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A notification hooks

Workflow example using /StreamStatusEvent hook

The /StreamStatusEvent REST hook is a notification hook. Such hook may be used to notify the backend about some operation results.

For instance, the /StreamStatusEvent hook passes a results of video stream operations such as publishing or playback.

The backend server should simply accept the notification hook, for example to save information about the stream in the database.

 

On this diagram you can see that the /StreamStatusEvent event goes in two directions:

  1. To the client - step 4
  2. To the backend server - step 5 

Example:

POST /rest/my_api/StreamStatusEvent HTTP/1.1
Accept: application/json
Content-Type: application/json;charset=UTF-8
User-Agent: Java/1.8.0_111
Host: 192.168.1.101
Connection: keep-alive
Content-Length: 3614

{
    "nodeId":"Hw47CFMBEchVOpBMDr29IxjudnJ1sjOY@192.168.1.101",
    "appKey":"defaultApp",
    "sessionId":"/192.168.1.102:4388/192.168.1.101:8443",
    "mediaSessionId":"56141d10-fddc-11e6-ac3a-4d67d5b3360d",
    "name":"b4e7",
    "published":true,
    "hasVideo":true,
    "hasAudio":true,
    "status":"PUBLISHING",
    "sdp":".....",
    "record":false,
    "width":0,
    "height":0,
    "bitrate":0,
    "quality":0,
    "mediaProvider":"WebRTC"
}

HTTP/1.1 200 OK
Date: Tue, 28 Feb 2017 17:35:44 GMT
Server: Apache/2.2.15 (CentOS)
X-Powered-By: PHP/5.3.3
Content-Length: 3656
Connection: close
Content-Type: application/json

{
   "nodeId":"Hw47CFMBEchVOpBMDr29IxjudnJ1sjOY@192.168.1.101",
    "appKey":"defaultApp",
    "sessionId":"/192.168.1.102:4388/192.168.1.101:8443",
    "mediaSessionId":"56141d10-fddc-11e6-ac3a-4d67d5b3360d",
    "name":"b4e7",
    "published":true,
    "hasVideo":true,
    "hasAudio":true,
    "status":"PUBLISHING",
    "sdp":".....",
    "record":false,
    "width":0,
    "height":0,
    "bitrate":0,
    "quality":0,
    "mediaProvider":"WebRTC"
}

Error handling

By default, WCS does not check the response status of the /StreamStatusEvent hook invocation. That is, if the backend server returns HTTP error status 403 or 500 or any other, WCS ignores that.

To make WCS react to the error, set restOnError: FAIL in the settings of the /StreamStatusEvent hook, in restClientConfig when establishing the connection.

In this case, the client receives an additional event ErrorEvent and is notified about the error

On the step 6, the backend returns the HTTP status 500 Internal Error in response to invocation of the /StreamStatusEvent hook. The WCS server on the step 7 notifies the client about the error occurred.

Example:

POST /rest/my_api/StreamStatusEvent HTTP/1.1
Accept: application/json
Content-Type: application/json;charset=UTF-8
User-Agent: Java/1.8.0_111
Host: 192.168.1.101
Connection: keep-alive
Content-Length: 3624

{
    "nodeId":"Hw47CFMBEchVOpBMDr29IxjudnJ1sjOY@192.168.1.101",
    "appKey":"defaultApp",
    "sessionId":"/192.168.1.102:25301/192.168.1.101:8443",
    "mediaSessionId":"e9c002d0-fde2-11e6-a2bf-c99492323844",
    "name":"dc6a",
    "published":true,
    "hasVideo":true,
    "hasAudio":true,
    "status":"PUBLISHING",
    "sdp":".....",
    "record":false,
    "width":0,
    "height":0,
    "bitrate":0,
    "quality":0,
    "mediaProvider":"WebRTC"
}

HTTP/1.1 500 Internal Server Error
Date: Tue, 28 Feb 2017 18:22:49 GMT
Server: Apache/2.2.15 (CentOS)
X-Powered-By: PHP/5.3.3
Content-Length: 0
Connection: close
Content-Type: text/html; charset=UTF-8