Node-http-proxy 全功能的 Node.js Http 代理

Question

Node-http-proxy 是一个 HTTP 代理支持 WebSocket 编程库。它适用于执行元件如反向代理服务器和负载均衡，拥有普通代理的全部功能，专为 Node.js 设置制作。

安装

npm install http-proxy --save

核心概念

A new proxy is created by calling createProxyServer and passing an options object as argument (valid properties are available here)

var httpProxy = require('http-proxy');
var proxy = httpProxy.createProxyServer(options); // See (†)

†Unless listen(..) is invoked on the object, this does not create a webserver. See below.

An object will be returned with four values:

• web req, res, [options] (used for proxying regular HTTP(S) requests)
• ws req, socket, head, [options] (used for proxying WS(S) requests)
• listen port (a function that wraps the object in a webserver, for your convenience)
• close [callback] (a function that closes the inner webserver and stops listening on given port)

It is then possible to proxy requests by calling these functions

http.createServer(function(req, res) {
  proxy.web(req, res, { target: 'http://mytarget.com:8080' });
});

Errors can be listened on either using the Event Emitter API

proxy.on('error', function(e) {
  ...
});

or using the callback API

proxy.web(req, res, { target: 'http://mytarget.com:8080' }, function(e) { ... });

When a request is proxied it follows two different pipelines (available here) which apply transformations to both the req and res object. The first pipeline (ingoing) is responsible for the creation and manipulation of the stream that connects your client to the target. The second pipeline (outgoing) is responsible for the creation and manipulation of the stream that, from your target, returns data to the client.

使用举例

设置基本的独立代理服务器

var http = require('http'),
    httpProxy = require('http-proxy');
//
// Create your proxy server and set the target in the options.
//
httpProxy.createProxyServer({target:'http://localhost:9000'}).listen(8000); // See (†)

//
// Create your target server
//
http.createServer(function (req, res) {
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.write('request successfully proxied!' + '\n' + JSON.stringify(req.headers, true, 2));
  res.end();
}).listen(9000);

†Invoking listen(..) triggers the creation of a web server. Otherwise, just the proxy instance is created.

设置自定义的独立代理服务器

This example show how you can proxy a request using your own HTTP server and also you can put your own logic to handle the request.

var http = require('http'),
    httpProxy = require('http-proxy');

//
// Create a proxy server with custom application logic
//
var proxy = httpProxy.createProxyServer({});

//
// Create your custom server and just call `proxy.web()` to proxy
// a web request to the target passed in the options
// also you can use `proxy.ws()` to proxy a websockets request
//
var server = http.createServer(function(req, res) {
  // You can define here your custom logic to handle the request
  // and then proxy the request.
  proxy.web(req, res, { target: 'http://127.0.0.1:5060' });
});

console.log("listening on port 5050")
server.listen(5050);

设置代理请求标头重新编写独立的代理服务器

This example shows how you can proxy a request using your own HTTP server that modifies the outgoing proxy request by adding a special header.

var http = require('http'),
    httpProxy = require('http-proxy');

//
// Create a proxy server with custom application logic
//
var proxy = httpProxy.createProxyServer({});

// To modify the proxy connection before data is sent, you can listen
// for the 'proxyReq' event. When the event is fired, you will receive
// the following arguments:
// (http.ClientRequest proxyReq, http.IncomingMessage req,
//  http.ServerResponse res, Object options). This mechanism is useful when
// you need to modify the proxy request before the proxy connection
// is made to the target.
//
proxy.on('proxyReq', function(proxyReq, req, res, options) {
  proxyReq.setHeader('X-Special-Proxy-Header', 'foobar');
});

var server = http.createServer(function(req, res) {
  // You can define here your custom logic to handle the request
  // and then proxy the request.
  proxy.web(req, res, {
    target: 'http://127.0.0.1:5060'
  });
});

console.log("listening on port 5050")
server.listen(5050);

从代理服务器中修改响应内容

Sometimes when you have received a HTML/XML document from the server of origin you would like to modify it before forwarding it on.

Harmon allows you to do this in a streaming style so as to keep the pressure on the proxy to a minimum.

设置独立的代理服务器延迟

var http = require('http'),
    httpProxy = require('http-proxy');

//
// Create a proxy server with latency
//
var proxy = httpProxy.createProxyServer();

//
// Create your server that makes an operation that waits a while
// and then proxies the request
//
http.createServer(function (req, res) {
  // This simulates an operation that takes 500ms to execute
  setTimeout(function () {
    proxy.web(req, res, {
      target: 'http://localhost:9008'
    });
  }, 500);
}).listen(8008);

//
// Create your target server
//
http.createServer(function (req, res) {
  res.writeHead(200, { 'Content-Type': 'text/plain' });
  res.write('request successfully proxied to: ' + req.url + '\n' + JSON.stringify(req.headers, true, 2));
  res.end();
}).listen(9008);

使用 HTTPS

You can activate the validation of a secure SSL certificate to the target connection (avoid self signed certs), just set secure: true in the options.

HTTPS -> HTTP

//
// Create the HTTPS proxy server in front of a HTTP server
//
httpProxy.createServer({
  target: {
    host: 'localhost',
    port: 9009
  },
  ssl: {
    key: fs.readFileSync('valid-ssl-key.pem', 'utf8'),
    cert: fs.readFileSync('valid-ssl-cert.pem', 'utf8')
  }
}).listen(8009);

HTTPS -> HTTPS

//
// Create the proxy server listening on port 443
//
httpProxy.createServer({
  ssl: {
    key: fs.readFileSync('valid-ssl-key.pem', 'utf8'),
    cert: fs.readFileSync('valid-ssl-cert.pem', 'utf8')
  },
  target: 'https://localhost:9010',
  secure: true // Depends on your needs, could be false.
}).listen(443);

代理 WebSockets

You can activate the websocket support for the proxy using ws:true in the options.

//
// Create a proxy server for websockets
//
httpProxy.createServer({
  target: 'ws://localhost:9014',
  ws: true
}).listen(8014);

Also you can proxy the websocket requests just calling the ws(req, socket, head) method.

//
// Setup our server to proxy standard HTTP requests
//
var proxy = new httpProxy.createProxyServer({
  target: {
    host: 'localhost',
    port: 9015
  }
});
var proxyServer = http.createServer(function (req, res) {
  proxy.web(req, res);
});

//
// Listen to the `upgrade` event and proxy the
// WebSocket requests as well.
//
proxyServer.on('upgrade', function (req, socket, head) {
  proxy.ws(req, socket, head);
});

proxyServer.listen(8015);

可选参数

httpProxy.createProxyServer supports the following options:

• target: url string to be parsed with the url module
• forward: url string to be parsed with the url module
• agent: object to be passed to http(s).request (see Node's https agent and http agent objects)
• ssl: object to be passed to https.createServer()
• ws: true/false, if you want to proxy websockets
• xfwd: true/false, adds x-forward headers
• secure: true/false, if you want to verify the SSL Certs
• toProxy: passes the absolute URL as the path (useful for proxying to proxies)
• prependPath: true/false, Default: true - specify whether you want to prepend the target's path to the proxy path
• ignorePath: true/false, Default: false - specify whether you want to ignore the proxy path of the incoming request (note: you will have to append / manually if required).
• localAddress: Local interface string to bind for outgoing connections
• changeOrigin: true/false, Default: false - changes the origin of the host header to the target URL
• auth: Basic authentication i.e. 'user:password' to compute an Authorization header.
• hostRewrite: rewrites the location hostname on (301/302/307/308) redirects.
• autoRewrite: rewrites the location host/port on (301/302/307/308) redirects based on requested host/port. Default: false.
• protocolRewrite: rewrites the location protocol on (301/302/307/308) redirects to 'http' or 'https'. Default: null.
• headers: object with extra headers to be added to target requests.

NOTE: options.ws and options.ssl are optional. options.target and options.forward cannot both be missing

If you are using the proxyServer.listen method, the following options are also applicable:

• ssl: object to be passed to https.createServer()
• ws: true/false, if you want to proxy websockets

监听代理事件

• error: The error event is emitted if the request to the target fail. We do not do any error handling of messages passed between client and proxy, and messages passed between proxy and target, so it is recommended that you listen on errors and handle them.
• proxyReq: This event is emitted before the data is sent. It gives you a chance to alter the proxyReq request object. Applies to "web" connections
• proxyReqWs: This event is emitted before the data is sent. It gives you a chance to alter the proxyReq request object. Applies to "websocket" connections
• proxyRes: This event is emitted if the request to the target got a response.
• open: This event is emitted once the proxy websocket was created and piped into the target websocket.
• close: This event is emitted once the proxy websocket was closed.
• (DEPRECATED) proxySocket: Deprecated in favor of open.

var httpProxy = require('http-proxy');
// Error example
//
// Http Proxy Server with bad target
//
var proxy = httpProxy.createServer({
  target:'http://localhost:9005'
});

proxy.listen(8005);

//
// Listen for the `error` event on `proxy`.
proxy.on('error', function (err, req, res) {
  res.writeHead(500, {
    'Content-Type': 'text/plain'
  });

  res.end('Something went wrong. And we are reporting a custom error message.');
});

//
// Listen for the `proxyRes` event on `proxy`.
//
proxy.on('proxyRes', function (proxyRes, req, res) {
  console.log('RAW Response from the target', JSON.stringify(proxyRes.headers, true, 2));
});

//
// Listen for the `open` event on `proxy`.
//
proxy.on('open', function (proxySocket) {
  // listen for messages coming FROM the target here
  proxySocket.on('data', hybiParseAndLogMessage);
});

//
// Listen for the `close` event on `proxy`.
//
proxy.on('close', function (res, socket, head) {
  // view disconnected websocket connections
  console.log('Client disconnected');
});

关闭代理

• When testing or running server within another program it may be necessary to close the proxy.
• This will stop the proxy from accepting new connections.

var proxy = new httpProxy.createProxyServer({
  target: {
    host: 'localhost',
    port: 1337
  }
});

proxy.close();

相关链接

• Github地址：https://github.com/nodejitsu/node-http-proxy
• 从0.8.x升级到目前版本：https://github.com/nodejitsu/node-http-proxy/blob/master/UPGRADING.md