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mFabrik Blog is about mobile and web software development, open source and Linux. We tell exciting tales where business, technology, web and mobile convergence.

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Native mobile application development with Plone, WordPress and Python

We have just released two mobile applications backed by Plone, WordPress and Python middleware code. In this blog post I’ll tell some background information what we have learnt with mobile applicationand Python development.

mFabrik News – download now for iPhone and Android

Why create a mobile application?

The first question is why one rather create a mobile application when the same task can be accomplished with a mobile site? Most people even prefer mobile sites over applications. From a pure engineering viewpoint, mobile applications are usually just glorified RSS readers that embed Webkit and add some native user interface bling bling over it. With an app, you are limiting your target audience, because an application is limited to one platform. Maintaining application(s) and application developers is more expensive compared to a mobile site which few (cheap) PHP junkies can throw together.

But is not always technology or price which matters. Mobile applications have prestige value – having or showing success, rank, wealth, etc. If you have a high quality brand, you probably want to have a mobile application too. When you see the brand logo swinging forth and back in an iPhone application with smooth animation running 60 frames per second, you see that it is a proper placement for the brand logo. The output is more luxury, more carefully planned, and does not look like it was thrown together by few cheap web developers.

There are even rationale reason for going after applications. First, you are in a business of making money. It is a lot of easier when the platform itself is offering you a payment solution without a monthly fees (iTunes payment). Other good reason is that there exists interaction between the application and your content beyond the browser window.  You can push messages or do things even if the user is not on your site (see more information about the push solution we implemented below).

Mobile application development and Python

As most of this post readers are probably fellow Python developers, here are some thoughts specifically aimed for them. Python itself is not a very good alternative what comes to mobile application development. Though, the application itself may not contain Python code, Python still shines on the backend side of the things. For example, we’ll hope to publish an example application using Google App Engine in the near future.

The only future proof platform where Python is 1st class citizen for building applications, is Nokia’s Meego with its Pyside and Qt bindings. Unfortunately Meego doesn’t have any shipped handsets and looks like it never will.

Android has script bindings, but they are not good enough for real application development, as interaction with the native platform happens over TCP/IP sockets. However, Android has seen some recent exciting development from PyPy project, possibly enabling native Android development for Python in the future.

iOS with Python could be a go, now when Apple has lift ban on interpreted languages. I haven’t heard anybody doing it yet, though. CTypes had some problems long time ago regarding run-time generated code for Python bindings.

Python has also a port for Series 60 (Symbian) – don’t go there if you are not prototyping. It is good platform for students for  playing around, but unfortunately it has never been considered as serious development environment by the handset manufacturer. You have tons of headaches if you actually want to release a product version of your application.  Nokia N900, soon supported. is better prototyping platform for Python than Series 60 as you get full Debian userland.

Mobile application development and wrappers

There exist various wrapper technologies which help you to wrap your HTML5 application to a native application shell. With simplistic APIs provided through Javascript bindings, you can access a limited subset of native platform APIs. Wrapper technologies are mostly aimed for web developers, who do not have any experience on application development and they might want to skip the learn experience of native development.

Wrapper technologies do their job and produce decent apps. But if you are a Python developer I recommend you skip the wrapper step and build your own native user interface and embed Webkit yourself. Designing an user interface is much is easier with Apple’s Interface Builder or Google’s  Android tools than with half-baked Javascript bindings. The fact that you are actually able to insert a real breakpoint into your code is itself worth of skipping wrappers. If you already are a Python developer you already know at least one real programming language and mastering Objective-C or Java should be an easy task for you.

Webkit itself has bugs. You will regularly hit obscrure bugs when the amount of  Javascript and CSS code grows. In the worst cases Webkit just dies under your application without a way to debug the problem – sometimes without a workaround available for the problem. This means dead end for your lovely application. You don’t want to end up to this situation. So, just to have more low level control, using native tools is good.

mFabrik News application

mFabrik News mobile application allows you to follow the latest news of mobile and web development, produced by our hacking team. The applications source the news from our Plone based web site and WordPress blog (which you are currently reading). It uses special RSS streams prepared with our Web and Mobile multichannel publishing solution: news images are optimized for mobile device screens using a handset database (Wurfl) and some other HTML preproessing is done to make the posts look better in embedded WebKit. Processing is done using mobile.sniffer and mobile.htmlprocessing Python packages which are generic Python packages and should be usable in various environments, including App Engine.

iOS mFabrik News application has push notification support. Android doesn’t yet implement push solution, but it is coming for Android 2.2 handsets.  Please see the earlier blog post how we use Apple Push Notifications with Python.

Download, give the apps a spin and report any feedback! (direct links at the beginning of the post)

We may or may not release the source code of the applications, depending if anybody thinks they actually would find it useful.

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Python 2.3, Python for Series 60 1.4.5 still in use… and insight into Symbian deployment process and user experience

Nokia’s Python for Series 60 has a long history. It is a Python interpreter, originally escaped from Nokia prototype labs, running in your phone. It is said to been awesome to show mobile/embedded developers, who were love with their static C compilers and 4 hours built times, opening a Python prompt in your phone and typing import audio; audio.say(“your phone loves Python”) by keypad (Nokia Series 60 phones come with a speech synthetizer). Python for Series 60 is the best tool of building a simple proof of concept mobile applications. The lack of speed, lack of good UI libraries and difficult deployment problems makes it challenging to use it in production grade environments.

PyS60 has also a history of staying in archaid Python version – namely Python 2.3. It was not until this February when stable PyS60 2.0.0 with Python 2.5 was released (1.9.x was considered experimental according to the release notes). Luckily looks like new winds are blowing (Qt acquisition, Meego/Maemo) and Python is getting higher priority. For example, PySide Qt bindings is very high profile project. Based on this, we hope to expect Python to the first class citizen in the future Meego and Symbian devices.

My company had a little side venture with PyS60 Community Edition when we were still betting that Symbian and Python would rock the world – the era before iPhone changed the game.  PyS60 community edition was effectively a revamped PyS60 1.4.x with Python 2.3 toolchain which actually made PyS60 application production deployment possible. Possible…? -you ask. Madness… no. It is Symbian. It is certification and signing and obscure error messages. Basically vanilla PyS60 is being shipped as an external SIS (Symbian package format) and Symbian platform security makes it impossible to deploy two production signed applications using vanilla PyS60 on the same device. The only cure was statically building Python for both apps from the scratch, which is exactly what PyS60 Community Edition was doing.

But this all was long long time ago. Aeons in mobile time. So I was today surprised when I got email from a person (David) using PyS60 Community Edition. We never upgraded PyS60 Community Edition to Python 2.5 . In fact we haven’t touched the project about two years. David was effectively using Python 2.3 and asked questions about the tool chain internals.

My first answer was a question Why on Earth you are still using Python 2.3? I thought maybe the guy had somehow missed the last two years or was a stuck with an old phone.

However… this was not the case and the answer was very insigtful.

Yes, I’m aware of PyS60 2.0.0, but I prefer PythonCommunity, at least for the moment: no OpenC neither Platform Services dependencies; smaller .SIS size and memory footprint. I think that the final .SIS produced with PythonCommunity, with everything necessary to run contained in it and with a clean installation without multiple dependencies, is a better fit for a mass-market than the files produced by PyS60 2.0.0, above all taking into account that people don’t know what S60 or Symbian are.

Also, the runtime deployment on the new PyS60 isn’t automatic for S60_3rd and S60_FP1 devices, so in the worst case scenario, users may end having to learn to install the different files (pips.sis, ssl.sis, stdioserver.sis, Python_2.0.0.sis, PythonScriptShell_2.0.0.sis) in the correct order, which is a big no-no for a mass-market deployment.

So…. I hope someone in Nokia is reading this blog entry carefully. Do it like Apple does. Make your application deployment static. Make OpenC static. Make every freaking library which is not shipped with the device statically buildable. It should be possible now when everything is open source. It will consume precious device RAM, but at least it will make mass market application development possible. SIS hell is worse hell than deb hell, or DLL hell, as the end user cannot fix it due to device security.

In the related news SIS smart installer was announced few weeks ago. Personally I wouldn’t bet it can deal with all the problems of versioning and Symbian platform security. Forum reports aren’t promising and looks like very Symbianish user experience can be expected. In positive light, it seems that Python is being considered for this process.

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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:

Building a mobile site and applications with Django and Python

Recently we created a mobile site for an interactive bicycle tour. oulugo.mobi (you need to use mobile browser to access the site or you’ll get a redirect) is a multimedia enriched bicycle tour through the historic parts of the city of Oulu. All content is provided by OnGo.

The route, which you can bicycle through is drawn on Google Maps. There are nine  action points where the user can listen to streaming audio clips, with still images, in his/her mobile phone. This is sort of  augmented reality experience: The user sees the real world (where he/she is now bicycling) combined with the historic events (audio playback narrative). For example, at Linnansaari (a location on the route) you’ll see the actual 17th century castle ruins and the narrator tells how the castle exploded when fire, caused by a lighting, reached gunpowder warehouse… boom. The explosion caused stones fly over 400 meters.

Alternatively, the clips are available as podcasts from Oulu Tourism pages. You can download them into your iPod for offline listening and use in conjuction with a paper map. This demostrates interesting mix of multichannel publishing: paper, web, mobile and podcasts.

The tour is bilingual in Finnish and English.

There exists unreleased iPhone application, based on PhoneGap, which allows the user to track his/her location real-time on the web page. We didn’t see it worth of trouble to go through Apple iPhone application review process. When location based service support comes for the browser this feature is indended to be included as the standard HTML5 feature of the service.

There also exists Nokia Series 60 mobile application, based on PyS60 and Series 60 BrowserControl API, which allows the user to track his/her location in real-time. The application provides wrapper around Series 60 WebKit control and allows Javascript to access phone native functions (GPS) over localhost socket communication. Like with Apple, we didn’t see real-time tracking feature interesting enough to go through Symbian Signed process to get our application released. Also, BrowserControl had seriousquality problems and we didn’t consider it stable enough for the end users. Some work is available in PyS60 Community Edition repository.

The service is hosted on Python specific virtual server on Twinapex services server farm.

Features

  • Premium content tailored for audio listening
  • Dubbed in English and Finnish by a professional voice actor
  • Bilingual: English/Finnish
  • Adapts for smartphones (WebKit based browsers) and low end phones (XHTML mobile profile browsers)
  • Streaming video and audio (RTSP / progressive HTTP download forv iPhone). Different audio quality is provided on depending on the handset features.
  • Screen resolution detection based on user agent sniffing. Three different version of images are used.
  • Custom Google Maps component for mobile is used. The component adapts for different mobile phones based on sniffing. Features include zoom, show action point, show the current location, search street address name. This component can be published on a request.
  • Management interface features include video upload, video transcoding different mobile versions and editing bilingual content
  • Apex Vertex handset database is used to detect the user’s mobile phone capabilities
  • Apex Vertex logging and traffic analytics capabilities are used for the site statistics

Software stack

Development effort

Development time: Around 100 hours. Three different developers where involved. Used development tools: Eclipse, PyDev, Subclipse, Subversion. There were around five meetings between the content provider and the technology provider. Few beta testing rounds using iPhone application were performed by bicycling in -10 celcius degrees weather (north and so on…). No polar bears were harmed during the creation of this mobile service.

The service is linked in from Oulu Tourism pages and thousands of paper brochures printed for Oulu summer season 2009.

About the author Mikko Ohtamaa