Send GET, POST, PUT, and DELETE requests via AJAX to the DataService API server. These four HTTP request methods correspond to the four CRUD verbs (Create = POST, Retrieve = GET, Update = PUT, Delete = DELETE).

Have a look at the Wikipedia article on REST (Representational State Transfer) if you're not familiar with this style of web services.

Due to browser security constraints, you cannot easily fetch data via JavaScript from a URL on a different domain/port than the one the page is being served from. For example, if your DataService is at http://API.example.org/ and the WebApp with your JavaScript is on http://www.example.org/, the browser will block AJAX requests to the DataService URL. See http://en.wikipedia.org/wiki/Same_origin_policy for details.

There are two possible workarounds:

• Configure Web.config in your ServiceStack to use CORS
• Use JSONP for your requests.

To retrieve a User with ID 1:

Plain JSON	JSONP
```js jQuery.ajax({ url: '/users/1.json', success: function(data) { alert('User '+data.user.id+' is '+data.user.username+'!') } }) ```	```js jQuery.ajax({ url: 'http://API.example.org/users/1.json', dataType: 'jsonp', success: function(data) { alert('User '+data.user.id+' is '+data.user.username+'!') } }) ```

You can also retrieve a User by their username, like this:

Plain JSON	JSONP
```js jQuery.ajax({ url: '/users/jalal.json', success: function(data) { // do something with the user data } }) ```	```js jQuery.ajax({ url: 'http://api.example.org/users/jalal.json', dataType: 'jsonp', success: function(data) { // do something with the user data } }) ```

To create a new User, send a POST request along with the User's data:

Plain JSON

JSONP

```js jQuery.ajax({ url: '/users.json', method: 'POST', data: { user: { username: 'JH', display_name: 'Jalal Hejazi', password: 'secret', kind: 'Instructor', metadata: { 'hair colour': 'Black and some White' } } }, success: function(data) { alert("User "+data.user.username+" created with ID "+data.user.id+"!") }, error: function(data, statusCode) { alert("ERROR: "+data) } }) ```

```js jQuery.ajax({ url: 'http://api.example.org/users.json', dataType: 'jsonp', data: { _method: 'POST', user: { username: 'JH', display_name: 'Jalal Hejazi', password: 'secret', kind: 'Instructor', metadata: { 'hair colour': 'Black and some White' } } }, success: function(data) { if (data.error) alert("ERROR: "+data.error) else alert("User "+data.user.username+" created with ID "+data.user.id+"!") } }) ```

To authenticate a user (i.e. start a session for a user):

Plain JSON	JSONP
```js jQuery.ajax({ url: '/sessions.json', method: 'POST', data: { session: { username: 'JH', password: 'topsecret' } }, success: function(data) { alert("Authenticated! Your token is: "+data.session.token) }, error: function(data, statusCode) { alert("ERROR: "+data) } }) ```	```js jQuery.ajax({ url: '/sessions.json', data: { _method: 'POST', session: { username: 'JH', password: 'topsecret' } }, success: function(data) { if (data.error) alert("ERROR: "+data.error) else alert("Authenticated! Your token is: "+data.session.token) } }) ```

To validate a session token and retrieve user info from the session:

Plain JSON	JSONP
```js jQuery.ajax({ url: '/sessions/validate_token.json', method: 'GET', data: { token: }, success: function(data) { console.log(data.session) console.log(data.session.user) }, error: function(data, statusCode) { alert("ERROR: "+data) } }) ```	```js jQuery.ajax({ url: '/sessions/validate_token.json', dataType: 'jsonp', data: { _method: 'GET', token: }, success: function(data) { if (data.error) alert("ERROR: "+data.error) else alert("Token is valid for user: "+data.session.user.username) } }) ```

• Use Nodejs with ServiceStack for next generation DataService.