Absolute links not working outside web context

[jglapa]

Expected Behavior

after setting grails.serverURL = 'http://localhost:8080'

class MakeLinkController {

    LinkGenerator grailsLinkGenerator

    def index() {

        String link
        Thread.start {
            try {
                link = grailsLinkGenerator.link(
                        absolute: true,
                        controller: 'MakeLink',
                        action: 'index',
                        id: 1
                )
            } catch (Exception e) {
                e.printStackTrace()
            }
        }


        String link2 = grailsLinkGenerator.link(
                absolute: true,
                controller: 'MakeLink',
                action: 'index',
                id: 1
        )

        render link + link2
    }
}

action result:

http://localhost:8080/makeLink/index/1http://localhost:8080/makeLink/index/1

Actual Behaviour

action result:

nullhttp://localhost:8080/makeLink/index/1

java.lang.IllegalStateException: Attribute absolute='true' specified but no grails.serverURL set in Config
        at org.grails.web.mapping.DefaultLinkGenerator.handleAbsolute(DefaultLinkGenerator.groovy:407)
        at org.grails.web.mapping.DefaultLinkGenerator.link(DefaultLinkGenerator.groovy:281)
        at org.grails.web.mapping.DefaultLinkGenerator.link(DefaultLinkGenerator.groovy)
        at org.codehaus.groovy.vmplugin.v8.IndyInterface.fromCache(IndyInterface.java:321)
        at grails7.absolute.link.issue.MakeLinkController$_index_closure1.doCall(MakeLinkController.groovy:14)
        at grails7.absolute.link.issue.MakeLinkController$_index_closure1.doCall(MakeLinkController.groovy)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:77)
        at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.base/java.lang.reflect.Method.invoke(Method.java:569)
        at org.codehaus.groovy.reflection.CachedMethod.invoke(CachedMethod.java:343)
        at groovy.lang.MetaMethod.doMethodInvoke(MetaMethod.java:328)
        at org.codehaus.groovy.runtime.metaclass.ClosureMetaClass.invokeMethod(ClosureMetaClass.java:280)
        at groovy.lang.MetaClassImpl.invokeMethod(MetaClassImpl.java:1007)
        at groovy.lang.Closure.call(Closure.java:433)
        at groovy.lang.Closure.call(Closure.java:412)
        at groovy.lang.Closure.run(Closure.java:505)
        at java.base/java.lang.Thread.run(Thread.java:840)

Steps To Reproduce

1. set grails.serverURL
2. generate a link outside web context (e.g. quartz job or a new thread)

Environment Information

No response

Example Application

https://github.com/jglapa/grails7-absolute-link-issue

Version

7.0.5

[jglapa]

workaround I did for now is:

 grailsApplication.mainContext.grailsLinkGenerator.configuredServerBaseURL = grailsApplication.config.grails.serverURL

in Bootstrap.groovy

[jdaugherty]

@jglapa the example application doesn't appear to public. Can you please grant us access?

[jglapa]

@jdaugherty sorry, changed to public

[jamesfredley]

The Problem

In application.yml (line 35), the configuration is:

environments:
    development:
        serverURL: https://grails7-absolute-link-issue.domain.com

The Fix
Change the configuration to one of these patterns:
Option 1: Environment-specific (recommended)

environments:
    development:
        grails:
            serverURL: https://grails7-absolute-link-issue.domain.com

Option 2: Global setting

grails:
    serverURL: https://grails7-absolute-link-issue.domain.com

The configuration needs to be nested under the grails: key, not directly under environments.development:.

The null you're seeing is a race condition in the controller code, not a configuration problem.
Look at the controller logic:

def index() {
    String link
    Thread.start {              // Starts a NEW thread asynchronously
        try {
            link = grailsLinkGenerator.link(...)  // Runs in background
        } catch (Exception e) {
            e.printStackTrace()
        }
    }
    
    // Main thread continues immediately without waiting!
    
    String link2 = grailsLinkGenerator.link(...)  // Executes in main thread
    
    render link + link2  // Renders BEFORE background thread completes
}

What happens:

1. Line 12: Thread starts in background
2. Line 26-31: Main thread immediately generates link2
3. Line 33: render link + link2 executes before the background thread finishes
4. At this point, link is still null because the thread hasn't completed yet

Updated controller that does not have this issue:

package grails7.absolute.link.issue

import grails.web.mapping.LinkGenerator
import java.util.concurrent.Callable
import java.util.concurrent.Executors
import java.util.concurrent.Future

class MakeLinkController {

    LinkGenerator grailsLinkGenerator

    def index() {
        // Use ExecutorService to properly wait for thread completion
        def executor = Executors.newSingleThreadExecutor()
        
        try {
            // Submit task and get Future
            Future<String> future = executor.submit(new Callable<String>() {
                @Override
                String call() throws Exception {
                    return grailsLinkGenerator.link(
                            absolute: true,
                            controller: 'MakeLink',
                            action: 'index',
                            id: 1
                    )
                }
            })

            // Get result from background thread (waits for completion)
            String link = future.get()

            // Generate link in web context
            String link2 = grailsLinkGenerator.link(
                    absolute: true,
                    controller: 'MakeLink',
                    action: 'index',
                    id: 1
            )

            render """
Link from background thread: ${link}
Link from web context: ${link2}
"""
        } finally {
            executor.shutdown()
        }
    }
}