mob.dev

We have moved – Please update your bookmarks!

ukio — Fri, 15 Sep 2006 11:39:55 +0000

We have moved the site to mobdev.tknerr.de, please update your bookmarks!

Do-It-Yourself Nokia Firmware Updates

ukio — Mon, 04 Sep 2006 09:59:43 +0000

MobileCrunch reports that Nokia offers a free service to upgrade your phone’s firmware. This is finally a nice and long expected move from Nokia, as it was always a hassle to find a Nokia Service Center for updating the firmware (and not always free). Currently only a few devices are supported and you need a data cable to connect them to your PC. However, the Nokia site linked above suggests that OTA (Over the Air) updates will be supported in the future, and I guess the list of supported devices will grow soon.

How To Make J2ME Apps Work for the WAP Flat, Part II (Example: Google Maps Mobile)

ukio — Sat, 02 Sep 2006 12:24:46 +0000

Last week I posted a tool to “make J2ME apps work with the o2 WAP Flat”. All the magic it does is inserting some HTTP headers into a fully compiled (and often obfuscated) J2ME application.

Some users asked how to get the .jar and .jad files of the J2ME application to your desktop PC in order to patch them with the o2 WAP Flat Patcher. There are many possibilities to accomplish this, but here’s my recommendation:

Use your J2ME devices native browser to download the application. For example, visit http://www.google.com/gmm to get the latest version of Google Maps Mobile. It is important to use the devices native browser because most J2ME apps are tailored for a specific device — and the native browser uniquely identifies the device using its User-Agent and Profile headers. In my case this leads me to a site which says “Download Google Maps for Nokia 6630″ and links to the appropriate .jad file (note: the .jad file is a plain text file and contains amongst others the location of the .jar file).
A caveat of my Nokia 6630′s native browser is that I can not download .jad files. When I click the link above, it will directly install the application. But this is ok, since the browser will download and store both files on the device before installation. Just go ahead and install the application (we will reinstall the patched version later).
Now find the Google Maps Mobile .jar and .jad files on your devices file system. On my Symbian OS based Nokia smartphone the installed J2ME apps reside in a subfolder of either “C:/System/MIDlets” (if installed to phone memory) or “E:/System/MIDlets” (if installed to memory card). Navigate to this location and copy the .jar and .jad files to your Desktop PC, e.g. via Bluetooth or USB cable (note: you may need to use FExplorer, a pimped file explorer, to access these locations and copy the files).
Once you have the .jar and .jad files on the desktop, use the o2 WAP Flat Patcher to patch the files.
Copy the patched files back to the device, but DO NOT overwrite the files in “E:/System/MIDlets”. Just save them to a convenient location, e.g. “E:/myapps/”. Then use the devices native file manger to navigate to “E:/maypps/” and click the patched .jad file. This will trigger the installation of the patched Google Maps Mobile (note: this won’t work with FExplorer, as FExplorer v1.15 does not recognize .jad files). If you already installed the unpatched application (see step 2), you don’t need to uninstall first — you can safely overwrite/replace the existing version.

Web Services Resource Framework (WSRF) for J2ME – version 0.1

ukio — Sat, 26 Aug 2006 22:11:51 +0000

The Web Services Resource Framework (WSRF) is a set of specifications to enable stateful Web Services. The WSRF Primer document gives a quick introduction what WSRF is all about. WSRF is heavily used in Grid Computing. The Globus Toolkit for example, an “open source software toolkit used for building grids”, exposes most of it’s Grid functionality as WSRF-based Web Services.

During a school project I was researching different possibilities to connect to a Grid System with mobile devices. It seemed to be logical that most of the approaches used a proprietary protocol (over plain HTTP) between the mobile client and a gateway, which in turn translated the proprietary protocol into standards-based WSRF calls to the actual grid system. The main reasons for using “lightweight” proprietary protocol instead of using WSRF-based Web Services directly were said to be the “constrained resources” (such as low bandwith, limited processing power, less memory, small display, etc…) of mobile devices, which I believe is only partially true with current mobile devices.

To cut the long story short, there are no WSRF implementations available for J2ME, thus I had to develop one from scratch. Well, not totally from scratch, because WSRF 4 J2ME builds upon the kSOAP2 API. The class diagram above (click to enlarge) gives an overview of the WSRF 4 J2ME. For more details, source code and a J2ME sample application please refer to the wsrf4j2me project on Google Code. The sample application is located here (note: you don’t need to have Globus Toolkit 4 completely installed – the Java WS Core container is sufficient to test the application):

o2 WAP Flat Patcher – version 0.1

ukio — Sat, 26 Aug 2006 15:01:26 +0000

The o2 WAP Flat Patcher is a Java program which “patches” J2ME applications for the o2 WAP flatrate. What it actually does is adding the required User-Agent and X-WAP-Profile header (see previous posts) to the application. You don’t need the application’s sourcecode, and it doesn’t matter whether the J2ME app has been obfuscated or not – the WAP Flat Patcher takes care of the magic. It uses the bytecode engineering technique I described previously.

In order to run it, you need to have Java 1.4 or higher and Sun’s Java Wireless Toolkit installed.

Specify the Java and WTK directory, then pick your J2ME application (preferably the .jad file, but you can specify the .jar file also if there is no .jad) and hit the “Start” button. The WAP Flat Patcher will then do the ‘magic’ and the J2ME app should work with the o2 WAP Flat afterwards. I would be glad to hear some feedback if it worked for you.

Either get the sources from Google code and build it yourself, or download the binary release as an executable jar.

It should fix any J2ME application that communicates via HTTP. Here’s a list of applications that have I have successfully tested with:

UPDATE: more “patchable” applications reported by users:

How To Make J2ME Apps Work for the WAP Flat

ukio — Sat, 26 Aug 2006 14:07:35 +0000

Because I am a big fan of networked J2ME applications, such as Google Maps Mobile, I want to use them with my WAP flatrate. The downside is that the WAP flat requires some special HTTP headers to be set, otherwise the HTTP requests get blocked by their gateway – and most of the J2ME apps don’t have these headers.

So what can you do?

If the application is open source, fine. Go ahead, add the headers to the sourcecode and recompile. With closed source applications, e.g. Google Maps Mobile, it gets a little tricky. Here are the basic steps you need to do:

download j2me app (.jar + .jad)
extract class files from .jar file
decompile (*)
search decompiled classes for networking code
add special http headers to networking code
recompile changed classes
preverify changed classes
update .jar file with changed classes
update .jad file if necessary

(*) note: obfuscation and preverification of class files makes it hard to decompile the j2me app with a decompiler such as JAD Decompiler (http://www.kpdus.com/jad.html). It results in decompilation errors and thus you can not recompile the code, as the sources are full of errors.

Because the standard decompile/change/recompile procedure does not work if decompilation fails, the only way to add the required HTTP headers is to modify the application’s bytecode directly without decompiling the class files. For this purpose you could use the javassist bytecode engineering API (http://www.csg.is.titech.ac.jp/~chiba/javassist/):

if (m.getClassName().equals(“javax.microedition.io.Connector”)
&& m.getMethodName().equals(“open”)) {
m.replace(“{“
+ “$_ = $proceed($$);”
+ “$_.setRequestProperty(\”User-Agent\”,\”Profile/MIDP-2.0 Configuration/CLDC-1.0\”);”
+ “$_.setRequestProperty(\”X-WAP-Profile\”,\”foo\”);”
+ “}”);
}

The snippet above sets the User-Agent and X-WAP-Profile header directly after each call to Connector.open(). “$_ = $proceed($$)” inserts the original call to Connector.open(), with “$_” being the returned value (an object of type HttpConnection in this case) and “$$” being the parameters (the URL of the server in this case). After the connection has been opened, we use the returned HttpConnection object (“$_”) to set the User-Agent and X-WAP-Profile headers. See the complete source code here.

For more information about the javassist library you might want to check out their javassist tutorial or this article from IBM developerworks.

o2 WAP Flat – Required HTTP Headers

ukio — Thu, 24 Aug 2006 18:16:47 +0000

As I’ve already posted in the o2 WAP Flat Basics, you can use any HTTP(S) services — as long as your application sends some special HTTP headers. Most J2ME application don’t, thus they don’t work with the WAP flat. However, here’s what you need to consider if want your application to work with the WAP flat:

HTTP header requirements:
According to their terms and conditions you may only download contents originally designed to be displayed on a WAP browser. They try to emforce this by filtering the requests based on the User-Agent and Profile HTTP headers. For example, the headersof a real-world Nokia phone’s browser will pass the proxy:

User-Agent: Nokia6600/1.0 (4.03.24) SymbianOS/6.1 Series60/2.0 Profile/MIDP-2.0 Configuration/CLDC-1.0
X-WAP-Profile: nds.nokia.com/uaprof/N6600r100.xml

The generic User-Agent header of a J2ME apps will pass the gateway too, but you have to add a Profile or X-WAP-Profile (either one works, presence is sufficient) header:

User-Agent: Profile/MIDP-2.0 Configuration/CLDC-1.1
Profile: foo

Desktop browsers are usually blocked because a) of a filtered User-Agent and b) missing Profile / X-WAP-Profile header. I have not said would not be possible to change these headers…

More resources:
For more details about the o2 WAP Flat and which mobile browsers / applications are supported see the FAQ on telefon-treff.de or Andi’s WAP Flat FAQ (sorry, german only). Stay tuned for an upcoming post on how to modify J2ME apps to make them work with the o2 WAP flat!

HTTP Binding for Mobile Google Talk – version 0.1

ukio — Sun, 20 Aug 2006 21:00:23 +0000

This is an extension of the existing Open Source project MGTalk. It is a J2ME Jabber client that supports some specific Google Talk features. Since many mobile operators do not allow plain socket connections (which is the standard binding for XMPP), the original MGTalk client will not work in their networks. Therefore I added support for the HTTP Binding (JEP 124), so that it should work on any HTTP enabled network.

The HTTP Binding code will eventually be included in the original MGTalk project. However, the plan is to continue this as a separate project with the aim to provide a more Google Talk like interface and provide more Google specific features.

For more details check out the project on Google Code:

http://code.google.com/p/mobile-google-talk-http/

Get the .jar and .jad files of the HTTP Binding enabled MGTalk here:

…and yes, it works with the O2 WAP Flat

o2 WAP Flat Basics

ukio — Wed, 16 Aug 2006 22:27:24 +0000

Mobile operator o2 Germany offers a WAP flatrate (“Surf & E-Mail-Pack“) for your mobile phone at a cost of 5€/month. Despite the name, not only WAP traffic but also HTTP is allowed to pass their gateway. It is not ultra-fast, but hey, it gives you everywhere access to the net (as long as it is WAP or HTTP(S)) along with a real flatrate for a reasonable price! Although nothing new (it exists since 2004 afaik), it deserves a quick introduction. Enough said, here are the details:

Quick facts:
- Supported protocols: HTTP, HTTPS, WTP, WSP
- Speed: GPRS 56kbps, UMTS (limited to) 64kbps
- Unlimited traffic for 5€/month
- max. filesize for downloads: 5MB

Configuration:
- Bearer: packet data
- Access Point (APN): wap.viaginterkom.de
- WAP 2.0 Proxy (HTTP): 195.182.114.52:8080
- WAP 2.0 Proxy (HTTPS): 195.182.114.52:8080
- WAP 1.x Proxy (WTP): 195.182.114.52:9201
- WAP 1.x Proxy (WSP): 195.182.114.52:9203
- No username/password authentication (leave empty)

If you want to do me a favor, please click the banner on the right before ordering

Welcome to mob.dev

ukio — Mon, 14 Aug 2006 07:12:03 +0000

…yet another blog about J2ME and other tech-related stuff.