> ## Documentation Index
> Fetch the complete documentation index at: https://help.dingtalk.io/llms.txt
> Use this file to discover all available pages before exploring further.
# Receive messages with a Bot
> Describes the development flow for a bot to receive messages, guiding developers to build the server-side receiver.
To develop a Bot that receives messages, follow the steps in this document to complete the server-side development for message reception.
## Background
Bots can receive messages in two modes: Stream mode and HTTP mode. This document describes how to receive messages in both modes.
## Prerequisites
1. Complete the [Create an app](/open/dingstart/create-application) process.
2. Complete the process of adding app capabilities.
## Procedure
### Stream mode (recommended)
> For more languages, refer to the Server-side Stream mode documentation.
1. Prepare the Java development environment:
* Runtime: JDK 1.8 or later
* Install the Java SDK:
Add the dependency to your project's `pom.xml` file or download the corresponding JAR package. You can view and download the latest SDK version [here](https://s01.oss.sonatype.org/?spm=openapi-amp.sdkpublish.0.0.78cefAyIfAyImO#nexus-search;quick~app-stream-client).
```xml lines theme={"theme":{"light":"github-light","dark":"github-dark"}}
com.dingtalk.open
app-stream-client
{sdk-version}
```
2. Server-side integration example:
```java lines theme={"theme":{"light":"github-light","dark":"github-dark"}}
public class BotExample {
public static void main(String[] args) {
OpenDingTalkClient client = OpenDingTalkStreamClientBuilder
.custom()
.credential(new AuthClientCredential("${ClientId}", "${ClientSecret}"))
.registerCallbackListener("${topic}", new RobotMsgCallbackConsumer())
.build();
client.start();
}
public static class RobotMsgCallbackConsumer implements OpenDingTalkCallbackListener {
/*
* @param request
* @return
*/
@Override
public JSONObject execute(JSONObject request) {
System.out.println(JSON.toJSONString(request));
try {
JSONObject text = request.getJSONObject("text");
if (text != null) {
// Content of the message received by the Bot
String msg = text.getString("content").trim();
String openConversationId = request.getString("conversationId");
}
} catch (Exception e) {
log.error("receive group message by robot error:" +e.getMessage(), e);
}
return new JSONObject();
}
}
}
```
| **Name** | **Description** |
| ------------ | ---------------------------------------------------------------- |
| ClientId | The ClientId of the Internal app credential. |
| ClientSecret | The ClientSecret of the Internal app credential. |
| topic | The Bot callback name. Fixed value: `/v1.0/im/bot/messages/get`. |
3. After the development is complete, [add the Bot to a group](/open/dingstart/add-robot-to-group). When you send "Hello" by @ the Bot, the server receives a message in the following format:
```json lines theme={"theme":{"light":"github-light","dark":"github-dark"}}
{
"conversationId": "cidjMOsz******AhS4Jg==",
"atUsers": [
{
"dingtalkId": "$:LWCP_v1:$v*********f1+2ow21Zzg"
}
],
"chatbotCorpId": "ding9f50*****6741",
"chatbotUserId": "$:LWCP_v1:$v*********1+2ow21Zzg",
"msgId": "msg2*****p+w==",
"senderNick": "DingTalk Bot",
"isAdmin": true,
"senderStaffId": "452523285939877041",
"sessionWebhookExpiredTime": 1695204671648,
"createAt": 1695199269062,
"senderCorpId": "ding9f50*****6741",
"conversationType": "2",
"senderId": "$:LWCP_v1:$C*********pnNGsP0HS+",
"conversationTitle": "Unified App Model - Test Group",
"isInAtList": true,
"sessionWebhook": "https://oapi.dingtalk.io/robot/sendBySession?session=c610ee93e4d96899d9236bd4bea185dd",
"text": {
"content": " Hello"
},
"robotCode": "ding1f*******dabddc",
"msgtype": "text"
}
```
| **Name** | **Description** |
| ------------------------- | ------------------------------------------------------------------------------------------ |
| conversationId | The conversation ID. |
| atUsers | Information about the @ mentioned users: - **dingtalkId**: The encrypted sender ID. |
| chatbotCorpId | The organization ID where the Bot resides. |
| chatbotUserId | The encrypted Bot ID. No use case for now; can be ignored. |
| msgId | The encrypted message ID. No use case for now; can be ignored. |
| senderNick | The sender's name. |
| isAdmin | Whether the sender is an Admin. |
| senderStaffId | The user ID of the person who @ the Bot in the internal group. |
| sessionWebhookExpiredTime | The expiration time of the Webhook URL for the current chat. |
| createAt | The message timestamp, in milliseconds. |
| senderCorpId | The organization ID of the sender's current group, available only in internal groups. |
| conversationType | The conversation type: - **1**: Direct Message - **2**: Group Chat |
| senderId | The encrypted sender ID. **Note** Use senderStaffId, which is the sender's userId value. |
| conversationTitle | The chat title, available only in group chats. |
| isInAtList | Whether the user is in the @ list. |
| sessionWebhook | The Webhook URL for the current chat. |
| text | The text message: - content: The text content. |
| robotCode | The Bot code. |
| msgtype | The message type. |
### HTTP mode
1. Prepare the Java development environment:
* Runtime: JDK 1.7 or later
2. Server-side integration example:
```java lines theme={"theme":{"light":"github-light","dark":"github-dark"}}
@RestController
public class RobotsController {
// The value = "/robots" below determines the Bot message receiving URL configured later, for example: https://example.com/robots
@RequestMapping(value = "/robots", method = RequestMethod.POST)
public String helloRobots(@RequestBody(required = false) JSONObject json) {
System.out.println(json);
// Content of the message received by the Bot
String content = json.getJSONObject("text").get("content").toString().replaceAll(" ", "");
return null;
}
}
```
3. After the development is complete, [add the Bot to a group](/open/dingstart/add-robot-to-group). When you send "Hello" by @ the Bot, the server receives a message in the following format:
```json lines theme={"theme":{"light":"github-light","dark":"github-dark"}}
{
"conversationId": "cidjMOsz******AhS4Jg==",
"atUsers": [
{
"dingtalkId": "$:LWCP_v1:$v*********f1+2ow21Zzg",
"staffId": "452523285939877041"
}
],
"chatbotCorpId": "ding9f50*****6741",
"chatbotUserId": "$:LWCP_v1:$v*********1+2ow21Zzg",
"msgId": "msg2*****p+w==",
"senderNick": "DingTalk Bot",
"isAdmin": true,
"senderStaffId": "452523285939877041",
"sessionWebhookExpiredTime": 1695204671648,
"createAt": 1695199269062,
"senderCorpId": "ding9f50*****6741",
"conversationType": "2",
"senderId": "$:LWCP_v1:$C*********pnNGsP0HS+",
"conversationTitle": "Unified App Model - Test Group",
"isInAtList": true,
"sessionWebhook": "https://oapi.dingtalk.io/robot/sendBySession?session=c610ee93e4d96899d9236bd4bea185dd",
"content": " Hello"
"msgtype": "text"
}
```
| **Name** | **Description** |
| ------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| conversationId | The conversation ID. |
| atUsers | Information about the @ mentioned users: - **dingtalkId**: The encrypted sender ID. - **staffId**: The userId value of the Employee in the current internal group. |
| chatbotCorpId | The organization ID where the Bot resides. |
| chatbotUserId | The encrypted Bot ID. No use case for now; can be ignored. |
| msgId | The encrypted message ID. No use case for now; can be ignored. |
| senderNick | The sender's name. |
| isAdmin | Whether the sender is an Admin. |
| senderStaffId | The user ID of the person who @ the Bot in the internal group. |
| sessionWebhookExpiredTime | The expiration time of the Webhook URL for the current chat. |
| createAt | The message timestamp, in milliseconds. |
| senderCorpId | The organization ID of the sender's current group, available only in internal groups. |
| conversationType | The conversation type: - **1**: Direct Message - **2**: Group Chat |
| senderId | The encrypted sender ID. **Note** Use senderStaffId, which is the sender's userId value. |
| conversationTitle | The chat title, available only in group chats. |
| isInAtList | Whether the user is in the @ list. |
| sessionWebhook | The Webhook URL for the current chat. |
| content | The message text. |
| msgtype | The message type. |
## Next steps
After completing the development of message reception by the Bot, you can reply to the received messages or send messages. Continue with the following:
* [Bot reply and send messages](/open/dingstart/robot-reply-and-send-messages)