The recent session list is maintained by SDK and SDK provides the interface for querying and monitoring changes. As long as there is any chat with a user or team (you send or receive messages), SDK will automatically update the recent session list and notify the top-level module, and the developer does not need to manually update the session list.

Recent session SessionData is also called session list or recent contact list, which contains the contact information of recent sessions, including contact account, contact type, time of the latest message, message status, message content, number of unread messages, etc.

SessionDataKey parameters:

Parameter Type	SessionInfo field	Description
String	id_	ID of recent contact (friend ID, team ID, etc.)
NIMSessionType	type_	Session type (team session, p2p message)
int	unread_count_	Unread count of the current session
NIMSessionCommand	command_	Change operation type of the current session (add, update, delete, etc., see NIMSessionCommand for details.
string	msg_id_	The unique ID of the latest message in the current session
string	msg_sender_accid_	Sender ID of the latest message in the current session
int64_t	msg_timetag_	Timestamp of the latest message in the current session (milliseconds)
NIMMessageType	msg_type_	Type of the latest message (including text, image, video, audio, etc. See NIMMessageType for details
string	msg_content_	Content of the latest message in the current session
string	msg_attach_	Attachment content of the latest message in the current session
NIMMsgLogStatus	msg_status_	Status of the latest message in the current session (read, unread, etc., see Message status for details.
NIMMsgLogSubStatus	msg_sub_status_	Sub-status of the latest message in the current session (played, unplayed, etc., see Message sub-status for details.
bool	last_updated_msg_	In batch message notification, specifies whether the message is the most recent one in the notifications when the message is added or updated
bool	placed_on_top_	Whether to pin the session (not supported now)
bool	is_robot_session_	Whether it is a robot message (not supported now)
string	extend_data_	Local extension field, limited to 4096 in length (not supported now)

NIMSessionTypeEnumeration value description:

Enumeration	Value	Description
kNIMSessionTypeP2P	0	Individual session, i.e. p2p session
kNIMSessionTypeTeam	1	Team session

NIMSessionCommandEnumeration value description:

Enumeration	Value	Description
kNIMSessionCommandAdd	0	Add session items
kNIMSessionCommandRemove	1	Delete a single session item
kNIMSessionCommandRemoveAll	2	Delete all session items
kNIMSessionCommandRemoveAllP2P	3	Delete all p2p session items
kNIMSessionCommandRemoveAllTeam	4	Delete all team session items
kNIMSessionCommandMsgDeleted	5	Delete messages of a single session item
kNIMSessionCommandAllMsgDeleted	6	Delete messages of all session items
kNIMSessionCommandAllP2PMsgDeleted	7	Delete messages of all p2p session items
kNIMSessionCommandAllTeamMsgDeleted	8	Delete messages of all team session items
kNIMSessionCommandUpdate	9	Update session item

Note: Recent session is a local session with no roaming. Roaming is related to messages, not to recent sessions. In the latest version, when multiple terminals log in at the same time and the Set the unread count zero interface is called, the same session will be set to 0 on other terminals as well.

Get Recent Session List

• API introduction

Get recent session list.

• API prototype

static void QueryAllRecentSessionAsync(const QuerySessionListCallabck& cb, const std::string& json_extension = "");

• Parameter Description

Parameter	Description
cb	Asynchronous callback function for notification query results
json_extension	Reserved field

• Example

nim::Session::QueryAllRecentSessionAsync((([&](int total_unread_count, const SessionDataList& sessions)
{
    for (auto session : sessions.sessions_)
    {
        ...
    }
});

Track the Change of Recent Session

• API introduction

While you are sending and receiving messages, SDK will update the contact information of the other party in the chat. When a message is sent or received, SDK will send out a notification regarding the latest contact update, and you can monitor the session item change by registering the event.

• API prototype

static void RegChangeCb(const ChangeCallback& cb, const std::string& json_extension = "");

CallbackChangeCallbackresponse parameters:

Type	Parameter	Description
NIMResCode	code	Error code (seeNIMResCodefor details)
SessionData	session	Session information, see SessionData for details
int	total_unread_counts	Sum of unread counts in all sessions

• Example

//Monitor event notification
nim::Session::RegChangeCb([&](NIMResCode code, const SessionData& session, int total_unread_counts)
{
    ...
});

//If it is no longer needed, cancel monitoring of the event
nim::Session::RegChangeCb(nullptr);

Set Unread Count Zero

• API introduction

To set the unread count zero in the current session, call the SetUnreadCountZerointerface to do the configuration, in earlier versions, after calling the SetUnreadCountZerointerface, you also need to call the MarkMessagesStatusReadinterface to configure the read status of the message database.

• API prototype

static bool SetUnreadCountZeroAsync(nim::NIMSessionType to_type, const std::string& id, const SetUnreadCountZeroCallback& cb, const std::string& json_extension = "");

• Parameter Description

Parameter	Description
to_type	Session type, see NIMSessionType for details
id	Session ID (receiver account or team ID)
cb	Asynchronous notification callback
json_extension	Reserved extension field

• Example

//Specify the session type and session ID for setting to read.

NIMSessionType sessionType = kNIMSessionTypeP2P;
std:string sessionId = "test1";

//Set the unread count of the session zero.
nim::Session::SetUnreadCountZeroAsync(sessionType, sessionId, [&](NIMResCode code, const SessionData& session, int total_unread_counts)
{
    ...
});

//In the latest version, you no longer need to call the nim::Msglog::BatchStatusReadAsync interface
//In earlier versions, you still need to call the interface as follows.
nim::Msglog::BatchStatusReadAsync(sessionId, sessionType, [&]((nim::NIMResCode res_code, const std::string& uid, nim::NIMSessionType to_type)
{
    ···
});

Delete Specified Recent Contact

Sessions will be deleted from the server and local database when deleting sessions

• API prototype

static bool DeleteRecentSession(nim::NIMSessionType to_type, const std::string& id, const DeleteRecentSessionCallabck& cb, const std::string& json_extension = "");

• Parameter Description

Parameter	Description
to_type	Session type
id	ID of recent contact (friend ID, team ID, etc.)
cb	Callback function of current operation
json_extension	Reserved extension field

• Example

NIMSessionType toType = kNIMSessionTypeP2P; //Personal session
std::string id = "test_account";//session ID
nim::Session::DeleteRecentSession(toType, ID, [&](NIMResCode code, const SessionData& session, int total_unread_counts)
{
    ...
});

Delete All Recent Contacts

• API introduction

Delete all session list items without setting the message database to read status. If you need to update the read status of the message database at the same time, please use the interface ofdelete all history.

• API prototype

static void DeleteAllRecentSession(const DeleteAllRecentSessionCallabck& cb, const std::string& json_extension = "");

• Parameter Description

Parameter	Description
cb	Callback function of current operation
json_extension	Reserved extension field

• Example

nim::Session::DeleteAllRecentSession([&](NIMResCode code, const SessionData& session, int total_unread_counts)
{
    ...
});