[fix] callback as optional error handler

lib/http-proxy/index.js

@@ -35,10 +35,17 @@ function createRightProxy(type) {
     });
 
     return function(req, res /*, [head], [opts] */) {
-      var self = this,
+      var passes = this.passes || passes,
           args = [].slice.call(arguments),
           cntr = args.length - 1,
-          head;
+          head, cbl;
+
+      /* optional args parse begin */ 
+      if(typeof args[cntr] === 'function') {
+        cbl = args[cntr];
+
+        cntr--;
+      }
 
       if(
         !(args[cntr] instanceof Buffer) &&
@@ -56,6 +63,8 @@ function createRightProxy(type) {
         head = args[cntr];
       }
 
+      /* optional args parse end */
+
       ['target', 'forward'].forEach(function(e) {
         if (typeof options[e] === 'string')
           options[e] = parse_url(options[e]);
@@ -71,7 +80,7 @@ function createRightProxy(type) {
          * refer to the connection socket
          * pass(req, socket, options, head)
          */
-        if(passes[i](req, res, this, head)) { // passes can return a truthy value to halt the loop
+        if(passes[i](req, res, cbl ? this : false, head, cbl)) { // passes can return a truthy value to halt the loop
           break;
         }
       }
@@ -84,6 +93,10 @@ function ProxyServer(options, web, ws) {
   this.web     = web;
   this.ws      = ws;
   this.options = options;
+
+  this.passes = Object.keys(passes).map(function(pass) {
+    return passes[pass];
+  });
 }
 
 ProxyServer.prototype.listen = function(port) {
@@ -102,7 +115,25 @@ ProxyServer.prototype.listen = function(port) {
   return this;
 };
 
-ProxyServer.prototype.before = function() {};
+ProxyServer.prototype.before = function(passName, callback) {
-ProxyServer.prototype.after = function() {};
+  var i = false;
+  this.passes.forEach(function(v, idx) { 
+    if(v.name === passName) i = idx;
+  })
+
+  if(!i) throw new Error('No such pass');
+
+  this.passes.splice(i, 0, callback);
+};
+ProxyServer.prototype.after = function(passName, callback) {
+  var i = false;
+  this.passes.forEach(function(v, idx) { 
+    if(v.name === passName) i = idx;
+  })
+
+  if(!i) throw new Error('No such pass');
+
+  this.passes.splice(i++, 0, callback);
+};
 
 require('util').inherits(ProxyServer, EE3);

lib/http-proxy/passes/web-incoming.js

@@ -89,8 +89,8 @@ web_o = Object.keys(web_o).map(function(pass) {
    * @api private
    */
 
-  function stream(req, res, server) {
+  function stream(req, res, server, _, clb) {
-    if(options.forward) {
+    if(server.options.forward) {
       // If forward enable, so just pipe the request
       var forwardReq = (server.options.forward.protocol === 'https:' ? https : http).request(
         common.setupOutgoing(server.options.ssl || {}, server.options, req, 'forward')
@@ -106,7 +106,12 @@ web_o = Object.keys(web_o).map(function(pass) {
 
     // Error Handler
     proxyReq.on('error', function(err){
-      server.emit('error', err);
+      if(server) { 
+        server.emit('error', err); 
+      }
+      else { 
+        clb(err); 
+      }
     });
 
     req.pipe(proxyReq);

lib/http-proxy/passes/ws-incoming.js

@@ -96,7 +96,7 @@ var passes = exports;
    *
    * @api private
    */
-  function stream(req, socket, server, head) {
+  function stream(req, socket, server, head, clb) {
     common.setupSocket(socket);
 
     if (head && head.length) socket.unshift(head);
@@ -107,7 +107,12 @@ var passes = exports;
     );
     // Error Handler
     proxyReq.on('error', function(err){
-      server.emit('error', err);
+      if(server) {
+        server.emit('error', err);
+      } 
+      else {
+        clb(err);
+      }
     });
 
     proxyReq.on('upgrade', function(proxyRes, proxySocket, proxyHead) {