Tag Archives: Software

How REST Can Relieve Your (Lack of) Documentation Guilt

A couple of months ago we hired a contractor to write a reporting interface for our high volume monitoring system. Our system exposes all of it’s data in RESTful web services, and his job has been to take that data and allow users to create reports based on it. This morning a couple of my […]

When To Use Exceptions

Marty Alchin recently posted about the “evils” of returning None (or nil or null depending on your language of choice). I think he has it basically right. Sure there are situations where returning nil1 is appropriate, but they are pretty rare. For example, if a method actually does what the client asked and there is […]

ActiveRecord race conditions

Ara Howard has discovered that the ActiveRecord validation mechanism does not ensure data integrity.1 Validations feel a bit like database constraints but it turns out they are really only useful for producing human friendly error messages. This is because the assertions they define are tested by reading from the database before the changes are written […]

HTTP Authentication with shared identities

Authentication has been bane of my existence lately. By which I mean, it is complicated and interesting and I am loving every minute of it (but, as you can see, I am not going to let that stop me from complaining about it). However tonight I have run into an authentication problem that I am […]

Hierarchical Resources in Rails

Consider a situation where you have a type of resource which always belongs to a resource of another type. How do you model the URI space using Rails? For example, say you have an address resource type. An address is always associated with exactly one user, but a user may have several addresses (work, home, […]

JSON Schema Definition Languages

We recently settled on using JSON as the preferred format for the REST-based distributed application on which I am working. We don’t need the expressiveness of XML and JSON is a lot cheaper to generate and parse, particularly in Ruby. Now we are busy defining dialects to encode the data we have, which is happy […]

REST vs WS-* War

David Chappell declares the REST vs WS-* war over To anybody who’s paying attention and who’s not a hopeless partisan, the war between REST and WS-* is over. The war ended in a truce rather than crushing victory for one side–it’s Korea, not World War II. The now-obvious truth is that both technologies have value, […]


Mr Whitney recently posted an article in which he described mock objects as “bug aggregators”. I once held a similar point of view. Back then my belief was that test doubles (mock, stub, etc) should only be used when real objects would not work, either because they were too hard to setup or because they […]

Hypermedia as the Engine of Application State

One of the least well understood core tenets of the REST architectural style is that “hypermedia is the engine of application state”. Which basically means that responses from the server will be documents that include URIs to everything you can do next. For example, if GET a blog post the response document will have URIs […]

Rake is Sweet

Rake is a really excellent build tool. It is basically Make on steroids (and minus a few of the annoying inconveniences of make). If you build software of any sort you owe it to yourself to check out Rake. The source of my Rake related euphoria today is that I just used a feature of […]