Scriptrunner for Confluence

import com.onresolve.scriptrunner.runner.rest.common.CustomEndpointDelegate
import groovy.json.JsonBuilder
import groovy.transform.BaseScript

import javax.ws.rs.core.MultivaluedMap
import javax.ws.rs.core.Response

import com.atlassian.sal.api.component.ComponentLocator
import bucket.user.UserAccessor

@BaseScript CustomEndpointDelegate delegate

def userAccessor = ComponentLocator.getComponent(UserAccessor)

user(
        httpMethod: "GET", groups: ["confluence-administrators"]
) {

    // validate we have username as a url parameter
    // extraPath is already available to use
    def extraPath = extraPath as String
    assert extraPath =~ "^/[a-zA-Z]+"
    def username = extraPath.split("/").last()

    def user = userAccessor.getUser(username)
    // user must exist in Confluence
    if (!user) {
        return Response.serverError().entity([error: "User $username does not exist"]).build()
    }

    def userResponse = [
            username: user.name,
            fullname: user.fullName,
            email: user.email
    ]

    return Response.ok(new JsonBuilder(userResponse).toString()).build()
}

jarvis:bin npn$ curl -X GET -u admin:Welcome1 http://localhost:8090/rest/scriptrunner/latest/custom/user/admin
{"username":"admin","fullname":"admin","email":"npn@netic.dk"}jarvis:bin npn$
jarvis:bin npn$