about java, groovy, grails, software development and more...: Custom error page for your grails application

I recently added a custom error page to my application, so that the users don't see the stacktrace and are shown a friendly message in case of a runtime error.

I simply added a controller that checks for the environment in which the application is running, and accordingly renders different views:

import grails.util.*;

class ErrorsController {
    def serverError = {
        def env = GrailsUtil.environment;

        if(env == "production")
            render(view:'/serverError')
        else
            render(view:'/error')
    }

    def notFound = {
        render(view:'/notFound')
    }
}

Added a new view file 'serverError.gsp' at \grails-app\views:

<html>
    <head>
        <title>Error on the server</title>
        <meta name="layout" content="main" />
    </head>
    <body>

      <h1 style="margin-left:20px;color:#006dba;" >
            An unexpected error occurred while processing your request. The admin team has been notified.             <br/>
            Please try again, or
              <a href="mailto:abc@xyz.com?
              subject= [${GrailsUtil.environment}] Application Error occured : '${exception?.message?.encodeAsHTML()}'">
              contact
              </a> the IT team

      </h1>

    </body>
</html>

To delegate the request to the ErrorController, add the following line to the UrlMappings.groovy file:

"500"(controller: "errors", action:"serverError") .

Handling 404 Not Found:

If you want to handle the 404 Not Found situation specifically, add the following line to your UrlMappings.groovy file (which you can find at \grails-app\conf)

class UrlMappings {

   static mappings = {
       "/$controller/$action?/$id?"{
           constraints {
               // apply constraints here
           }
       }

       "/"(view:"/index")
       "500"(controller: "errors", action:"serverError")
         "404"(controller:"errors", action:"notFound")
   }
}

The view file notFound.gsp looks like this:

<html>
    <head>
        <title>Page not found</title>
        <meta name="layout" content="main" />
    </head>
    <body>

       <h1 style="margin-left:20px;">
         <p style="margin-left:20px;width:80%">
            Page Requested not found, please check the URL
         </p>
       </h1>
    </body>
</html>