REST with Scala's Lift framework. Part 3 - PUT

In the previous posts I explained how to handle GET and POST requests in Scala's Lift framework in a RESTful manner. Now it's time to look into...

PUT requests

PUT is for updating objects. It's not really different from POST from developer's point of view. It's just that you get an identifier of the object from request.

(I already did that for Spring 3, you may want to take a look: REST with Spring 3: PUT.)

Retrieve the request

package bootstrap.liftweb

import me.m1key.rest.DogsRestService
import net.liftweb.http._

class Boot {
   def boot {
       // where to search snippet
       LiftRules.addToPackages("me.m1key")

       LiftRules.statelessDispatchTable.append {
           // ...
           case request @ Req(List("rest", "dogs"), _, PutRequest) =>
               () => DogsRestService.updateDog(request)
       }
   }
}

It's very similar to POST, so you can check out the POST post (really cunning game play here, folks!) for more details.

Processing the request

Processing the request is very similar to the PUT case.

    def updateDog(request: Req): Box[LiftResponse] = {
       var dogId = ""
       var dogName = ""
       request.xml match {
             case Full(<dog>{parameters @ _*}</dog>) => {
               for(parameter <- parameters){
                   parameter match {
                       case <name>{name}</name> => dogName = name.text
                       case <id>{id}</id> => dogId = id.text
                       case _ =>
                   }
               }
               val dog = new Dog(dogId, dogName)
               Log.info("Updating a dog with id: " + dog.id)
               return Full(InMemoryResponse(dog.toXml.toString.getBytes("UTF-8"), List("Content-Type" -> "text/xml"), Nil, 200))
           }
           case _ => Log.error("Invalid request");
               Log.error("Request: " + request);
               Log.error("Request.xml: " + request.xml);Full(BadResponse())
       }
   }

Summary

Similarly to the POST case, handling RESTful PUT requests in Lift 1.0 is not as comfortable as it is with Spring 3. I'm looking forward to seeing Lift 2.0 improvements in that matter.

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