[RFC][icedtea-web] Fix for single instance service with applets using jnlp_href

Jiri Vanek jvanek at redhat.com
Tue Sep 4 09:43:45 PDT 2012 

On 08/23/2012 10:31 PM, Danesh Dadachanji wrote:
>
> On 17/05/12 02:53 PM, Danesh Dadachanji wrote:
>>
>>
>> On 20/04/12 05:32 AM, Jiri Vanek wrote:
>>>>>
>>>>
>>>> Yeah, it was a confusing service to wrap my head around. :S
>>>>
>>>> Right now, SingleInstanceService is available to use from applets/applications run by javaws. I am
>>>> trying to port this over to the plugin so that when jnlp_href is used, applets have access to it.
>>>>
>>>> The point of the service itself is to only let one instance of an applet run at a time. There's a
>>>> catch to running another instance of the applet though. While the first one is running, it is setup
>>>> with a listener for later instances to use. The idea is that the second instance can communicate
>>>> with the running instance, passing along some args to be handled by the listener, and then exit.
>>>> When you run another instance of the applet, icedtea-web is supposed to recognize this as the second
>>>> instance and pass on a list of arguments provided by the dev. See the API for
>>>> SingleInstanceListener[1] for the methods. I think the following signleapp example[2] might help you
>>>> too.
>>>>
>>>> Here's an example run path:
>>>>
>>>> 1. Start single instance app. The dev has set it up to handle params accordingly, say to spit it out
>>>> on the screen to log.
>>>> 2. IcedTea-Web sets up a single instance server to keep track of the instance running.
>>>> 3. The second app is run, args are passed in by the dev again. Let's say they are the current
>>>> date/time.
>>>> 4. IcedTea-Web notices the second app is a second instance of the first one and checks that the
>>>> first one's server is still running, then denies init of the second applet. The second instance's
>>>> args are taken and passed along to the first instance's newActivation(String[] args) method.
>>>> 5. Dev's newActivation method reacts accordingly.
>>>>
>>>> I hope the example[2] helps clear up any doubts I have not covered but please ask if it doesn't!
>>>>
>>>>>> Attached is a patch to fix SingleInstanceService to work when applets
>>>>>> use jnlp_href.
>>>>>>
>>>>>> If a single instance exists, it'll throw a fatal exception for the
>>>>>> second applet and stop running it. The applet passes the args along
>>>>>> while checking. However, proprietary documentation is unclear about
>>>>>> which args are passed so for now I have left it as a FIXME until
>>>>>> that's cleared up.
>>>>> I believe applets parameters inside tag/jnlp descriptor are correct way.
>>>>
>>>> These args I was referring to are from the second instance being run so we're talking about
>>>> different things here. =) Please see above.
>>>>
>>> Well well... It was digging to find what this should be doing, and it looks tome like it is not doing something.
>>>
>>> Can I ask for large set of reproducers?
>>>
>>> two same javaws applications runnig together/ two same javaws applications running as SingleInstance and passing params / two different
>>> javaws running together/ two different javaws applications running as SingleInstance and "passing" params
>>>
>>> two same applets-in-javaws applications runig together/ two same applets-in-javaws applications running as SingleInstance and passing
>>> params / two different applets-in-javaws running together/ two different applets-in-javaws applications running as SingleInstance and
>>> "passing" params
>>>
>>> two same applets-in-browser running together/ two same applets-in-javaws applications running as SingleInstance and passing params /two
>>> different applets-in-browser running together/ two different applets-in-javaws applications running as SingleInstance and "passing"
>>> params
>>>
>>>
>>
>> Could you elaborate more on the purpose of "two same javaws applications running together"? Similarly for the "applets-in-browser" and
>> "applets-in-javaws" ones. As I understand it, these are just normal runs without SingleInstance, right? How is this related to the patch?
>>
>>>
>>> It will need similar approach as I have used in xfork test, but better then sleep use StdOut use contentReader listeners and do not
>>> wait for timeout (as it really delays test runs)
>>>
>>
>> I'm not sure how this would be run in the current engine. We need to ensure both apps (for each test) are running at the same time. I
>> don't think there is a way to guarantee this, is there? I know the tests are run one after another but they are only ordered
>> alphabetically right? There is no way to specify I want to run test X and then immediately after run test Y (while test X is still
>> running), is there?
>>
>>>
>>> The patch itself looks ok, and if will pass above tests, then it is ok for head. The only issue is passing params to applet. Yes,
>>
>> By param you mean through SingleInstance, not through <param> tags right?
>>
>>> specification is silent in this issue, but I'm against String[0] (at least it is hard to test!:)). My idea here is to pass new
>>> String{key1,value1, key2,value2...keyn,valuen}. Better then nothing I believe.
>>>
>>
>> Would you mind elaborating on this some more too? I don't understand what the String{key,value,...} is meant to be.
>>
>>> Thanx for hard work!
>>
>> Thanks for the comments! Sorry for the long delay.
>
> Hey all,
>
> I ran out of time and couldn't get a chance to finish the reproducer for this patch. The tests are in place, all that needs doing is getting the 2 applets to run side by side. I couldn't figure out the magic for that. I'm posting it here in case anyone wants to pick it up again.
>
> Here's the last ChangeLog I had (minus tests additions).
>
> +2012-01-31 Danesh Dadachanji <ddadacha at redhat.com>
> +
> + Fixed SingleInstanceService to work with jnlp_href.
> + * netx/net/sourceforge/jnlp/Launcher.java
> + (launchApplication): Print existing single instance in debug mode.
> + (launchApplet): Added check for single instance, throws launchError if
> + single instance already exists.
> + (getApplet): Same as above.
> + (launchInstaller): Added TODO reminder for when it is implemented.
> + * netx/net/sourceforge/jnlp/resources/Messages.properties:
> + Added LSingleInstanceExists.
> + * netx/net/sourceforge/jnlp/services/XSingleInstanceService.java
> + (initializeSingleInstance): Modified to always initialize if the applet is
> + being run by the plugin.
> + (checkSingleInstanceRunning): Modified args passed to SingleInstanceListener.
> + Marked applets' args as FIXME, for now it passes an empty args array.
> +
>
> Regards,
> Danesh

So here is his patch with finished and test:


2012-09-04  Jiri Vanek  <Jvanek at redhat.com>
             Danesh Dadachanji  <ddadacha at redhat.com>

	Single instance support for jnlp-href and tests
	* netx/net/sourceforge/jnlp/services/XSingleInstanceService.java:
	(initializeSingleInstance) fixed code for catching running instance
	(checkSingleInstanceRunning) Added handling of parameters.
	* netx/net/sourceforge/jnlp/Launcher.java: (launchApplication),
	(launchApplet) 	Added debug output that instance is already running.
	(getApplet) added check for services and debug output
	* netx/net/sourceforge/jnlp/resources/Messages.properties: added
	(LSingleInstanceExists) entry for exception.
	tests/reproducers/simple/SingleInstanceServiceTest/resources/SingleInstanceTest.jnlp
	* tests/reproducers/simple/SingleInstanceServiceTest/resources/SingleInstanceTestWS.jnlp:
	* tests/reproducers/simple/SingleInstanceServiceTest/resources/SingleInstanceTest_clasical.html:
	* tests/reproducers/simple/SingleInstanceServiceTest/resources/SingleInstanceTest_jnlpHref.html:
	Applet and application in jnlp or html launching files.
	* tests/reproducers/simple/SingleInstanceServiceTest/srcs/SingleInstanceChecker.java
	SingleInstance implementing applet/application
	* tests/reproducers/simple/SingleInstanceServiceTest/testcases/SingleInstanceTest.java
	Testfile for launching for above jnlps/htmls as testcases.



When looking to it now, I would suggest also  new type of exception instead of LaunchException (SingleInstanceLaunchException perhaps...)

Is (Will) it be ok for head/1.3?

J
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