对于刚接触IM（即时通讯）开发，通过阅读成熟的商业代码能够对即时通讯软件大体上有个认识，比如消息发送，消息接受，消息监听，群聊，单聊，聊天室。我这边直接拿[Gobelieve IM] 源码来做剖析。IMService在代码层级里起着承上启下的作用，负责发送消息，接受消息（聊天消息，系统消息，控制命令消息（比如邀请VOIP，退群，加群）），消息在客户端转发，消息类型判断和分发，消息observer的增加和删除，IMService本身会根据业务需求实现handlers对接到数据传输层（socket）。Observers是衔接IMService和UI层。如果只侧重于UI层开发，重点是Observers，比如PeerMessageObserver是一对一聊天监听，GroupMessageObserver:群聊天监听，RoomMessageObserver:聊天室监听。
下面直接上接口代码来说，
@class IMessage;
IMessage 模型类的前置声明
@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
一对一聊天的hanlder定义，IM有一个ACK的设计，用来显示消息是否已经通过服务器下发到对方客户端。具体的函数，handleMessage()接收到消息的处理函数。handleMessageACK()接收到消息已读的处理函数。 handleMessageFailure()接收到消息发送失败的处理函数。
@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定义，接口上比单聊多一个群状态改变的处理，还有就是单聊下发的是个人ID，群聊下发的是群聊ID，同样的函数，handleMessage()接收到消息的处理函数。handleMessageACK()接收到消息已读的处理函数。 handleMessageFailure()接收到消息发送失败的处理函数。handleGroupNotification(),处理群状态改变的函数，比如群名称改变，群成员改变，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定义。
@protocol LoginPointObserver <NSObject> //用户在其他地方登陆 -(void)onLoginPoint:(LoginPoint*)lp; @end
多端登录事件监听。
@protocol PeerMessageObserver <NSObject> @optional -(void)onPeerMessage:(IMMessage*)msg; //服务器ack -(void)onPeerMessageACK:(int)msgLocalID uid:(int64_t)uid; //消息发送失败 -(void)onPeerMessageFailure:(int)msgLocalID uid:(int64_t)uid; //对方正在输入 -(void)onPeerInputing:(int64_t)uid; @end
一对一聊天的Observer的定义，提供了对输入状态监听的接口，用来实现，实时获取对方是否在编辑消息。
@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的定义。
@protocol RoomMessageObserver <NSObject> @optional -(void)onRoomMessage:(RoomMessage*)rm; -(void)onRoomMessageACK:(RoomMessage*)rm; -(void)onRoomMessageFailure:(RoomMessage*)rm; @end
聊天室消息Observer的定义。
@protocol RTMessageObserver <NSObject> @optional -(void)onRTMessage:(RTMessage*)rt; @end @protocol SystemMessageObserver <NSObject> @optional -(void)onSystemMessage:(NSString*)sm; @end
系统消息的Observer的定义。
@protocol CustomerMessageObserver <NSObject> @optional -(void)onCustomerMessage:(CustomerMessage*)msg; -(void)onCustomerSupportMessage:(CustomerMessage*)msg; //服务器ack -(void)onCustomerMessageACK:(CustomerMessage*)msg; //消息发送失败 -(void)onCustomerMessageFailure:(CustomerMessage*)msg; @end
客服消息的Observer的定义。
@protocol VOIPObserver <NSObject> -(void)onVOIPControl:(VOIPControl*)ctl; @end
支持整合VOIP功能的Observer的定义。
@interface IMService : TCPConnection
@property(nonatomic, copy) NSString *deviceID;
@property(nonatomic, copy) NSString *token;
@property(nonatomic) int64_t uid;
//客服app需要设置，普通app不需要设置
@property(nonatomic) int64_t appID;
@property(nonatomic, weak)id<IMPeerMessageHandler> peerMessageHandler;//一对一聊天Handler
@property(nonatomic, weak)id<IMGroupMessageHandler> groupMessageHandler;//群聊handler
@property(nonatomic, weak)id<IMCustomerMessageHandler> customerMessageHandler;//客服handler
当前的IMService实现了三个（一对一聊天，群聊，客服）handler，可以按自己需要增加新的handler类型。消息统一在IMService做转发。
根据注册的Observer，传递到对该消息类型感兴趣的界面。
+(IMService*)instance;//IMService是单例的形式使用
-(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;
//顾客->客服
-(BOOL)sendCustomerMessage:(CustomerMessage*)im;
//客服->顾客
-(BOOL)sendCustomerSupportMessage:(CustomerMessage*)im;
-(BOOL)sendRTMessage:(RTMessage*)msg;
-(void)enterRoom:(int64_t)roomID;
-(void)leaveRoom:(int64_t)roomID;
//正在输入
-(void)sendInputing:(MessageInputing*)inputing;
//更新未读的消息数目
-(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，慢慢补充，完整的代码和DEMO可以到[Gobelieve IM]查看。