Merge pull request #142 from rzoller/gzip

Decode resources with gzip encoding correctly

lib/helpers.js

@@ -7,7 +7,9 @@
 var path = require('path');
 var url = require('url');
 var sriToolbox = require('sri-toolbox');
-var XMLHttpRequest = XMLHttpRequest || require('xhr2');
+var http = require('http');
+var https = require('https');
+var zlib = require('zlib');
 
 var resourceTypes = require('./resourceTypes.json');
 var secureHosts = require('./secureHosts.json');
@@ -47,17 +49,36 @@ var upgradeToHttps = function (urlString) {
   return url.format(urlObject);
 };
 
+/**
+ * Choose corresponding module (http or https) for downloading a resource.
+ *
+ * @param {string} urlString
+ * @return {Object} http or https module
+ */
+var moduleForProtocol = function (urlString) {
+  var urlObject = url.parse(urlString);
+
+  if (urlObject.protocol === 'https:') {
+    return https;
+  }
+
+  if (urlObject.protocol === 'http:') {
+    return http;
+  }
+
+  return false;
+};
 
 /**
  * Check XHR response headers for issues that could affect SRI eligibility
  *
  * @param {Object.XMLHttpRequest} fetchResource request
  * @return {Array} list of potential issues
  */
-var eligibility = function (request) {
+var eligibility = function (response) {
   var issues = [];
 
-  var acao = request.getResponseHeader('access-control-allow-origin');
+  var acao = response.headers['access-control-allow-origin'];
   if (!acao) {
     issues.push('non-cors');
   }
@@ -69,31 +90,27 @@ var eligibility = function (request) {
 /**
  * Handle server response.
  *
+ * @param {string} data
+ * @param {Object} response
  * @param {string} resourceUrl
  * @param {Function} cb - callback
  * @return {Function.cb}
  */
-var processResource = function (resourceUrl, cb) {
-  var request = this;
-
-  if (request.readyState !== 4) {
-    return false;
-  }
-
-  if (request.status !== 200) {
+var processResource = function (data, response, resourceUrl, cb) {
+  if (response.statusCode !== 200) {
     return cb({
       'success': false,
-      'status': request.status
+      'status': response.statusCode
     });
   }
 
   return cb({
     'success': true,
-    'status': request.status,
+    'status': response.statusCode,
     'url': resourceUrl,
-    'eligibility': eligibility(request),
-    'data': request.responseText,
-    'ct': request.getResponseHeader('content-type')
+    'eligibility': eligibility(response),
+    'data': data,
+    'ct': response.headers['content-type']
   });
 };
 
@@ -111,11 +128,25 @@ var fetchResource = function (resourceUrl, cb) {
     return cb(false);
   }
 
-  var request = new XMLHttpRequest();
-  request.onreadystatechange = processResource.bind(request, resourceUrl, cb);
+  moduleForProtocol(resourceUrl).get(resourceUrl, function (response) {
+    var output;
+    if (response.headers['content-encoding'] === 'gzip') {
+      var gzip = zlib.createGunzip();
+      response.pipe(gzip);
+      output = gzip;
+    } else {
+      output = response;
+    }
 
-  request.open('GET', resourceUrl);
-  request.send();
+    var data = [];
+    output.on('data', function (chunk) {
+      data.push(chunk);
+    });
+    output.on('end', function () {
+      data = Buffer.concat(data);
+      processResource(data, response, resourceUrl, cb);
+    });
+  });
 };
 
 

test/helpers.js

@@ -8,23 +8,6 @@
 var assert = require('assert');
 var helpers = require('../lib/helpers.js');
 
-/**
- * Simulate a XMLHttpRequest object
- */
-var FauxXHR = function (attributes) {
-  var that = this,
-    headers = {};
-
-  // Store header keys as lowercase
-  Object.keys(attributes.headers).map(function (header) {
-    headers[header.toLowerCase()] = attributes.headers[header];
-  });
-
-  that.getResponseHeader = function (header) {
-    return headers[header.toLowerCase()];
-  };
-};
-
 describe('upgradeToHttps()', function () {
   describe('CDNs', function () {
     it('Known', function () {
@@ -74,15 +57,15 @@ describe('upgradeToHttps()', function () {
 describe('eligibility()', function () {
   describe('Eligible', function () {
     it('CORS', function () {
-      var allGood = new FauxXHR({ headers: { 'access-control-allow-origin': '*' } });
+      var allGood = { headers: { 'access-control-allow-origin': '*' } };
       var result = helpers.eligibility(allGood);
       assert.deepEqual(result, []);
     });
   });
 
   describe('Non-eligible', function () {
     it('non-CORS', function () {
-      var nonCORS = new FauxXHR({ headers: { 'dnt': '1' } });
+      var nonCORS = { headers: { 'dnt': '1' } };
       var result = helpers.eligibility(nonCORS);
       assert.deepEqual(result, ['non-cors']);
     });