I have an Ember app consuming a rails based webservice.
On the Rails side, I have some enums, they are simply arrays.
Now, I would like to retreive those enums in the Ember app, and render them for select values.
The webservice returns a JSON response :
get '/grades.json'
{"grades":["cp","ce1","ce2","cm1","cm2"]}
On the Ember side, I created a GradesRoute like this :
App.GradesRoute = Ember.Route.extend({
model: function () {
return Em.$.getJSON('api/v1/grades.json')
}
}));
Then, I think I need it in the controllers where these enums are in use:
App.StudentsController = Ember.ArrayController.extend({
needs: ['grades'],
grades: Ember.computed.alias('controllers.grades')
}
));
So at least I thought I could iterate over the grades in the students template.
{{#each grade in grades}}
{{grade}}
{{/each}}
But I get no output at all... debugging from the template and trying templateContext.get('grades').get('model') returns an empty array []
Any idea on how I could load and access this data ?
So I ended up with ApplicationRoute, which is the immediate parent of StudentsRoute, so needs is relevant in this case.
App.ApplicationRoute = Ember.Route.extend({
setupController: function(controller) {
Em.$.getJSON('api/v1/enums.json').then(function(data){
controller.set('grades', data['grades']);
controller.set('states', data['states']);
}
}
});
Now I can create an alias for each enums I need to use accross my app.
App.StudentsController = Ember.ArrayController.extend({
needs: ['application'],
grades: Ember.computed.alias('controllers.application.grades'),
states: Ember.computed.alias('controllers.application.states')
});
I'm still not confident enough to be sure this is the way to go, any suggestion is welcome !
You just have some of your paths mixed up. In StudentsController, controllers.grades refers to the actual controller, not it's model. The following code should clear things up as it's a bit more explicit in naming.
App.StudentsController = Ember.ArrayController.extend({
needs: ['grades'],
gradesController: Ember.computed.alias('controllers.grades'),
grades: Ember.computed.alias('gradesController.model.grades')
});
Also, be aware that using needs only works if your grades route is a direct parent of your students route. If it's not a direct parent, you won't get back the data you want.
Related
I have a model:
export default Model.extend({
title: attr('string'),
attributes: attr('jsonb')
});
Where attributes is a custom json filed stored as jsonb in Postgres.
let say:
{
"name":"Bob",
"city":""
}
So I can easily manipulate attributes using template
<form.element .. #property="attributes.city"/> or model.set('attributes.city','city name')
Problem: hasDirtyAttributes do not changing because technically we have old object. But when I try to copy object let say
JSON.parse(JSON.stringify(this.get('attributes')) hasDirtyAttributes works as expected
So how to write some Mixin for a Model or other workaround which on the change of any attribute property will mark hasDirtyAttributes as true. I will update whole object so doesn't matter which property actually was changed.
Same problem: https://discuss.emberjs.com/t/hasdirtyattributes-do-not-work-with-nested-attributes-json-api/15592
existing solution doesn't work for me at all:
ember-dirtier
ember-data-relationship-tracker
ember-data-model-fragments (a lot of changes under the hood and broke my app)
Update:
Some not perfect idea that help better describe what I'm want to achieve:
Let say we adding observer to any object fileds:
export default Model.extend({
init: function(){
this._super();
this.set('_attributes', Object.assign({}, this.get('attributes'))); //copy original
Object.keys(this.get('attributes')).forEach((item) => {
this.addObserver('attributes.'+ item, this, this.objectObserver);
});
}
...
})
And observer:
objectObserver: function(model, filed){
let privateFiled = '_' + filed;
if (model.get(privateFiled) != model.get(filed)) { //compare with last state
model.set(privateFiled, this.get(filed));
model.set('attributes', Object.assign({}, this.get('attributes')) );
}
}
It's works, but when I change one filed in object due to copying object objectObserver faired again on every filed. So in this key changing every filed in object I mark observed filed as dirty
The further ember development will reduce using of event listener and two-way binding, actually Glimmer components supports only One-way Data Flow. So to be friendly with future versions of emberusing one-way data flow is good approach in this case to. So In my case as I use ember boostrap solution looks like
<form.element #controlType="textarea" #onChange={{action 'attributeChange'}}
where attributeChange action do all works.
New Glimmer / Octane style based on modifier and looks like:
{{!-- templates/components/child.hbs --}}
<button type="button" {{on "click" (fn #onClick 'Hello, moon!')}}>
Change value
</button>
So let's say I've got a massive JSON file, and the general structure is roughly like so:
{
"apples": { complex object },
"oranges": { complex object },
"grapes": { complex object }
}
Is there some way to specifically target an object to return while using express? As in, say, if someone made a simple get request to my server, it'd return specifically the given object(s). I know the syntax and concept is completely wrong in this instance but for lack of a better way to say it, something like...
let testData = 'testdata.json';
app.get('/thing', res => {
res.json(testData.oranges);
}
I know you can return the entire file, but that adds a good amount of loading time in this instance, and is impractical in this particular case.
Or, alternatively - would it be better to have node parse the JSON file and split it into an apples.json, oranges.json, etc files to use? Trying to understand A, the best practice for doing something like this, and B, the most effective way to translate this into a practical application for a medium sized project.
Any thoughts or advice along this line - even if it's a library recommendation - would be greatly appreciated.
It should work if you make a POST request caring the payload of the specific 'thing', and then returning an object based on that thing. Example:
let testData = {
"apples": { complex object },
"oranges": { complex object },
"grapes": { complex object }
};
app.post('/route', (req, res) => {
thing = req.body.thing;
res.json(testData[thing]);
}
This is a GET request for some data and essentially since the JSON file can be used as a key/value store to query for the desired response data.
Assuming the query parameter for specifying the desired key for the object to return is part then the following example would work:
const testData = require('./testdata.json');
app.get('/thing', (req, res) => res.json(testdata[req.query.part]);
Querying for /thing?part=apples would return testdata.apples in the response.
This is a slightly messy questions. Although it appears I'm asking question about amCharts, I really just trying to figure how to extract an array from HTTP request and then turn it into a variable and place it in to 3-party javacript.
It all starts here, with this question, which was kindly answered by AmCharts support.
As one can see from the plnker. The chart is working. Data for the chart is hard coded:
`var chartData = [{date: new Date(2015,2,31,0,0,0, 0),value:372.10,volume:2506100},{date: new Date(2015,3,1,0, 0, 0, 0),value:370.26,volume:2458100},{date: new Date(2015,3,2,0, 0, 0, 0),value:372.25,volume:1875300},{date: new Date(2015,3,6,0, 0, 0, 0),value:377.04,volume:3050700}];`
So we know the amCharts part works. Know where the problem is changing hard coded data to a json request so it can be dynamic. I don't think this should be tremendously difficult, but for the life of me I can't seem figure it out.
The first issue is I can't find any documentation on .map, .subscribe, or .observable.
So here is a plunker that looks very similar to the first one, however it has an http providers and injectable. It's broken, because I can't figure out how to pull the data from the service an place it into the AmCharts function. I know how pull data from a http provider and display it in template using NgFor, but I don't need it in the template (view). As you can see, I'm successful in transferring the data from the service, with the getTitle() function.
this.chart_data =_dataService.getEntries();
console.log('Does this work? '+this.chart_data);
this.title = _dataService.getTitle();
console.log('This works '+this.title);
// Transfer the http request to chartData to it can go into Amcharts
// I think this should be string?
var chartData = this.chart_data;
So the ultimate question is why can't I use a service to get data, turn that data into a variable and place it into a chart. I suspect a few clues might be in options.json as the json might not be formatted correctly? Am I declaring the correct variables? Finally, it might have something to do with observable / map?
You have a few things here. First this is a class, keep it that way. By that I mean to move the functions you have inside your constructor out of it and make them methods of your class.
Second, you have this piece of code
this.chart_data =_dataService.getEntries().subscribe((data) => {
this.chart_data = data;
});
What happens inside subscribe runs asynchronously therefore this.chart_data won't exist out of it. What you're doing here is assigning the object itself, in this case what subscribe returns, not the http response. So you can simply put your library initialization inside of the subscribe and that'll work.
_dataService.getEntries().subscribe((data) => {
if (AmCharts.isReady) {
this.createStockChart(data);
} else {
AmCharts.ready(() => this.createStockChart(data));
}
});
Now, finally you have an interesting thing. In your JSON you have your date properties contain a string with new Date inside, that's nothing but a string and your library requires (for what I tested) a Date object, so you need to parse it. The problem here is that you can't parse nor stringify by default a Date object. We need to convert that string to a Date object.
Look at this snippet code, I used eval (PLEASE DON'T DO IT YOURSELF, IS JUST FOR SHOWING PURPOSES!)
let chartData = [];
for(let i = 0; i < data[0].chart_data.length; i++) {
chartData.push({
// FOR SHOWING PURPOSES ONLY, DON'T TRY IT AT HOME
// This will parse the string to an actual Date object
date : eval(data[0].chart_data[i].date);
value : data[0].chart_data[i].value;
volume : data[0].chart_data[i].volume;
});
}
Here what I'm doing is reconstructing the array so the values are as required.
For the latter case you'll have to construct your json using (new Date('YOUR DATE')).toJSON() and you can parse it to a Date object using new Date(yourJSON) (referece Date.prototype.toJSON() - MDN). This is something you should resolve in your server side. Assuming you already solved that, your code should look as follows
// The date property in your json file should be stringified using new Date(...).toJSON()
date : new Date(data[0].chart_data[i].date);
Here's a plnkr with the evil eval. Remember, you have to send the date as a JSON from the server to your client and in your client you have to parse it to a Date.
I hope this helps you a little bit.
If the getEntries method of DataService returns an observable, you need to subscribe on it to get data:
_dataService.getEntries().subscribe(
(data) => {
this.chart_data = data;
});
Don't forget that data are received asynchronously from an HTTP call. The http.get method returns an observable (something "similar" to promise) will receive the data in the future. But when the getEntries method returns the data aren't there yet...
The getTitle is a synchronous method so you can call it the way you did.
Consider a REST URL like /api/users/findByCriteria which receives POSTed JSON that contains details of the criteria, and outputs a list of Users.
How would one call this with Restangular so that its results are similar to Restangulars getList()?
Restangular.all('users').post("findByCriteria", crit)... might work, but I don't know how to have Restangular recognize that the result will be a list of Users
Restangular.all('users').getListFromPOST("findByCriteria", crit)... would be nice to be able to do, but it doesn't exist.
Doing a GET instead of a POST isn't an option, because the criteria is complex.
Well,
I experience same problem and I workaround it with plain function, which return a plain array of objects. but it will remove all Restangular helper functions. So, you cant use it.
Code snippet:
Restangular.one('client').post('list',JSON.stringify({
offset: offset,
length: length
})).then(
function(data) {
$scope.clients = data.plain();
},
function(data) {
//error handling
}
);
You can get a POST to return a properly restangularized collection by setting a custom handler for OnElemRestangularized in a config block. This handler is called after the object has been Restangularized. isCollection is passed in to show if the obect was treated as a collection or single element. In the code below, if the object is an array, but was not treated as collection, it is restangularized again, as a collection. This adds all the restangular handlers to each element in the array.
let onElemR = (changedElem, isCollection, route, Restangular: restangular.IService) => {
if (Array.isArray(changedElem) && !isCollection ) {
return Restangular.restangularizeCollection(null, changedElem, changedElem.route);
}
return changedElem;
};
RestangularProvider.setOnElemRestangularized(onElemR);
I would like to know if any better way to create multiple collections fetching from a single big JSON file. I got a JSON file looks like this.
{
"Languages": [...],
"ProductTypes": [...],
"Menus": [...],
"Submenus": [...],
"SampleOne": [...],
"SampleTwo": [...],
"SampleMore": [...]
}
I am using the url/fetch to create each collection for each node of the JSON above.
var source = 'data/sample.json';
Languages.url = source;
Languages.fetch();
ProductTypes.url = source;
ProductTypes.fetch();
Menus.url = source;
Menus.fetch();
Submenus.url = source;
Submenus.fetch();
SampleOne.url = source;
SampleOne.fetch();
SampleTwo.url = source;
SampleTwo.fetch();
SampleMore.url = source;
SampleMore.fetch();
Any better solution for this?
Backbone is great for when your application fits the mold it provides. But don't be afraid to go around it when it makes sense for your application. It's a very small library. Making repetitive and duplicate GET requests just to fit backbone's mold is probably prohibitively inefficient. Check out jQuery.getJSON or your favorite basic AJAX library, paired with some basic metaprogramming as following:
//Put your real collection constructors here. Just examples.
var collections = {
Languages: Backbone.Collection.extend(),
ProductTypes: Backbone.Collection.extend(),
Menus: Backbone.Collection.extend()
};
function fetch() {
$.getJSON("/url/to/your/big.json", {
success: function (response) {
for (var name in collections) {
//Grab the list of raw json objects by name out of the response
//pass it to your collection's constructor
//and store a reference to your now-populated collection instance
//in your collection lookup object
collections[name] = new collections[name](response[name]);
}
}
});
}
fetch();
Once you've called fetch() and the asyn callback has completed, you can do things like collections.Menus.at(0) to get at the loaded model instances.
Your current approach, in addition to being pretty long, risks retrieving the large file multiple times (browser caching won't always work here, especially if the first request hasn't completed by the time you make the next one).
I think the easiest option here is to go with straight jQuery, rather than Backbone, then use .reset() on your collections:
$.get('data/sample.json', function(data) {
Languages.reset(data['Languages']);
ProductTypes.reset(data['ProductTypes']);
// etc
});
If you wanted to cut down on the redundant code, you can put your collections into a namespace like app and then do something like this (though it might be a bit too clever to be legible):
app.Languages = new LanguageCollection();
// etc
$.get('data/sample.json', function(data) {
_(['Languages', 'ProductTypes', ... ]).each(function(collection) {
app[collection].reset(data[collection]);
})
});
I think you can solve your need and still stay into the Backbone paradigm, I think an elegant solution that fits to me is create a Model that fetch the big JSON and uses it to fetch all the Collections in its change event:
var App = Backbone.Model.extend({
url: "http://myserver.com/data/sample.json",
initialize: function( opts ){
this.languages = new Languages();
this.productTypes = new ProductTypes();
// ...
this.on( "change", this.fetchCollections, this );
},
fetchCollections: function(){
this.languages.reset( this.get( "Languages" ) );
this.productTypes.reset( this.get( "ProductTypes" ) );
// ...
}
});
var myApp = new App();
myApp.fetch();
You have access to all your collections through:
myApp.languages
myApp.productTypes
...
You can easily do this with a parse method. Set up a model and create an attribute for each collection. There's nothing saying your model attribute has to be a single piece of data and can't be a collection.
When you run your fetch it will return back the entire response to a parse method that you can override by creating a parse function in your model. Something like:
parse: function(response) {
var myResponse = {};
_.each(response.data, function(value, key) {
myResponse[key] = new Backbone.Collection(value);
}
return myResponse;
}
You could also create new collections at a global level or into some other namespace if you'd rather not have them contained in a model, but that's up to you.
To get them from the model later you'd just have to do something like:
model.get('Languages');
backbone-relational provides a solution within backbone (without using jQuery.getJSON) which might make sense if you're already using it. Short answer at https://stackoverflow.com/a/11095675/70987 which I'd be happy to elaborate on if needed.