解决承诺后如何发送“结束”消息？有时我可以发送 4 条中的 2 条“结束”消息，有时是 3 条。正在下载来自 FTP 的文件，这没问题。唯一不起作用的是在下载文件后发送“结束”消息。你知道为什么这段代码不能正常工作吗？
此代码已更新：
const ftp = require("jsftp");
const fs = require("fs");
const net = require("net");
const mkdirp = require("mkdirp");
class ftpCredentials {
constructor(host) {
this.user = "xxx";
this.pass = "xxx";
this.host = host;
}
}
const downloadFromFTP = (credentials, file) => {
const client = new ftpCredentials(credentials.host);
const ftpClient = new ftp(client);
return new Promise((res, rej) => {
let buf = null;
ftpClient.get(file, (err, stream) => {
if (!err && typeof stream !== "undefined") {
// Events
stream.on("data", (data) => {
if (buf === null) buf = new Buffer(data);
else buf = Buffer.concat([buf, data]);
});
stream.on("close", (err) => {
if (err) rej("FILE_ERROR");
const actualPath = `${credentials.path}/${file}`;
fs.writeFile(actualPath, buf, "binary", (err) => {
if (err) rej(err);
ftpClient.raw("quit", (err, data) => {
if (err) rej(err)
res(file);
});
});
});
// Resume stream
stream.resume();
} else {
rej("STREAM_ERROR");
}
});
})
}
const handleSavingFile = (credentials, filesOnFTP) => {
mkdirp(credentials.path, () => {
fs.readdir(credentials.path, (err, fileNames) => {
if (err) return err;
const needToConnectToFTP = filesOnFTP.filter(name => fileNames.indexOf(name) !== -1).length === 0;
const socketForEndMsg = net.createConnection(18005, credentials.host, () => {
Promise.all(filesOnFTP.map((file) => {
return new Promise((resolve, reject) => {
// The problem is here:
const socketWrite = socketForEndMsg.write(`End|ftp://${credentials.host}/${file}`, "UTF16LE");
resolve(socketWrite);
// Events
socketForEndMsg.on("error", () => {
console.log("Problem with sending End message!");
reject();
});
});
})).then(() => {
socketForEndMsg.end();
}).catch((err) => {
console.log(err);
});
});
})
})
}
const getScheme = (credentials) => {
const socketForData = net.createConnection(18005, credentials.host, () => socketForData.write("Scheme", "UTF16LE"));
// Events
socketForData.on("close", () => console.log("TCP Connection closed"));
socketForData.on("error", err => console.log(err));
socketForData.on("data", (data) => {
socketForData.end();
const toUTF16Format = Buffer.from(data).toString("UTF16LE");
const arrayFromTCPMessage = toUTF16Format.split(/\||;/);
const filteredImages = arrayFromTCPMessage.filter(item => item.startsWith("scheme"))
const isOK = arrayFromTCPMessage[0] === "OK";
if (isOK) {
handleSavingFile(credentials, filteredImages);
}
})
}
module.exports = getScheme;Error message: Error: This socket is closed
at Socket._writeGeneric (net.js:722:18)
at Socket._write (net.js:782:8)
at doWrite (_stream_writable.js:407:12)
at writeOrBuffer (_stream_writable.js:393:5)
at Socket.Writable.write (_stream_writable.js:290:11)
at Promise (xxx\getScheme.js:56:29)
at new Promise (<anonymous>)
at Promise.all.filesOnFTP.map (xxx\getScheme.js:54:18)
at Array.map (<anonymous>)
at Socket.net.createConnection (xxx\getScheme.js:52:32)
我明白了，你喜欢听error事件，这让你Promise用来捕捉错误。但是，error事件处理程序注册的位置是错误的，因为它在.map函数调用内部。因此，error事件将被注册filesOnFTP长度的次数。
我已将该错误处理程序移至下一行并使用writable标志查看套接字在写入之前是否仍可写。我还添加了更多事件处理程序，它们将为您提供有关套接字状态的更多信息（用于调试，您可以稍后删除它们）。
const handleSavingFile = (credentials, filesOnFTP) => {
mkdirp(credentials.path, () => {
fs.readdir(credentials.path, (err, fileNames) => {
if (err) return err;
const needToConnectToFTP = filesOnFTP.filter(name => fileNames.indexOf(name) !== -1).length === 0;
const socketForEndMsg = net.createConnection(18005, credentials.host, () => {
for(let file of filesOnFTP) {
// Before write to socket, check if it is writable still!
if(socketForEndMsg.writable) {
socketForEndMsg.write(`End|ftp://${credentials.host}/${file}`, "UTF16LE");
}
else {
console.log('Socket is not writable! May be closed already?');
}
}
});
// This is the correct place for the error handler!
socketForEndMsg.on("error", (error) => {
console.log("Problem with sending End message!", error);
});
socketForEndMsg.on("close", () => {
console.log("Socket is fully closed!");
});
socketForEndMsg.on("end", () => {
console.log("The other end of the socket has sent FIN packet!");
});
});
});
}
让我知道这个是否奏效！
谢谢！
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我来说两句