Is a factory which creates a resource object that lets you interact with RESTful server-side data sources.
The returned resource object has action methods which provide high-level behaviors without
the need to interact with the low level $xhr service or
raw XMLHttpRequest.
$resource(url[, paramDefaults][, actions]);
url – {string} –
A parameterized URL template with parameters prefixed by : as in
/user/:username.
paramDefaults(optional) – {Object} –
Default values for url parameters. These can be overridden in
actions methods.
Each key value in the parameter object is first bound to url template if present and then any
excess keys are appended to the url search query after the ?.
Given a template /path/:verb and parameter {verb:'greet', salutation:'Hello'} results in
URL /path/greet?salutation=Hello.
If the parameter value is prefixed with @ then the value of that parameter is extracted from
the data object (useful for non-GET operations).
actions(optional) – {Object.<Object>} –
Hash with declaration of custom action that should extend the default set of resource actions. The declaration should be created in the following format:
{action1: {method:?, params:?, isArray:?, verifyCache:?},
action2: {method:?, params:?, isArray:?, verifyCache:?},
...}
Where:
action – {string} – The name of action. This name becomes the name of the method on your
resource object.method – {string} – HTTP request method. Valid methods are: GET, POST, PUT, DELETE,
and JSON (also known as JSONP).params – {object=} – Optional set of pre-bound parameters for this action.returns section.{Object}
– A resource "class" object with methods for the default set of resource actions
optionally extended with custom actions. The default set contains these actions:
{ 'get': {method:'GET'},
'save': {method:'POST'},
'query': {method:'GET', isArray:true},
'remove': {method:'DELETE'},
'delete': {method:'DELETE'} };
Calling these methods invoke an angular.service.$xhr with the specified http method,
destination and parameters. When the data is returned from the server then the object is an
instance of the resource class save, remove and delete actions are available on it as
methods with the $ prefix. This allows you to easily perform CRUD operations (create, read,
update, delete) on server-side data like this:
var User = $resource('/user/:userId', {userId:'@id'});
var user = User.get({userId:123}, function(){
user.abc = true;
user.$save();
});
It is important to realize that invoking a $resource object method immediately returns an
empty reference (object or array depending on isArray). Once the data is returned from the
server the existing reference is populated with the actual data. This is a useful trick since
usually the resource is assigned to a model which is then rendered by the view. Having an empty
object results in no rendering, once the data arrives from the server then the object is
populated with the data and the view automatically re-renders itself showing the new data. This
means that in most case one never has to write a callback function for the action methods.
The action methods on the class object or instance object can be invoked with the following parameters:
Resource.action([parameters], [callback])Resource.action(postData, [parameters], [callback])instance.$action([parameters], [callback]) // Define CreditCard class
var CreditCard = $resource('/user/:userId/card/:cardId',
{userId:123, cardId:'@id'}, {
charge: {method:'POST', params:{charge:true}}
});
// We can retrieve a collection from the server
var cards = CreditCard.query();
// GET: /user/123/card
// server returns: [ {id:456, number:'1234', name:'Smith'} ];
var card = cards[0];
// each item is an instance of CreditCard
expect(card instanceof CreditCard).toEqual(true);
card.name = "J. Smith";
// non GET methods are mapped onto the instances
card.$save();
// POST: /user/123/card/456 {id:456, number:'1234', name:'J. Smith'}
// server returns: {id:456, number:'1234', name: 'J. Smith'};
// our custom method is mapped as well.
card.$charge({amount:9.99});
// POST: /user/123/card/456?amount=9.99&charge=true {id:456, number:'1234', name:'J. Smith'}
// server returns: {id:456, number:'1234', name: 'J. Smith'};
// we can create an instance as well
var newCard = new CreditCard({number:'0123'});
newCard.name = "Mike Smith";
newCard.$save();
// POST: /user/123/card {number:'0123', name:'Mike Smith'}
// server returns: {id:789, number:'01234', name: 'Mike Smith'};
expect(newCard.id).toEqual(789);
The object returned from this function execution is a resource "class" which has "static" method for each action in the definition.
Calling these methods invoke $xhr on the url template with the given method and params.
When the data is returned from the server then the object is an instance of the resource type and
all of the non-GET methods are available with $ prefix. This allows you to easily support CRUD
operations (create, read, update, delete) on server-side data.
var User = $resource('/user/:userId', {userId:'@id'});
var user = User.get({userId:123}, function(){
user.abc = true;
user.$save();
});
It's worth noting that the callback for `get`, `query` and other method gets passed in the
response that came from the server, so one could rewrite the above example as:
var User = $resource('/user/:userId', {userId:'@id'});
User.get({userId:123}, function(u){
u.abc = true;
u.$save();
});
Let's look at what a buzz client created with the $resource service looks like: