We Keep Coding

Applying JSON.parse() to unusual JSON file

Trying to access the value field of this JSON file using JSON.parse() in Meteor, but I cannot get it to return anything. I suspect there is an error in my syntax in selecting the data from the imported JS object.
{"status":"success","data":{"subjects":[{"value":"ABC","descr":"Descriptions"}]},"message":null,"meta":{"copyright":"Copyright","referenceDttm":"Date"}}
I'm trying to store it into an array, subjectArray. This is the code I'm using:
var subjectArray = new Array();
subjectFile = HTTP.get("https://classes.cornell.edu/api/2.0/config/subjects.json?roster=FA15");
subjectJSON = JSON.parse(subjectFile);
for (int i=0; i<subjectJSON.length; i++) {
subjectArray.push(subjectJSON[i].value)
}
Pretty printed this is:
{
"data": {
"subjects": [
{
"descr": "Descriptions",
"value": "ABC"
}
]
},
"message": null,
"meta": {
"copyright": "Copyright",
"referenceDttm": "Date"
},
"status": "success"
}

Responses from HTTP calls can take a while to come back so you should read your replies in an async way. You should move all of your code related to the "get" inside a callback function. If you want to find out more about HTTP and callbacks in Meteor make sure you check the docs
If you know what "value" is in your for loop ('cause I don't), then this is your answer:
HTTP.get("https://classes.cornell.edu/api/2.0/config/subjects.json?roster=FA15", function (err, res) {
if(!!err) return false;
subjectJSON = JSON.parse(res);
for (var i = 0; i < subjectJSON.length; i++) {
subjectArray.push(subjectJSON[i].value);
}
return true;
});
Also, there is no int in JavaScript.

Converting mysql exported json object to a properly formatted javascript array of objects

Have got a json file exported from mysql. One particular line is not a well represented json object, i'm trying to convert this to a proper array of object.
var data = "{"54":
{"ID":"54",
"QTY":"1",
"NAME":"Large",
"TOTAL":1.86
},
"TOTAL":10.54,
"313":
{"ID":"313",
"QTY":2,
"NAME":"Quater Pounder",
"TOTAL":8.68
}
}"
//and wants to make it:
var data = [
{"ID" : "54",
"QTY" : "1",
"NAME": "Quarter Pounder",
"TOTAL": 8.68
},
{"ID":"313",
"QTY":2,
"NAME": "Quater Pounder",
"TOTAL":8.68
}
]

I was able to fix this by using angular.forEach(response, function(item){}), I then created a childArray, which I pushed the result of the above into.
Please see code:
angular.forEach( $scope.response, function (item) {
item.childrenList = [];
angular.forEach( JSON.parse( item.details ), function (value, id) {
item.childrenList.push( value );
})
});

How to manipulate JSON object to remove root key within Javascript?

I have a json url that returns data in the format
{
"photos" : [
{
"id": 1, "image":"https://path/to/my/image/1.jpg"
},
{
"id": 2, "image":"https://path/to/my/image/2.jpg"
}
]
}
I'm using the json in a javascript function, and need to manipulate it to remove the root key. i.e. I want something that looks like
[
{
"id": 1, "image":"https://path/to/my/image/1.jpg"
},
{
"id": 2, "image":"https://path/to/my/image/2.jpg"
}
]
I've been hacking around with various approaches, and have referred to several similar posts on SO, but nothing seems to work. The following seems like it should.
var url = 'http://path/to/my/json/feed.json';
var jsonSource = $.getJSON( url );
var jsonParsed = $.parseJSON(jsonSource);
var jsonFeed = jsonParsed.photos
What am I doing wrong?

A couple of issues there.
That's invalid JSON, in two different ways. A) The : after "photos" means that it's a property initializer, but it's inside an array ([...]) when it should be inside an object ({...}). B) There are extra " characters in front of the images keys. So the first thing is to fix that.
You're trying to use the return value of $.getJSON as though it were a string containing the JSON text. But $.getJSON returns a jqXHR object. You need to give it a success callback. That callback will be called with an object graph, the JSON is automatically parsed for you.
Assuming the JSON is fixed to look like this:
{
"photos": [
{
"id": 1,
"image": "https://path/to/my/image/1.jpg"
},
{
"id": 2,
"image": "https://path/to/my/image/2.jpg"
}
]
}
Then:
$.getJSON(url, function(data) {
var photos = data.photos;
// `photos` now refers to the array of photos
});

Ember-Data: How do "mappings" work

I'm currently trying to put something together with ember + emberdata + router + asp.net web api. Most of it seem to work, however I stuck in an error message I get when ember-data tries to findAll through the adapter for my models.
In my backend I have a model like this (C#):
public class Genre {
[Key]
public int Id { get; set; }
[Required]
[StringLength(50, MinimumLength=3)]
public string Name { get; set; }
}
Which in my app I represent it like this using ember-data:
App.Genre = DS.Model.extend({
id: DS.attr("number"),
name: DS.attr("string")
}).reopenClass({
url: 'api/genre'
});
I have also a Store defined in my App using the RESTAdapter like so:
App.store = DS.Store.create({
revision: 4,
adapter: DS.RESTAdapter.create({
bulkCommit: false
})
});
And the store is used in my controller as below:
App.GenreController = Ember.ArrayController.extend({
content: App.store.findAll(App.Genre),
selectedGenre: null
});
The router is defined as
App.router = Em.Router.create({
enableLogging: true,
location: 'hash',
root: Ember.Route.extend({
//...
genre: Em.Route.extend({
route: '/genre',
index: Ember.Route.extend({
connectOutlets: function (router, context) {
router.get('applicationController').connectOutlet('genre');
}
})
}),
//...
})
})
When I run my application, I get the following message for every object that has this same structure:
Uncaught Error: assertion failed: Your server returned a hash with the
key 0 but you have no mappings
For reference, here's the json the service is returning:
[
{
"id": 1,
"name": "Action"
},
{
"id": 2,
"name": "Drama"
},
{
"id": 3,
"name": "Comedy"
},
{
"id": 4,
"name": "Romance"
}
]
I cannot tell exactly what the problem is and since the assertion is mentioning that I need mapping, I'd like to know:
What this mapping is and how to use it.
Since the returned json is an array, should I be using a different type of controller in my app ,or is there anything I should know about when working with this type of json in ember-data? or should I change the JsonFormatter options in the server?
Any help is welcome.
I can definitely add more information if you feel this isn't enough to understand the problem.
EDIT: I've changed a few things in my backend and now my findAll() equivalent action in the server serializes the the output as the following json:
{
"genres": [
{ "id": 1, "name": "Action" },
{ "id": 2, "name": "Drama" },
{ "id": 3, "name": "Comedy" },
{ "id": 4, "name": "Romance" }
]
}
But I still can't get it to populate my models in the client and my error message has changed to this:
Uncaught Error: assertion failed: Your server returned a hash with the
key genres but you have no mappings
Not sure what else I might be doing wrong.
The method that throws this exception is sideload and checks for the mappings like this:
sideload: function (store, type, json, root) {
var sideloadedType, mappings, loaded = {};
loaded[root] = true;
for (var prop in json) {
if (!json.hasOwnProperty(prop)) { continue; }
if (prop === root) { continue; }
sideloadedType = type.typeForAssociation(prop);
if (!sideloadedType) {
mappings = get(this, 'mappings');
Ember.assert("Your server returned a hash with the key " + prop + " but you have no mappings", !!mappings);
//...
This call sideloadedType = type.typeForAssociation(prop); returns undefined and then I get the error message. The method typeForAssociation() checks for the for 'associationsByName' key which returns an empty Ember.Map.
Still no solution for this at the moment.
By the way...
My action is now like this:
// GET api/genres
public object GetGenres() {
return new { genres = context.Genres.AsQueryable() };
}
// GET api/genres
//[Queryable]
//public IQueryable<Genre> GetGenres()
//{
// return context.Genres.AsQueryable();
//}
I had to remove the original implementation which gets serialized by json.NET as I could not find config options to produce a json output as Ember-Data expects ( as in {resource_name : [json, json,...]}). Side effect of this is that I've lost built-in OData support, but I'd like to keep it. Does anyone know how could I configure it to produce different json for a collection?

The mapping can be defined in the DS.RESTAdapter. I think you could try to define something like this:
App.Store = DS.Store.extend({
adapter: DS.RESTAdapter.create({
bulkCommit: true,
mappings: {
genres: App.Genre
},
// you can also define plurals, if there is a unregular plural
// usually, RESTAdapter simply add a 's' for plurals.
// for example at work we have to define something like this
plurals: {
business_process: 'business_processes'
//else it tries to fetch business_processs
}
}),
revision: 4
});
Hope this resolves your problem.
Update:
At this time, this is not well documented, I don't remember if we found it by ourself reading the code, or perhaps Tom Dale pointed on it.
Anyway, here is the point for plurals
For the mappings, I think we were driven by the same error as you, and either we tried, either Tom teached us about this.

The RESTAdapter expects the returned JSON to be of the form:
{
"genres": [{
"id": 1,
"name": "action"
},{
"id": 2,
"name": "Drama"
}]
}
The tests are a good source of documentation, see https://github.com/emberjs/data/blob/master/packages/ember-data/tests/unit/rest_adapter_test.js#L315-329

I'm using Ember Data rev. 11 and it seems that the plurals config in DS.RESTAdapter.create never works. I looked into the codes and found a solution as following:
App.Adapter = DS.RESTAdapter.extend({
bulkCommit: false
})
App.Adapter.configure('plurals', {
series: 'series'
})

The confuse about use jquery $.ajax to read javascript file

suppose I have a config javascript file:
window.Config = {};
Config.UI = {
"Area": {},
"Layer": {},
"Sprites": {},
"Audio": {}
};
Config.UI.Area = {
"prop": {
"uuid": {
"_type": "string",
},
"frame": {
"_type": "rect",
"_value": {
"x": "0",
},
"_aka": "frame"
},
"zIndex": {
"_type": "string",
}
},
then I want use $.ajax to read this file:
$.ajax({
url:'js/config.js',
success:function (data, textStatus) {
console.log(data);
}
})
the question is how can I get some key's value in the config,by use the data $.ajax return?
like the "Config.UI" or the 'uuid' in ui.area.prop?Or can I convert them to json?

Rather than use AJAX, why not just insert a script?
var script = $('<script>');
script.attr('type', 'text/javascript');
script.attr('src', 'js/config.js');
script.bind('load', function() {
// use window.Config
});
script.appendTo('head');

icktoofay has a good suggestion, and the issue with the jQuery.ajax call looks to be a missing dataType: 'script' option which will evaluate the response and should give you object access. You might want to look into jQuery.getscript() as well.

I find it very useful and powerful to store data on the server as javascript objects and read them using Ajax. And it is very easy to do. Let me give you an example from an educational application I have written.
This is an example table of contents file (l1contents.js) that I would store on the server:
{
title : "Lesson 1",
topics : [
{name : "Topic 1", file : "l1t1data.js" },
{name : "Topic 2", file : "l1t2data.js" },
]
}
This is the javascript code I use to process the file:
$.ajax({
url : contentsFileName, // would be set to 'l1contents.js'
dataType : 'text', // yes this is correct, I want jquery to think this is text
cache : false,
success: function(data) {
var contentsObj = eval('(' + data + ')');
var lessonTitle = contentsObj.title;
for (var i = 0; i < contentsObj.topics.length; i++) {
var topic = contentsObj.topics [i];
// process topic.name and topic.file here
}
}
});
Obviously, this is simplified, but hopefully you get the idea. I simply use eval to set the object. And note that I don't even need any javascript code defining the structure of contentsObj. (I, of course, do have extensive comments defining the structure of my objects, but they are simply comments, not code.)

if your json file contains json data than you can use parseJSON() , toJSON() method.
and another solution is use eval(), this conver json data to javascript object so you can easly get a value by giving key.