin tool for multiple backend systems. The app is built on top of Mean.js.
I have setup a /proxy route using "express-http-proxy" to send all sub-routes to their respective backend system endpoints. However, I need to have each request authenticated within my admin app and then decorated with the targeted backendSystem credentials before the "express-http-proxy" can continue. Here's an example of my /proxy route...
app.use('/proxy', users.requiresLogin, expressHttpProxy(config.backendSystem.host, {
forwardPath: function (req) {
return '/1.0' + require('url').parse(req.url).path;
},
decorateRequest: function (req) {
req.headers['content-type'] = 'application/json';
req.headers['backend-system-id'] = config.backendSystem.id;
req.headers['backend-system-key'] = config.backendSystem.key;
return req;
}
}));
NOTE:
Currently the backendSystem credentials are stored based on the environment my admin app is ran in. However, in the future the backendSystem credentials will be specified by the user, and this /proxy route will differently than what is currently shown.
THE ISSUE:
Proxy routes that require data within the request body don't work.
e.g. POST /comments {"user": user_id, "text": "rabble rabble rabble"}
WHAT I'VE FOUND:
bodyParser.json() and "express-https-proxy" don't play nice. I've confirmed this by removing bodyParser.json() from express.js.
However, this isn't a full solution since almost all of my other routes need bodyParser.json, e.g. /auth/signin.
Does anyone have a clean way that I can make a route exception for my /proxy route so that bodyParser.json won't be called for it?
I was able to resolve my issue by adding a regex that excluded my /proxy route to where bodyParser.json was being added within express.js. I found that from this answer
While this approach doesn't scale well, it solved my immediate issue.
As far as I understand, the root of problem is so:
if you were reading a POST request by pure node, you should be using a code like this
if (req.method == 'POST') {
console.log("POST");
var body = '';
req.on('data', function (data) {
body += data;
console.log("Partial body: " + body);
});
req.on('end', function () {
console.log("Body: " + body);
});
res.writeHead(200, {'Content-Type': 'text/html'});
res.end('post received');
}
in other words, you need to use the req.on('data') & req.on('end') events. but the problem is,that you can use this code only once. after the 'end' is called, the request is consumed.
so then you use bodyParser , it consumes the request, and the proxy have nothing to do with it.
actually, in my opinion, the proxy wait for the 'data' event to appear , but it will newer happen, so the code halts.
The solution:
you need to 're-enable' the events. I used this code and it works for me.
var express = require('express');
var bodyParser = require('body-parser');
var http = require('http');
//call for proxy package
var devRest = require('dev-rest-proxy');
//init express (as default)
var users = require('./routes/users');
var app = express();
app.use(bodyParser.json());
//set the proxy listening port
app.set('port', 8080);
//process the POST request
app.post('/users/*', function(req, res) {
//just print the body. do some logic with it
console.log("req.body: ",req.body);
//remove listeners set by bodyParser
req.removeAllListeners('data');
req.removeAllListeners('end');
//add new listeners for the proxy to use
process.nextTick(function () {
if(req.body) {
req.emit('data', JSON.stringify(req.body));
}
req.emit('end');
});
//forward the request to another server
devRest.proxy(req,res, 'localhost', 3000);
});
//start the proxy server
http.createServer(app).listen(app.get('port'), function(){
console.log("Express server listening on port " + app.get('port'));
});
module.exports = app;
the solution found on schumacher-m post (github of nodejitsu)