AMQP/RabbitMQ数据丢失的问题

stackoverflow --- RabbitMQ lose message before consumer reconnect

情景：

• 普通订阅模式很容易造成message lose，特别是Client断开网络，服务器连续发送message，Client再次连接网络，消息就会lose；

 [_queue subscribe:^(RMQMessage * _Nonnull message) {
        NSString *msg  = [[NSString alloc] initWithData:message.body encoding:NSUTF8StringEncoding];
        NSLog(@"Received %@", msg);
    }];

解决方案：
官网案例二 - OC版

• 订阅模式需要采取ack模式，才能告诉服务器我准确接收到了消息；

RMQBasicConsumeOptions manualAck = RMQBasicConsumeNoOptions;
    [_queue subscribe:manualAck handler:^(RMQMessage * _Nonnull message) {
        NSString *messageText = [[NSString alloc] initWithData:message.body encoding:NSUTF8StringEncoding];
        NSLog(@"Received %@", messageText);
        
        [_channel ack:message.deliveryTag];
    }];