17 březen 2013
Gaelyk plugin system
allows you to define after hook which is called when groovlet
execution is finished. Since Gaelyk 2.0 the
result returned from the groovlet is bound to the after closure so you can e.g. turn that result into the JSON response.
Let say you have a groovlet serving some JSON content by id and you want to simplify it's flow.
JSON groovlet, standard version
response.contentType = 'application/json'
if(users.isUserLoggedIn){
response.status = 401
json(error: 'You must be logged in')
} else {
// uses @Entity annotation
Item item = Item.get(params.id as long)
if(!item){
response.status = 404
json(error: 'Item not found')
} else {
json(id: item.id, title: item.title)
}
}
In fact, this example is pretty trivial but still it would be handy if we can cut off some unnecessary branching:
JSON groovlet, version with plugin
// see following
request.renderAsJson = true
if(users.isUserLoggedIn){
return [status: 401, error: 'You must be logged in']
}
// uses @Entity annotation
Item item = Item.get(params.id as long)
if(!item){
return [status: 404, error: 'Item not found']
}
[id: item.id, title: item.title]
This can be actually quite simply accomplished by creating plugin which will render groovlet result as JSON.
You can follow the guide on Gaelyk website.
Basically, you need a script containing the after handler:
JSON renderer plugin
after {
// render as json only when this attribute is set to groovy truth
if(request.renderAsJson){
// sets the json
response.contentType = 'application/json'
// result is stored in 'result' closure variable
if(result instanceof Map && result?.status){
// set the status from the status map value
response.status = result.remove('status') as int
}
// render the result
JsonBuilder json = new JsonBuilder()
json result
json.writeTo(response.writer)
}
}
Save the script as WEB-INF/plugins/jsonRenderer.groovy and create another file WEB-INF/plugins.groovy with single line install jsonRenderer
and you can try it yourself in your Galeyk 2.0 application.
If you got another idea how to use result of groovlet exection in your application, please, leave a message under the post.