| 126 | |
| 127 | // 订阅消息 |
| 128 | subscribe<T>(topic: string, handler: MessageHandler<T>) { |
| 129 | const fullTopic = `${this.name}${topic}`; |
| 130 | |
| 131 | if (this.middlewares.length === 0) { |
| 132 | // 没有中间件，直接订阅 |
| 133 | return this.messageQueue.subscribe(fullTopic, handler); |
| 134 | } else { |
| 135 | // 有中间件，需要包装处理函数 |
| 136 | const wrappedHandler = async (message: T) => { |
| 137 | let index = 0; |
| 138 | |
| 139 | const next = async (): Promise<void> => { |
| 140 | if (index < this.middlewares.length) { |
| 141 | const middleware = this.middlewares[index++]; |
| 142 | const result = middleware(fullTopic, message, next); |
| 143 | if (result instanceof Promise) { |
| 144 | await result; |
| 145 | } |
| 146 | } else { |
| 147 | // 所有中间件都执行完毕，执行最终的处理函数 |
| 148 | handler(message); |
| 149 | } |
| 150 | }; |
| 151 | |
| 152 | await next(); |
| 153 | }; |
| 154 | |
| 155 | return this.messageQueue.subscribe(fullTopic, wrappedHandler); |
| 156 | } |
| 157 | } |
| 158 | |
| 159 | // 发布消息 |
| 160 | publish<T>(topic: string, message: NonNullable<T>) { |