Grails <g:link> rewriting links to match UrlMappings instead of controller/action - grails

Question

Currently using grails 4.0.3.
I'm trying to generate a link to a controller action using a simple <g:link> tag:
<g:link controller="myController" action="myAction" params="[someParam:'myValue']">Link text</g:link>
In my UrlMappings file, I have this controller mapped to a common URL for external calls. This mapping forces some parameters that I want forced when coming to this mapping:
class UrlMappings {
static mappings = {
"/service/someExposedUrl" {
controller = "myController"
action = "myAction"
someParam = "defaultValue"
}
}
}
However, the link that gets written to the page in my application gets written using the UrlMapping definition.
http://serverUrl/service/someExposedUrl?someParam=<ignored>
instead of
http://serverUrl/myController/myAction?someParam=myValue
In this case, the parameters are ignored on the /service URL because they're hard-coded in the UrlMapping.
Is there a way to force grails to link to the specified controller/action instead of the mapping?

Answer 1

Up front caveat: I have not tested this for this specific situation, though I have used these pieces individually. Second caveat: I would not be remotely surprised to learn there's an even better way to do this...grails has a lot of options sometimes!
You should be able to create a named mapping in your UrlMappings, then reference that in your createLink.
UrlMappings:
name arbitraryName: "/myController/myAction" {
controller = "myController"
action = "myAction"
}
Link:
<g:link mapping="arbitraryName" params="[someParam:'myValue']">Link text</g:link>

Answer 2

You may be able to get what you need with a combination of Custom URL mapping and the exclude keyword in the original URLMappings.
Create MyControllerUrlMappings. This guide gives several examples of different ways of writing them out. I found it helpful.
class MyControllerUrlMappings {
static mappings = {
// Url Mappings specific only to this controller
}
}
https://guides.grails.org/grails_url_mappings/guide/index.html#_multiple_urlmappings_files
Your app will still be running the original UrlMappings file though. So you'll have the new custom Url mappings and the default ones. To fix that you can exclude your controller and it's methods in the original UrlMappings file.
class UrlMappings {
static excludes = [
"/myController",
"/myController/*"
]
static mappings = {...}
...
Not as elegant as I'd like, but in a similar situation this is how I got it working.