Lift Cookbook

Chapter 4. REST

This chapter looks at recipes around REST web services, via Lift’s RestHelper trait. For an introduction, take a look at the Lift wiki page and Chapter 5 of Simply Lift.

The sample code from this chapter is at https://github.com/LiftCookbook/cookbook_rest.

DRY URLs

Problem

You find yourself repeating parts of URL paths in your RestHelper and you Don’t want to Repeat Yourself (DRY).

Solution

Use prefix in your RestHelper:

package code.rest

import net.liftweb.http.rest.RestHelper
import net.liftweb.http.LiftRules

object IssuesService extends RestHelper {

  def init() : Unit = {
    LiftRules.statelessDispatch.append(IssuesService)
  }

  serve("issues" / "by-state" prefix {
    case "open" :: Nil XmlGet _ => <p>None open</p>
    case "closed" :: Nil XmlGet _ => <p>None closed</p>
    case "closed" :: Nil XmlDelete _ => <p>All deleted</p>
  })
}

This service responds to URLs of /issues/by-state/open and /issues/by-state/closed and we have factored out the common part as a prefix.

Wire this into Boot.scala with:

import code.rest.IssuesService
IssuesService.init()

We can test the service with cURL:

$ curl -H 'Content-Type: application/xml'
    http://localhost:8080/issues/by-state/open
<?xml version="1.0" encoding="UTF-8"?>
<p>None open</p>

$ curl -X DELETE -H 'Content-Type: application/xml'
    http://localhost:8080/issues/by-state/closed
<?xml version="1.0" encoding="UTF-8"?>
<p>All deleted</p>

Discussion

You can have many serve blocks in your RestHelper, which helps give your REST service structure.

In this example, ...