C2C chat on the app: C2C messages are applicable to C2C chats on the app.
App administrator sends messages: C2C messages can be sent by the app administrator from the backend, or by the app administrator simulating other users.
App administrator simulates system messages: The app administrator can simulate sending system messages from the backend. These simulated messages are notifications delivered to users, and custom messages from the app administrator received by the app will be specially handled.
Instant Messaging (Chat) provides comprehensive C2C messaging capabilities. At the same time, the permission control and extension capabilities of C2C messaging provide features such as getting message history, multi-device synchronization, offline message push, and carrying sender profiles in messages.
C2C Message Types
Message Type
Description
Text message
The message content is plain text.
Emoji message
Emoji messages are customized by developers.
Location message
The message content includes the caption, longitude, and latitude of the location.
Image message
The message content includes the URL, dimensions, and size of the image. The maximum supported image file size is 28 MB.
Voice message
The message content includes the URL, size, and duration of the voice. The maximum supported voice file size is 28 MB.
File message
The message content includes the URL, size, and format of the file. All file formats are allowed, and the maximum supported file size is 100 MB.
Short video message
The message content includes the URL, duration, size, and format of the short video. The maximum supported short-video file size is 100 MB.
Custom message
Message types that are customized by developers, such as red packet and rock-paper-scissor.
System notification message
This type of messages is divided into built-in system notification messages and system notification messages customized by developers.
C2C Messaging Capabilities
C2C Messaging Capability
Description
Use Cases
Send C2C messages
C2C messages can be sent through the SDK or RESTful API.
C2C chat on the app.
App administrator sends messages.
App administrator sends system messages.
Receive C2C messages
C2C messages can be received through the SDK.
Receive online messages.
Receive offline messages.
Query historical messages.
C2C Messaging Permission Control
C2C Messaging Permission Control
Description
Use Cases
Two app users can send C2C messages.
Any two strangers can send C2C messages to each other.
Strangers send C2C messages to each other.
App administrator sends C2C messages.
App administrator can send C2C messages to any user.
App administrator impersonates other users to send messages.
App administrator sends system messages.
Only friends are allowed to send C2C messages to each other.
Only friends can send C2C messages to each other.
Friends send C2C messages to each other.
Block messages from someone.
You can add a user to the blocklist to block their messages.
Unfriend someone.
Block messages from someone.
C2C Messaging Extension Capabilities
C2C Messaging Extension Capability
Description
Use Cases
Obtain history messages
Historical messages can be obtained through the SDK or RESTful API.
Obtain real-time chat history.
Download message history on a regular basis.
Multi-device synchronization
C2C messages can be synchronized across devices.
Users synchronize messages across clients.
Offline push of C2C messages
Support offline message push on Apple, Huawei, Xiaomi, OPPO, vivo, and Meizu mobile phones.
Push messages offline.
C2C messages carry sender profiles
Sender profiles can be carried by messages.
Display sender information such as the nickname and profile photo.
Processing of Offline C2C Messages
Offline cache and roaming of C2C messages:
1. User A calls sendMessage to send messages to user B who is offline.
User A is added to user B’s recent contacts, with up to 100 messages cached.
Messages are stored in the offline cache for 7 days.
Messages are stored on the roaming server for 7 days.
2. User B calls the login API to log in to Chat.
3. The SDK automatically pulls messages from the offline cache and delivers via the OnNewMessage callback.
4. The SDK automatically pulls recent contacts and delivers via the OnNewMessage callback.
5. The user is notified via the OnRefresh callback when message synchronization is completed.
6. The user calls getMessage. If local messages are incomplete, the SDK automatically pulls them from the roaming server.
