Event queue - Revision history

Acryline at 10:04, 3 March 2015

2015-03-03T10:04:17Z

Justincc: /* Polling */

2014-08-11T23:15:28Z

‎Polling

Justincc at 22:57, 11 August 2014

2014-08-11T22:57:12Z

Justincc at 17:30, 27 June 2014

2014-06-27T17:30:35Z

Justincc at 17:29, 27 June 2014

2014-06-27T17:29:54Z

Justincc at 19:26, 26 June 2014

2014-06-26T19:26:05Z

Justincc: /* Introduction */

2014-06-26T18:37:00Z

‎Introduction

Justincc: /* Introduction */

2014-06-26T18:32:35Z

‎Introduction

Justincc: Created page with "=Introduction= The event queue is a Linden Lab viewer protocol mechanism whereby the simulator can place messages on a queue which is regularly TCP polled by a client/viewer...."

2014-06-26T18:29:54Z

Created page with "=Introduction= The event queue is a Linden Lab viewer protocol mechanism whereby the simulator can place messages on a queue which is regularly TCP polled by a client/viewer...."

New page

=Introduction=

The event queue is a Linden Lab viewer protocol mechanism whereby the simulator can place messages on a queue which is regularly TCP polled by a client/viewer. In this way, a simulator can directly send data back to a viewer.

The Linden Lab wiki [http://wiki.secondlife.com/wiki/Second_Life_Grid_Protocols/Foundation#Event_Queue has a very short description of the event queue] but no further detail.

In OpenSimulator, the event queue is implemented by the EventQueueGetModule in the OpenSim.Region.ClientStack.LindenCaps package. This fulfils the interface IEventQueue.

As events are distinguished by a message parameter, one could construct an arbitary for a modified client/viewer that can recognize it with the EventQueueHelper.BuildEvent() static method and then inject that data by obtaining a reference to EventQueueGetModule, for example with

<source lang="csharp">
IEventQueue eq = scene.RequestModuleInterface<IEventQueue>();
if (eq != null)
eq.Enqueue(EventQueueHelper.BuildEvent("myevent", eventBodyOsd));
</source>

I believe (justincc) that the viewer polls the event queue every second, though that needs to be re-confirmed via specific testing.

← Older revision		Revision as of 10:04, 3 March 2015
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		+	{{Languages\|Event queue}}
	The event queue is a Linden Lab viewer protocol mechanism whereby the simulator can place messages on a queue which is regularly TCP polled by a client/viewer. In this way, a simulator can directly send data back to a viewer.		The event queue is a Linden Lab viewer protocol mechanism whereby the simulator can place messages on a queue which is regularly TCP polled by a client/viewer. In this way, a simulator can directly send data back to a viewer.

← Older revision		Revision as of 23:15, 11 August 2014
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	==Polling==		==Polling==
	The PollServiceRequestManager in OpenSim.Framework.Servers.HttpServer sets up 3 PollServiceWorkerThreads and 1 LongPollServiceWatcherThread to handle poll requests such as the EventQueue.		The PollServiceRequestManager in OpenSim.Framework.Servers.HttpServer sets up 3 PollServiceWorkerThreads and 1 LongPollServiceWatcherThread to handle poll requests such as the EventQueue.
		+
		+	===LongPollServiceWatcherThread===
		+	Every 500ms checks poll requests to see if there are events waiting to be sent back or if the timeout has expired.

← Older revision		Revision as of 22:57, 11 August 2014
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	I believe (justincc) that the viewer polls the event queue a second after the previous response. In addition, if the server returns an error then there is a 15 second wait until the queue is polled again. However, this needs to be confirmed by checking the behaviour of a current viewer.		I believe (justincc) that the viewer polls the event queue a second after the previous response. In addition, if the server returns an error then there is a 15 second wait until the queue is polled again. However, this needs to be confirmed by checking the behaviour of a current viewer.
		+
		+	==Polling==
		+	The PollServiceRequestManager in OpenSim.Framework.Servers.HttpServer sets up 3 PollServiceWorkerThreads and 1 LongPollServiceWatcherThread to handle poll requests such as the EventQueue.

← Older revision		Revision as of 17:30, 27 June 2014
Line 19:		Line 19:
	One would want to pick message names that are unlikely to clash with any future Linden Lab additions or other OpenSimulator extensions.		One would want to pick message names that are unlikely to clash with any future Linden Lab additions or other OpenSimulator extensions.

−	I believe (justincc) that the viewer polls the event queue a second after the previous response. In addition, if the server returns an error then there is a 15 second wait until the queue is polled again. However, this needs to be confirmed by checking the behaviour of a current viewer~~.specific testing~~.	+	I believe (justincc) that the viewer polls the event queue a second after the previous response. In addition, if the server returns an error then there is a 15 second wait until the queue is polled again. However, this needs to be confirmed by checking the behaviour of a current viewer.

← Older revision		Revision as of 17:29, 27 June 2014
Line 19:		Line 19:
	One would want to pick message names that are unlikely to clash with any future Linden Lab additions or other OpenSimulator extensions.		One would want to pick message names that are unlikely to clash with any future Linden Lab additions or other OpenSimulator extensions.

−	I believe (justincc) that the viewer polls the event queue ~~every~~ second, ~~though that~~ needs to be ~~re-~~confirmed ~~via~~ specific testing.	+	I believe (justincc) that the viewer polls the event queue a second after the previous response. In addition, if the server returns an error then there is a 15 second wait until the queue is polled again. However, this needs to be confirmed by checking the behaviour of a current viewer.specific testing.

← Older revision		Revision as of 19:26, 26 June 2014
Line 1:		Line 1:
−	~~=Introduction=~~
−
	The event queue is a Linden Lab viewer protocol mechanism whereby the simulator can place messages on a queue which is regularly TCP polled by a client/viewer. In this way, a simulator can directly send data back to a viewer.		The event queue is a Linden Lab viewer protocol mechanism whereby the simulator can place messages on a queue which is regularly TCP polled by a client/viewer. In this way, a simulator can directly send data back to a viewer.

@@ Line 6: / Line 6: @@
 In OpenSimulator, the event queue is implemented by the EventQueueGetModule in the OpenSim.Region.ClientStack.LindenCaps package.  This fulfils the interface IEventQueue.
 As events are distinguished by a message parameter, one could construct an arbitary for a modified client/viewer that can recognize it with the EventQueueHelper.BuildEvent() static method and then inject that data by obtaining a reference to EventQueueGetModule, for example with
@@ Line 16: / Line 18: @@
 [[OpenStructuredData]] (OSD) is the name of a data format that is a superset of [http://wiki.secondlife.com/wiki/LLSD Linden Lab Structured Data (LLSD)].  It's XML which contains some information about embedded types.
 I believe (justincc) that the viewer polls the event queue every second, though that needs to be re-confirmed via specific testing.

@@ Line 14: / Line 14: @@
      eq.Enqueue(EventQueueHelper.BuildEvent("myevent", eventBodyOsd));
 </source>
 I believe (justincc) that the viewer polls the event queue every second, though that needs to be re-confirmed via specific testing.