全局范围 createReadStream 不适用于回调

Question

const http = require("http");
const { createReadStream } = require("fs");
const stream = createReadStream("./big.txt", "utf-8");
const server = http.createServer((req, res) => {
console.log("hehehe");
//   const stream = createReadStream("./big.txt", "utf-8");
stream.on("open", () => {
console.log("hohoho");
stream.pipe(res);
});
});
server.listen(5000);

(代码结果)

hehehe

1. 如果const stream = createReadStream("./big.txt", "utf-8");是外部回调服务器连接不正常

2. 如果我把const stream = createReadStream("./big.txt", "utf-8");在回调，然后一切工作。

3. 似乎stream.pipe(res)做了res.end()做的事情。但我不明白pipe(res)是怎么做到的。

Answer 1

我刚刚也遇到了这个问题，我的猜测是因为在创建服务器之前已经打开了用于读取流的文件。因此，stream.on("open")的回调函数将永远不会被调用。