|
PyDev, Python and system default Unicode encoding problemPosted on January 24, 2010 by Mikko OhtamaaFiled Under aptana studio, eclipse, plone, pydev, technology Python 2 has a thing called “default encoding” to automagically encode Unicode strings when they are presented as byte strings. This is evil and has been discussed various times before. What could be even more evil? Something in your development environment messes this setting set for you, without telling you that. This way you never encounter Unicode problems on your development computer and when you roll out your seemingly working code to production, the world goes haywire. Evil. Evil. Evil. Thousands of curses and overworking hours to fix the problems. I encountered this problem. And this is the code I used to track the problem down in site.py: # Trap the bastard messing with the default encoding
# using a monkey patch
old_set_default_encoding = sys.setdefaultencoding
def aargh(x):
import pdb ; pdb.set_trace()
sys.setdefaultencoding = aargh
And the result was surprising:
Looks like the culprint was PyDev (Eclipse Python plug-in). The interfering source code is here. Looks like the reason was to co-operate with Eclipse console. However it has been done incorrectly. Instead of setting the console encoding, the encoding is set to whole Python run-time environment, messing up the target run-time where the development is being done. There is a possible fix for this problem. In Eclipse Run… dialog settings you can choose Console Encoding on Common tab. There is a possible value US-ASCII. I am not sure what Python 2 thinks “US-ASCII” encoding name, since the default is “ascii”. Creating a drag’n'drop basket with jQueryUIPosted on January 5, 2010 by Mikko OhtamaaFiled Under jquery, jqueryui, technology I have created an example how to create a “basked” with jQuery and jQueryUI with the following features
This kind of user interface pattern is suitable for
The example in fact bears the name “travel planner” but it is not tied to travel anyhow. Note: this is just a screenshot - please see live example
The example code uses
The example code is well-documented with links to the further documentation. Nokia N900, sports tracking and geotaggingPosted on November 29, 2009 by Mikko OhtamaaFiled Under geotagging, mobile, n900, nokia, sports tracker, technology This blog contains some tips how to use your Nokia N900 smart phone as a “augmented reality” sports device. Sports trackingSport tracking is about collecting your sports activity data using GPS and other equipment. After running/cycling/skiing/whatever you see where you have been, how much time it took and how fast you are. In same cases you are able to calculate burnt calories and estimated heart rate. N900 has at least one sports tracking application out there, eCoach. eCoach is also suitable for professionals as it has heart rate monitor integration. eCoach allows you record and store sport activities. During the activity it uses Open Street Map based map viewer to show your current location. At least Helsinki area has very detailed maps available there, showing even the smallest trails, so you can safely venture to unknown neighbourhoods. eCoach exports its tracks as GPX gps data file format. eCoach does not have any service integration yet, but you can upload this file to Nokia Sports Tracker and Map My Tracks. The recommend the latter as it has better social media integration and seems to be under active development. On the otherhand I have been using Nokia Sportstracker since 2007 and it has not really development during the whole this time and seems to lack will to go forward. Also Nokia has disabled track profile for imported GPX files which gives a message “we really don’t care about this service”. There is also a service called mapmyrun.com with various domain names like “maymysomething.com”. Steer away from this service as I tested it and it didn’t live up to my expections (too much advertising, horrible user interface). Some sport tracks I have made
GeotaggingGeotagging is about having GPS coordinates on your photos. This way photos can be put on the map autotically in photo sharing services like Yahoo Flick or Google Picasa. When you known location, capture time and sharing license of the photo, all kind of fantastic services can be created, like Microsoft Photosynth. Technically geotagging works by embedded GPS coordiates into the EXIF metadata of JPEG files. N900 has geotagging as out of the box feature – no additional software needed. Just turn on it on in Camera application settings. Also, you can retrofit your photos with geotagging information afterwards. You can do this by hand using labels and drag and drop in the most of photo sharing applications, like Google Picasa. Also there exist automated tools if you have relates GPS records available as GPX or KML file: checkout GPicSync. This is handy if you record your sports in eCoach and forgot to turn on geotagging in N900 camera. GPicSync also has a Google Maps export feature if you want to create custom maps for your friends or customers.
Sports tracking + geotagging = ?I am still trying to figure out how to combine sports tracking and geotagging to something cool. Maybe something along the lines of urban exploration. But in any case here are some of cities I have “collected” from my travels PhoneGap ported on N900 (Maemo)Posted on November 24, 2009 by Mikko OhtamaaFiled Under maemo, mobile, n900, phonegap, technology We have ported PhoneGap mobile application framework to the new Nokia N900 smartphone and its Maemo operating system. PhoneGap is a framework to build mobile applications easily with HTML and Javascript. With the new Maemo port PhoneGap platform support covers iPhone, Android, Nokia Series 60, Blackberry, Windows Mobile and Maemo, making it one of the most portable mobile application development solution available.
The demo application currently supports only Device Info and Accelerometer APIs. The porting work is still in its early stages and we suggest novice developers steer away from it. We’ll develop and maintain the work as long as we have client cases for mobile applications. If you are looking forward to port your commercial PhoneGap application to N900, please contact us. PhoneGap port was done using QT and QWebView controller. The native shell source code is in C++. Build and packaging scripts are standard Makefiles. More technical information on the release notes page. Code is available on GitHub. So what’s cool about Maemo (compared to other PhoneGap platforms)?Shortly: The openess of Maemo platforms enables developer innovation never seen before. There are zero artificial limitations chaining your imagination.
So what’s cool about PhoneGap (compared to other mobile application technologies)?
Installing Python Imaging Library (PIL) under virtualenv or buildoutPosted on November 19, 2009 by Mikko OhtamaaFiled Under plone, python, technology I have greatly struggled to have PIL library support in isolated Python environments like virtualenv –no-site-packages. For example, when installing Satchmo shop under virtualenv:
Though it clearly is there, installed by easy_install PIL command: ls ../lib/python2.5/site-packages/PIL-1.1.7-py2.5-linux-x86_64.egg ArgImagePlugin.py ExifTags.py GimpGradientFile.pyc... Does anyone know if this problem is with PIL itself, eggified PIL or something else? In any case, there is an easy workaround: use system-wide PIL (sudo apt-get install python-imaging) and symlink PIL from your site-wide installation under the isolated Python environment: (satchmo-py25)mulli% pwd /srv/plone/mmaspecial/satchmo-py25/lib/python2.5/site-packages (satchmo-py25)mulli% ln -s /usr/lib/python2.4/PIL . That works for now, but I’d like to learn how to make virtualenv and buildout install PIL egg bullet-proof way.
Setting up multi-touch scrolling for Ubuntu 9.10 Karmic Koala Linux on Asus Eee 1005HA netbookPosted on October 11, 2009 by Mikko OhtamaaFiled Under linux, technology, ubuntu This post is specific to Asus Eee 1005HA netbook, but the technique explained here can be used on any computer having Synaptics touchpad. Multi-touch gestures allow you to perform user interface actions by doing two finger gestures on touchpad. Apple introduced this feature on Macbooks and after you get used to it, it greatly enhances your web browsing on mouseless netbook. The most important gesture is scroll text by swiping the touchpad with two fingers. Apple has also many patents related to the gestures so they are not enabled by default. The real multi-finger touch support needs multi-finger aware (capacitive) touchpad. Most PC laptops are not equipped with one. Luckily some of the simple gestures, like two finger scrolling, can be emulated on normal pressure point sensitive touchpad via clever calculations and other tricks. Note: Ubuntu HAL support for Synaptics seem to be broken. Only shell script at the end of the post will work. HAL options in FDI file are being ignored. Setting up Synaptics driverType in terminal gksudo gedit /etc/hal/fdi/policy/11-x11-synaptics.fdi Create and save file with this content: <?xml version="1.0" encoding="ISO-8859-1"?>
<deviceinfo version="0.2">
<device>
<match key="info.capabilities" contains="input.touchpad">
<merge key="input.x11_driver" type="string">synaptics</merge>
<merge key="input.x11_options.SHMConfig" type="string">On</merge>
<merge key="input.x11_options.EmulateTwoFingerMinZ" type="string">40</merge>
<merge key="input.x11_options.VertTwoFingerScroll" type="string">1</merge>
<merge key="input.x11_options.HorizTwoFingerScroll" type="string">1</merge>
<merge key="input.x11_options.TapButton1" type="string">1</merge>
<merge key="input.x11_options.TapButton2" type="string">3</merge> <!--two finger tap -> middle clieck(3) -->
<merge key="input.x11_options.TapButton3" type="string">2</merge> <!--three finger tap -> right click(2). almost impossible to click -->
</match>
</device>
</deviceinfo>
This allows us to use synclient utility to watch touchpad real-time data in console window. Now restart X sudo /etc/init.d/gdm restart And open terminal again. Type in command synclient -m 100 And you should see data like this scrolling in the terminal: 129.355 2912 3469 59 1 4 0 0 0 0 0 00000000 0 0 0 0 0 129.455 2952 3529 59 1 4 1 0 0 0 0 00000000 0 0 0 0 0 time x y z f w l r u d m multi gl gm gr gdx gdy 129.555 3283 3516 60 1 4 1 0 0 0 0 00000000 0 0 0 0 0 129.656 3928 3517 60 1 4 1 0 0 0 0 00000000 0 0 0 0 0 129.756 4364 3637 60 1 4 1 0 0 0 0 00000000 0 0 0 0 0 129.856 4020 3329 49 1 4 0 0 0 0 0 00000000 0 0 0 0 0 129.956 3634 3122 58 1 4 0 0 0 0 0 00000000 0 0 0 0 0 130.057 3320 2957 60 1 4 0 0 0 0 0 00000000 0 0 0 0 0 130.157 2779 3312 61 1 4 0 0 0 0 0 00000000 0 0 0 0 0 130.257 2557 3739 61 1 4 0 0 0 0 0 00000000 0 0 0 0 0 130.358 2636 3485 39 1 4 0 0 0 0 0 00000000 0 0 0 0 0 130.458 2659 3104 60 1 4 0 0 0 0 0 00000000 0 0 0 0 0 130.558 2671 2988 60 1 4 0 0 0 0 0 00000000 0 0 0 0 0 f column tells the number of fingers. w is the touched area width. z is the pressure. If you put two fingers on touchpad and you see value f=2 then your hardware has multi-touch aware touchpad. Unfortunately Asus Eee 1005HA doesn’t seem to have one Emulation approachSynaptics driver can emulate two-finger touch with the following conditions
When the conditions are met the driver thinks “Wow looks this guy is pressing us really hard. maybe he is using two fingers?” Note that touchpad values are touchpad specific and values applying for one model don’t work on another computer. Synaptics driver settings are described here. Synaptic driver settings can be modified run-time using xinput command. Run synclient -m 100 in one terminal window and change threshold values in other until you find correct emulation parameters for your laptop. Below is my xinput tests. Test scrolling on Firefox and any long web page. moo@huiskuttaja:~$ xinput set-int-prop "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Width" 32 7 moo@huiskuttaja:~$ xinput set-int-prop "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Pressure" 32 280 moo@huiskuttaja:~$ xinput set-int-prop "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Width" 32 11 moo@huiskuttaja:~$ xinput set-int-prop "SynPS/2 Synaptics TouchPad" "Synaptics Two-Finger Pressure" 32 50 moo@huiskuttaja:~$ Looks like the following parameters are good for two finger emulation for Asus Eee 1005HA:
You can also use command synclient -l to dump the current settings. Below is the final script you need to run during log-in (see note about broken HAL at the beginning of the post):
Jumpy cursor after two finger scroll When you do a two-finger scroll and lift your one finger before the other the mouse cursor/scrolling may jump. Synaptics driver does not seem to have an option to filter out this bad event. If anyone knows solution for this please comment. Other resources
Cannot sort custom content item in Plone folder listingPosted on October 5, 2009 by Mikko OhtamaaFiled Under plone, technology Bug: Plone folder manual sorting does not move items even though you try all tricks. The first suspect would be a Javascript bug, but it isn’t. It is bug 8161. Your custom content meta_type must not contain spaces. You can fix this on-line by editing meta type in portal_types in ZMI and remove all spaces from meta type name. Subversion global-ignores and .egg-info in Python/Plone developmentPosted on October 3, 2009 by Mikko OhtamaaFiled Under plone, python, technology Subversion does a good job by ignoring most of build/temporary/unwanted files by default. However, there is one exception still existing at least in Subversion 1.6: Python egg folders. All folders whose name ends up with .egg-info should not committed or considered in version controlling actions. your.package.name.egg-info folder is generated inside your Python egg source folder when you run setup.py / setuptools. If you are working with Python source code eggs, add the following line to your ~/.subversion/config global-ignores = *.o *.lo *.la #*# .*.rej *.rej .*~ *~ .#* .DS_Store *.egg-info *.pyc *.pyo .project .pydevproject Otherwise development tools like Mr. Developer might get confused. Cross-platform mobile application development and paymentsPosted on September 30, 2009 by Mikko OhtamaaFiled Under android, blackberry, html5, iphone, javascript, locationing, payment, series 60, symbian, technology 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
Sounds easy, right? Well it isn’t… Below are some notes for our due diligence work which you fellow developers might find interesting. SDKsMobile 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.
All these wrap the browser component (WebKit) and provide some extra Javascript APIs when your web pages as executed under the application mode.
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 purchasesThere 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.
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 prospectsIn 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 PythonPosted on September 30, 2009 by Mikko OhtamaaFiled Under Business, django, iphone, linux, mobile, pys60, python, technology 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
Software stack
Development effortDevelopment 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 |
