Heh, I'm on the flip side; I don't know anything about GWT.
John V Denley wrote:
> Thanks for this Rusty, Im not sure I understand all of it right away
> (perhaps with more investigation I will work it out)
> However Its worth mentioning that as far as I know Im not using Spring
> or Stripes or Struts (not even sure what any of these are!)
> I am using native GWT (v2.0)/GAE (v1.2.8) and using RPC to make calls
> to the server side.
>
> I have tried creating a "public" function in my main java file (right
> above the onModuleLoad() function) as follows:
> public void testqueues()
> {
> Window.alert("hello test queues");
> }
>
> The thinking then being that I might be able to make a call to
> http://your-gae-app.appspot.com/testqueues and it would show the alert
> box. (I would like to prove this in the dev environment, but Im not
> sure how to do this now that the URL for that is currently
> http://localhost:8888/IDeBanet.html/testqueues?gwt.codesvr=192.168.0.6:9997)
>
> Its entirely possible that I have totally misunderstood how this is
> meant to be working and if so I apologise for asking stupid questions,
> or making incorrect/confusing statements, but it seems theres no real
> way of figuring out this stuff until you just try to implement it! Ive
> learnt a huge amount about web development and in particular GWT/GAE
> over the last 4-5 months!!
>
> Cheers,
> J
>
> On Dec 13, 5:46 am, Rusty Wright <[email protected]> wrote:
>> I think I got the gist of it. As a test I modified the Stripes action bean
>> that handles my first page and added the following to its @DefaultHandler
>> method:
>>
>> final Queue queue = QueueFactory.getDefaultQueue();
>> queue.add(TaskOptions.Builder.url("/zugzug.zug")); // web.xml maps *.zug
>> to stripes
>>
>> It's adding a task to the queue.
>>
>> Then I created an action bean for the gae task queue automaton to poke:
>>
>> @UrlBinding("/zugzug.zug")
>> public class TaskQueueActionBean implements ActionBean { ...
>>
>> and its @DefaultHandler method contains:
>>
>> @SuppressWarnings("unchecked")
>> final List headerNames =
>> Collections.list(getContext().getRequest().getHeaderNames());
>> this.log.debug("header names: {}", headerNames);
>>
>> And then the log received:
>>
>> header names: [Content-Type, User-Agent, Referer, Host,
>> X-AppEngine-QueueName, X-AppEngine-TaskName, X-AppEngine-TaskRetryCount,
>> Content-Length]
>>
>> The first time I tried it I forgot to create the corresponding jsp view
>> file, zugzug.jsp (which is essentially empty), and the task queue automaton
>> kept retrying because stripes was returning an error because the jsp file
>> was missing; lots of those log.debug lines in the log file. After I fixed
>> that then it was only in there once for each time I went to my first page.
>>
>> The first page action bean enqueued the task, the task queue automaton sent
>> an http request to the url zugzug.zug, then the TaskQueueActionBean was
>> invoked and its success caused the automaton to dequeue the task (but not if
>> it returned an error; then the automaton retries).
>>
>>
>>
>> Rusty Wright wrote:
>>> The docs say "The default queue will call the request handler at the URL
>>> /worker ..." So it sounds to me that if you were, for example, using
>>> Spring MVC, and had a Spring controller with
>>> @Controller
>>> @RequestMapping("/worker")
>>> public final class WorkerController {
>>> @RequestMapping(method = RequestMethod.GET)
>>> public String handleGetRequest(final ModelMap model) {
>>> this.log.debug("called");
>>> return (null);
>>> }
>>> }
>>> then it would call your handleGetRequest() method 5 times a second, by
>>> sending an http GET (or POST?) request to your /worker url each time.
>>> Similarly, with Stripes (and for Struts 2 probably something similar) it
>>> would be something like
>>> @UrlBinding("/worker")
>>> public class WorkerActionBean implements ActionBean {
>>> @DefaultHandler
>>> public Resolution handleRequest() {
>>> this.log.debug("called");
>>> return (null);
>>> }
>>> }
>>> I'm returning null because I don't know what the task queue thing does
>>> with what it gets back (I didn't read much of their docs; to tell the
>>> truth, I stopped at that sentence I quoted at the top because it sounds
>>> very similar to their cron thing, which docs I did read most of). I'm
>>> undoubtedly also lacking the code needed to pull the next task off the
>>> queue and do something with it.
>>> I'm assuming that you have some web framework in front of everything and
>>> thus don't need a servlet mapping in your web.xml for the /worker url
>>> since the web framework is handling the url mapping.
>>> So they're "pinging" your /worker url using a plain old http request to
>>> initiate running each task; your controller or action bean is what
>>> performs the task. Think of it like you typed in your browser's address
>>> boxhttp://your-gae-app.appspot.com/worker?task_queue_params_go_hereor
>>> you used the command line programs cURL or wget.
>>> If I understand this correctly then I would say that their sentence I
>>> quoted isn't as clear as it could be. Given the way it's stated, is the
>>> task queue really able to bypass all of the http request processing and
>>> directly invoke my handler method? How would it know which class+method
>>> handles that url? I would think that the servlet container calls the
>>> request method, as a result of their task queue automaton diddling the url.
>>> John VDenleywrote:
>>>> Yes, I would like a "real" example of how to do this too, I get that
>>>> we need to use a URL to accept the request to do something, but where
>>>> does the URL start executing code. obviously its not going to be at
>>>> the "onModuleLoad" entry point.
>>>> Thanks,
>>>> John
>>>> On Nov 11, 1:23 am, edarroyo <[email protected]> wrote:
>>>>> Is there any gae samples usingtaskqueues that we can look at?
>>>>> I am having a really hard time understanding how to useTaskQueues.
>>>>> Thanks!
>>>>> On Oct 27, 6:18 pm, Vincent <[email protected]> wrote:
>>>>>> Thanks , Jason. It's very helpful for me to understand how to use this
>>>>>> new API.
>>>> --
>>>> You received this message because you are subscribed to the Google
>>>> Groups "Google App Engine for Java" group.
>>>> To post to this group, send email to
>>>> [email protected].
>>>> To unsubscribe from this group, send email to
>>>> [email protected].
>>>> For more options, visit this group at
>>>> http://groups.google.com/group/google-appengine-java?hl=en.
>
> --
>
> You received this message because you are subscribed to the Google Groups
> "Google App Engine for Java" group.
> To post to this group, send email to [email protected].
> To unsubscribe from this group, send email to
> [email protected].
> For more options, visit this group at
> http://groups.google.com/group/google-appengine-java?hl=en.
>
>
--
You received this message because you are subscribed to the Google Groups
"Google App Engine for Java" group.
To post to this group, send email to [email protected].
To unsubscribe from this group, send email to
[email protected].
For more options, visit this group at
http://groups.google.com/group/google-appengine-java?hl=en.
