Daniel Rocha's Forum Nokia Blog

Shake your music with Python

Wed, 11 Jun 2008 17:52:55 +0000

I was preparing demos for the next Forum Nokia Tech Days, to be held in São Paulo, Brazil next week, and it came to mind I should do something with the sensors using Python.

Here is the result: Sensor-powered music player for Nokia N95. Nothing too sophisticated, but it goes to show how you can showcase your ideas pretty quickly using PyS60: it took me about 2 hours to develop.

Which technology should I use? Round 3: Python

Tue, 03 Jun 2008 18:49:17 +0000

The comic above pretty much sums it up: Python is a refreshing look at the world of programming. Being so easy to learn and use, it has gained lots of attention from the developer community and it's used for several different purposes such as: web development, desktop apps, utilities, scientific computing, scripting language for games and special effects software, flying and of course mobile development. In fact, I am very surprised that it took so long before any mobile platform offered Python as a viable software creation vehicle.

In our platforms, Python is offered as a runtime option for S60 devices, ranging from 2nd. to 3rd Edition and all their feature packs. That makes it pretty wide reaching platform, since we have some 130 million+ devices in the market for which you can write Python applications.

The core technologies for mobile development have been analyzed here before: C++ is the raw power of Symbian OS available to developers, with its immense API and functionality sets but steep learning curve; Java is easy to learn and use and it's present in more than a billion devices. Its functionality is good but restricted by the Java Community Process since all APIs have to be agreeded upon by participants of each JSR spec.

Python comes in the middle, and that's in my view its main advantage: it is as easy as Java but (almost) as powerful as C++, and not limited by any industry standard processes: you want a Flying API which is not available? Just create an extension and you're good to go. Our good friend and Forum Nokia Champion Pankaj Nathani (a.k.a. croozeus) has in his website a great list of resources for Python development, including how-to's on writing extensions and more: http://croozeus.googlepages.com/py60extensions. Also, if you are the kind of developer who likes to hack around, Python for S60 runtime is open source, so you can spend your days and nights hunting bugs, adding new features and creating your own version of it!

First part of this article: Which technology should I use for development? Round 1: Java
Second part of this article: Which technology should I use for development? Round 2: C++

Technology: Python for S60

Good for:

Internet mashups - You can easily mix the Location API with urlib and Google Maps and create a powerful mobile/web hybrid application which can leverage both platforms strengths. For example, take a look at MobyMaps, a geocoding application in just 104 lines of code, or Fupper, pyAmazon, Mobile Google Maps and many others.
Productivity applications - Access to the filesystem, contacts database, local connectivity, camera, gallery with incredible simple APIs lets you quickly write applications through which you can interact with your device and other people. MobileGTD, PyS60RemoteControl, PySpy are some examples.
Rapid prototyping - This is probably one of the most popular uses of Python for S60, and you should consider it very seriously. It seems that RP is still not very popular, as people usually choose a technology and develop an app with it; if something goes wrong or doesn't work, they will only find it out at the end of the project, when it's too late. I have seen countless cases like this, specially with Java development: "What, I cannot intercept a phone call with Java? But the product is almost ready!". Python helps you tackle this issue in a very elegant and effective way: you have an idea, want to check whether it works or not, just write a PyS60 script to test it. If you're satisfied, just tweak it a bit more and make it your final product, otherwise implement the final version in C++ or Java if you need more power or portability. I cannot stress enough the importance of showing your customer something working from Day One; this is much more effective than showing slides or specification documents.
Utilities - If you have a special event or need and you need to cook up a quick solution for a simple problem, use PyS60. To give you an example, I needed some sample apps for a talk I gave back in March. I was able to develop 10 utilities (photo takers, Bluetooth FTP client, video recorder, etc.) in less than a week.
Games - Given Python's powerful API set that can be used in games, such as: Sensor API, Open GL ES access, graphics and image manipulation, it is a good tool for churning out casual games meant to have a short lifecycle. It can compete well with Flash Lite for this purpose; even though its graphics facilities are not as nice, the powerful APIs will help you create the "wow" factor in your mini-games.

Why?

API/functionality availability - The S60-only list of APIs is reasonably extensive, and you can always add new ones by programming extensions using Python/C API. Many times modules can be added from other platforms without modification (for example, Python debugger - pdb).
Ease of use - It's by far one of the easiest languages to learn and work with. In a matter of weeks you can be highly productive with it.
Community support - There's a lot of Python code written by the open source community out there that can be used in your application.

Bad for:

High performance apps - Python's performance is reasonable, but it is slower than C++, Java and Flash. So if you need to develop a scientific application which requires a lot of number crunching, or a video streaming application, this is probably not the best solution.
Commercial apps, destinated to operator channels - Please take this one with a grain of salt. Applications for sale at operator channels usually are required to go through Symbian Signed process, and Python apps don't play very well with it.
Portability - Although the core Python language is the same, there are several APIs which are S60-exclusive so they won't work in any other platforms without several modifications.

Why?

Symbian Signed - In theory Python is compatible with the program, but in reality Symbian Signed was designed for C++ applications, so in some situations PyS60 apps may fail the tests so you have either to get a waiver for the failure or use the Express Signed option. For lack of a better option, I put Python on the "bad for" side of this article, but in the real world you may have different options that make it suitable for operator channels.
Platform security - Although it's very noble on its purpose (securing users' devices against malware), platform security can be a pain to live with during the development cycle. The whole Symbian Signed environment and platform security API restrictions slow down development time and can increase development costs, because of test fees, certificate purchasing, re-test, etc. This also affects Python for S60 so I left it here from the previous article.
Performance - Don't forget Python runs on an interpreter, so it has some performance disavantages when compared to native applications.
Tools - As it's a very new platform on S60, its tools are not as mature as other technolgies'. You can use the C++ SDK with the Python plug-in for testing your scripts, Python Shell for running scripts on your device, and py2sis or Ensymble to package them in an installable .sis file. There's still no integration with Carbide, and the emulator runs only on Windows. This is a pretty basic selection when compared to NetBeans or EclipseME for Java, Adobe CS3 for Flash Lite or Carbide.c++ for, hm, C++.

Python brings back the fun of hacking your device the way you want, with just a few lines of code. It's also a powerful tool for fast development of applications and utilities, besides being ideal for rapid prototyping of more complex software. The learning curve is smooth, the API set is big, and the support of open source community gives it a large set of libraries you can use in your application. As it's still in an incipient phase in the mobile software development, you can use it and contribute for its evolution in the next releases, making it a sweet platform for innovation on S60.

If you are interested in learning more, there's a ton of resources on PyS60 in Forum Nokia web site and also in its wiki page. For impatient people who can't wait to try it, I have posted a few months back a complete presentation on how to get started with Python, along with a collection of sample source code; both can be found here.

Happy hacking!

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Which technology should I use for development? Round 1: Java

Tue, 27 May 2008 18:29:05 +0000

If I had just made a dollar each time I heard this question... *sigh*.

With the availability of so many different development technologies in Nokia's platforms today, sometimes is hard to decide which of them we should use to build our application, isn't it? There's Java, Symbian C++, Open C, Flash Lite, WidSets, WRT Widgets, Python, and the list is still growing.

This is good news for developers, since not everybody has the same technical background nor is developing the same kinds of applications; this means at least one of the technologies will fit our experience and purpose like a glove, and we are going to use it. On the other side, this may confuse newcomers to the wonderful but fragmented mobile software world. Usually it goes like this:

Question: "I want to write an application that opens a file and sends it out to a web server. What should I use to create it?"
Answer 1: "Java ME, FileConnection API"
Answer 2: "Don't bother, use C++ or you will get a lot of security prompts."
Answer 3: "Why use C++ when you can do the same with Python? C++ is way too hard!"
Answer 4: "Python does not run on S40, use Java."
Answer 5: "Do you really need all that jazz? Why don't you go with Flash Lite and use server-based persistence? Your application will look great!"
Answer 6: "Flash Lite is too fragmented. Use Java, but beware of the MIDlet signing issues or your app's user experience will be crap!"

Go check the Discussion Boards. It is crowded with examples of conversations like the one above. Having answered this question so many times before, I decided to summarize my answers in this blog, in the hopes of helping developers decide what use from the growing technology options pool offered in mobile devices these days. Please keep in mind that the following are my opinions on the subject; yours may differ and even prove mine wrong, but that's the beauty of interacting with people within a community. As the number of technologies it too big for a single post, I will continue my analysis in the upcoming posts. I will start off with the most popular mobile developmentp platform, Java ME.

Technology: Java

Good for:

Productivity applications - Examples: sports trackers, expense control apps, Personal Information Management (calendar, phonebook, etc.).
Games - Both casual and complex.
Enterprise applications - These don't require fancy user interfaces. Using LCDUI and the standard packages can go a long way pretty fast.
Rapid prototyping and proof-of-concept applications.
Network applications - RSS readers, weather services, blogging applications, mobile versions of Web applications.
Creating truly portable apps

Why?

Java and its mobile version are very simple to use and learn - An experienced programmer, even coming from other C/C++-based languages, can get a pretty good working knowledge of how everything works in a matter of weeks and start producing applications quickly. This leads to faster time-to-market for Java ME apps.
Applications are generally portable between S60 and S40 platforms - Although there are some differences in implementation, supported packages, audio/video formats and so on, those are few in number and thus easier to work around. You don't need to entirely rewrite your application so it will run on N95 instead of 6131: a few runtime checks and versioning tools will be enough.
Game API combined with optional packages makes it a killer for game development
Straightforward network API makes it easy to communicate with web services - The GCF (Generic Connection Framework) is a simple and unified way of using the network on Java ME applications. Once you learn how to do one kind of connection, you will have learned them all.

Bad for:

Accessing device resources - Examples: SMS Inbox, file system, gallery, hardware.
Multimedia applications - Examples: Video streaming players, audio and video recorders, camera applications.
Performance-intensive applications - Scientific computing, image processors, video decoders, sound processors.

Why?

Java's functionalities depend on Java Community Process process: if there's no official, industry-standard API for what you want to do, you are out of luck. Example: accessing SMS inbox.
Mobile Media API implementation is (too) highly modular, a lot of runtime checks are needed. Also, most functionality is implemented on the native side and then made available to Java's virtual machine, such as the camera access. This may have a serious impact on performance.
Fine-grained control over video, audio and camera is generally not available. Although JSR 234 (Advanced Multimedia Supplements) tackles some of these issues, it still can't be compared to what's available on other technologies, and its device availability is still low.
Access to the file system is provided by FileConnection API, but it's somewhat restricted and requires the midlet to be signed, otherwise multiple security prompts will be displayed, taking your user to tears (believe me). The signing process itself costs money and has some bureaucracy, so be prepared.

As I said before, these are my opinions on the technologies. It does not mean that X is better than Z, and Z should be thrown into the dirt and kicked in the head, like XML in the funny The Parable of the Languages. If you get your requirements right, it's very likely that your question of "what to use" will answer itself. Need to access the Inbox? Down with Java. Need portability? Down with Python and C++. Fancy UI? Flash. Requirements management is a science, not an art, so when you get it right from the start, the development technology to use will pop up naturally.

Next time I will cover the darling of all Internet programmers, now getting much of the attention on S60 platform: Python.

See you!

Make your widgets and Flash Lite applications fly!

Mon, 24 Mar 2008 19:09:47 -0100

As I mentioned in my last post, I have been thinking a lot lately about how to extend applications that run on sandboxed environments, such as Java ME, Flash Lite and Widgets, using some powerful native technologies such as C++, Python and Mobile Web Server.

I did my research and turns out some people have already been thinking (and doing) this for a while now, so I wanted to share this with you, for a reason I will explain later:

- Our very own Sr. Technology Expert Petro Soininen has created a widget that's able to send text messages and read the SMS inbox of an S60 device, using a creative combination of Widgets, Python, PHP and the Mobile Web Server. Here's the link for the article with complete source code: http://wiki.forum.nokia.com/index.php/How_to_utilize_device_resources_from_a_WRT_widget

- Forum Nokia Champion Felipe Andrade and his company have been working for quite some time in the Flyer Framework, a server application written in Python for S60 whose goal is to provide enhanced native functions to Flash Lite applications. It looks pretty mature, and I wonder if it could be used with Widgets as well with some adjusts in connectivity (full HTTP vs XML sockets).

I mentioned these two ways of extending widgets and Flash Lite apps because of the Global Code Camp Contest. I figured that an application/widget with enhanced functionality has more room for being innovative and delight users in many different ways.

As nothing was mentioned in the contest rules, I asked the Forum Nokia team responsible for the competition whether applications produced with these extension methods would be valid or not. An the answer is that these turbo web widgets and Flash apps are allowed, so you have a lot more options to introduce cool features in your apps via sweet Python and PHP scripts.

So take a look at them both and make your widgets and Flash apps fly higher than ever!

Hurrah! Widgets! - and more

Thu, 20 Mar 2008 17:43:40 -0100

If you have been reading Forum Nokia web site regularly, you've probably noticed the big Win 15k Euros! posted on the main page since March 18th. If you click the link, you'll be redirected to the Forum Nokia Code Camp Competion we're hosting. It's all about you developing a winning Web Run-Time (WRT) or Flash Lite application and raking in a lot of nice prizes from Forum Nokia.

Registration has already begun, so come up with your bright idea for either platform and enter the competition!

If you have a concept but don't have a command in any of these technologies, a good idea would be to register for one of the Forum Nokia Regional Code Camps happening worldwide and get started with both WRT and Flash in nice hands-on workshops.

Yours truly will be probaly hosting a Flash Lite somewhere in April, stay tuned.

If you're more into widgets, you can also get started by checking out this article I wrote back in November 07. It covers everything you need to know to develop your first widget, including SDK and live testing with our Remote Device Access service:

Widgets on S60: Web Runtime

* * *

I have been thinking a lot about Python for S60, Mobile Web Server and how to extend Flash and Java applications using the former technologies. I wonder if it would be possible to extend Widgets as well, having a C++ or Python light web server running on the phone while a widget makes local XMLHttpRequest connections to this service, thus getting more native-related functionality. Mobile Web Server seems like a good candidate for this type of experimentation. I may give it a try soon. (evil laugh)

My first post, and it comes fully loaded with Python!

Wed, 19 Mar 2008 13:37:36 -0100

Hello all,

This is my first post at Forum Nokia's Blogs, and certainly won't be the last since I like to talk a lot.

I have been working with Forum Nokia since 2005 and with Nokia technologies since 2000, and it's been a pleasant journey I can say. I am based in Sao Paulo, Brazil, where we Forum Nokians have the mission of building awareness for Nokia technologies and platforms and of course help the developer community (which is huge) grow interest in mobile software development.

As one of the lucky people (according to Hartti) to attend BOSSA 08 Mobile Open Source Software conference held in Recife, Brazil. I gave a lengthy workshop on everything you need to know to get started with Python for S60 application development. I had a lot of fun preparing the workshop, since until 2 weeks ago I knew very little about the technology, and after reading all of the project's material and the amazing Mobile Python book from Forum Nokia Champion Jürgen Scheible, I became sort of an expert on it (at least compared to myself in the beginning of March). It always nice when you can have the opportunity of learning something new, specially when it makes your life so easy as Python for S60 does.

For those interested on it, the material I've presented is linked below so it's free for you to download and enjoy. It contains a .ppt presentation about all things PyS60 (from downloading to start developing and running apps on the phone) and some source code examples, many of them written by my, others taken from the book cited above.

Here are the links:

python_pres.pdf (pdf document containing the presentation)

python.zip (source code)

Of course, your feedback is always appreciated!

[]s
Daniel