Is possible to overwrite the behaviour of the methods CreateLink and CreateLinkTo?
You could use meta programming to replace the closure on ApplicationTaglib.
ApplicationTagLib.metaClass.getCreateLink = {->
return {attrs->
// your code here
}
}
I've never tried it but it might work :)
All you need to do is create a taglib of your own and define the tags yourself ie
class MyTabLib {
def createLink = {attrs, body ->
.... etc ....
}
def createLinkTo = {attrs, body ->
.... etc ....
}
}
Grails will use your taglib first.
Hope this Helps!
This is a little late, but the solutions above didn't work for me. I was able to successfully do this, though:
public class MyTagLib extends ApplicationTagLib {
def oldResource
public MyTagLib() {
// save the old 'resource' value
oldResource = resource;
resource = staticResource;
}
def staticResource = { attrs ->
// dork with whatever you want here ...
// ...
out << oldResource(attrs);
}
}
you're basically extending the original tag lib. Since the 'resource' tag is a property of the object (and not a method) I don't think you can actually override it. Instead, just save the original value and call it after you've make your changes to the tag request.
Related
How do I return values from a taglib that has been called in a controller action such that it automatically retains the full type structure of the values setup in the taglib?
I can use the out << approach but this returns strings or array of strings.
I have tried to use a [] mapping as used transfer a set of values at the end of an action to its view.
I have also tried a return statement again unsuccessfully - besides I need to return more than one set of values.
-mike
from the top of the documentation http://grails.org/doc/latest/guide/theWebLayer.html#tagReturnValue
class ObjectReturningTagLib {
static returnObjectForTags = ['content']
def content = { attrs, body ->
someValue()
}
}
I think this could solve your problem
package com.campaign
import java.util.*;
class UserDetailsTagLib {
def springSecurityService
static namespace = "jft"
#here we are defining that this getPrincipal and getArrayListAsObj tag used to return object
static returnObjectForTags = ['getPrincipal','getArrayListAsObj']
#this tag will return obj
def getPrincipal = {
return springSecurityService.principal
}
# this tag is used to return the array list of string
def getArrayListAsObj = { attrs , body ->
ArrayList arrayList = new ArrayList();
arrayList.add("C");
arrayList.add("A");
arrayList.add("E");
arrayList.add("B");
arrayList.add("D");
arrayList.add("F");
return arrayList
}
}
I understand your problem. If you want to have the Intellisense on the var you got from a taglib, the only thing you can have is this (it's a little redundant)
In a gsp for example, if you have a TagLib with namespace myTaglib:
First call the action of your taglib to set the value of a var:
<myTaglib:person var="currentUserFromTaglib" />
Where the person tag in the myTaglib is just for this purpose:
def person = { attrs ->
this.pageScope."$attrs.var" = new Person(name:'Giuseppe', surname:'Iacobucci')
}
After this, you need to write:
<g:set var="currentUser" value="${currentUserFromTaglib as Person}"/>
And include in you gsp:
<%# page import="your.package.Person" %>
After that, in the gsp currentUser is recognized as type Person.
In a controller, you simply call the myTaglib and cast the result like so:
def myvar = myTaglib.person() as Person
Obviously if you need more a complex object as I read from your comments, then create a plain UI object with all information you need inside and do the same trick.
I want to override a method definition in Grails. I am trying to use Groovy metaprogramming as the class which I want to override belongs to a framework.
Below is the original class.
class SpringSocialSimpleSignInAdapter implements SignInAdapter {
private RequestCache requestCache
SpringSocialSimpleSignInAdapter(RequestCache requestCache) {
this.requestCache = requestCache;
}
String signIn(String localUserId, Connection<?> connection, NativeWebRequest request) {
SignInUtils.signin localUserId
extractOriginalUrl request
}
}
I am trying to override like below
SpringSocialSimpleSignInAdapter.metaClass.signIn = {java.lang.String str, org.springframework.social.connect.Connection conn, org.springframework.web.context.request.NativeWebRequest webreq ->
println 'coming here....' // my implementation here
return 'something'
}
But for some reason overriding is not hapening. I am not able to figure it out. Any help would be greatly appretiated.
Thanks
Yeah, seems like that bug. I don't know your whole scenario, but anyway, here's a small workaround i made:
In your class definition, you don't implement the interface
You create your object and do your metamagic
Use groovy coercion to make it act as the interface and then you can pass it around
Here is a small script i made using JIRA bug to prove it:
interface I {
def doIt()
}
class T /*implements I*/ {
def doIt() { true }
}
def t = new T()
assert t.doIt()
t.metaClass.doIt = { -> false }
// here the coercion happens and the assertion works fine
def i = t as I
assert !i.doIt()
assert !t.doIt()
// here the polymorphism happens fine
def iOnlyAcceptInterface(I i) { assert !i.doIt() }
iOnlyAcceptInterface(i)
Lets assume that I have the following configuration in my conf/InjectionConfig.groovy file:
x {
a = { attrs, body -> out << "hello" }
b = { attrs, body -> out << "goodbye" }
}
and that I have a simple taglib such as
class XTagLib {
static namespace = "x"
}
What I want to do is that when I type <x:a /> to any of my views, it would print hello. I've already tried to inject these to the metaclass of the taglib as both property and method but neither seem to work. As an example, here's basically what I'm doing right now in a service:
public void afterPropertiesSet() throws Exception {
GroovyClassLoader classLoader = new GroovyClassLoader(getClass().classLoader)
def slurper = new ConfigSlurper(GrailsUtil.environment)
ConfigObject xConfig
try {
xConfig = slurper.parse(classLoader.loadClass('InjectionConfig'))
}
catch (e) {
e.printStackTrace()
}
xConfig.x.each({
if ( !XTagLib.metaClass.hasMetaProperty(it.key) ) {
XTagLib.metaClass.registerBeanProperty(it.key, { args ->
def attrs = args[0], body = args[1]
it.value.call(attrs, body)
}
}
})
}
Am I just doing it wrong or is this even possible currently?
Well, this
def shell = new GroovyShell() // or get a GroovyClassLoader
Class yTagLibClass = shell.evaluate("class YTagLib { static namespace = 'x' }; return YTagLib")
yTagLibClass.metaClass.a = { attrs, body -> delegate.out << 'blabla' }
grailsApplication.addArtefact(TagLibArtefactHandler.TYPE, yTagLibClass)
<x:a/> nearly worked for me - registered a tag, except for it didn't output anything. You still need to make the closure resolve out against Grails' taglib's out property.
I don't see a pretty way to do it, as there's no access to instance variables, and out is an instance variable. See Grails source, JspInvokeGrailsTagLibTag.doStartTagInternal() - you might find a way.
EDIT: I added delegate. prefix that should resolve out property of target object. Now I believe I deserve an acceptance :)
What I want to do is that when I type
to any of my views, it would
print hello
I think there's an alternative way to do what you intend: combine template & tagLib. First, create a template, then add it in your TagLib (with no complex configuration).
In my opinion, it's more simple than your approach.
Please take a look at this tutorial:
http://jan-so.blogspot.com/2008/02/example-of-template-and-taglib-with.html
Wanna do the following:
BootStrap {
def init = {servletContext ->
........
MyDomainClass.metaClass.save = {->
delegate.extraSave()
//////// how to call original save() here?
}
}
.........
}
P.S. MyDomainClass#extraSave is defined as public void extraSave(){.....}
First of all, Bootstrap.groovy may not be the best place to do this kind of metaprogramming. The problem with this approach is that the changes to the classes will be applied when the application starts, but you may lose these changes when the application is reloaded. Obviously this is only an issue during development, and not an issue at all if you don't mind restarting the server every time you make a change, but I'll bet this would quickly become a major annoyance. In order to have the changes applied when app is reloaded as well, you should move the metaprogramming into a plugin, where you can hook into the onChange application lifecycle event.
So the steps are:
Create a plugin
Do the metaprogramming in the doWithDynamicMethods and onChange closures of the plugin descriptor
Here's a complete example where I "override" the chain() method on all the controller classes. The code to do likewise for the save() method of domain classes should only require some obvious replacements, e.g. use application.domainClasses instead of application.controllerClasses
def doWithDynamicMethods = {ctx ->
application.controllerClasses.each {controller ->
replaceChain(controller)
}
}
def onChange = {event ->
if (application.isArtefactOfType(ControllerArtefactHandler.TYPE, event.source)) {
def clz = application.getControllerClass(event.source?.name)
replaceChain(clz)
}
}
private replaceChain(controllerClass) {
// Save a reference to the grails chain() method
def grailsChain = controllerClass.metaClass.pickMethod("chain", [Map] as Class[])
controllerClass.metaClass.chain = {Map params ->
println "My code to execute before chain goes here"
// Invoke the grails chain() method
grailsChain.invoke(delegate, [params] as Object[])
println "My code to execute after chain goes here"
}
}
why not leveraging the GORM events for this purpose? In the Domain class:
def extraSave() {
// ...
}
def beforeInsert = {
extraSave()
}
def beforeUpdate = {
extraSave()
}
IMHO this a cleaner approach. Documentation can be found here
Not sure if the following works, but this might be a solution:
MyDomainClass.metaClass.origSave = MyDomainClass.metaClass.save
MyDomainClass.metaClass.save = {->
delegate.extraSave()
delegate.origSave()
}
Please give me feedbeck if the above worked...
In a Grails application I would like to add a foo() method to all my controller classes. I know that I can do this inside a plugin's doWithDynamicMethods closure using code like:
application.controllerClasses.toList()*.metaClass*.foo = { println 'foo called' }
However, I don't want to create a plugin just for this purpose. Is there anywhere else I can do this. I suspect it might be possible within the init closure of BootStrap.groovy, but I don't know how to get access to the GrailsApplication instance in this closure.
Thanks,
Don
def grailsApplication = org.codehaus.groovy.grails.commons.ApplicationHolder.application
The question was asked a long time ago, so my answer might not have been possible back then - but now it's April 2014. This code shows the most straightforward way of adding a method to all your controllers (from within BootStrap.init):
grailsApplication.controllerClasses.each { controllerClass ->
if (controllerClass.clazz.name.contains("org.idurkan.foo")) {
controllerClass.metaClass.respondError = { String message, int status = 404 ->
response.status = status
render([errorMessage: message] as JSON)
}
}
}
In BootStrap.groovy, inject grailsApplication like this: def grailsApplication
Make a call like mine above, substituting your own package name - to avoid messing around with plugins' classes.
Now in any controller you can use the repondError closure (invoke it like a method).
Note this does not add an action! It's just a utility closure/method available in every
controller.
class BootStrap {
def grailsApplication
def init = { servletContext ->
...
}
}