ARI: Add ability to raise arbitrary User Events

User events can now be generated from ARI.  Events can be signalled with
arbitrary json variables, and include one or more of channel, bridge, or
endpoint snapshots.  An application must be specified which will receive
the event message (other applications can subscribe to it).  The message
will also be delivered via AMI provided a channel is attached.  Dialplan
generated user event messages are still transmitted via the channel, and
will only be received by a stasis application they are attached to or if
the channel is subscribed to.

This change also introduces the multi object blob mechanism used to send
multiple snapshot types in a single message.  The dialplan app UserEvent
was also changed to use multi object blob, and a new stasis message type
created to handle them.

ASTERISK-22697 #close
Review: https://reviewboard.asterisk.org/r/3494/
........

Merged revisions 414405 from http://svn.asterisk.org/svn/asterisk/branches/12


git-svn-id: https://origsvn.digium.com/svn/asterisk/trunk@414406 65c4cc65-6c06-0410-ace0-fbb531ad65f3

rest-api/api-docs/events.json

@@ -30,6 +30,66 @@
 					]
 				}
 			]
+		},
+		{
+			"path": "/events/user/{eventName}",
+			"description": "Stasis application user events",
+			"operations": [
+				{
+					"httpMethod": "POST",
+					"summary": "Generate a user event.",
+					"nickname": "userEvent",
+					"responseClass": "void",
+					"parameters": [
+						{
+							"name": "eventName",
+							"description": "Event name",
+							"paramType": "path",
+							"required": true,
+							"allowMultiple": false,
+							"dataType": "string"
+						},
+						{
+							"name": "application",
+							"description": "The name of the application that will receive this event",
+							"paramType": "query",
+							"required": true,
+							"allowMultiple": false,
+							"dataType": "string"
+						},
+						{
+							"name": "source",
+							"description": "URI for event source (channel:{channelId}, bridge:{bridgeId}, endpoint:{tech}/{resource}, deviceState:{deviceName}",
+							"paramType": "query",
+							"required": false,
+							"allowMultiple": true,
+							"dataType": "string"
+						},
+						{
+							"name": "variables",
+							"description": "custom key/value pairs added to the user event",
+							"paramType": "body",
+							"required": false,
+							"allowMultiple": false,
+							"dataType": "containers"
+						}
+					],
+					"errorResponses": [
+						{
+							"code": 404,
+							"reason": "Application does not exist."
+						},
+						{
+							"code": 422,
+							"reason": "Event source not found."
+						},
+						{
+							"code": 400,
+							"reason": "Invalid even tsource URI or userevent data."
+						}
+					]
+				}
+			]
 		}
 	],
 	"models": {
@@ -451,9 +511,19 @@
 					"description": "The name of the user event."
 				},
 				"channel": {
-					"required": true,
+					"required": false,
 					"type": "Channel",
-					"description": "The channel that signaled the user event."
+					"description": "A channel that is signaled with the user event."
+				},
+				"bridge": {
+					"required": false,
+					"type": "Bridge",
+					"description": "A bridge that is signaled with the user event."
+				},
+				"endpoint": {
+					"required": false,
+					"type": "Endpoint",
+					"description": "A endpoint that is signaled with the user event."
 				},
 				"userevent": {
 					"required": true,