Showing posts with label groovy. Show all posts
Showing posts with label groovy. Show all posts

Saturday, June 13, 2009

Adding pagination to a Grails WebFlow state

I noticed a few unanswered questions relating to paginating a WebFlow state on the users mailing list and thought I'd post the solution I came up with for a Refactor project I was working on last week.

It basically involves splitting the behaviour into an action and a view state with a transition between them called 'paginate'
loadResults {
 action {
    def criteria = MyDomain.createCriteria(){
    flow.myDomainResults  = criteria.list([max: 9, offset: flow.myDomainOffset ?: 0])   
    flow.totalMyDomains = flow.myDomainResults.totalCount
    return success()
 on(Exception).to "handleError"
browse {
 on('paginate') {
    flow.myDomainOffset = params.offset
One point to note is that I use a criteria in order to get the totalCount property populated for me automatically so that I don't have to run a separate query. Also, the above only works if your domain class is Serializable, in my real application this wasn't the case so I stored a list of maps containing the properties I wanted to display instead of the list of domain objects.

Then in the view all we need to do is to pass the current page from the flow scope to the paginate tag. The paginate tag also contains an extra parameter in order to trigger the paginate event when the generated links are clicked.
<g:each in="${myDomainResults}" status="i" var="myDomain">
    <g:form action="myFlow">
        <input name="id" value="${}" type="hidden">
        URL: ${myDomain.url}
        <g:submitbutton name="selectItem" value="Select"/>
<div class="paginateButtons">
   <g:paginate max="9" offset="${myDomainOffset}" total="${totalMyDomains}" params="${[_eventId_paginate:true]}" />

You can also see I render each item as a separate form with a hidden id field and a submit button to trigger the 'selectItem' event and move onto the next state.

I haven't tried messing with all the options for g:paginate to make sure they still work so please let me know if you find any problems with the above code.

Thursday, May 21, 2009

Grails JSR-186 Portlets Plugin Released

Kenji Nakamura has taken the reins of my initial work on the Grails Portlets plugin and done an awesome job of refactoring it into more manageable sub-plugins.

You can now plug-in portal implementations with Pluto and Liferay supported initially.

JSR-286 will be supported when the underlying version of Spring used by Grails is updated to Spring 3.0.

Check it out at the Grails plugin portal.

Great work Kenji!

Friday, December 5, 2008

Sydney Groovy/Grails User Group

In between meeting all the interesting folk at OSDC, I attended the Sydney Groovy (and Grails) User Group. I presented a short talk on the new features in Grails 1.1 then demoed the Portlets Plugin and new features in the WebTest Plugin 0.6. Dave Peterson then gave a great Intro to Gant talk with comparisons to buildr. Come along next time to hear more from Dave about Gradle :) The group is organsied by Nick Carrol from Thoughtworks and the venue (in The Rocks near Sydney harbour) was great. If you're ever in the area, get onto the mailing list and see when the next meeting is.

Monday, November 10, 2008

Grails WebTest Plugin 0.6 alpha

I've been working on committing some improvements to the Grails WebTest Plugin. You can download the alpha version here (I haven't yet released it to the plugin repository). I'd appreciate feedback from users with existing applications with non-trivial webtests regarding any regressions or upgrade issues they have. If all looks ok I will update the official repository version shortly.

Release Notes

  • setUp/tearDown at the method and class level

    • classSetUp() and classTearDown() are run as individual test cases. SetUp() and tearDown() are run as the first and last steps of each test case.

  • New superclass AutoWebTest

    • This new superclass will automatically run all methods starting with test. This saves you having to manually maintain the suite method unless you really want to for test order reasons.

    • AutoWebTest will also generate the test case name from the class and method name removing the need for repetitive webtest('blah'){...} code. The generated test name also makes it much easir to find the failing test from the generate reports.

    • MethodMissing code has been added so you can refactor a group of steps without having to wrap them in and closure.

    • You can now call config() as the first step in your test method to set WebTest options like host, port and ajax support

  • -nostart option allows you to runthe tests against a server that is already running. It should come after run-webtest on the command line

  • System parameters now passed through to WebTest. They need to be placed directly after grails on the command line e.g. grails -Dwt.headless=true run-webtest

    • -Dwt.headless=true to hide Swing monitor and stop browser launching

    • -Dserver.port=XXXX to get the tests to run against a server on a non-default port

  • The plugin has been updated with the latest WebTest release which includes an update of HtmlUnit to version 2.3

  • Application lib folder now on WebTest classpath. This avoids the need to duplicate/move libraries into webtest/home/lib

  • Custom steps

    • You can now extend com.canoo.webtest.steps.Step by placing groovy classes in webtest/tests/step. They will be automatically loaded at runtime and allow for easy testing of complicated scenarios such as JSON interfaces and email integration

      • The last project I worked on used these custom steps to start, check then stop an embedded Wiser SMTP server for testing email functionality.

Upgrade Instructions

delete plugins/webtest-0.x

svn delete webtest/home, commit.

This avoids svn issues as the install script deletes the folder and extracts the latest build over the top, removing the .svn directories

grails install-plugin

You need to copy the zip file into the root folder of your project and run the command there.

Thursday, October 30, 2008

Open Source Developers Conference - Sydney Dec 2008

Myself and colleagues from Refactor will be attending the Open Source Developers Conference (OSDC) in Sydney from 2-5 Dec. It's a great conference to get in touch with developers who use and contribute to open source and find out what's on the horizon. I didn't get organised early enough to present any main sessions on Grails but am keen to do some lightening talks about it and also demo Balsamiq MockUps which I came across a few weeks ago. I think it's a great tool for agile BA's and product owners to really get their customers engaged. If you see me there, make sure you come over and say hi!

Wednesday, September 17, 2008

How to WebTest a site using an invalid SSL certificate

UPDATE: there is a option you can pass to the config step which should achieve the same thing: useInsecureSSL

A very short post regarding an issue I recently came across while testing an application I'm working on.

My application needs to interface with and existing PHP application that uses SSL. To acceptance test this functionality I am writing a WebTest that drives both applications to assert information is flowing correctly between them.

Unfortunately the test instance of the PHP application I have been given to use has a self-signed SSL certificate which causes WebTest to fail with a SSLHandshakeException.

To ignore the self signed certificate, add the following line to your test:

groovy('step.context.currentWebClientContext.webClient.useInsecureSSL = true')

Wednesday, July 16, 2008

Switchable Grails DataSource

As part of my day job I needed to write an administration app that could be easily pointed at multiple environments. To achieve this I used a technique I found a while ago based on Spring's AbstractRoutingDataSource. It basically works by using a facade to switch the connection between one to many child data sources. First off SwitchableDataSource.groovy
package com.leebutts 
import org.springframework.jdbc.datasource
import com.leebutts.Environment 
import org.springframework.context.ApplicationContextAware 
import org.springframework.context.ApplicationContext 
import javax.sql.DataSource 
import org.springframework.jdbc.datasource.DriverManagerDataSource 

class SwitchableDataSource extends AbstractRoutingDataSource 
    implements ApplicationContextAware { 
    def applicationContext 
    public void setApplicationContext(ApplicationContext 
                                           applicationContext) { 
        this.applicationContext = applicationContext 

    protected DataSource determineTargetDataSource() { 
        DriverManagerDataSource ds = 
        def env = EnvironmentHolder.getEnvironment() 
        if (env && env.passwordRequired && ds) { 
        return ds 

    protected Object determineCurrentLookupKey() { 
        def env = EnvironmentHolder.getEnvironment() 
        return env?.id ?: Environment.list()[0]?.id 
SwitchableDataSource is the facade that delegates to the list of standard DriverManager data sources. They are defined in grails-app/conf/spring/resources.groovy using the environment settings from the Environment class. Here's my spring config in resources.groovy:
import com.leebutts.SwitchableDataSource 
import com.leebutts.Environment 
import org.springframework.jdbc.datasource.DriverManagerDataSource 

beans = { 
    parentDataSource(DriverManagerDataSource) {
        bean -> bean.'abstract' = true; 
        driverClassName = 'com.mysql.jdbc.Driver' 
        username = "root" 
    Environment.list().each {env -> 
        "${env.prefix}DataSource"(DriverManagerDataSource) {bean -> 
            bean.parent = parentDataSource 
            bean.scope = 'prototype' 
            def port = env.port ?: 3306 
            url = "jdbc:mysql://${}:${port}/switchingDemo" 
            if (env.user) { 
                username = env.user 
            if (env.password) { 
                password = env.password 

    def dataSources = [:] 
    Environment.list().each {env -> 
        dataSources[] = ref(env.prefix + 'DataSource') 

    dataSource(SwitchableDataSource) { 
        targetDataSources = dataSources 
Environment currently uses a static list to hold the environment config. This could be done better via a reloadable properties file or by adding a view/controller to modify the environment settings on the fly. Environment.groovy:
package com.leebutts

class Environment {

    static environments = []

    static {
        environments << [id: 1, name: 'local', prefix: 'local', 
                          host: 'localhost']
        environments << [id: 2, name: 'UAT', prefix: 'uat',
                            host: '']
        environments << [id: 3, name: 'Testing', prefix: 'testing',
                         host: ''] 
        environments << [id: 4, name: 'Beta', prefix: 'beta',
                         host: '', 
                         passwordRequired: true] 
        environments << [id: 5, name: 'Prod', prefix: 'prod', 
                         host: '', user:'grails', 
                         port: 13306, 
                         passwordRequired: true] 

        //unique id check 
        environments.each {env ->
            assert environments
                .findAll { ==}.size() == 1}

    static list() {
        return environments
SwitchableDataSource needs a way to determine which environment the current request wishes to use. It does this via a ThreadLocal holder EnvironmentHolder.groovy:
package com.leebutts

class EnvironmentHolder {

    private static final ThreadLocal contextHolder
                                = new ThreadLocal();

    static void setEnvironment(Map environment) {

    static getEnvironment() {
        return contextHolder.get();

    static void clear() {
Now that the infrastructure is in place, the next step is to add a controller to allow users to select the environment they wish to use and a filter to set a default environment if one has not yet been chosen. The controller is called via ajax (in my application) but could be used as a standard controller just as easily. It looks up the Environment based on an ID and then tests the connection to make sure the password supplied is valid (if a password is required as specified in the environment config). If a password is being used it takes a copy of the environment config map, adds the password and stores it in the session so that the user doesn't have to re-enter the password on every screen and so that only this user has access to the password. EnvironmentController.groovy:
import com.leebutts.Environment
import com.leebutts.EnvironmentHolder
import javax.servlet.http.HttpServletResponse
import org.codehaus.groovy.grails.commons.ApplicationAttributes
import org.codehaus.groovy.grails.web.context.ServletContextHolder

class EnvironmentController {

    def change = {
        if (params.environment) {
            def env = Environment.list()
                     .find { == new Integer(params.environment)}
            if (env) {
                if (env.passwordRequired) {
                    if (params.password) {
                        //take a copy and add a pword
                        env = addPasswordToEnvCopy(params, env)
                    } else {
                        render 'PASSWORD REQUIRED'

                //test connection
                def oldEnv = EnvironmentHolder.getEnvironment()
                EnvironmentHolder.setEnvironment env
                def ds = getDataSourceForEnv()
                try {
                    def con = ds.getConnection()
                    session.environment = env
                    render 'Environment change complete.'
                } catch (e) {
                    EnvironmentHolder.setEnvironment oldEnv
                    render 'Unable to connect to database: '
                              + e.message
            } else {
                render 'No such environment'
        } else {
            render 'Missing parameter environment'

    private def getDataSourceForEnv() {
        def servletContext = ServletContextHolder.servletContext
        def ctx = servletContext
        return ctx.dataSource

    private Map addPasswordToEnvCopy(Map params, env) {
        def myEnv = [:]
        env.each {key, val ->
            myEnv[key] = val
        myEnv.password = params.password
        return myEnv
As mentioned, there is also a simple filter for defaulting the environment to the first one in the list if one has not been selected and storing it in the ThreadLocal holder. Filters.groovy:
import com.leebutts.EnvironmentHolder
import com.leebutts.Environment

class Filters {
    def filters = {
        all(uri: '/**') {
            before = {
                if (!session.environment) {
                    session.environment = Environment.list()[0]
The final step is to add an environment selection form to your layout so that users can choose their environment. views/layouts/main.gsp:
    <title>Administration System</title>
    <link rel="stylesheet"
            href="${createLinkTo(dir: 'css', file: 'main.css')}"/>
    <g:javascript library="application"/>
    <g:javascript library="prototype"/>
    <script type="text/javascript">
        function refresh()

        function loading() {
            document.getElementById('spinner').style.display = 'inline';
            document.getElementById('error').style.display = 'none';
        function showError(e) {
            var errorDiv = document.getElementById('error')
            errorDiv.innerHTML = '<ul><li>'
                     + e.responseText + '</li></ul>';
   = 'block';
<div class="logo">
    <div style="margin-left:10px;">
        <h1>Current Environment: 
               ${session.environment?.name ?: 'None'}</h1>
        <form action="">
            <g:select name="environment" 
                      optionKey="id" optionValue="name" 
            <g:passwordField name="password"/>
            <g:submitToRemote value="Select" controller="environment" 
             action="change" update="currentEnv"
             onSuccess="refresh()"/> <br/>
            <div class="errors" id="error" 

            <img id="spinner" style="display:none;"
              src="${createLinkTo(dir: 'images', file: 'spinner.gif')}"
The finished screen looks something like this:
Photobucket - Video and Image Hosting

Photobucket - Video and Image Hosting

Photobucket - Video and Image Hosting

Photobucket - Video and Image Hosting

As this is an internal admin application it has not been tested as thoroughly as standard prod code so please do so before using it in a "live" application. Please post any corrections/bug fixes.

Sunday, July 6, 2008

Some initial Grails Portlets documentation

I've started documenting how the Grails Portlets plugin currently (hopefully?) works. You can try it out (with some effort) by checking it out from subversion: You'll also need to checkout and build a Grails 1.1 snapshot: