I've got a very simple object, called "tag" that has only a string primary key. When I go to edit it...
var tag = Restangular.one('tags', 'cat')
.get(function() { // fetches { id: 'cat' } from server
// edit the tag
tag.id = 'dog';
// save changes
tag.post().then(beHappy, beSad);
});
The request that gets sent off is a call to:
POST /tags/cat/dog
with the correct data:
{ id: 'dog' }
I have no doubt that everything work fine if I wasn't trying to modify my primary key, but my server-side REST API isn't expecting the /oldId/newId format, and so I get a 404. Is this a bug in Restangular, or does my REST API need repairing?
Apparently I've been doing CRUD wrong, doing POST for updates and PUT for creates, which is exactly backwards.
Changing it to tag.put() fixed it.
Related
I have this Backbone.js model and view code, where I am trying to get a value from a text field, and fetch data from REST api based on this value. I am having problems modifying the base URL.
Model with base URL:
var TodoItem = Backbone.Model.extend({
urlRoot : 'http://localhost/Codeigniter/index.php/testcontroller',
initialize: function(){
this.set('id', 1);
},
defaults: {
name: '',
age: ''
}
});
var todoitem = new TodoItem({name: "name"});
Function where I am setting new URL:
getUrl: function(celebname){
var urlstr = "http://localhost/Codeigniter/index.php/testcontroller/getdatabasedata?searchvalue="+celebname;
return urlstr;
},
Function that fetches data from the REST api.
getdata: function (event) {
var celebname = $('#celebname').val();
this.model.set({name: celebname});
this.model.save({}, { urlRoot: this.getUrl(celebname)});
this.model.fetch();
},
At the moment I am getting this error:
GET http://localhost/Codeigniter/index.php/testcontroller/1
I cannot change the base url using the getURL function to search for the value from input field.Instead is using the base url and the id at the end.
If I am not setting out the ID in the initialize function of the model, then I get this error:
POST http://localhost/Codeigniter/index.php/testcontroller/getdatabasedata?searchvalue=Rome
From what I have read online this is because there is no id assigned to the model.
How can I get the input field value, build the URL, and fetch data using the GET method?
Thank you
Backbone works incredibly well with true RESTful APIs. Part of the issue here is that the API you have does not really map well with the Backbone model i.e. it's not exactly RESTful. As a result, you're going to have to resort to "hacks" to have the client and server get along. Dynamically modifying the route of a model is an example of one such hack.
What might help get you better answers is if you could elaborate a bit more on the use-case you have in mind.
From what I can tell, you're not really trying to persist a TodoItem. Rather, you're trying to pre-populate it with some base data. If this is true, then you really should not be doing a save -- you should just be doing a fetch.
getdata: function (event) {
var celebname = $('#celebname').val();
var id = this.model.id;
this.model.id = 'getdatabasedata';
this.model.fetch({data: {searchvalue: celebname}});
this.model.id = id;
}
Passing the data option will tell jQuery to use it as a query string param.
Again, this is very hacky and I would not recommend it, but it will accomplish what you're trying to do.
I am using the latest versions of Angular, breeze, EF.
I am constructing a complex object on a client called a Quote which is added to a job. This has a QuoteMeasure added to it. One of the properties of QuoteMeasure is a navigation property called measure:
var quote = em.createEntity("Quote", { id: breeze.core.getUuid() }),
quoteMeasure,
measure;
measure = _getMeasureFromLookups(4);
quoteMeasure = em.createEntity("QuoteMeasure", { id: breeze.core.getUuid(), quoteId: quote.id });
I have tried the following which executes a query to the server
quoteMeasure.measureId = measure.id;
quoteMeasure.entityAspect.loadNavigationProperty("measure").then(function () {
console.log(quoteMeasure.measure);
});
quote.quoteMeasures.push(quoteMeasure);
job.quotes.push(quote);
to url /Breeze/Data/Measure?$filter=Id%20eq%204&
which does not exist. I would ideally like to set the navigation property manually as it is static data and previously obtained from a breeze query lookups on the server:
[HttpGet]
public object Lookups()
{
var measures = UnitOfWork.MeasureRepository.Get(null, q => q.OrderBy(m => m.Ordinal)).ToList();
return new { measures = measures };
}
This is what the function _getMeasureFromLookups does, it looks up the previously stored measure. I would like to do assign it this way:
quoteMeasure.measure = measure;
But I get the following meaningless error on the client:
Error: A is undefined M#//llhst/X/Scripts/breeze.min.js:1 d/f.set#//llhst/X/Scripts/breeze.min.js:5 _createNewQuote#//llhst/X/Scripts/app/services/jobService.js:76
This I assume is because a full tree of objects has been downloaded via the lookup rather than an individual measure entity. In http://www.breezejs.com/documentation/navigation-properties there is a section on 'Omitting navigation properties' but then it neglects to tell you how to do this.
So my question is what is best practise for loading navigation property data offline? How can I modify the sample above so that it works?
If I understand your requirement correctly, you should be able to construct your quote and quoteMeasure entities as follows:
var quote = em.createEntity("Quote", { id: breeze.core.getUuid() });
//the assignment quoteId: quote.id is the same as quote.quoteMeasures.push(quoteMeasure)
//you don't need to add it again to the collection
var quoteMeasure = em.createEntity("QuoteMeasure", { id: breeze.core.getUuid(), quoteId: quote.id });
var measure = _getMeasureFromLookups(4);
quoteMeasure.measure = measure;
//or
//quoteMeasure.measureId = measure.id
//your _getMeasureFromLookups should look something like this
function _getMeasureFromLookups(measureId) {
//getEntityByKey will look up Measure from client cache
return em.getEntityByKey('Measure', measureId);
}
Calling loadNavigationProperty will initiate a query to the server.
The 'Omitting navigation properties' section actually tells you how you can omit the principal side of the association. So for example, to apply it to your EF model, if you don't want a Quote to be able to navigate to all QuoteMeasures, you can do the following:
//EF Model on Server
public class Quote {
//Simply remove or comment this collection navigation property
//public virtual ICollection<QuoteMeasure> QuoteMeasures { get; set; }
}
Hope this helps.
Seems the problem was the ommission of these statements:
Configuration.ProxyCreationEnabled = false;
Configuration.LazyLoadingEnabled = false;
Not having this caused the preloading of not only the navigation properties but all of theirs as well which caused the obscure error I noted above. No other modifications were required to get the code working.
EntityAspect.loadNavigationProperty() always makes a request to the server. If you want properties be loaded without making a separate request, do Eager loading with EF.
If you have several properties which are null when breeze fetches them, and you don't want to make several loadNavigationProperty calls, use EntityQuery.expand() method. You can list any properties you need to be loaded
So thanks to SO I can pass an object from node to the client, but then getting it into a knockout view model is a bit awkward. These are the steps I have so far (I've included links to the relevant lines as they appear in my github project. Thought the context might help.):
Apply JSON.stringify and pass to the jade file
recipeJSON: JSON.stringify(recipe);
Wrap this in a function in a header script that just parses the JSON and returns the result
script
function getRecipeObject() {
var r = '!{recipeJSON}';
return JSON.parse(r);
}
Call this function and pass the result to a view model constructor
self.recipe = ko.observable(new Recipe(getRecipeObject()));
This works but is there a better way?
Question clarification (Edit): I feel step 2 shouldn't be necessary. Is there a way to directly pass the JSON from node to the Recipe() constructor, without the getRecipeObject() acting as an intermediate step? I tried passing recipeJSON in directly like so
self.recipe = ko.observable(JSON.parse('!{recipeJSON}'));
That doesn't work I think because its not a jade template and has no access to the variable.
According to the answer to this question rendering data into scripts is bad practice and I should instead make an XHR call on page load instead.
Edit
I just saw you linked a github repo! So you're already familiar with most of this...you even have an endpoint set up at /recipe/:id/view, so now I'm really confused...what isn't working out for you? Just the last step of deserialization using ko.utils.*?
Sorry about all the exposition -- I thought this was way more rudimentary than it actually was; I hope no offense taken there!
You really don't want to return a script to execute -- instead, treat this as a DTO: an object that just stores data (no behaviors). An example would be:
{
recipeID: 12,
reviewIDs: [42, 12, 55, 31],
rating: 4.2
recipeName: "A super tasty pie!"
}
This object (representation) is a projection -- a simplified version of the full data stored in the database.
The next step is to create an endpoint to access that data on the server. Let's assume you're using Express:
var app = express();
app.get('/recipes/:recipeID', function(req, res) {
var recipeID = req.params.recipeID;
// It would be cool if this existed, huh?
getRecipeAsync(recipeID, function(recipe) {
res.status(200).json(recipe);
});
});
If you send a GET request to your (hypothetical) application (let's say it's https://localhost:8080/recipes/12), you'll get json representing the (admittedly imaginary) recipe with ID 12.
You can accomplish getting the JSON with jQuery (or any other library that makes XHR nice and pretty)
var recipeID = 12;
$.ajax({
url: "/recipes/" + recipeID,
type: "GET"
}).then(function(recipe) {
console.log("Hey! I got the recipe: %O", recipe);
// Note: you might need to use ko.utils.fromJS(recipe) if the returned
// data is JSON that ISN'T deserialized into an object
var recipeObservable = ko.utils.fromJS(recipe);
});
That's about everything you need to know. Obviously, the devil's in the details, but that's basic idea; let me know if that helps!
I have the following Model:
window.MyModel = Backbone.Model.extend({
initialize: function(props){
this.url = props.url;
}
parse: function(){
// #override- parsing data fetched from URL
}
});
// instantiate
var mod = new MyModel({url: 'some/url/here'});
I use this global variable 'mod' to fetch some data into this model from backend.
// fetch
mod.fetch({
success: function(){ ...},
error: ...
});
All above works well....
My Issue: I want to reuse this model by changing resetting the url and call fetch but it does not update the url somehow. I have tried the following:
mod.fetch({
data: {url:'/some/other/url'},
postData: true,
success: function(){ //process data},
error: ...
});
mod.set({url: '/some/other/url'});
// called fetch() without data: and postData: attributes as mentioned in previous
How do I set the url for my model so that I could call fetch() and it fetches data from updated url? Am I missing something. Thanks for any pointers..
UPDATE 1: Basically, I am unable to get updated values if I did
model.set({url: 'new value'});
followed by
model.fetch();
'model' is a global variable. Creating a fresh instance of 'model' works:
model = new Model({url:'/some/other/url'});
model.fetch();
however, works as required. Does this mean that a model instance is permanently attached to a url and it cannot be reset?
ANSWER TO MY QUESTION in UPDATE 1 Model instance is not permanently attached to a url. It can be reset dynamically. Please read through #tkone's thorough explanation and then #fguillens' solution for a better understanding.
After have understood the #tkone 's explanation...
If you still want to have a dynamic Model.url you always can delay its construction to run time, try this:
window.MyModel = Backbone.Model.extend({
url: function(){
return this.instanceUrl;
},
initialize: function(props){
this.instanceUrl = props.url;
}
}
Well the answer here is that you want to do:
mod.url = '/some/other/url'
The URL isn't part of the instance of the model itself, but rather an attribute of the MyModel object that you're creating your model instance from. Therefore, you'd just set it like it was an normal JavaScript object property. set is used only when the data you're setting (or conversely getting with get) is actually an attribute of the data you want to send/receive from the server.
But why you're changing the URL is the question we should be asking. The idea behind Backbone's model/collection system is that you speak to a REST endpoint and each model has a corresponding endpoint.
Like you've got a blog and that blog has an "entry" object which is available at:
/rest/entry/
And you've got a Backbone model for Entry:
Entry = Backbone.Model.extend({urlBase: '/rest/entry'});
Now when you save or fetch Backbone knows how this works.
So like you're making a new model:
e = new Entry();
e.set({title: "my blog rulez", body: "this is the best blog evar!!!!1!!"});
e.save();
This would then make Backbone do an HTTP POST request to /rest/entry with the body:
{
"title": "my blog rulez",
"body": "this is the best blog evar!!!!1!!"
}
(When you do your mod.set({url: '/some/other/url'}); you're actually adding a field called url to the dataset, so the server would send "url": "/some/other/url" as part of that JSON POST body above:
{
"title": "my blog rulez",
"body": "this is the best blog evar!!!!1!!",
"url": "/some/other/url"
}
The server would then respond with an HTTP 200 (or 201) response with the same model, only with, like, say, and ID attached:
{
"id": 1,
"title": "my blog rulez",
"body": "this is the best blog evar!!!!1!!"
}
And that's not what you're looking for, right?)
Now you've got this model and it's got an ID. This means if you change it:
e.set('title', 'my blog is actually just ok');
e.save()
Backbone now makes an HTTP PUT request on /rest/entry/1 to update the resource on the server.
The server sees that you're talking about ID 1 on the /rest/entry/ endpoint, so knows to update an existing record (and send back an HTTP 200).
TL;DR
Don't change the URL, Backbone will. Make a new model for a new piece of data.
model.urlRoot = "/your/url"
OR
model.urlRoot = function(){ return "/your/url"; }
OR
model.url = "/your/url"
OR
model.url = function(){ return "/your/url"; }
Default 'url' property of a Backbone.Model object is as below. Backbone.js doc says:
Default URL for the model's representation on the server -- if you're using Backbone's restful methods, override this to change the endpoint that will be called.
url: function() {
var base = getValue(this, 'urlRoot') || getValue(this.collection, 'url') || urlError();
if (this.isNew()) return base;
return base + (base.charAt(base.length - 1) == '/' ? '' : '/') + encodeURIComponent(this.id);
},
Clearly, It first gets the value of urlRoot, if not available, it will look at the url of the collection to which model belongs. By defining urlRoot instead of url has an advantage of falling back to collection url in case urlRoot is null.
You can set url as option in fetch function, like this:
var mod = new MyModel();
mod.fetch({
url: '/some/other/url',
data: {}
});
I've used the webOS Ares tool to create a relatively simple App. It displays an image and underneath the image are two labels. One is static, and the other label should be updated with new information by tapping the image.
When I tap the image, I wish to obtain a JSON object via a URL (http://jonathanstark.com/card/api/latest). The typcial JSON that is returned looks like this:
{"balance":{"amount":"0","amount_formatted":"$0.00","balance_id":"28087","created_at":"2011-08-09T12:17:02-0700","message":"My balance is $0.00 as of Aug 9th at 3:17pm EDT (America\/New_York)"}}
I want to parse the JSON's "amount_formatted" field and assign the result to the dynamic label (called cardBalance in main-chrome.js). I know that the JSON should return a single object, per the API.
If that goes well, I will create an additional label and convert/assign the "created_at" field to an additional label, but I want to walk before I run.
I'm having some trouble using AJAX to get the JSON, parse the JSON, and assign a string to one of the labels.
After I get this working, I plan to see if I can load this result on the application's load instead of first requiring the user to tap.
So far, this is my code in the main-assistant.js file. jCard is the image.
Code:
function MainAssistant(argFromPusher) {}
MainAssistant.prototype = {
setup: function() {
Ares.setupSceneAssistant(this);
},
cleanup: function() {
Ares.cleanupSceneAssistant(this);
},
giveCoffeeTap: function(inSender, event) {
window.location = "http://jonathanstark.com/card/#give-a-coffee";
},
jcardImageTap: function(inSender, event) {
//get "amount_formatted" in JSON from http://jonathanstark.com/card/api/latest
//and assign it to the "updatedBalance" label.
// I need to use Ajax.Request here.
Mojo.Log.info("Requesting latest card balance from Jonathan's Card");
var balanceRequest = new Ajax.Request("http://jonathanstark.com/card/api/latest", {
method: 'get',
evalJSON: 'false',
onSuccess: this.balanceRequestSuccess.bind(this),
onFailure: this.balanceRequestFailure.bind(this)
});
//After I can get the balance working, also get "created_at", parse it, and reformat it in the local time prefs.
},
//Test
balanceRequestSuccess: function(balanceResponse) {
//Chrome says that the page is returning X-JSON.
balanceJSON = balanceResponse.headerJSON;
var balanceAmtFromWeb = balanceJSON.getElementsByTagName("amount_formatted");
Mojo.Log.info(balanceAmtFromWeb[0]);
//The label I wish to update is named "updatedBalance" in main-chrome.js
updatedBalance.label = balanceAmtFromWeb[0];
},
balanceRequestFailure: function(balanceResponse) {
Mojo.Log.info("Failed to get the card balance: " + balanceResponse.getAllHeaders());
Mojo.Log.info(balanceResponse.responseText);
Mojo.Controller.errorDialog("Failed to load the latest card balance.");
},
//End test
btnGiveCoffeeTap: function(inSender, event) {
window.location = "http://jonathanstark.com/card/#give-a-coffee";
}
};
Here is a screenshot of the application running in the Chrome browser:
In the browser, I get some additional errors that weren't present in the Ares log viewer:
XMLHttpRequest cannot load http://jonathanstark.com/card/api/latest. Origin https://ares.palm.com is not allowed by Access-Control-Allow-Origin.
and
Refused to get unsafe header "X-JSON"
Any assistance is appreciated.
Ajax is the right tool for the job. Since webOS comes packaged with the Prototype library, try using it's Ajax.Request function to do the job. To see some examples of it, you can check out the source code to a webOS app I wrote, Plogger, that accesses Blogger on webOS using Ajax calls. In particular, the source for my post-list-assistant is probably the cleanest to look at to get the idea.
Ajax is pretty much the way you want to get data, even if it sometimes feels like overkill, since it's one of the few ways you can get asynchronous behavior in JavaScript. Otherwise you'd end up with code that hangs the interface while waiting on a response from a server (JavaScript is single threaded).