Before Group Message Is Sent

Feature Overview
This webhook event is used by the app backend to check users' group messages in real time, including:
Records group messages in real time, for example, by recording a log or synchronizing the messages to other systems.
Blocks users' requests to send messages in a group.
Caution: 
 The timeout period of the webhook before message sending is two seconds by default, and we recommend you not adjust it. This webhook may time out when used for text moderation. If you need to moderate text, use the content webhook.
Limits
To enable this webhook, you must configure a webhook URL and enable the corresponding switch for this webhook. For more information on the configuration method, see Webhook Configuration.
During this webhook event, the Chat backend initiates an HTTP POST request to the app backend.
After receiving the webhook request, the app backend must check whether the SDKAppID contained in the request URL is the SDKAppID of the app.
For more security considerations, see the Security Considerations section in Webhook Overview.
Webhook Triggering Scenarios
An app user sends a group message on the client.
The app admin sends a group message via RESTful APIs.
Webhook Triggering Timing
The webhook is triggered before the Chat backend sends a group message to group members.
API Calling Description
Sample request URL
In the following sample, the webhook 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
Parameter
Description
https
The request protocol is HTTPS, and the request method is POST.
www.example.com
Webhook URL
SdkAppid
The SDKAppID assigned by the Chat console when the app is created
CallbackCommand
Fixed value: Group.CallbackBeforeSendMsg.
contenttype
Fixed value: JSON.
ClientIP
Client IP, such as 127.0.0.1
OptPlatform
Client platform. For valid values, see the description of OptPlatform in the Webhook Protocols section of Webhook Callback Overview.
Sample requests
{
    "CallbackCommand": "Group.CallbackBeforeSendMsg", // Webhook command
    "GroupId": "@TGS#2J4SZEAEL", // Group ID
    "Type": "Community", // Group type
    "From_Account": "jared", // Sender
    "Operator_Account":"admin", // Request initiator
    "Random": 123456, // Random number
    "OnlineOnlyFlag": 1, // The value is `1` if it is an online message and `0` (default) if it’s not. For audio-video groups, the value is `0`.
    "MsgBody": [ // Message body. For more information, see the `TIMMessage` message object.
        {
            "MsgType": "TIMTextElem", // Text
            "MsgContent":{
                "Text": "red packet"
            }
        }
    ],
    "CloudCustomData": "your cloud custom data",
    "TopicId":"@TGS#_@TGS#cQVLVHIM62CJ@TOPIC#_TestTopic",// Topic ID, which applies only to topic-enabled communities
    "EventTime":"1670574414123"// Event trigger timestamp in milliseconds		
}
Request fields
Field
Type
Description
CallbackCommand
String
Webhook command
GroupId
String
ID of the group that generates group messages
Type
String
Type of the group that generates group messages, such as Public. For details, see Group Types section in Group System.
From_Account
String
UserID of the message sender
Operator_Account
String
UserID of the request initiator, based on which the system can identify whether the request is initiated by the admin.
Random
Integer
A 32-bit random number in the request
OnlineOnlyFlag
Integer
The value is 1 if it is an online message and 0 (default) if it’s not. For audio-video groups, the value is 0.
MsgBody
Array
Message body. For more information, see Message Formats.
CloudCustomData
String
Custom message data. It is saved in the cloud and will be sent to the receiver. Such data can be pulled after the app is uninstalled and reinstalled.
TopicId
String
Topic ID, which indicates message sending in the topic and applies only to topic-enabled communities.
EventTime
Integer
Event trigger timestamp in milliseconds
Sample response
Allowing group message sending
The user is allowed to send group messages, and the content of the message is not modified.
{
    "ActionStatus": "OK",
    "ErrorInfo": "",
    "ErrorCode": 0 // `0` indicates the user is allowed to send messages.
}
Forbidding group message sending
The user is not allowed to send group messages. In this case, the message is not sent, and the error code 10016 is returned to the caller.
{
    "ActionStatus": "OK",
    "ErrorInfo": "",
    "ErrorCode": 1 // `1` indicates that the user is not allowed to send messages.
}
Discarding messages silently
The user is not allowed to send group messages. In this case, the message is not sent, but a success message will be returned to the caller.
{
    "ActionStatus": "OK",
    "ErrorInfo": "",
    "ErrorCode": 2 // The value `2` indicates the message is silently discarded.
}
Modifying the message content
In the following response sample, the group message sent by the user is modified (a custom message is added), and the Chat backend will send 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, // This field must be set to `0` so that the modified message can be sent normally.
    "MsgBody": [ // Message modified by the app backend. If the app backend does not modify the message, the message sent by the user is delivered.
        {
            "MsgType": "TIMTextElem", // Text
            "MsgContent":{
                "Text": "red packet"
            }
        },
        {
            "MsgType": "TIMCustomElem", // Custom message
            "MsgContent":{
                "Desc": "CustomElement.MemberLevel", // Description
                "Data": "LV1" // Data
            }
        }
    ],
    "CloudCustomData": "your cloud custom data"
}
Response fields
Field
Type
Required
Description
ActionStatus
String
Yes
Request result. OK: Successful; FAIL: Failed
ErrorCode
Integer
Yes
Error code returned. 0: allows group message sending; 1: forbids group message sending; 2: discards the message silently. If the business side wants to forbid a user to send group messages and send ErrorCode and ErrorInfo to the client, ensure that the value of ErrorCode is set within the range of [10100, 10200].
ErrorInfo
String
Yes
Error information
MsgBody
Array
No
Message body modified by the app backend. The Chat backend sends the modified message to the group. For more information on the format, see Message Formats.
CloudCustomData
String
No
Custom message data. It is saved in the cloud and will be sent to the peer end. Such data can be pulled after the app is uninstalled and reinstalled.
References
Webhook Callback Overview
RESTful API: Sending Ordinary Messages in a Group

Feature Overview
Limits
Webhook Triggering Scenarios
Webhook Triggering Timing
API Calling Description
References

Parameter	Description
https	The request protocol is HTTPS, and the request method is POST.
www.example.com	Webhook URL
SdkAppid	The `SDKAppID` assigned by the Chat console when the app is created
CallbackCommand	Fixed value: `Group.CallbackBeforeSendMsg`.
contenttype	Fixed value: `JSON`.
ClientIP	Client IP, such as 127.0.0.1
OptPlatform	Client platform. For valid values, see the description of `OptPlatform` in the Webhook Protocols section of Webhook Callback Overview.

Field	Type	Description
CallbackCommand	String	Webhook command
GroupId	String	ID of the group that generates group messages
Type	String	Type of the group that generates group messages, such as `Public`. For details, see Group Types section in Group System.
From_Account	String	`UserID` of the message sender
Operator_Account	String	`UserID` of the request initiator, based on which the system can identify whether the request is initiated by the admin.
Random	Integer	A 32-bit random number in the request
OnlineOnlyFlag	Integer	The value is `1` if it is an online message and `0` (default) if it’s not. For audio-video groups, the value is `0`.
MsgBody	Array	Message body. For more information, see Message Formats.
CloudCustomData	String	Custom message data. It is saved in the cloud and will be sent to the receiver. Such data can be pulled after the app is uninstalled and reinstalled.
TopicId	String	Topic ID, which indicates message sending in the topic and applies only to topic-enabled communities.
EventTime	Integer	Event trigger timestamp in milliseconds

Field	Type	Required	Description
ActionStatus	String	Yes	Request result. `OK`: Successful; `FAIL`: Failed
ErrorCode	Integer	Yes	Error code returned. `0`: allows group message sending; `1`: forbids group message sending; `2`: discards the message silently. If the business side wants to forbid a user to send group messages and send `ErrorCode` and `ErrorInfo` to the client, ensure that the value of `ErrorCode` is set within the range of [10100, 10200].
ErrorInfo	String	Yes	Error information
MsgBody	Array	No	Message body modified by the app backend. The Chat backend sends the modified message to the group. For more information on the format, see Message Formats.
CloudCustomData	String	No	Custom message data. It is saved in the cloud and will be sent to the peer end. Such data can be pulled after the app is uninstalled and reinstalled.