Post-Redirect-Get in Rails

For a while now I've been flying the flag for using a post-redirect-get design pattern when writing web applications. In my opinion the current crop of web frameworks still make it very easy to do the "bad" thing since to do PRG properly you need to think what kind of an interaction you want with users and not cop out saying its technically very difficult in . If you resort to ActiveX controls, popups without navigation bars and/or weird javascript hacks to stop users from clicking refresh or back buttons then perhaps you should have written a better web application....

Testing anti-patterns for developers

I've been saving this rant for a while now: 1. Test everything at the front-end, in exquisite detail - every project sponsor understands what tooltip 0 really means. Also a great idea if you like long-running and fragile tests that require deployments, browsers, testing frameworks and the kitchen sink. Testing at different layers, and perhaps even without a browser or (in java) a servlet container is for the weak. 2. Perform a database cleanup before and after every test, whether it needs to be done or not....

UUID as an ActiveRecord primary key

I like non-sequential identifiers for resources. Easy to do in Java (with java.util.UUID) and in Python (using the uuid module). This has been a bit of a pain in Rails, until now - check out Ariejan de Vroom's post. I especially like his solution as it plays well with RSpec, although to be picky I would have chosen UUID.random_create rather than UUID.timestamp_create....

PicoContainer and Jersey

The Jersey JAX-RS project provides bindings for springframework and google-guice. However I wanted to see what it would take to use PicoContainer as an IoC container within Jersey. Verdict: not much at all. Nicely extensible. To see what I mean please take a look at my jersey-pico project on GitHub. I can now create JAX-RS services in Java or Groovy with a very simple IoC container....

Django RESTful resources

Last year I blogged about a neat trick in Django to have multiple views per HTTP verb. Since then I’ve been playing with RESTful applications and decided to see if there was a nicer way to expose “resources” in Django. The following is what I’ve come up with so far. Listing: router.py from django.http import Http404, HttpResponseNotAllowed def get_handler_method(request_handler, http_method): try: handler_method = getattr(request_handler, http_method.lower()) if callable(handler_method): return handler_method except AttributeError: pass class Resource: http_methods = ['GET', 'POST', 'HEAD', 'PUT', 'DELETE', 'OPTIONS', 'TRACE'] @classmethod def dispatch(cls, request, *args, **kwargs): request_handler = cls() if request....

From Java to Groovy

Recently I’ve been playing with some old Java Swing applications and I found myself wishing that I could replace all the anonymous inner-classes with some clean Groovy closures. The job of converting a java source file to a groovy source file is pretty simple and eminently scriptable. Here’s my take on a python script to do just that: from optparse import OptionParser from subprocess import Popen, PIPE import os def rename(src, dest, use_svn): if use_svn: output = Popen(['svn', 'rename', src, dest], stdout=PIPE)....

Logging Guidelines

Logging - this is something we as developers do very badly - perhaps we need to ban the debugger. Unless you've worked in first-line support or in OPS, the only time you ever look at a log file is as a last resort. This is unfortunate, since the last resort may occur when you are trying to figure out why someone has lost money or when your company is about to be sued by a client (usually for losing their money, video, kids photo, etc)....

HTTP method primer for RESTful web services

The following is just a reminder to stop me from getting confused ;-) GET Used to fetch a resource. The server sends back a representation of the resource in the response body. Safe operation (see below). DELETE Used to delete a resource. The response from a server may contain a status message or nothing at all. It is usually nice to send back at least a 204 (No Content)....

Reading code Vs searching code

Modern IDEs now allow you to search for a class or a file and go to it from the search results. On my last few projects I've seen developers using this feature almost exclusively rather than navigating their code tree. This is a very nice feature that I really enjoy using but does it have a dark side? I'm an old school hacker and I like to know how my_code is structured - its packages, dependencies, web root folders, output folders for the IDE and for automated build scripts, etc....

Concept To Cash Every Week

Turning on a sixpence - No excuses: Concept To Cash Every Week. Just saw this on InfoQ and it blew my mind. This is what I'm talking about when I mean that details matter and that there has to be a better way to deliver value to a customer. Have got to try the Pomodoro technique on my current project to see if it can improve pairing between developers (er, mostly between me and whomever is unlucky to be pairing with me)....