Hands-On Sencha Touch 2

Chapter 8. Remote Connections (Server Proxies)

Models and stores can load and save data via a so-called proxy. Sencha Touch has two main types of proxies: client proxies and server proxies. Client proxies save and load their data locally. Server proxies interact with a remote server. You can read more about client proxies and saving data offline (with techniques such as Local Storage, Session Storage, Web SQL, and AppCache) in Chapter 10. In this chapter, I will talk about the different kinds of server proxies.

A server proxy communicates by sending requests to some remote server. There are four types of server proxies you can use out of the box:

Ext.data.proxy.Ajax

Sends a request to the server on the same domain by using—you guessed it—AJAX.

Ext.data.proxy.JsonP

Sends a request to a server on a different domain by using JSON with padding (JSONP).

Ext.data.proxy.Rest

A kind of AJAX proxy that automatically maps to four readable actions, the RESTful HTTP verbs: create, read, update, and destroy.

Ext.data.proxy.Direct

Uses the Ext.Direct technology (originally created for Ext JS) to remote server-side methods to the client side. Ext.Direct allows communication between the client side of a Sencha app and all popular server platforms.

Let’s implement the two most used server proxies for receiving data: the AJAX proxy and the JSONP proxy. We’ll also discuss how to communicate with a server without using a proxy, by making AJAX and JSONP requests.

For the FindACab app, you will ...