Invoke a Callback Before Delivering Group Messages

Feature Description

The app backend can use this callback to monitor users’ group messages in real time, including:

• Recording group messages in real time, for example, recording a log or synchronizing the messages to other systems
• Blocking users’ requests for sending group messages
• Modifying the content of users’ messages, for example, filtering out sensitive words or adding custom information defined by the app

Precautions

• To enable this callback, you must configure the callback URL and toggle on the corresponding protocol. For details on the configuration method, see Third-Party Callback Configuration.
• Callback direction: the IM backend initiates an HTTP POST request to the app backend.
• After receiving the callback request, the app backend must check whether the SDKAppID contained in the request URL is consistent with its own SDKAppID.
• For other security-related issues, see Third-Party Callback Overview: Security Considerations.

Callback Triggering Scenarios

• An app user sends a group message through the client.
• The app admin sends a group message through a RESTful API.

Callback Triggering Time

The callback is triggered before the IM backend sends a group message to group members.

API Description

Request URL example

In the following example, the callback URL configured in the app is https://www.example.com.
Example:

https://www.example.com?SdkAppid=$SDKAppID&CallbackCommand=$CallbackCommand&contenttype=json&ClientIP=$ClientIP&OptPlatform=$OptPlatform

Request parameters

Request packet example

{
    "CallbackCommand": "Group.CallbackBeforeSendMsg", // Callback command
    "GroupId": "@TGS#2J4SZEAEL", // Group ID
    "Type": "Public", // Group type
    "From_Account": "jared", // Sender
    "Operator_Account":"admin", // Request initiator
    "Random": 123456, // Random number
    "MsgBody": [ // Message body. For more information, see the TIMMessage message object.
        {
            "MsgType": "TIMTextElem", // Text
            "MsgContent": {
                "Text": "red packet"
            }
        }
    ]
}

Request packet fields

Response packet example

Allowing to send a group message

The user is allowed to send a group message, and the content of the sent message is not modified.

{
    "ActionStatus": "OK",
    "ErrorInfo": "",
    "ErrorCode": 0 // The 0 value indicates allowing to send group messages.
}

Disallowing to send a group message

The user is not allowed to send a group message. In this case, the message is not sent, and the error code 10016 is returned to the caller.

{
    "ActionStatus": "OK",
    "ErrorInfo": "",
    "ErrorCode": 1 // The 1 value indicates that the user is disallowed to send group messages.
}

Discarding a message silently

The user is not allowed to send a group message. In this case, the message is not sent, but a successful sending message will be returned to the caller to pretend that the message has been sent.

{
    "ActionStatus": "OK",
    "ErrorInfo": "",
    "ErrorCode": 2 // The 2 value indicates the message is silently discarded.
}

Modifying message content

In the following response example, the group message sent by the user is modified (in this case, a custom message is added), and the IM backend will deliver the modified message. With this feature, the app backend can add special content, such as the user level and title, to the message sent by the user.

{
    "ActionStatus": "OK",
    "ErrorInfo": "",
    "ErrorCode": 0, // The parameter value must be 0 so that the modified message can be sent normally.
    "MsgBody": [ // The message modified by the app. If no modification is made, the message sent by the user is used by default.
        {
            "MsgType": "TIMTextElem", // Text
            "MsgContent": {
                "Text": "red packet"
            }
        },
        {
            "MsgType": "TIMCustomElem", // Custom message
            "MsgContent": {
                "Desc": "CustomElement.MemberLevel", // Description
                "Data": "LV1" // Data
            }
        }
    ]
}

Response packet fields

References

• Third-party callback overview
• RESTful APIs: Sending common messages in a group