separate ajax proxy as middleware for reuse in other project

Author: stomita

Procfile

@@ -1 +1 @@
-web: node proxy.js
+web: node lib/app.js

README.md

@@ -21,7 +21,7 @@ $ npm install
 Run proxy server :
 
 ```
-$ node proxy.js
+$ npm start
 ```
 
 When you use JSforce in your JavaScript app, set `proxyUrl` when creating `Connection` instance. 
@@ -38,6 +38,25 @@ conn.query('SELECT Id, Name FROM Account', function(err, res) {
 });
 ```
 
+## Using as Middleware
+
+Ajax proxy works as connect middleware. For example you can include the proxy functionality in your express.js app :
+
+```javascript
+var express = require('express');
+var jsforceAjaxProxy = require('./proxy');
+var app = express();
+
+app.all('/proxy/?*', jsforceAjaxProxy());
+```
+
+If you want to accept http request from other origin, set `enableCORS` option to true.
+
+```javascript
+app.all('/proxy/?*', jsforceAjaxProxy({ enableCORS: true });
+```
+
+
 ## Note
 
 You don't have to use this app when you are building a JSforce app in Visualforce,

lib/proxy.js

@@ -0,0 +1,77 @@
+var request = require('request');
+var debug = require('debug')('jsforce-ajax-proxy');
+
+/**
+ * Allowed request headers 
+ */
+var ALLOWED_HEADERS = [
+  'Authorization',
+  'Content-Type',
+  'Salesforceproxy-Endpoint',
+  'X-Authorization',
+  'X-SFDC-Session',
+  'SOAPAction',
+  'SForce-Auto-Assign',
+  'If-Modified-Since',
+  'X-User-Agent'
+];
+
+/**
+ * Endpoint URL validation
+ */
+var SF_ENDPOINT_REGEXP =
+  /^https:\/\/[a-zA-Z0-9\.\-]+\.(force|salesforce|cloudforce|database)\.com\//;
+
+/**
+ * Create middleware to proxy request to salesforce server
+ */
+module.exports = function(options) {
+
+  options = options || {}
+  var proxyCounter = 0;
+
+  return function(req, res) {
+    if (options.enableCORS) {
+      res.header('Access-Control-Allow-Origin', options.allowedOrigin || '*');
+      res.header('Access-Control-Allow-Methods', 'GET,POST,PATCH,PUT,DELETE');
+      res.header('Access-Control-Allow-Headers', ALLOWED_HEADERS.join(','));
+      res.header('Access-Control-Expose-Headers', 'SForce-Limit-Info');
+      if (req.method === 'OPTIONS') {
+        res.end();
+        return;
+      }
+    }
+    var sfEndpoint = req.headers["salesforceproxy-endpoint"];
+    if (!SF_ENDPOINT_REGEXP.test(sfEndpoint)) {
+      res.send(400, "Proxying endpoint is not allowed.");
+      return;
+    }
+    var headers = {};
+    ALLOWED_HEADERS.forEach(function(header) {
+      header = header.toLowerCase();
+      var value = req.headers[header]
+      if (value) {
+        var name = header === 'x-authorization' ? 'authorization' : header;
+        headers[name] = req.headers[header];
+      }
+    });
+    var params = {
+      url: sfEndpoint || "https://login.salesforce.com//services/oauth2/token",
+      method: req.method,
+      headers: headers
+    };
+    proxyCounter++;
+    debug("(++req++) " + new Array(proxyCounter+1).join('*'));
+    debug("method=" + params.method + ", url=" + params.url);
+    req.pipe(request(params))
+      .on('response', function() {
+        proxyCounter--;
+        debug("(--res--) " + new Array(proxyCounter+1).join('*'));
+      })
+      .on('error', function() {
+        proxyCounter--;
+        debug("(--err--) " + new Array(proxyCounter+1).join('*'));
+      })
+      .pipe(res);
+  }
+};

lib/server.js

@@ -0,0 +1,24 @@
+/*global process */
+var http = require('http');
+var express = require('express');
+var jsforceAjaxProxy = require('./proxy');
+
+var app = express();
+
+app.configure(function () {
+  app.set('port', process.env.PORT || 3123);
+});
+
+app.configure('development', function () {
+  app.use(express.errorHandler());
+});
+
+app.all('/proxy/?*', jsforceAjaxProxy({ enableCORS: true }));
+
+app.get('/', function(req, res) {
+  res.send('JSforce AJAX Proxy');
+});
+
+http.createServer(app).listen(app.get('port'), function () {
+  console.log("Express server listening on port " + app.get('port'));
+});

package.json

@@ -1,8 +1,21 @@
 {
-  "name": "node-salesforce-proxy",
-  "private": true,
+  "name": "jsforce-ajax-proxy",
+  "description": "Ajax proxy server to access Salesforce APIs from browser JavaScript resides in outer domain.",
+  "version": "1.0.0",
+  "main": "lib/proxy.js",
+  "scripts": {
+    "start": "node lib/server.js"
+  },
+  "files": [
+    "lib",
+    "LICENSE",
+    "Procfile",
+    "README.md",
+    "package.json"
+  ],
   "dependencies": {
-    "express": "3.12.x",
-    "request": "2.36.x"
+    "debug": "^2.1.2",
+    "express": "^3.12.1",
+    "request": "^2.36.0"
   }
 }