AngularJS: factory $http.get JSON file

问题:

I am looking to develop locally with just a hardcoded JSON file. My JSON file is as follows (valid when put into JSON validator):

{
    \"contentItem\": [
            {
            \"contentID\" : \"1\", 
            \"contentVideo\" : \"file.mov\",
            \"contentThumbnail\" : \"url.jpg\",
            \"contentRating\" : \"5\",
            \"contentTitle\" : \"Guitar Lessons\",
            \"username\" : \"Username\", 
            \"realname\" : \"Real name\",
            \"contentTags\" : [
                { \"tag\" : \"Guitar\"},
                { \"tag\" : \"Intermediate\"},
                { \"tag\" : \"Chords\"}
            ],      
            \"contentAbout\" : \"Learn how to play guitar!\",
            \"contentTime\" : [
                { \"\" : \"\", \"\" : \"\", \"\" : \"\", \"\" : \"\"},
                { \"\" : \"\", \"\" : \"\", \"\" : \"\", \"\" : \"\"}
            ],          
            \"series\" :[
                { \"seriesVideo\" : \"file.mov\", \"seriesThumbnail\" : \"url.jpg\", \"seriesTime\" : \"time\", \"seriesNumber\" : \"1\", \"seriesTitle\" : \"How to Play Guitar\" },
                { \"videoFile\" : \"file.mov\", \"seriesThumbnail\" : \"url.jpg\", \"seriesTime\" : \"time\", \"seriesNumber\" : \"2\", \"seriesTitle\" : \"How to Play Guitar\" }
            ]
        },{
            \"contentID\" : \"2\", 
            \"contentVideo\" : \"file.mov\",
            \"contentThumbnail\" : \"url.jpg\",
            \"contentRating\" : \"5\",
            \"contentTitle\" : \"Guitar Lessons\",
            \"username\" : \"Username\", 
            \"realname\" : \"Real name\",
            \"contentTags\" : [
                { \"tag\" : \"Guitar\"},
                { \"tag\" : \"Intermediate\"},
                { \"tag\" : \"Chords\"}
            ],      
            \"contentAbout\" : \"Learn how to play guitar!\",
            \"contentTime\" : [
                { \"\" : \"\", \"\" : \"\", \"\" : \"\", \"\" : \"\"},
                { \"\" : \"\", \"\" : \"\", \"\" : \"\", \"\" : \"\"}
            ],          
            \"series\" :[
                { \"seriesVideo\" : \"file.mov\", \"seriesThumbnail\" : \"url.jpg\", \"seriesTime\" : \"time\", \"seriesNumber\" : \"1\", \"seriesTitle\" : \"How to Play Guitar\" },
                { \"videoFile\" : \"file.mov\", \"seriesThumbnail\" : \"url.jpg\", \"seriesTime\" : \"time\", \"seriesNumber\" : \"2\", \"seriesTitle\" : \"How to Play Guitar\" }
            ]
        }
    ]
}

I\'ve gotten my controller, factory, and html working when the JSON was hardcoded inside the factory. However, now that I\'ve replaced the JSON with the $http.get code, it doesn\'t work. I\'ve seen so many different examples of both $http and $resource but not sure where to go. I\'m looking for the simplest solution. I\'m just trying to pull data for ng-repeat and similar directives.

Factory:

theApp.factory(\'mainInfoFactory\', function($http) { 
    var mainInfo = $http.get(\'content.json\').success(function(response) {
        return response.data;
    });
    var factory = {}; // define factory object
    factory.getMainInfo = function() { // define method on factory object
        return mainInfo; // returning data that was pulled in $http call
    };
    return factory; // returning factory to make it ready to be pulled by the controller
});

Any and all help is appreciated. Thanks!

回答1:

Okay, here\'s a list of things to look into:

1) If you\'re not running a webserver of any kind and just testing with file://index.html, then you\'re probably running into same-origin policy issues. See:

https://code.google.com/archive/p/browsersec/wikis/Part2.wiki#Same-origin_policy

Many browsers don\'t allow locally hosted files to access other locally hosted files. Firefox does allow it, but only if the file you\'re loading is contained in the same folder as the html file (or a subfolder).

2) The success function returned from $http.get() already splits up the result object for you:

$http({method: \'GET\', url: \'/someUrl\'}).success(function(data, status, headers, config) {

So it\'s redundant to call success with function(response) and return response.data.

3) The success function does not return the result of the function you pass it, so this does not do what you think it does:

var mainInfo = $http.get(\'content.json\').success(function(response) {
        return response.data;
    });

This is closer to what you intended:

var mainInfo = null;
$http.get(\'content.json\').success(function(data) {
    mainInfo = data;
});

4) But what you really want to do is return a reference to an object with a property that will be populated when the data loads, so something like this:

theApp.factory(\'mainInfo\', function($http) { 

    var obj = {content:null};

    $http.get(\'content.json\').success(function(data) {
        // you can do some processing here
        obj.content = data;
    });    

    return obj;    
});

mainInfo.content will start off null, and when the data loads, it will point at it.

Alternatively you can return the actual promise the $http.get returns and use that:

theApp.factory(\'mainInfo\', function($http) { 
    return $http.get(\'content.json\');
});

And then you can use the value asynchronously in calculations in a controller:

$scope.foo = \"Hello World\";
mainInfo.success(function(data) { 
    $scope.foo = \"Hello \"+data.contentItem[0].username;
});

回答2:

I wanted to note that the fourth part of Accepted Answer is wrong .

theApp.factory(\'mainInfo\', function($http) { 

var obj = {content:null};

$http.get(\'content.json\').success(function(data) {
    // you can do some processing here
    obj.content = data;
});    

return obj;    
});

The above code as @Karl Zilles wrote will fail because obj will always be returned before it receives data (thus the value will always be null) and this is because we are making an Asynchronous call.

The details of similar questions are discussed in this post

---

In Angular, use $promise to deal with the fetched data when you want to make an asynchronous call.

The simplest version is

theApp.factory(\'mainInfo\', function($http) { 
    return {
        get:  function(){
            $http.get(\'content.json\'); // this will return a promise to controller
        }
});


// and in controller

mainInfo.get().then(function(response) { 
    $scope.foo = response.data.contentItem;
});

The reason I don\'t use success and error is I just found out from the doc, these two methods are deprecated.

The $http legacy promise methods success and error have been deprecated. Use the standard then method instead.

回答3:

this answer helped me out a lot and pointed me in the right direction but what worked for me, and hopefully others, is:

menuApp.controller(\"dynamicMenuController\", function($scope, $http) {
$scope.appetizers= [];
$http.get(\'config/menu.json\').success(function(data) { 
    console.log(\"success!\");
    $scope.appetizers = data.appetizers;
        console.log(data.appetizers);
    });    
});

回答4:

I have approximately these problem. I need debug AngularJs application from Visual Studio 2013.

By default IIS Express restricted access to local files (like json).

But, first: JSON have JavaScript syntax.

Second: javascript files is allowed.

So:

1. rename JSON to JS (data.json->data.js).

2. correct load command ($http.get(\'App/data.js\').success(function (data) {...

3. load script data.js to page (<script src=\"App/data.js\"></script>)

Next use loaded data an usual manner. It is just workaround, of course.

回答5:

++ This worked for me. It\'s vanilla javascirpt and good for use cases such as de-cluttering when testing with ngMocks library:

<!-- specRunner.html - keep this at the top of your <script> asset loading so that it is available readily -->
<!--  Frienly tip - have all JSON files in a json-data folder for keeping things organized-->
<script src=\"json-data/findByIdResults.js\" charset=\"utf-8\"></script>
<script src=\"json-data/movieResults.js\" charset=\"utf-8\"></script>

This is your javascript file that contains the JSON data

// json-data/JSONFindByIdResults.js
var JSONFindByIdResults = {
     \"Title\": \"Star Wars\",
     \"Year\": \"1983\",
     \"Rated\": \"N/A\",
     \"Released\": \"01 May 1983\",
     \"Runtime\": \"N/A\",
     \"Genre\": \"Action, Adventure, Sci-Fi\",
     \"Director\": \"N/A\",
     \"Writer\": \"N/A\",
     \"Actors\": \"Harrison Ford, Alec Guinness, Mark Hamill, James Earl Jones\",
     \"Plot\": \"N/A\",
     \"Language\": \"English\",
     \"Country\": \"USA\",
     \"Awards\": \"N/A\",
     \"Poster\": \"N/A\",
     \"Metascore\": \"N/A\",
     \"imdbRating\": \"7.9\",
     \"imdbVotes\": \"342\",
     \"imdbID\": \"tt0251413\",
     \"Type\": \"game\",
     \"Response\": \"True\"
};

Finally, work with the JSON data anywhere in your code

// working with JSON data in code
var findByIdResults = window.JSONFindByIdResults;

Note:- This is great for testing and even karma.conf.js accepts these files for running tests as seen below. Also, I recommend this only for de-cluttering data and testing/development environment.

// extract from karma.conf.js
files: [
     \'json-data/JSONSearchResultHardcodedData.js\',
     \'json-data/JSONFindByIdResults.js\'
     ...
]

Hope this helps.

++ Built on top of this answer https://stackoverflow.com/a/24378510/4742733

UPDATE

An easier way that worked for me is just include a function at the bottom of the code returning whatever JSON.

// within test code
let movies = getMovieSearchJSON();
.....
...
...
....
// way down below in the code
function getMovieSearchJSON() {
      return {
         \"Title\": \"Bri Squared\",
         \"Year\": \"2011\",
         \"Rated\": \"N/A\",
         \"Released\": \"N/A\",
         \"Runtime\": \"N/A\",
         \"Genre\": \"Comedy\",
         \"Director\": \"Joy Gohring\",
         \"Writer\": \"Briana Lane\",
         \"Actors\": \"Brianne Davis, Briana Lane, Jorge Garcia, Gabriel Tigerman\",
         \"Plot\": \"N/A\",
         \"Language\": \"English\",
         \"Country\": \"USA\",
         \"Awards\": \"N/A\",
         \"Poster\": \"http://ia.media-imdb.com/images/M/MV5BMjEzNDUxMDI4OV5BMl5BanBnXkFtZTcwMjE2MzczNQ@@._V1_SX300.jpg\",
         \"Metascore\": \"N/A\",
         \"imdbRating\": \"8.2\",
         \"imdbVotes\": \"5\",
         \"imdbID\": \"tt1937109\",
         \"Type\": \"movie\",
         \"Response\": \"True\"
   }
}