Rest Service not seeing parameters from Grails Res

Question

So I have a simple Grails UI which takes a few fields .. firstName, lastName etc. in a form. The controller calls a service method which then uses the Rest Client Builder plugin to call a REST service.

The rest service is not recognizing the parameters however.

Here is the simple rest call.

    def resp = rest.post(baseUrl, params)
            {
                header 'Accept', 'application/json'
                contentType "application/x-www-form-urlencoded"
            }

Using version 2.0.1 of the plugin.

params looks like

[firstName:Kas, action:index, format:null, controller:myController, max:10]

Rest Service Method looks like ...

@POST
@Path("/employees")
@Produces({MediaType.APPLICATION_JSON, MediaType.APPLICATION_XML})
@Consumes({MediaType.APPLICATION_FORM_URLENCODED})
public IdmResult createNewEmployee(@FormParam("firstName") String firstName) {
    try {
        if(firstName == null) return constructFailedIdmResult("First Name is a required field");

        // Do some other stuff
    }
 }

Service responds with "First Name is a required field"

When I submit the Post from Postman it works fine. Successful request from Postman looks like

POST /idm/employees HTTP/1.1
Host: <ip>:<url>
Accept: application/json 
firstName: Kas
Cache-Control: no-cache
Content-Type: application/x-www-form-urlencoded

Would like to figure how I can see the request that the plugin is constructing so I can compare differences, but ultimately I just need to know how to properly send the request from the plugin so that the Rest Service recognizes the form parameters.

Answer 1

To pass the values cleanly in the request body, use a MultiValueMap and the (undocumented, from what I see) 'body()' method as per this answer. https://stackoverflow.com/a/21744515/17123

Answer 2

Rest client should be using request body to POST:

def resp = rest.post(baseUrl) {
    header 'Accept', 'application/json'
    contentType "application/x-www-form-urlencoded"
    json {
        firstName = "Kas"
    }
}

or simply,

def resp = rest.post(baseUrl) {
    header 'Accept', 'application/json'
    contentType "application/x-www-form-urlencoded"
    json firstName: "Kas"
}

Refer docs for detail.

UPDATE:

Since producer is expecting request params as big query string instead of JSON, you might end up doing this instead:

def queryString = params.collect { k, v -> "$k=$v" }.join(/&/)

def resp = rest.post("$baseUrl?$queryString") {
    header 'Accept', 'application/json'
    contentType "application/x-www-form-urlencoded"
}

or just def resp = rest.post("$baseUrl?$queryString")