How to prevent data input for being erase in Grails with reCaptcha

Question

I have gsp with two textfield for firstname-lastname and reCaptcha. What I want is for every wrong captcha code the user's input for firstname and last name won't be erased.

snippet for controller:

       ***captcha_code****
       if (result) {
        def person = new Person(params)
        person.save()
        render "Success!"
    } else {
        flash.message = message(code: 'forgotPassword.captcha.wrong')
        redirect(controller:'person', action:'form')
    }

snipper for form.gsp

***captcha_code_here***
<g:form controller="person" action="save">
<label>First Name: </label>
<g:textField name="firstName"/><br/>
<label>Last Name: </label>
<g:textField name="lastName"/><br/>
<g:if test="${flash.message}">
    <div class="message" role="status" style="font-size: medium;color: green;">${flash.message}</div>
</g:if>
***captcha_code_here***
<g:actionSubmit value="Save"/>

Answer 1

To repopulate the fields you can use the same flash scope you're using for the message. On error, add the first and last name to the flash scope, and then in your GSP use those values when they are available:

PersonController

class PersonController {
    def save() {
        ...

        if(/* recaptcha failed */) {
            flash.firstName = params.firstName
            flash.lastName = params.lastName
        }

        ...
    }
}

GSP

<label>First Name: </label>
<g:textField name="firstName" value="${flash.firstName ?: ''}"/><br/>
<label>Last Name: </label>
<g:textField name="lastName" value="${flash.lastName ?: ''}"/><br/>