TcpCatcher - WorkShop n°20 : Emulate the iPhone User-Agent with a hook

WorkShop n°20 : Emulate the iPhone User-Agent with a hook

In this workshop, we demonstrate how the iPhone User-Agent can be emulated using a synchronous Hook.

This can be useful when testing an iPhone compatible web site.

The Hook can be built with few clicks using the "Hook Builder" accessible from the Settings panel

We just need to remove the User-Agent HTTP header and insert the iphone's one, then press 'Apply' and check the option 'Apply an automatic transformation to packets' back on the Settings panel

Now you can check that this is working visiting web sites that serve a dedicated content for the iPhone (for instance here www.google.com)

Now, let's see how the very same hook can be implemented with your own java class plugin

Create a java project and import the TcpCatcher jar into it. Then, write a class that implements the tcpcatcher.CustomHook interface and that may look like this one
(Notice that your class must not belong to any package in order to be loaded at runtime.)

        
import tcpcatcher.TcpCatcherPacket;

public class ChangeHeaderUserHook implements tcpcatcher.CustomHook {

	/**
	 * Initialize your hook
	 */
	public void setUp() {
		try {
			System.out.println("Init my hook !!!");
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * This method is called each time a packet goes through TcpCatcher.
	 * 
	 * @param tcpcatcherPacket
	 *            : The tcp packet you can modify
	 */
	public void modifyPacket(TcpCatcherPacket tcpcatcherPacket) {
		try {
			if (tcpcatcherPacket.fromClient) {
				tcpcatcherPacket.removeHttpHeader("User-Agent");
				tcpcatcherPacket.insertHttpHeader("User-Agent",
						"Mozilla/5.0 (iPhone; U; CPU iPhone OS 3_1_2 like Mac OS X; en-us) " +
						"AppleWebKit/528.18 (KHTML, like Gecko) Version/4.0 Mobile/7D11 Safari/528.16");
			}
		} catch (Exception e) {
			e.printStackTrace();
		}
	}

	/**
	 * Shutdown your hook
	 */
	public void shutDown() {
		try {

			System.out.println("Shutting down my hook");

		} catch (Exception e) {
			e.printStackTrace();
		}
	}

}

TcpCatcher provides an API to remove or insert HTTP headers, but you can also perform your own programmatic modifications on the TcpCatcherPacket.packetbytes array..

Now, engage the synchronous hook from the Settings panel and apply settings. You should be getting the same results.