Event Message Notification

Last updated: 2020-05-19 10:50:20

    When an LVB event is triggered, you can use the event message notification to receive the event information. Message notifications are supported for the following events:

    • LVB push event
    • LVB push interruption event
    • LVB recording file generation event
    • LVB screencapturing file generation event

    This document does not cover the callback notification for porn detection events. For more information, please see Best Practice - LVB Porn Detection.

    Event Message Notification Flow

    Overall process:

    1. The host configures an event message notification URL and related features such as recording and screencapturing in the console or through TencentCloud APIs.
    • The host pushes a stream or interrupts the push.
    • When an event occurs inside the LVB service, a message will be sent to viewers via the event message notification service.

    Event Message Notification Configuration

    The event message notification can be configured with:

    • TencentCloud API
    • Console

    Different event message notification URLs can be configured for different types of events, including:

    • Push event notification URL (StreamBeginNotifyUrl)
    • Push interruption event notification URL (StreamEndNotifyUrl)
    • Recording event notification URL (RecordNotifyUrl)
    • Screencapturing event notification URL (SnapshotNotifyUrl)

    Event Message Notification Protocol

    Network protocol

    Request: HTTP POST request with a JSON packet. The specific packet content of each type of message is described later.

    Response: HTTP STATUS CODE = 200. The server ignores the specific content of the response packet. For protocol-friendliness, it is recommended to add JSON: {"code":0} to the response.

    Notification reliability

    The event notification service has a retry mechanism with an interval of 60 seconds for a total of 3 retries. In order to avoid the impact of retries on your server and network bandwidth, make sure that the response packet can be returned normally. A retry is triggered in the following cases:

    • No response packet is returned for a long time (at least 20 seconds).
    • The HTTP status code in the response is not 200.

    Event Message Notification Parameter Descriptions

    Descriptions of common parameters

    Field Name Type Description
    event_type int Event notification message type. 1: push event; 0: push interruption event; 100: recording event; 200: screencapturing event
    sign string Event notification signature
    t int64 Event notification signature expiration time (UNIX timestamp)
    • t (expiration time): the default expiration time of a message notification from Tencent Cloud is 10 minutes. If the time specified by the t value in a message notification has elapsed, it can be determined that this notification is invalid, thereby preventing network replay attacks. The format of t is a decimal UNIX timestamp, i.e., the number of seconds that has elapsed since January 1, 1970 00:00 (UTC/GMT time).
    • sign (security signature): sign = MD5(key + t). Tencent Cloud splices the encryption key and t, calculates the sign value through MD5, and places it in the notification message. After your backend server receives the notification message, it can confirm whether the sign is correct based on the same algorithm and then determine whether the message is indeed from the Tencent Cloud backend.

      key is the callback key in Feature Template > Callback Configuration, which is mainly used for authentication. In order to protect the security of your data, you are recommended to enter it.

    Message bodies in various types

    LVB push and push interruption events

    • For an LVB push event, event_type = 1
    • For an LVB push interruption event, event_type = 0
    Field Name Type Description
    appid int User APPID
    app string Push domain name
    appname string Push path
    stream_id string Stream name
    channel_id string Same as stream name
    event_time int64 UNIX timestamp when the event message is generated
    sequence string Message serial number that identifies a push activity. The same push activity generates push and interruption messages with the same serial number
    node string IP of LVB access point
    user_ip string User's push IP
    stream_param string Parameters in user's push URL
    push_duration string Push duration in push interruption event notification in milliseconds
    errcode int Push interruption error code
    errmsg string Push interruption error message
    • errcode (push interruption error code)
    Error Code Error Description Reason
    1 recv rtmp deleteStream The host actively interrupted the push
    2 recv rtmp closeStream The host actively interrupted the push
    3 recv() return 0 The host actively closed the TCP connection
    4 recv() return error Exception with the TCP connection to the host
    7 rtmp message large than 1M Exception with the received stream data
    Other LVB service internal exception If you need help, contact your Tencent Cloud sales rep or submit a ticket


    "stream_id":" test_stream",

    LVB recording file generation event

    • event_type = 100
    Field Name Type Description
    appid int User APPID
    stream_id string Stream name
    channel_id string Same as stream name
    file_id string VOD file ID, which can uniquely locate a VOD video file on the VOD platform
    file_format string flv, hls, mp4, aac
    start_time int64 Start timestamp of recording file
    end_time int64 End timestamp of recording file
    duration int64 Recording file duration in seconds
    file_size uint64 Recording file size in bytes
    stream_param string Parameters in user's push URL
    video_url string Recording file download URL



    LVB screencapturing file generation event

    • event_type = 200
    Field Name Type Description
    stream_id string Stream name
    channel_id string Same as stream name
    create_time int64 UNIX timestamp when the screenshot is generated
    file_size int Screenshot file size in bytes
    width int Screenshot width in pixels
    height int Screenshot height in pixels
    pic_url string Screenshot file path /path/name.jpg
    pic_full_url string Screenshot download URL


    "channel_id":" stream_name",

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