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Cross-platform mobile application development and payments

We have been piloting multi-platform mobile application development and payments in few client projects. Target platforms usually include iPhone, Android, Blackberry and Nokia Series 60. Also there are two notable usual cases which need to be specially handled

  • Image uploads
  • Payments for subscribed content

Sounds easy, right? Well it isn’t… Below are some notes for our due diligence work which you fellow developers might find interesting.

SDKs

Mobile phone vendors are jealously and don’t want to co-operate with each other. Building application which works in all handsets is major headache.

We found some reasonable candidates for cross-platform mobile development doing HTML and Javascript. HTML and Javascript pages are converted to native application using a wrapper technology (a.k.a. appaccelerator). Doing Flash Lite or Java ME can be pretty much forgotten nowadays as they won’t run on the most hyped platform, iPhone. Flash Lite has poor support for anything except content authoring due to primitive and limited APIs. Java ME provides horrible user experience.

(X)HTML is the only common language spoken by mobile phones. Thus, there has been a rise of “appaccelerators”, technologies which allow to create mobile applications with HTML(5) and Javascript.

  • Phonegap: iPhone, Android, Blackberry and possibly S60 in the future. Pluses: BSD license, very active community. Minuses: bad documentation, difficult deployment process.
  • Titanium: iPhone, Android. Pluses: Professional, Apache license. Minuses: Too tightly coupled with Appacclerator Inc. company.
  • Rhomobile: iPhone, Android, Blackberry, S60, Windows Mobile. Pluses: Professional, tries to build open source community, the widest platform support. Minuses: Dual licensing and tightly coupled with Rhomobile Inc.
  • Nokia Web-runtime: Nokia S60 and some other Symbian based phones. Pluses: Professional, good documentation. Minuses: Not open source, impossible to extend, Nokia has little interest to make this cross-platform, Nokia doesn’t like updating old models and web-runtime is useable only in the latest S60 5th edition models.
  • Palm Pre supports web applications natively. However Palm Pre application business is still taking a shape.

All these wrap the browser component (WebKit) and provide some extra Javascript APIs when your web pages as executed under the application mode.

  • Locationing
  • Contacts
  • SMS
  • Client-side database
  • and so on…

Rhomobile has little different use cases  from the rest of the bunch as it provides client-side programming using Ruby and less focuses on Javascript/web applications.

Payments and in-application purchases

There are four major way to do mobile payments “inside” the application for bought content and subscriptions. The price tag on the application itself is left out on this discussion as the application stores themselves take care of it.

  • Credit card
  • SMS
  • App Store payment (thus far Apple only)
  • Direct operator payments – you have a service provider (Bango) which can directly charge items to the operator phone bill based on handset identification.

App Store payment is the most attractive as it provides the best end user experience.  It allows you to use App Store payment mechanism inside the application. It is safe and no need to hassle with external payment providers. However, App Store payment can be used only for content consumed directly inside the application. You cannot use it e.g. for ordering a pizza. I think this might be related to recent EU legislation forbidding SMS payments for services not consumed in the phone itself.

SMS payment is ok for little payments. Operators take big cut of the revenue, generally 30% – 70% depending on the country. Short code fees usually start from 500€ set-up fee + 500€ / month. SMS cannot be often send as a background, but the user is presented the normal SMS editor which reduces the user experience somehow.

For credit card payments there exists several providers. Credit card has the cheapest entry fees, but the downside is that the user needs to have the credit card. This excludes teenager audience.

Direct operator payments are not very well supported yet globally. Most western operators support them. The operator also takes a big share and the fixed fee is pretty high.

My favorite payment provider thus far is Bango which provides credit card payment starting 9€ / mo. and scales up to worldwide SMS payments which cost few grannies per month.

In most cases, the payment experience will not be smooth. You need to open the phone main browser on the payment provider page to do the payment. This usually will close your own application. Rarely you can do the payment inside the application and support multiple platforms. After doing the payment most platforms allow you to close the browse and reopen your application using a special URL handler.

Wikipedia mobile payments page is also useful.

Image upload

<input type=”file”> won’t work on iPhone and some other platforms as those don’t have user browsable file system. Also the file dialog usually doens’t have image preview making it useless.

Phonegap has a branch which supports images picking using iPhone’s own gallery browser.

In any case, there is not yet cross-platform solution for this.

Future prospects

In some time-frame we will get rid of the need to wrap HTML applications natively as the web browser applications will support all HTML5 features without extensions and probably have some proprietary extensions for mobile specific features like SMS. We already have had some taste for this:

Introducing Python for Series 60 Community Edition

This blog post will introduce Python for Series 60 Community Edition.

Pythor for Series 60 Community Edition is a new open source effort to push Python for high quality mobile phone development. It aims to provide a maintained software stack for creating real mobile applications. The codebase is derived from the original Nokia’s Python for Series 60 codebase, but has been refactored for better integration with third party extensions and patches and commercial grade application deployment.

Motivation

Building and distribution

It is difficult to distribute Python for Series 60 applications to the end user with the current Nokia’s PyS60 distribution. You probably want to modify or extend PyS60 in some way. Since the build chain and deployment model is not designed for changes this would collide with the other PyS60 installations. Symbian Platform security prevents installing conflicting binaries. Thus, one can effectively have one Nokia PyS60 application in the phone once.

There are other problems: Nokia PyS60 distribution has UIDs in Nokia protected range. Embedded SIS file cause extra installation dialog and an application manager uninstall entry. Trimming down Nokia PyS60 distribution is a little bit difficult.

To overcome all these issues we created a build chain which spits out monolithic PyS60 distributions. We build only one DLL whose name and UID can be decided. Also the build chain is Scons for Symbian, scrapping the obscure, inflexible and difficult to understand Symbian ABLD once for all.

Evolution towards higher quality

Currently there is no centralized authority to co-ordinate PyS60 open source developers and maintain the repository of all the extension and patches. This effectively prevents the biggest benefit of open source: open innovation and gradual evolution of the product. It would be very nice having all those third party extensions, now scattered around the internet, under one maintained source – making PyS60 more functional out of the box.

The community maintained repositories do not have the same restrictions as ones managed by a big public corporations. It is not a probable target of a trigger happy lawyer action and ungentlemanly competition: the discussion and plans can be public and due dilugence check of the code more relax.

We started the project in the Launchpad. Launchpad provide a distributed version control system (Bazaar) which streamlines the process of integrating third party commits and patches. This should encourage contribution. The standard build system makes it easy to roll out applications and extensions from bare  C++ source up to the end user distributable SIS files.

It is yet to see what kind of co-operation possibilities between the community and Nokia exists. In the future, it should be possible to cherry pick patches from PyS60 community edition to Nokia’s own version.

Showing the commercial potential of PyS60 in the mobile application development

On Python you can write native Series 60 applications with very little effort compared to hardcore C++ banging, lowering the barries to enter the mobile application development.

We do not deny that we have an extrinct motivation called money. Of course we have also instrict motivations like thinking Python is the best programming language in the world and we all want to be most respectable gurus in it. Gurus need to eat still, though. We hope that our effort does not go unnoticed in the mobile application development world and good subcontract offers fill our inboxes.

Also, there is the John McClane effect. Unless we had done it, no one had. Somebody has to save the world, despite the hangover.

It runs on Linux

Since we are no longer dependend on .BAT/Perl/Windows hindered ABLD buildchain, we can (almost) crosscompile and build native Symbian binaries in Linux and  Python applications. All good hackers use Linux – but currently there are still kinks and you need to use WINE for some parts – all sane Symbian developers are tied to Windows based tools for now and so are these instructions.

Prerequisitements

You need all this stuff to get things running.

Install Bazaar

You need Bazaar distributed version control client. We are not planning to have fixed releases for Python for Series 60 community edition any time soon. This is because 1) the most magic happens at a compiler level and we are providing a buildchain 2) we hope this fosters incoming patches.

Why Bazaar?

  • Distributed (patching made easy)
  • Works in Windows
  • User friendly
  • Integrates with Launcpad.

Install ActiveState Perl

Series 60 SDK has ActiveState as a prerequisitement for running its installer.

http://www.activestate.com/Products/activeperl/index.mhtml

Install Series 60 SDK

Use only Series 60 3.0 maintenance release. Other releases have SDK bugs preventing correct Python compilation.

Get the Windows installer from http://forum.nokia.com. Forum Nokia Registration is required.

Please use the default installation location C:\Symbian\9.1\S603rd_MR.

Install Carbide.c++ express

Carbide.c++ comes with a Windows compiler to compile the emulator binaries. You need this only if you indend to develop and test your applications on Series 60 emulator.

http://www.forum.nokia.com/info/sw.nokia.com/id/dbb8841d-832c-43a6-be13-f78119a2b4cb.html

Forum Nokia Registration is required.

Use Software updater in Carbide.c++ to install PyDev, Python developer extensions for Eclipse.

http://pydev.sourceforge.net/

Install Python 2.5

Scons build chain and our utility scripts use Python.

http://www.python.org/download/releases/2.5.2/

Use the installer EXE and the default installation location C:\Python25. If you want to use advanced Bluetooth shell (PUTools) you also need wxPython and pyserial packages.

Install SCons

Python for Series 60 build script are based on SCons. It is a build system using Python as a recipe langauge.

http://sourceforge.net/project/showfiles.php?group_id=30337

Install Subversion

Install Subversion client for Windows. This is needed for checking out Scons for Series 60.

http://www.collab.net/downloads/subversion/

Registration to CollabNet is needed to download Windows binaries.

Scons for Series 60

SCons for Series 60 is available as a separate project. SCons for Symbian is a build toolchain intended as a replacement for Perl and MMP files used on regular Symbian projects. SCons for Symbian is not limited to build Python – You can use it to build any Series 60 C++ application.

http://code.google.com/p/scons-for-symbian/

This is later checked out during to the environment construction, so you do not need to install it now.

We have included a workaround for a problem with limited command line length on Windows.

Included tools

The following tools are included in the trunk tools folder:

These tools are not licensed under Apache license. Some of them are under GPL license. However, we believe that distribution them is ok, since this falls under GPL’s mere aggregation clause. However if you indent to distribute commercial applications built from PyS60 Community codebase, make sure that you understand the set of different licenses involved.

Set up build environment

Ensure that Bazaar is properly in your Windows path.

Create a workspace folder

First you need to subst (make a folder appear as a driver letter) in Windows. Open command line. Go to SDK folder.

C:\Symbian\9.1>subst t: S60_3rd_MR
T:
mkdir workspace

Now choose this folder as a workspace folder in Carbide C++ and create an Empty Symbian C++ project called ”pys60” there.

Checkout PyS60 community edition

The go to this folder

T:
cd workspace\pys60
bzr branch lp:pys60community
cd pys60community\src

Preparing the build

This needs to be done only once.

We need to pacth the existing Series 60 SDK headers which have some bugs.

T:
cd \epoc32\include
\workspace\pys60\pys60community\src\tools\patch.exe -p1 < \workspace\pys60\pys60community\src\pys60-fix-3rded-sdk.diff

EPOCROOT must be set for some Series 60 SDK tools to work. We point to T: drive root.

T:
cd workspace\pys60\src
set EPOCROOT=\

As we still have some dependencies to the legacy system, one needs to configure the build system using PyS60 setup. This will generate some files and defines for Series 60 versio 3.0.

c:\Python25\python.exe setup.py configure 30

Do not run bldmake bldfiles.

You need to convert legacy MMP build files to SCons based. First we need to possibly fix up PATH, since Carbide C++ might break it.

set PATH=c:\program files\bazaar;c:\program files\CSL Arm Toolchain\arm-none-symbian elf\bin;c:\program files\CSL Arm Toolchain\libexec\gcc\arm-none-symbianelf\3.4.3;C:\program files\CSL Arm Toolchain\bin;t:\epoc32\gcc\bin;t:\epoc32\tools;t:\epo c32\tools;C:\program files\CSL Arm Toolchain\bin;C:\Program Files\Common Files\Symbian\Tools;C:\Perl\site\bin;C:\Perl\bin;C:\Windows\system32;C:\Windows;C:\Windows\System32\Wbem

c:\Python25\python tools\mmp2scons.py
ext\\calendar\\calendar.mmp:60:7: warning: no newline at end of file
Creating recipe ext\miso\build.py
Creating recipe ext\socket\build.py
...
Done!

Checkout SCons for Symbian. We assume it lives in src tree.

"c:\Program Files\CollabNet Subversion"\svn checkout http://scons-for-symbian.googlecode.com/svn/trunk/ scons_symbian

Running the build

Now we can execute the actual Python build script. This will create one monolithic emulator DLL which has almost all the PyS60 extensions built in – some extensions need manual building, since they rely on headers not found from standard Series 60 SDK.  You might need to reset PATH to default to Carbide C++ after the previous mmp2cons step by reopening the console window.

c:\Python25\Scripts\scons

You should see the following output. As you can see, UIDs are being allocated dynamically as instructed in Scontruct UID_BASE argument.

scons: Reading SConscript files ...
EPOCROOT=\
Info: SIS creation disabled
Building winscw udeb
Defines []
Getting dependencies for e32socket.pyd
Getting dependencies for _topwindow.pyd
Getting dependencies for zlib.pyd
Getting dependencies for _locationacq.pyd
Getting dependencies for _location.pyd
Getting dependencies for _graphics.pyd
Getting dependencies for _sysinfo.pyd
Getting dependencies for Python222Config.lib
Getting dependencies for Python222.dll
Getting dependencies for Python_appui.dll
Allocated UID:0xE1000000
Getting dependencies for Python.exe
Allocated UID:0xE1000001
Getting dependencies for Python_launcher.exe
Allocated UID:0xE1000002
scons: done reading SConscript files.
scons: Building targets ...

...

scons: done building targets.

Now you should be able to start a custom built Python shell in the emulator. You should see the following applications in Installation menu: helloworld, btconsole and filebrowser. Try launch helloworld and if it opens a pop up dialog the build has been succesful.

Building a SIS file for mobile phones

To build a target distribution type:

scons release=urel compiler=gcce dosis=true

This should yield to the result:

scons: Building targets ...
ensymble(["MyPythonForSymbian.sis"], [])
scons: warning: no package version given, using 1.0.0
scons: warning: no certificate given, using insecure built-in one
scons: done building targets.

If you want to build a SIS file signed with your developer certificate:

c:\python25\scripts\scons compiler=gcce release=urel dosis=true simplesis={'--privkey':'C:\\Certificates\\PrivateKeyNoPassphrase.pem','--cert':'C:\\Certificates\\MyApp.cer','--passphrase':''}

For now, installing the SIS file works only for C drive  – we’ll fix this little issue soon.

If you do not have a symbiansigned.com developer certificate you can sign the SIS file online for one phone (one IMEI code).

  1. Go to symbiansigned.com
  2. Register
  3. Enter your IMEI and upload the SIS file to OpenSigned Beta

Building your own application

The purpose of this project is to make rolling out your PyS60 applications possible – so here we go. Currently we make a quite bad assumption that all the application live in the same source tree with PyS60 community edition due to problems with absolute file paths with Symbian build tools – we will figure out a long term solution for this later.

PyS60 applications are stub Symbian executables which boostrap Python virtual machine and start the Python code execution. Executables are linked against a custom PyS60 DLL and they are restricted by capabilities given to the EXE file.

PyS60 applications live in applications source tree. The source tree comes with Bluetooth console, Hello world and File browser sample applications.

Scons build scripts takes as applications parameter a comma separated list which applications are included in the build.

scons builtin=all applications=helloworld,filebrowser

Applications consist of

  • default.py boostrapper module
  • icon.svg SVGT icon
  • Any number of Python modules (.py) files

See applications\helloworld folder to examine what files are needed to build an application. All application Python modules go to the private application folder (/private/myapplicationuid). Default.py must boostrap PYTHONPATH (sys.path) for this folder – PYTHONPATH defines where Python interpreter looks for the code. Application UIDs can be chosen manually or they are picked automatically by Scons for the unprotected test range.

Note that Python Script Shell application is handled out of this flow due to its legacy heritage.

Adding in your own extension

If you have development an PyS60 extension you can drop in into the buildchain easily. Each extension is defined in ext subfolder. It consists of necessary CPP, H and Python files. The building structure is defined in build.py using SConstruct command PyS60Extension().

Build.py files can be automatically generated from legacy code using mmp2scons.py converter.

  • Drop files to ext/yourmodule folder.
  • Run MMP -> build.py. This needs GCC or valid C compiler for preprocssing MMP files.
c:\Python25\python.exe tools\mmp2scons.py

ext\calendar\calendar.mmp:60:7: warning: no newline at end of file
ext\progressnotes\progressnotes.mmp:38:7: warning: no newline at end of file
ext\uikludges\uikludges.mmp:37:7: warning: no newline at end of file
Creating recipe ext\\socket\build.py
Creating recipe ext\\glcanvas\build.py
Creating recipe ext\\graphics\build.py
...
...Done!
  • Recompile. New ext modules are automatically picked as built in modules.
c:\Python25\scripts\scons
  • Now test importing your module in the script shell in emulator
>> import applicationmanager

If your extension is using thread local storage (Dll::Tls()) you might need to figure out how to workaround with it. See socket  module for example. You may also need to play around with the init function of the Python extension – it must be init + module name.

Developing on target

If you want to develop your application on a mobile phone, you do not need to go through the full development cycle for every little change. It is possible to update Python files on a phone without SIS installation. You can either automatically synchronize changed files from your PC to Phone (the example below) or you can edit files in-place on the Phone either using PCSuite or Series 60 SMB server.

Here are short instructions how to update files using PUTools console (btconsole). PUTools is wxPython based remote Python shell which allows you to run Python console commands over a Bluetooth connection from your PC. PUTools also has a file syncrhonization feature – after editing source code on the PC changes are reflected automatically to the phone.

  1. Put application Python files to a shared folder on the phone e.g. the memory card root (E:\). Add startup.py to E:\ which will modify sys.path to include your files.
  2. Add incoming Bluetooth serial port on windows (Control panel -> Bluetooth -> COM ports)
  3. Start Bluetooth shell on the computer (tools\putools\pcfiles\console.bat)
  4. T:\workspace\pys60\pys60community\src\tools\putools\pcfiles>c:\python25\python.exe putools.py com5
  5. Start Bluetooth shell on the phone (btconsole icon)
  6. Edit PUTools sync.config file on PC and run sync command on Bluetooth terminal to update changes made on PC to phone
  7. Run application launcher in the console (depends on the application structure how it is best to bootstrap in the shell):
>> import filebrowser
>> filebrowser.FileBrowser.run()

Release notes

Here is the short summary of differences with the current PyS60 community edition and one available from Nokia. This information is also available in divergence.txt file in the source folder.

2008-08-29 Mikko Ohtamaa <mikko@redinnovation.com>

    * PyS60 general

        New build chain and static config generation

        Migration tool for MMP -> Scons based extensions

        Added several tools included in the core distribution: sisinfo, ensymble, cog, patch

        Patched py2sis tool

        Contains extension: applicationmanager

        Contains extension: uikludges

        Contains extension: progressnotes

        Contains extension: miso

        Contains application: Bluetooth shell

        Contains example applications: filebrowser, helloworld

        Changed Bluetooth console bootstrap to e:\startup.py         

2008-08-15 Antti Haapala <antti@redinnovation.com>

    * e32socketmodule.cpp:

        socket.access_points has more information, two new
        fields is given per access point: isptype and bearertype,
        whose values are integers corresponding to values returned
        by CApSelect::Type and CApSelect::BearerType respectively.
        No symbolic constants are yet exported.

    * appuifwmodule.cpp:

        multi_select_list has a new argument, selected, which defaults
        to None. Given a list of integers, the items with the given indices
        are initially selected.

Conclusion

We hope this helps you to get started with PyS60 community edition. It’s still a bit complicated, since setting up the build environment on Windows is a such a pain. In the future, when the Linux based build system is reading settings up the development environment should be easier – all those boring steps happen automatically.

This might be still too difficult for some of the readers, since a lot of prerequirement work must be done before anything useful can be done. Feel free to comment the article in this blog, but we hope that you use Answers section in Launchpad to ask help and technical questions related to PyS60 community edition.

Logging with LogMan

This is my first post on our company blog and I thought I’d tell you something about LogMan, which is developer’s utility for getting logging messages from Symbian device over a USB cable. It is written by me and mostly on my own time. I started the project because I had to do a Symbian excercise for university course and I thought I’d do something useful instead of quickly tinkering something small and easy.

LogMan supports both C++ and Python. With LogMan, you can send data to the same location from Python and C++ in real-time instead of using log file(s). Browsing through multiple log files can be tedious and you can’t see the debug output while using your application, because on Symbian you must read the file after the debugging session – Symbian cannot share opened files between applications. It is also possible that you create too much log and you run out of Phone internal memory. LogMan helps by removing the use of log files and you never run out of disk space because messages can be stored directly to PC. On simulator, the messages are also sent to RDebug (%TEMP%\epocwind.out). Surprisingly I have not seen a Python module, which would enable use of RDebug. Even though it is very easy to implement. With RDebug, there is no need to open a serial port on simulator for reading the logging messages.

Of course, I tried to use RDebug on device first, but I never got it working. I also tried REcmt, which is supported on S60 only and the service just kept on crashing on my phone. This is why I decided to write LogMan. Plus both are closed software, which effectively prevented me from fixing the problems.

Just wondering what kind of benefit Symbian or Nokia gets from keeping development tools such as these closed? What is there so secret about them? It didn’t take me very long to write the first working version. *sigh*

The use of LogMan is similar to RDebug. There are static class methods, which are a bit slower but easier, and instance methods. Check the project’s homepage for more examples.


#include "LogMan.h" //RLogMan
RLogMan::Log( _L("Hello world ") );

I recently added a new feature for LogMan, which allows you to log stack and heap usage of the current thread with one function. When you are unsure about your heap or stack usage, these might come handy. Of course there is some memory used when calling these so take that into consideration. Python can access MemoryInfo only, which logs both stack and heap (Well, I got a bit lazy at that point). There are equivalent macros for these, so check them out from “logmanutils.h”.


// Store this as a member of your class, for example
RLogMan logman;

logman.HeapInfo();
logman.StackInfo();
logman.MemoryInfo(); // Both stack and heap
logman.Close();

The output from MemoryInfo is something like this:

StackInfo
Free:1039000, Used:9576, Size:1048576
HeapInfo
Free:25856, Used:101004, Size:126860

Browser for PyS60

I have been trying, unsuccessfully, to get Browser Control working on PyS60. In a nutshell, CBrCtlInterface wrapper for Python. I have developed it against PyS60Community version in Launchpad. See /src/appui/appuifw/. I have used LogMan extensively to debug the extension so if you want a real example, check out “browsercontrol.cpp”.

Browser Control would allow one to embed a browser into his PyS60 application, which would be quite cool. No need to do user interfaces with “appuifw”, which is not very portable. With Browser Control, one could create his user interface with html and javascript, which are a lot more portable indeed. Less work leads to more time. And what is time?… it’s money. Or so I have heard. And being able to handle events with Python instead of C++ is another bonus.

Unfortunately, the API is not very stable as you can see by searching for “CBrCtlInterface” at Forum Nokia. The browser worked fine on the simulator with small pages such as “www.google.com”, but it crashed miserably with larger pages. The crash happens in browsercontrol.dll when calling e32.Ao_sleep() in Python. On device it was unable to open any page and crashed instantly when trying to load one. With LogMan, I was able to verify that the crash happened in e32.Ao_sleep() on device also. This reminds me to test on device all the time, which I didn’t do for the first versions. But this is why I added the memory logging feature to LogMan, but it only revealed that I was not out of stack or heap. At least not before the browser started to mess around.

I tried to compile the WebKit myself to see what is going on, but the build instructions didn’t work and the build scripts are written in Perl(my eyes started to hurt). What a mess. I don’t wonder anymore if there are bugs in browsercontrol.dll. I finally gave up because my idea pool dried up. Any help getting the wrapper working would be very much appreciated.

Plans for LogMan

I’m planning to add remote shell interface so that you could control your phone from PC. I want access to the file system first. Transfer files, list folders and such. If you have TCB rights ( or hacked phone ) you can speed up development remarkably by simply replacing your binaries in \sys\bin or your Python files with new versions. No need to install sis files and fiddle with certificates and play with memory cards. It would be so nice… I can use 1 day in a week for a personal project so this may happen in near future ;)