#47: Passing camera related errors to the init callback

README.md

@@ -1,7 +1,7 @@
 quaggaJS
 ========
 
-- [Changelog](#changelog) (2015-06-21)
+- [Changelog](#changelog) (2015-07-06)
 
 ## What is QuaggaJS?
 
@@ -80,12 +80,16 @@ version `quagga.min.js` and places both files in the `dist` folder.
 You can check out the [examples][github_examples] to get an idea of how to
 use QuaggaJS. Basically the library exposes the following API:
 
-### Quagga.init(config, callback)
+### <a name="quaggainit">Quagga.init(config, callback)</a>
 
 This method initializes the library for a given configuration `config` (see
-below) and invokes the `callback` when Quagga is ready to start. The
+below) and invokes the `callback(err)` when Quagga has finished its
-initialization process also requests for camera access if real-time detection is
+bootstrapping phase. The initialization process also requests for camera
-configured.
+access if real-time detection is configured. In case of an error, the `err`
+parameter is set and contains information about the cause. A potential cause
+may be the `inputStream.type` is set to `LiveStream`, but the browser does
+not support this API, or simply if the user denies the permission to use the
+camera.
 
 ```javascript
 Quagga.init({
@@ -96,7 +100,11 @@ Quagga.init({
     decoder : {
       readers : ["code_128_reader"]
     }
-  }, function() {
+  }, function(err) {
+      if (err) {
+          console.log(err);
+          return
+      }
       console.log("Initialization finished. Ready to start");
       Quagga.start();
   });
@@ -357,6 +365,11 @@ on the ``singleChannel`` flag in the configuration when using ``decodeSingle``.
 
 ## <a name="changelog">Changelog</a>
 
+### 2015-07-06
+- Improvements
+  - Added `err` parameter to [Quagga.init()](#quaggainit) callback
+  function
+
 ### 2015-06-21
 - Features
   - Added ``singleChannel`` configuration to ``inputStream`` (in [config]

dist/quagga.js

@@ -8187,11 +8187,15 @@ define('camera_access',["html_utils"], function(HtmlUtils) {
      * @param {Object} failure Callback
      */
     function getUserMedia(constraints, success, failure) {
+        if (typeof navigator.getUserMedia !== 'undefined') {
             navigator.getUserMedia(constraints, function (stream) {
                 streamRef = stream;
                 var videoSrc = (window.URL && window.URL.createObjectURL(stream)) || stream;
                 success.apply(null, [videoSrc]);
             }, failure);
+        } else {
+            failure(new TypeError("getUserMedia not available"));
+        }
     }
 
     function loadedData(video, callback) {
@@ -8230,7 +8234,7 @@ define('camera_access',["html_utils"], function(HtmlUtils) {
             video.addEventListener('loadeddata', loadedDataHandler, false);
             video.play();
         }, function(e) {
-            console.log(e);
+            callback(e);
         });
     }
 
@@ -8253,7 +8257,7 @@ define('camera_access',["html_utils"], function(HtmlUtils) {
                 facing: "environment"
             }, config);
 
-        if ( typeof MediaStreamTrack.getSources !== 'undefined') {
+        if ( typeof MediaStreamTrack !== 'undefined' && typeof MediaStreamTrack.getSources !== 'undefined') {
             MediaStreamTrack.getSources(function(sourceInfos) {
                 var videoSourceId;
                 for (var i = 0; i != sourceInfos.length; ++i) {
@@ -8473,7 +8477,7 @@ function(Code128Reader,
                 if (!err) {
                     _inputStream.trigger("canrecord");
                 } else {
-                    console.log(err);
+                    return cb(err);
                 }
             });
         }

example/live_w_locator.js

@@ -11,12 +11,20 @@ $(function() {
     });
     var App = {
         init : function() {
-            Quagga.init(this.state, function() {
+            var self = this;
+
+            Quagga.init(this.state, function(err) {
+                if (err) {
+                    return self.handleError(err);
+                }
                 Quagga.registerResultCollector(resultCollector);
                 App.attachListeners();
                 Quagga.start();
             });
         },
+        handleError: function(err) {
+            console.log(err);
+        },
         attachListeners: function() {
             var self = this;
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "quagga",
-  "version": "0.6.11",
+  "version": "0.6.12",
   "description": "An advanced barcode-scanner written in JavaScript",
   "main": "dist/quagga.js",
   "devDependencies": {

spec/camera_access.spec.js

@@ -1,6 +1,5 @@
 define(['camera_access'], function(CameraAccess){
     var originalURL,
-        originalUserMedia,
         originalMediaStreamTrack,
         video,
         stream;
@@ -11,7 +10,6 @@ define(['camera_access'], function(CameraAccess){
         }];
         
         originalURL = window.URL;
-        originalUserMedia = window.getUserMedia;
         originalMediaStreamTrack = window.MediaStreamTrack;
         window.MediaStreamTrack = {};
         window.URL = null;
@@ -23,10 +21,7 @@ define(['camera_access'], function(CameraAccess){
             }
         };
         sinon.spy(tracks[0], "stop");
-        navigator.getUserMedia = function(constraints, cb) {
+
-            cb(stream);
-        };
-        sinon.spy(navigator, "getUserMedia");
         video = {
             src: null,
             addEventListener: function() {
@@ -48,11 +43,20 @@ define(['camera_access'], function(CameraAccess){
     });
     
     afterEach(function() {
-        navigator.getUserMedia = originalUserMedia;
         window.URL = originalURL;
         window.MediaStreamTrack = originalMediaStreamTrack;
     });
     
+    describe('success', function() {
+        beforeEach(function() {
+            sinon.stub(navigator, "getUserMedia", function(constraints, success) {
+                success(stream);
+            });
+        });
+
+        afterEach(function() {
+            navigator.getUserMedia.restore();
+        });
         describe('request', function () {
             it('should request the camera', function (done) {
                 CameraAccess.request(video, {}, function () {
@@ -75,3 +79,45 @@ define(['camera_access'], function(CameraAccess){
             });
         });
     });
+
+    describe('failure', function() {
+        describe("permission denied", function(){
+            before(function() {
+                sinon.stub(navigator, "getUserMedia", function(constraints, success, failure) {
+                    failure(new Error());
+                });
+            });
+
+            after(function() {
+                navigator.getUserMedia.restore();
+            });
+
+            it('should throw if getUserMedia not available', function(done) {
+                CameraAccess.request(video, {}, function(err) {
+                    expect(err).to.be.defined;
+                    done();
+                });
+            });
+        });
+
+        describe("not available", function(){
+            var originalGetUserMedia;
+
+            before(function() {
+                originalGetUserMedia = navigator.getUserMedia;
+                navigator.getUserMedia = undefined;
+            });
+
+            after(function() {
+                navigator.getUserMedia = originalGetUserMedia;
+            });
+
+            it('should throw if getUserMedia not available', function(done) {
+                CameraAccess.request(video, {}, function(err) {
+                    expect(err).to.be.defined;
+                    done();
+                });
+            });
+        });
+    });
+});

src/camera_access.js

@@ -13,11 +13,15 @@ define(["html_utils"], function(HtmlUtils) {
      * @param {Object} failure Callback
      */
     function getUserMedia(constraints, success, failure) {
+        if (typeof navigator.getUserMedia !== 'undefined') {
             navigator.getUserMedia(constraints, function (stream) {
                 streamRef = stream;
                 var videoSrc = (window.URL && window.URL.createObjectURL(stream)) || stream;
                 success.apply(null, [videoSrc]);
             }, failure);
+        } else {
+            failure(new TypeError("getUserMedia not available"));
+        }
     }
 
     function loadedData(video, callback) {
@@ -56,7 +60,7 @@ define(["html_utils"], function(HtmlUtils) {
             video.addEventListener('loadeddata', loadedDataHandler, false);
             video.play();
         }, function(e) {
-            console.log(e);
+            callback(e);
         });
     }
 
@@ -79,7 +83,7 @@ define(["html_utils"], function(HtmlUtils) {
                 facing: "environment"
             }, config);
 
-        if ( typeof MediaStreamTrack.getSources !== 'undefined') {
+        if ( typeof MediaStreamTrack !== 'undefined' && typeof MediaStreamTrack.getSources !== 'undefined') {
             MediaStreamTrack.getSources(function(sourceInfos) {
                 var videoSourceId;
                 for (var i = 0; i != sourceInfos.length; ++i) {

src/quagga.js

@@ -99,7 +99,7 @@ function(Code128Reader,
                 if (!err) {
                     _inputStream.trigger("canrecord");
                 } else {
-                    console.log(err);
+                    return cb(err);
                 }
             });
         }