Thursday, December 3, 2009

Software Maintenance

This entry talks about some of the problems faced by current software maintenance practices. It highlights some of the various maintenance methods used to maintain deployed software. Of course, not many seem to do it right.

Problems arise mainly because of incompatibility between software versions. Typically, the entire software package has a version assigned to it. This includes all the constituent parts of the application such as modules and data structures. What if this individual components were giving a version instead of the whole? Well, there are systems out there in existence that do just that according to the entry.

What about taking this atomic version schema idea to the URIs of RESTful APIs. Indeed, this idea isn't anything new as many APIs support this feature. The main problem faced by web applications when performing server-side upgrades is the cached clients. Javascript that interacts with the URIs on the client's behalf may be stuck using an old API version. This is fine if the API version number is part of the URI. But backward compatibility can only be maintained so far back. This can be dealt with much easier if the expected version is part of the URI. If an unexpected version is requested, a message can be displayed to the client telling them to download a newer client. Alternatively, the new client code could be transparently delivered to the client as a response to using an incorrect version number.