Permalink codec

So, for about a week I've been working on my fun little "social" Grails web application and I've been having a lot of fun.

Yesterday, while jyting I've been taking a note of its URL structure. Let's say you have a claim, and then in order to see it, the URL to it is not something like http://jyte.com/claim/show/12345 , but rather more readable, like http://jyte.com/cl/dima767.myopenid.com-is-the-only-grails-hacker-on-jyte

That's called "permalink" (for permanent link) and is done by converting the text of the claim (or any user submition for that matter) into permalink string (removing all the special characters e.g. \W, and replacing them with '-'). Then permalink essentially becomes a searchable attribute of the submission, so instead of doing something like Claim.get(1234) you do Claim.findByPermalink(params.permalink). It's just a way of creating "user friendlier" interfaces.

Thanks to Grails and its nice custom URL mapping, and custom codecs facility, I was able to implement "permalink" functionality very easily!

Lets' say I have a domain class "Submission":

class Submission {
  String title

  //permalink property here is for nicer URLs
  String permalink

}

So then I simply create "PermalinkCodec" utility class and place it in grails-app/utils so the Grails "ExpandoMetaClass" machinery could "weave" this functionality into all Strings!

class PermalinkCodec {

   static encode = { str ->
       str.toLowerCase().replaceAll(/\W/,'-')
   }
}

Then in my "SubmissionController's" "save" action I do something like this:

...
def save = {
   def s = new Submission()
   s.properties = params
   s.permalink = params.title.encodeAsPermalink()
   s.save()
   ...
}

And finally, i define the custom mapping:

class MyAppUrlMappings {
   static mappings = {
      ...
      "/s/$permalink" {
         controller = 'submission'
         action = 'show'
      }
      ...
   }
}

So this will give users nice URLs like http://myapp/s/my-shiny-and-the-best-in-the-world-submission instead of http://myapp/submission/show/1234

I think it's a little thing, but nice, nevertheless.

Later...