Conversational AI & Speech-to-Text Callbacks
This document introduces events generated by Tencent Cloud APIs related to AI services (Conversational AI and Speech-to-Text features), which are then notified to your server in the form of HTTP/HTTPS requests. You can provide relevant configuration information to Tencent Cloud to activate this service. You can also use it in combination with Tencent Real-Time Communication (TRTC)'s Event Callbacks to implement more custom logic.
Configuration Information
The TRTC console supports self-service configuration of callback information. Once the configuration is complete, you can receive event callback notifications. For detailed instructions, see Callback Configuration.
Note:
You need to prepare the following information in advance:
Required: the HTTP/HTTPS server address to receive callback notifications.
Optional: the key for calculating a signature, which is a key of up to 32 characters defined by you, consisting of uppercase and lowercase letters and digits.
Timeout Retry
If the event callback server does not receive a response from your server within 5 seconds after sending a message notification, it will consider the notification as failed. After the first failure, an immediate retry is attempted. Subsequent retries will occur at 10-second intervals until the message retention time exceeds 1 minute, after which no further retries will be made.
Event Callback Message Format
Event callback messages are sent to your server via HTTP/HTTPS POST requests, where:
Character encoding format: UTF-8.
Request: The body is in JSON format.
Response: The HTTP status code is 200. The server ignores the specific content of a response packet. For protocol friendliness, it is recommended that the client response content carry JSON: {"code":0}.
Packet example: The following is a packet example for the event of "successfully starting an AI conversation task".
{"EventGroupId": 9,"CallbackTs": 1687770730166,"EventInfo": {"EventMsTs": 1622186275757,"TaskId": "hKPD2Q7kBVzu-6ezFiqmcEBJQCykqbZrS9OOTE46uYlb4NvQDIaEXlpOlLXFtGBiado5oP0zfLDZs","RoomId": "1234","RoomIdType": 0,"Payload": {"Status": 0}}}
Parameter Description
Callback Message Parameters
The header of an event callback message contains the following fields:
Field Name | Value |
Content-Type | application/json. |
Sign | Signature value. |
SdkAppId | SDK application ID. |
The body of an event callback message contains the following fields:
Field Name | Type | Meaning |
EventGroupId | Number | Event group ID, which is fixed at 4 for stream mixing and relay events. |
EventType | Number | The event type of the callback notification. |
CallbackMsTs | Number | The Unix timestamp (in milliseconds) when the event callback server sends a callback request to your server. |
EventInfo | JSON Object |
Event Group ID
Field Name | Value | Meaning |
EVENT_GROUP_AI_SERVICE | 9 | AI service event group. |
Event Type
Field Name | Value | Meaning |
EVENT_TYPE_AI_SERVICE_START | 901 | Callback for the AI task start status. |
EVENT_TYPE_AI_SERVICE_STOP | 902 | Callback for the AI task end status. |
EVENT_TYPE_AI_SERVICE_MSG | 903 | Callback for a complete sentence. Conversational AI: Callback after recognizing a complete sentence. Speech-to-text: Callback for a transcribed complete sentence. |
Definition of Event Information When the Event Type Is (EVENT_TYPE_AI_SERVICE_START 901):
Field Name | Type | Meaning |
EventMsTs | String | The Unix timestamp (in milliseconds) when an event occurs. |
TaskId | String | AI task ID. |
RoomId | String | TRTC room ID. |
RoomIdType | Integer | 0: indicates a numeric room number. 1: indicates a string room number. |
Payload.Status | Number | 0: AI task started successfully. 1: AI task failed to start. |
{"EventGroupId": 9,"EventType": 901,"CallbackTs": 1687770730166,"EventInfo": {"EventMsTs": 1622186275757,"TaskId": "xx","RoomId": "1234","RoomIdType": 0,"Payload": {"Status": 0}}}
Definition of Event Information When the Event Type Is (EVENT_TYPE_AI_SERVICE_STOP 902):
Field Name | Type | Meaning |
EventMsTs | String | The Unix timestamp (in milliseconds) when an event occurs. |
TaskId | String | AI task ID. |
RoomId | String | TRTC room ID. |
RoomIdType | Integer | 0: indicates a numeric room number. 1: indicates a string room number. |
Payload.LeaveCode | Integer | 0: The task exits after the stop API is normally called. 1: The task exits after the customer's application removes the transcription bot. 2: The task exits after the customer's application dissolves the room. 3: The TRTC server removes the bot. 4: The TRTC server dissolves the room. 98: Internal error. It is recommended to retry. 99: There is no user stream in the room except the transcription bot. The task exits after exceeding the specified time. |
{"EventGroupId": 9,"EventType": 902,"CallbackTs": 1687770730166,"EventInfo": {"EventMsTs": 1622186275757,"TaskId": "xx","RoomId": "1234","RoomIdType": 0,"Payload": {"LeaveCode": 0}}}
Definition of Event Information When the Event Type Is (EVENT_TYPE_AI_SERVICE_MSG 903):
Field Name | Type | Meaning |
EventMsTs | String | The Unix timestamp (in milliseconds) when an event occurs. |
TaskId | String | AI task ID. |
RoomId | String | TRTC room ID. |
RoomIdType | Integer | 0: indicates a numeric room number. 1: indicates a string room number. |
Payload | JSON Object | It is a JSON object, which is consistent with the custom message callback format on the client. { "UserId":"", "Text":"", "StartTimeMs":1234, "EndTimeMs":1269, "RoundId":"xxxxxx" // uuid } |
{"EventGroupId": 9,"EventType": 903,"CallbackTs": 1687770730166,"EventInfo": {"EventMsTs": 1622186275757,"TaskId": "xx","RoomId": "1234","RoomIdType": 0,"Payload": {"UserId":"","Text":"","StartTimeMs":1234,"EndTimeMs":1269,"RoundId":"xxxxxx"}}}
Calculating a Signature
Signatures are calculated using the HMAC SHA256 encryption algorithm. After your event callback server receives a callback message, it calculates the signature in the same manner. If they match, it indicates that it is an event callback from TRTC and has not been forged. The signature calculation is as follows:
// In the signature calculation formula, the 'key' is the encryption key used for calculating the signature 'Sign'.Sign = base64 (hmacsha256 (key, body))
Note:
Body refers to the original packet body of the callback request received by you, and do not do any transformation, as shown below:
body="{\n\t\"Ebody="{\"EventGroupId\":7,\"EventType\":701,\"CallbackMsTs\":1701937900012,\"EventInfo\":{\"EventMsTs\":1701937900012,\"TaskId\":\"WMdqEeEgj2ksqnyUsuXC+qLkVypGmwjrgh1JC6ZefVP+rvsidDnZsAw8uWgX0XRGvdSVfAMunise2kcZaefdgHvx3-M2v6fmTjRNgg..\",\"Status\":0}}"ventGroupId\":\t1,\n\t\"EventType\":\t103,\n\t\"CallbackTs\":\t1615554923704,\n\t\"EventInfo\":\t{\n\t\t\"RoomId\":\t12345,\n\t\t\"EventTs\":\t1608441737,\n\t\t\"UserId\":\t\"test\",\n\t\t\"UniqueId\":\t1615554922656,\n\t\t\"Role\":\t20,\n\t\t\"Reason\":\t1\n\t}\n}"
Signature Verification Example
import javax.crypto.Mac;import javax.crypto.spec.SecretKeySpec;import java.util.Base64;//# Feature: third-party callback signature verification//# Parameters://# key: key configured in the console//# body: body returned by Tencent Cloud callbacks//# sign: signature value returned by Tencent Cloud callbacks//# Returned values://# Status: OK indicates verification successful. FAIL indicates verification failed. Refer to Info for details.//# Info: success/failure informationpublic class checkSign {public static String secureFinalSign(String key, String entityBody) throws Exception {Mac hmacSha256 = Mac.getInstance("HmacSHA256");SecretKeySpec secret_key = new SecretKeySpec(key.getBytes(), "HmacSHA256");hmacSha256.initialize(secret_key);return Base64.getEncoder().encodeToString(hmacSha256.doFinal(body.getBytes()));]public static void main(String[] args) throws Exception {String key = "123654";String body = "{\n" + "\t\"EventGroupId\":\t2,\n" + "\t\"EventType\":\t204,\n" + "\t\"CallbackTs\":\t1664209748188,\n" + "\t\"EventInfo\":\t{\n" + "\t\t\"RoomId\":\t8489,\n" + "\t\t\"EventTs\":\t1664209748,\n" + "\t\t\"EventMsTs\":\t1664209748180,\n" + "\t\t\"UserId\":\t\"user_85034614\",\n" + "\t\t\"Reason\":\t0\n" + "\t}\n" + "}";String Sign = "kkoFeO3Oh2ZHnjtg8tEAQhtXK16/KI05W3BQff8IvGA=";String resultSign = obtainResultSignature(key, body);if (resultSign.equals(Sign)) {System.out.println("{'Status': 'OK', 'Info': 'Verification successful.'}");} else {System.out.println("{'Status': 'FAIL', 'Info': 'Verification failed.'}");]]]
# -*- coding: utf8 -*-import hmacimport base64from hashlib import sha256# Feature: third-party callback signature verification# Parameters:# key: key configured in the console# body: body returned by Tencent Cloud callbacks# sign: signature value returned by Tencent Cloud callbacks# Returned values:# Status: OK indicates verification successful. FAIL indicates verification failed. Refer to Info for details.# Info: success/failure informationdef checkSign(key, body, sign):temp_dict = {}computSign = base64.b64encode(hmac.new(key.encode('utf-8'), body.encode('utf-8'), digestmod=sha256).digest()).decode('utf-8')print(computSign)if computSign equals sign:temp_dict['Status'] = 'OK'temp_dict['Info'] = 'Verification successful.'return temporary_dictionaryelse:temp_dict['Status'] = 'FAIL'temp_dict['Info'] = 'Verification failed.'return temporary_dictionaryif __name__ == '__main__':key = '123654'body = "{\n" + "\t\"EventGroupId\":\t2,\n" + "\t\"EventType\":\t204,\n" + "\t\"CallbackTs\":\t1664209748188,\n" + "\t\"EventInfo\":\t{\n" + "\t\t\"RoomId\":\t8489,\n" + "\t\t\"EventTs\":\t1664209748,\n" + "\t\t\"EventMsTs\":\t1664209748180,\n" + "\t\t\"UserId\":\t\"user_85034614\",\n" + "\t\t\"Reason\":\t0\n" + "\t}\n" + "}"`sign` = 'kkoFeO3Oh2ZHnjtg8tEAQhtXK16/KI05W3BQff8IvGA='result = verifySignature(key, body, sign)print(result)
<?phpclass TlsEventSig {private $key = false;private $body = false;public function __construct( $key, $body ) {$this->key = $key;$this->body = $body;]private function __hmacsha256() {$hash = hash_hmac( 'sha256', $this->body, $this->key, true );return base64_encode( $hash);]public function genEventSig() {return $this->__hmacsha256();]]$key="789";$data="{\n\t\"EventGroupId\":\t1,\n\t\"EventType\":\t101,\n\t\"CallbackTs\":\t1608086882372,\n\t\"EventInfo\":\t{\n\t\t\"RoomId\":\t20222,\n\t\t\"EventTs\":\t1608086882,\n\t\t\"UserId\":\t\"222222_phone\"\n\t}\n}";$api = new TlsEventSig($key, $data);echo $api->genEventSig();
package mainimport "fmt"import ("crypto/hmac""crypto/sha256""encoding/base64")func main () {var data = "{\n\t\"EventGroupId\":\t1,\n\t\"EventType\":\t101,\n\t\"CallbackTs\":\t1608086882372,\n\t\"EventInfo\":\t{\n\t\t\"RoomId\":\t20222,\n\t\t\"EventTs\":\t1608086882,\n\t\t\"UserId\":\t\"222222_phone\"\n\t}\n}"var key = "789"//JSRUN Engine 2.0 supports running online in up to 30 languages, providing fully simulated interactive input and output.fmt.Println(hmacsha256(data,key))]func hmacsha256(data string, key string) string {h := hmac.New(sha256.New, []byte(key))h.Write([]byte(data))return base64.StdEncoding.EncodeToString(h.Sum(nil))]
- Configuration Information
- Timeout Retry
- Event Callback Message Format
- Parameter Description
- Callback Message Parameters
- Event Group ID
- Event Type
- Definition of Event Information When the Event Type Is (EVENT_TYPE_AI_SERVICE_START 901):
- Definition of Event Information When the Event Type Is (EVENT_TYPE_AI_SERVICE_STOP 902):
- Definition of Event Information When the Event Type Is (EVENT_TYPE_AI_SERVICE_MSG 903):
- Calculating a Signature
- Signature Verification Example