Tag Archives: Django

The Python Scene, Accepting Javascript, and Lots of REST

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Life continues at a breakneck pace.  Despite my best laid plans, the surest way of getting things done at the moment is in a sort of out-order manner.  However I did want to share a brief update on my journey into the Python and web application development world.  Instead of separate long form articles, I will briefly touch upon various topics.  (Note that this post itself has been in my work queue for over 3 weeks.  Mea culpae.)

The Python Scene in Toronto: Django Toronto and PyCon

I’ve now gone to two Django Toronto meetups and really enjoyed meeting with the Python community in Toronto.  The majority of web application developers in Toronto, deal with Java, Ruby or PHP (and of course Javascript).  However the Python community is there and growing.  They are very welcoming, and I have enjoyed each of the Django Toronto meetups I have gone to.  Also I feel like everytime I go there, I learn a lot and come back a better (or at least better informed) developer.  At the last meetup, I gained a deeper insight into crafting REST web services.  Something that I immediately applied to my day job the next day.  The one funny thing about Django Toronto, is that while the Django framework is an amazing platform, many Python developers move away from it once they scale up.  That is reflected in the meetups, since the topic of different platforms such as Flask come up.

The most exciting thing that is happening in the Toronto area for Python developers is PyCon.  This will be the first year that PyCon comes to Toronto.  I will definitely be there and I have been preparing by working on some real world Python applications.  If you will be there, I’d love to meet up with you!

How I Stopped Worrying and Started to Like Javascript

Javascript has been a language and platform I have avoided as much as possible.  If I can I try to stick to fancy tricks that one can pull off HTML5 and CSS3.  However one can only go so far without adding scripting to a web application.  Plain old Javascript still is a pain in the neck in a browser environment.  In other environments, it might be different as a scripting language.  However in such cases, I usually reach for Python rather than Javascript.  In a web app environment most of my experience has been with Sencha ExtJS.  While ExtJS is a remarkably powerful and flexible platform, it is problematic.  Aside from the licensing confusion of the original versions of ExtJS, I found that ExtJS contains a lot of automagic.  Building a ExtJS application consists more of configuring a number of components, and getting them to do more or less what you want to do.  Finding the right configuration has resulted in many stressful hours for myself and many other developers that I know.  Given all that developing with Javascript has left a bad taste in my mouth, until recently.

Two main things have changed my mind about Javascript.  Aside from the fact any sort of more advanced web application requires a full-on Javascript powered client, Javascript is not an entirely evil language for the web.  Doug Crawford (of JSLint fame) makes a good claim in his book Javascript: The Good Parts, that Javascript has some nice parts.  Yes, there are some ugly parts and needs a lot of love in the coming version.  But it is quite good for what is essentially a Schema-like functional/prototype language with Java-ish syntax.  Especially considering how quickly it was created at Netscape, it is not a terrible language.  If you are not convinced, I highly recommend watching the video below:

 

 

The other thing that changed my mind about Javascript is jQuery.  After fighting with ExtJS, the minimalist approach to Javascript development espoused in jQuery is refreshing.  I essentially learned the basics of jQuery overnight, trying to firefight a work project where office politics had gone amok.  (Aside: My take on politics in general is avoid it.  Get stuff done, not argue about it.)  Yes you have to know what you are doing with jQuery, and you don’t get a fancy MVC/MVT/etc. framework with jQuery.  But if you don’t fear writing Javascript by hand, and you want a library that abstracts the cross-browser stupidity, then jQuery is the answer.  For the next big web application that I am currently writing I will definitely be using jQuery.

Lots of REST and JSON

As mentioned earlier in the post, I have been dealing with a lot of REST service and JSON.  It is an infinitely nicer and simpler manner to talk with a server application, than via SOAP and XML.  (XML has its place, but it has been overused and abused in the Java world.)  When working with Java I’ve worked with Jersey and SpringMVC for building REST services.  Spring in general just works better, aside from its crazy arcane configuration.  In Python I’ve started working with Flask to handle building REST services, which I find a lot lighter than Django that sort of thing.  Also JSON is an awesome idea.  More people should use it for more of their data interchange needs. 🙂

IntelliJ IDEA Makes It All Better

Not to sound like a promotional campaign (since I work in what essentially amounts to the advertising industry, it happens more often I’d like) but one of the best decisions I’ve made recently is to switch IDEs.  I used to swear by Eclipse as the be-all-end-all of development environments.  Then I discovered PyCharm for Python.  Soon after that I got to meet Jessamyn Smith at a Django Toronto meetup.  While were talking about the joys of switching away from Subversion to Git–Jessamyn wrote a great article about her own experiences of migrating to Git–she convinced me to look into IntelliJ IDEA as it had a better interface for managing Git operations.  She was pretty convincing, as that is my primary IDE nowadays.  No more mucking around and wasting time with Eclipse’s temperamental setup.  Things.  Just.  Work.  Meaning I can do work.

Hitting the Flask

Somethings die hard.  One of those things is my own insistence on having lots of control over my computing environment and development platforms.  This led me to using Linux late in high school.  After playing around with Django, and wanting to build my own applications I found myself hunting down various odd ways to get around Django’s defaults.  Do not get me wrong, Django has a ton of nice pre-build features and default that just work.  Unfortunately being a web application developer, I have my own experiences, expectations and assumptions.  They are not always right.  However I prefer frameworks that I can plug-and-play and give me a finer grain of control.  (Hence I prefer using Spring in my Java web apps.)  So I’ve discovered Flask, a great micro-framework for Python.  I like how it makes web programming easy, without making a whole wack-load of design assumptions.  It very much reminds of me of the best parts of Spring, and apparently it is very “Ruby on Rails” like.

Penguins and Pythons, Oh My!

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Note: I have been meaning to get this post up for a while now.  However since I am swamped with work in general, everything is delayed and taking longer than expected.  Sorry about that.

As I mentioned in an early post, I am working on building up my professional experience in Python.  It has been a few months–time sure does fly when you are busy as heck–so it makes sense for me to update you on my experiences with Python so far.

Living in Large in Python-landia

I always enjoyed writing Python scripts.  Nothing quite beats Python when you need to write a script to search-and-destroy empty files or automatically converting files.  Sure you can suffer through BASH scripting or BATCH for the poor souls stuck in Windows.  You could write a one-liner Perl script that you could never ever read again.  Or you could bring in a 800 pound gorilla into the mess by coding a full-on program in Java or C++.  But why would you want to, if you can write a fully functional script in Python?

Writing scripts is one thing and writing applications is another.  An full application contains a lot of complexity, structure and code, and initially I felt uncomfortable building a large web application in Python.  Turns out it is not as big of a deal as I thought.  First of all a lot of the code that I write in Java is boilerplate or object manipulation or setter/getter fetish.  All of that goes away in Python.  Also it is easy to simply use other people’s libraries for much of that other work, so the size of a Python application is considerably smaller.  With a bit of careful organization and good code modularization, most of the problems go away by itself.

I found the last sections of Learning Python the Hard Way by Zed A. Shaw, an excellent reference as a both a refresher in Python and working with complex Python applications.  Incidentally I found the book so good, I think I will use it as a textbook when teaching programming.

As I use Python more and more, the more I like it the way it is.  Yes, I even have gotten over the whole whitespaces and tabs issue that most people get hung up about in Python.  Besides the brevity and elegance of the language, how can you not like a language that:

  • Has a Zen statement built into it.  (Hint: run import this in a Python shell.)
  • Refuses requests to be anything that it isn’t. (Hint: run from __future__ import braces)
  • Links to a xkcd comic about Python!  (Hint: run import antigravity)

Using PIP and PyPi (Or Shopping at The Cheeseshop)

One of the fun things I recently discovered in Java with Maven, Ivy and Gradle was the concept of automatically downloading and installation of dependencies.  I loved it that you could list the types of libraries that you’re application and everything automatically installed during the first build.  Also having lived with Linux package management, I got used installing all my software via a package manager.  Unfortunately many of the packages in Ubuntu are not the latest and greatest libraries that I need.  Also building a Debian deb or RPM is an exercise in yak shaving.

Fortunately all those issues are addressed in Python.  For package management you have the PIP utility, that installs packages available in a large web repository of Python libraries and applications called PyPi [http://pypi.python.org/].  This combination lets you install packages with a simple <code>sudo pip install $AWESOME_PYTHON_PACKAGE</code>.  Pretty nifty, eh?

If you are wondering about the reference to “The Cheeseshop”.  Apparently PyPi (not to confuse with the Python implementation of Python called PyPy) used to be called “The Cheeseshop” in reference to the Monty Python sketch by the same title.  Fortunately finding software that you want in PyPi is much easier than shopping for cheese at the Cheeseshop.

Charming Code with PyCharm and PyDev

Python code like I mentioned is one of those rare languages where you do not need an IDE to use, outside of a text editor and a shell/console.  I could not imagine doing the same with Java or C++.  For anything more complicated than a small function you really do need a full-blown IDE like Eclipse.  However after working with my favourite text editors Kate and Vim, I realized that I was missing better text highlighting and tab completion when writing Python code.  A good IDE really does help and not hinder when hacking in Python too.

Being familiar with Eclipse, I started using PyDev, a great Eclipse plug-in for Python with Django and Google App Engine support.  I highly recommend it, if you already use and are familiar with Eclipse.  However even when using the Eclipse plugins for Git and Syntax colour themes, I found that Python on Eclipse is still sort of a second class citizen compared to Java.  (Not sure if PHP or C++ developers on Eclipse have it any better in that case though.)

I experimented with quite a few different IDEs, while each offered something nice none of them really stood out.  Then I met the nicest Python IDE out there: PyCharm.   Of all the IDEs I’ve looked at PyCharm has the nicest tools, themes and feels much nicer than any other IDE out there.  Yes, I know that PyCharm is proprietary and that I am breaking my own rules about using libre software.  However there isn’t any IDE high quality enough that does what PyCharm does, including refactor, style checking and really good Django support.  The Git support could be nicer, but for any complex Git operation I end up using a console anyways.  Still I was impressed enough with PyCharm, that I actually bought a license for myself pretty much on the spot.

Other IDEs I’ve looked at included:

Dancing to the Sound of Django

While working with Python is pretty sweet, for me the big question is whether or not I can potentially make a living using Python.  Since most of my expertise is in web or web-powered mobile applications, I was most interested in what Python can do in that area.  Hence my interest in Django.

After using Django for a while, I can confirm that it is an amazing framework.  Django has captured my imagination of what can be done with Python.  While it takes some time to get used to the framework, it makes building web applications easy and enjoyable.  A lot of the tedious and mundane work like building administrative forms, mapping models to database tables and input validation, are dealt with for you.  Django is very modular, so with a bit of effort various underlying technologies can be swapped in and out.  Django provides smart defaults, but allows you to easily override the parts that don’t make sense.  One example is that it is fairly easy to override the default ORM SQL that is auto-generated from a model, to match the model or database better.

Documentation can make or break one’s perception of a library or framework.  Django has awesome documentation, and so do many of the community-contributed apps and systems of Django.  Some the add-on components really add a lot like Taggit and South, which provide tagging and database migration to Django.  Also there are some great books on Django:

One of the best parts of Django that I’ve encountered is the community of Django developers.  Unlike some communities, Django seems to get developers who are knowledgeable, friendly and approachable.  By hanging out on the #django IRC channel and asking the right questions, the devs there were able to help me out and answer some of my questions faster than I could of possibly been able to find the answers myself.  Of course as with any open source project community, you need to ask smart questions.  There are also local Django groups.  In fact I am looking forward to going to my first Django Toronto meetup.

Django is a really cool web framework for Python.  The designers of Django, really put a lot of effort in making a great framework.  The documentation is top notch.  The community is amazing.  To top it all, it is named after an amazing and cool French-Belgian jazz guitarist Django Reinhardt.  If you are into jazz or swing music I highly recommend checking out his music.

Using Python in Anger

 All the theory in the world, does not help if you can not put theory into practise.  Same goes with the theory of using Python in a professional setting.  Coming from the Java EE and Android worlds, I do expect certain tools.  Now since Python is interpreted on the fly, one can skip all of the compilation and packaging nonsense of Java.  (Yes, I know that Python code gets compiled into bytecode on the first run.  Why can’t Java do the same?)  As for API documentation, Python is quite a bit different than Java.  However epydoc does great job of API documentation, Sphinx does an incredible job with making in-depth documentation using the reStructured Text format.  Currently for my projects I have used epydoc mostly, and I’ve built a script to run it in Linux.  I have yet to figure out how to make a pure Python automated script for it, and I might switch to Sphinx if my documentation becomes extensive enough.
Interestingly in a company that I interviewed at recently, also uses Python and namely Pylons/Pyramid for the backend.  Also they have some Django components to if I remember correctly.  In fact a few of the people involved commercially in Python use a combination of Pyramid/Pylons, Django and some Zope, depending on the job.

Leave-A-Note Portfolio Project

While I have learned a lot about Django in the past few months, I still would hesitate on quitting my day job and becoming a Django consultant.  😛  However I have started working on a portfolio project to highlight my Django, web frontend and Android development skills.  This project is a simple device-to-device pull messaging system called  Leave-A-Note licensed under the AGPL.  While I could of easily made this application in PHP, I decided to build the server-web application in Django.  (I’m also working on another web app, but I can’t reveal much about that project yet.)  I am still in the initial phase of development, so there isn’t much to see yet.  I might build a few of the projects in the Practical Django Projects before I head off on my own.
All in all I am quite excited by Django.  Hopefully with it, I can start adding in more Python development in my professional programming repetiore, if not working with Python outright.

Diving into the Deep End with Python

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Where I Stand with Java

Most of my professional experience in software development has centered around Java.  That should be no surprise as I learnt Java in university, and all the trappings that go with it: Javadoc, the Java Standard API, Eclipse and JUnit.  My professional work exposed me to JSP, Servlets, SpringMVC, Struts, JDBC, TestNG, Ant and the Android SDK.  Sure I’ve used other languages such as PHP, Perl, Scheme (mmm… functional programming…), C and Prolog.  The mainstay of my experience is still Java.

All that said, even as I include more and more exotic features of Java as language (i.e. enumeration, annotations, reflection, etc.) and as a platform, I find myself more and more constrained by the language itself.  Sure I feel comfortable with it, and I’ve written code personally that spans tens of thousands of lines.  However I find a lot of the code is boilerplate code.  Heck thanks to JAXB, I can quickly describe a series of classes using a XML schema.  That is right, a XML schema, one of those awfully obscure XML trappings that only enterprise application developers really should ever care about (or those working with complex document-style data).  Also a large Java codebase is nearly unapproachable with anything less than a powerful IDE.  Thank goodness for Eclipse!  (I write this wearing an Eclipse branded fleece jacket.)

Java is a wonderful and powerful language with great tooling.  However it just seems so wrong to have so much complexity.  I fear that this has more to do with the design decisions in the language itself than anything else.

Enter the Competitor: Python

I also learnt Python in university but I ended up using it largely for building system administration scripts rather than a general programming tool.  Instead of fighting with unwieldly BASH or Batch scripts for admin work, I use Python.  And I have created some powerful scripts using Python for tools for hunting down empty directories and rogue files for automated renaming.  After fighting with Java to do my bidding, I felt the need to look for some better language when building my new hobby project.  Also my recent attempts at learning Qt and C++ at the same time, have made me want to first learn the platform and then the language.  This is where Python seemed to hit a sweet spot.

While talking with one of my old university friends, Dan D’Alimonte, the topic of learning Qt came up.  Instead of using C++ for his Qt apps, Dan used PyQt.  After looking at his code, I decided to experiment with PySide and lo and behold I made a Qt app myself!  On the web side of things I heard a lot of good things about the Django web framework.  Hence I started experimenting with and investigating Python, PySide and Django.  In addition to the simple can-I-do-this-with-that experiments, and playing around with the tutorials, I researched the tooling and performance of Python based applications.

I am impressed so far with what I have found out about Python.  Coding in Python is a breeze and enjoyable.  I can comfortably use any text editor to program in Python.  I found that PyDev makes Python development while using Eclipse easy.  Getting new packages for Python is simple, and I do not have to rely on a package maintainer.  The standard libraries in Python are on par with Java’s.  You can always extend Python with a C or Java binding.  Building a desktop app using PySide turned out incredibly easy, compared to the standard C++ way of doing things.  Django is proving to be a very capable, and apparently *gasp* fast web framework especially when run on the optimized PyPy version of Python.  There is even mention of Python being able to build web frontends, at least in the documentation.  And importantly for me, Python has various XML, database layer, testing, and other enterprise and mobile capable libraries that I can potentially use in my day-to-day work.

Now naturally the quirks of a language become more readily visible once you actually start working on a real-life project.  That is my next step.  Then I can figure out if Python could really replace Java as my go-to language.  I will keep you posted once I get further in the project I am working on.  In the meantime, I’ve collected a bunch of links related to my investigation with Python.  Enjoy!

Python Related Links

Does Complexity Necessarily Translate Into Capability?

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Two months ago I started work as a Java developer at Bluerush Media Group.  Shifting gears back into Java EE/JSP/Servlet and mostly backend work from Android development definitely took a while.  On one hand my work now is hidden behind layers and layers of servers, middleware and other “businessy” systems.  I definitely miss being able to have my work appreciated by many people.  Now only my fellow developers can compliment or complain about my work.  But on the other hand, I enjoy working with tested and tried technologies and platforms.  No more worrying about inconsistencies between devices.  No more fretting about what systems I communicate with.  No more frustrating moments of dealing with performance and optimization issues.  Instead there is more than enough computational power lying around that automation and abstraction become powerful tools to approaching and solving problems.  I feel less guilty about using some crazy library to configure itself, gather the necessary data and build part of the system for me.  In short, as with everything in life there are pros and cons to my work.

Just recently I discovered the joy of using JAXB.  It is mindbogglingly convenient to build entire packages of Java model classes from a single XML schema, and having JAXB handle the serialization and deserialization of Java models into XML and back again.   Using JAXB, some XML configuration files, a TestNG suite and some result data in CSV form, I could build out a pretty sweet and rather involved automated testing setup.  This let me run real stress tests on the application I am working on and letting me flesh out the code much faster and with greater confidence.  Or take the use of dependency injection from Spring or Guice, to help a developer initialize a large number of objects with complicated dependencies without getting lost.  The amount of automation and abstraction in Java EE is simply overwhelming.  However it does come with a price: complexity.  So while using the full power of Java EE and various libraries gives my applications a lot of capability, they also make the applications terribly complex.  It only gets more complex, the more “enterprisey” the application becomes.  There is simply no way I could even build the applications that I do, without having lots of complex tools such as a full-on IDE like Eclipse.

This brings me to the point of my post.  At same time as I delved further into Java EE, I am getting more and more interested in Python and Django.  After playing around a tiny bit with PySide building Qt apps in Python, and looking into Django I am surprised by how terse yet functional Python is.  Yes, Python being a scripted language will never outperform a compiled program (or even byte-code compiled Java app) in terms of performance.  But looking at how much computing power is available and how many more steps it takes to write a Java or other compiled source app… I wonder if programming in something like Python can not be more efficient.  What I am especially curious to find out is if one can build and maintain a large complex web app as one can in Java EE, but in Django and Python.  Basically I am curious of the capability of an app is proportional to its complexity.  Or is this just an illusion from living with a language and platform that lets you easily craft monolithic monsters?  Can one get the same results with good architecture, some smart engineering and a flexible language?