商業化IM 客戶端接口設計分析

　　對于剛接觸IM（即時通訊）開發，通過閱讀成熟的商業代碼能夠對即時通訊軟件大體上有個認識，比如消息發送，消息接受，消息監聽，群聊，單聊，聊天室。我這邊直接拿[Gobelieve IM] 源碼來做剖析。IMService在代碼層級里起著承上啟下的作用，負責發送消息，接受消息（聊天消息，系統消息，控制命令消息（比如邀請VOIP，退群，加群）），消息在客戶端轉發，消息類型判斷和分發，消息observer的增加和刪除，IMService本身會根據業務需求實現handlers對接到數據傳輸層（socket）。Observers是銜接IMService和UI層。如果只側重于UI層開發，重點是Observers，比如PeerMessageObserver是一對一聊天監聽，GroupMessageObserver:群聊天監聽，RoomMessageObserver:聊天室監聽。

@class IMessage;

　　IMessage 模型類的前置聲明

@protocol IMPeerMessageHandler <NSObject>
-(BOOL)handleMessage:(IMMessage*)msg uid:(int64_t)uid;
-(BOOL)handleMessageACK:(int)msgLocalID uid:(int64_t)uid;
-(BOOL)handleMessageFailure:(int)msgLocalID uid:(int64_t)uid;
@end

    一對一聊天的hanlder定義，IM有一個ACK的設計，用來顯示消息是否已經通過服務器下發到對方客戶端。具體的函數，handleMessage()接收到消息的處理函數。handleMessageACK()接收到消息已讀的處理函數。 handleMessageFailure()接收到消息發送失敗的處理函數。 

@protocol IMGroupMessageHandler <NSObject>

-(BOOL)handleMessage:(IMMessage*)msg;
-(BOOL)handleMessageACK:(int)msgLocalID gid:(int64_t)gid;
-(BOOL)handleMessageFailure:(int)msgLocalID gid:(int64_t)gid;

-(BOOL)handleGroupNotification:(NSString*)notification;
@end

     群聊天的hanlder定義，接口上比單聊多一個群狀態改變的處理，還有就是單聊下發的是個人ID，群聊下發的是群聊ID，同樣的函數，handleMessage()接收到消息的處理函數。handleMessageACK()接收到消息已讀的處理函數。 handleMessageFailure()接收到消息發送失敗的處理函數。handleGroupNotification(),處理群狀態改變的函數，比如群名稱改變，群成員改變，群解散等等事件。 

@protocol IMCustomerMessageHandler <NSObject>
-(BOOL)handleCustomerSupportMessage:(CustomerMessage*)msg;
-(BOOL)handleMessage:(CustomerMessage*)msg;
-(BOOL)handleMessageACK:(CustomerMessage*)msg;
-(BOOL)handleMessageFailure:(CustomerMessage*)msg;
@end

　　客服聊天的handler定義。 

@protocol LoginPointObserver <NSObject>
//用戶在其他地方登陸
-(void)onLoginPoint:(LoginPoint*)lp;
@end

　　多端登錄事件監聽。 

@protocol PeerMessageObserver <NSObject>
@optional
-(void)onPeerMessage:(IMMessage*)msg;

//服務器ack
-(void)onPeerMessageACK:(int)msgLocalID uid:(int64_t)uid;

//消息發送失敗
-(void)onPeerMessageFailure:(int)msgLocalID uid:(int64_t)uid;

//對方正在輸入
-(void)onPeerInputing:(int64_t)uid;

@end

　　一對一聊天的Observer的定義，提供了對輸入狀態監聽的接口，用來實現，實時獲取對方是否在編輯消息。 

@protocol GroupMessageObserver <NSObject>
@optional
-(void)onGroupMessage:(IMMessage*)msg;
-(void)onGroupMessageACK:(int)msgLocalID gid:(int64_t)gid;
-(void)onGroupMessageFailure:(int)msgLocalID gid:(int64_t)gid;

-(void)onGroupNotification:(NSString*)notification;
@end

　　群聊天的Observer的定義。 

@protocol RoomMessageObserver <NSObject>
@optional
-(void)onRoomMessage:(RoomMessage*)rm;
-(void)onRoomMessageACK:(RoomMessage*)rm;
-(void)onRoomMessageFailure:(RoomMessage*)rm;

@end

　　聊天室消息Observer的定義。 

@protocol RTMessageObserver <NSObject>

@optional
-(void)onRTMessage:(RTMessage*)rt;

@end

@protocol SystemMessageObserver <NSObject>
@optional
-(void)onSystemMessage:(NSString*)sm;

@end

　　系統消息的Observer的定義。 

@protocol CustomerMessageObserver <NSObject>
@optional
-(void)onCustomerMessage:(CustomerMessage*)msg;
-(void)onCustomerSupportMessage:(CustomerMessage*)msg;

//服務器ack
-(void)onCustomerMessageACK:(CustomerMessage*)msg;
//消息發送失敗
-(void)onCustomerMessageFailure:(CustomerMessage*)msg;
@end

　　客服消息的Observer的定義。 

@protocol VOIPObserver <NSObject>

-(void)onVOIPControl:(VOIPControl*)ctl;

@end

　　支持整合VOIP功能的Observer的定義。 

@interface IMService : TCPConnection
@property(nonatomic, copy) NSString *deviceID;
@property(nonatomic, copy) NSString *token;
@property(nonatomic) int64_t uid;
//客服app需要設置，普通app不需要設置
@property(nonatomic) int64_t appID;

@property(nonatomic, weak)id<IMPeerMessageHandler> peerMessageHandler;//一對一聊天Handler
@property(nonatomic, weak)id<IMGroupMessageHandler> groupMessageHandler;//群聊handler
@property(nonatomic, weak)id<IMCustomerMessageHandler> customerMessageHandler;//客服handler

當前的IMService實現了三個（一對一聊天，群聊，客服）handler，可以按自己需要增加新的handler類型。消息統一在IMService做轉發。
根據注冊的Observer，傳遞到對該消息類型感興趣的界面。

+(IMService*)instance;//IMService是單例的形式使用

-(BOOL)isPeerMessageSending:(int64_t)peer id:(int)msgLocalID;
-(BOOL)isGroupMessageSending:(int64_t)groupID id:(int)msgLocalID;
-(BOOL)isCustomerSupportMessageSending:(int)msgLocalID
                            customerID:(int64_t)customerID
                         customerAppID:(int64_t)customerAppID;
-(BOOL)isCustomerMessageSending:(int)msgLocalID storeID:(int64_t)storeID;

-(BOOL)sendPeerMessage:(IMMessage*)msg;
-(BOOL)sendGroupMessage:(IMMessage*)msg;
-(BOOL)sendRoomMessage:(RoomMessage*)msg;
//顧客->客服
-(BOOL)sendCustomerMessage:(CustomerMessage*)im;
//客服->顧客
-(BOOL)sendCustomerSupportMessage:(CustomerMessage*)im;
-(BOOL)sendRTMessage:(RTMessage*)msg;

-(void)enterRoom:(int64_t)roomID;
-(void)leaveRoom:(int64_t)roomID;

//正在輸入
-(void)sendInputing:(MessageInputing*)inputing;
//更新未讀的消息數目
-(void)sendUnreadCount:(int)unread;

-(void)addPeerMessageObserver:(id<PeerMessageObserver>)ob;
-(void)removePeerMessageObserver:(id<PeerMessageObserver>)ob;

-(void)addGroupMessageObserver:(id<GroupMessageObserver>)ob;
-(void)removeGroupMessageObserver:(id<GroupMessageObserver>)ob;

-(void)addLoginPointObserver:(id<LoginPointObserver>)ob;
-(void)removeLoginPointObserver:(id<LoginPointObserver>)ob;

-(void)addRoomMessageObserver:(id<RoomMessageObserver>)ob;
-(void)removeRoomMessageObserver:(id<RoomMessageObserver>)ob;

-(void)addSystemMessageObserver:(id<SystemMessageObserver>)ob;
-(void)removeSystemMessageObserver:(id<SystemMessageObserver>)ob;

-(void)addCustomerMessageObserver:(id<CustomerMessageObserver>)ob;
-(void)removeCustomerMessageObserver:(id<CustomerMessageObserver>)ob;

-(void)addRTMessageObserver:(id<RTMessageObserver>)ob;
-(void)removeRTMessageObserver:(id<RTMessageObserver>)ob;
    
-(void)pushVOIPObserver:(id<VOIPObserver>)ob;
-(void)popVOIPObserver:(id<VOIPObserver>)ob;

-(BOOL)sendVOIPControl:(VOIPControl*)ctl;

@end

　　坑下挖好，慢慢補充，完整的代碼和DEMO可以到[Gobelieve IM]查看。

[1]: http://developer.gobelieve.io/