In-app Chat(Flutter) Offline login

Function introduction

Offline login is typically used when the application is cleared from memory, and the user relaunches the application by clicking on the application icon. In this scenario, the user can directly access the local SDK data without network connectivity or a successful login.

Note

Users can only perform an offline login using the UserID from their previous successful login; otherwise, the login will not succeed.

Technical principle

When the offline login interface is called, the ZIM SDK performs verification (UserID verification; if token-based login is used, it also verifies the token's validity period). After successful verification, the SDK returns a login success callback, allowing users to query local data, while the SDK internally attempts to establish a connection with the backend service automatically.

Implementation Steps

In the case of no network and the app being cleared, you can call the login interface with the isOfflineLogin parameter set to true in ZIMLoginConfig to achieve offline login using the user information from the last login. After successful login, you can access the local SDK data.

Note

We recommend caching the user information used for each login. When the app is opened, read the cache and implement the following logic:

If it is determined that the user did not use the UserID from the last online login, the isOfflineLogin should be false. In this case, offline login will fail and the user will not be allowed to access the local SDK data for that UserID.
If the user uses the UserID from the last online login, in order to achieve automatic login, speed up entering the app's main page, and pre-render the UI, the isOfflineLogin should be true to achieve offline login.

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// This Login interface is the new login interface. The original login interface has been deprecated since version 2.13.0 and is no longer maintained.
  Future<void> login(String userID,ZIMLoginConfig config);

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Parameter	Type	Required	Description
userID	String	Yes	The user ID for the previous online login. It can contain up to 32 bytes in length, including digits, letters, and the following characters: '!', '#', '$', '%', '&', '(', ')', '+', '-', ':', ';', '< ', '= ', '. ', '> ', '?', '@', '[', ']', '^', '_', '{','}' '\|', '~'.
config	ZIMLoginConfig	Yes	Login configuration.

The parameter config needs to be configured using the following parameters of the ZIMLoginConfig class:

Parameter	Type	Required	Description
userName	String	No	User name. A string with a maximum of 256 bytes. If empty, it will be the UserName set during the last login.
token	String	No	Token. When using Token authentication, this parameter is required. When using AppSign authentication, this parameter is not required.
isOfflineLogin	bool	No	Whether this login is an offline login. If empty, it will be an online login.

Example

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ZIMLoginConfig loginConfig = ZIMLoginConfig();
loginConfig.userName = 'username';
// This parameter is not required when using AppSign authentication
loginConfig.token = 'token';
// Whether it is an offline login
login.isOfflineLogin = true;

try {
    await ZIM.getInstance()!.login('zego', loginConfig);
    // Login successful
} on PlatformException catch (onError) {
    // Login failed
}

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2 Accessing Local SDK Data

After a successful offline login, users can perform the following operations when offline (as of version 2.12):

Category	Interface
User-related	queryUsersInfo
Group-related	queryGroupList searchLocalGroups queryGroupInfo queryGroupAttributes queryGroupAllAttributes queryGroupMemberList searchLocalGroupMembers queryGroupMemberInfo queryGroupMemberCount queryGroupMessageReceiptReadMemberList queryGroupMessageReceiptUnreadMemberList
Message-related	queryHistoryMessage updateMessageLocalExtendedData searchLocalMessages searchGlobalLocalMessages insertMessageToLocalDB deleteAllMessage: Only supports deleting messages in the local database. deleteMessages: Only supports deleting messages in the local database. queryMessageReceiptsInfo queryMessageReactionUserList
Call Invitation-related	queryCallInvitationList
Conversation-related	queryConversation queryConversationList queryConversationPinnedList searchLocalConversations clearConversationUnreadMessageCount clearConversationTotalUnreadMessageCount deleteConversation: Only supports deleting conversations in the local database. deleteAllConversations: Only supports deleting conversations in the local database.

3 Event Listening

Users can listen to the onConnectionStateChanged event notification to get the connection status between the SDK and the ZIM backend service.

When offline login is successful, onConnectionStateChanged returns ZIMConnectionState as Connecting (enum value 1).

When the user's network is restored and the ZIM SDK successfully connects to the ZIM backend service, onConnectionStateChanged returns ZIMConnectionState as Connected (enum value 2). Only then does the ZIM SDK allow calling interfaces that depend on a stable network connection and synchronizing backend data.

Offline login