如何在寫入完成時關閉文件？

Question

我正在使用lame軟件包[1]將一些MP3數據寫入文件。數據在套接字上以原始音頻形式發送，並在接收到數據時寫入文件流，並且每寫入一個新文件10分鐘。我遇到的問題是，當這種情況持續很長時間時，由於文件未關閉，系統將耗盡文件句柄。類似這樣的：

var stream; 

var encoder = lame.Encoder({ 
    // Input 
    channels: 2, 
    bitDepth: 16, 
    sampleRate: 44100, 

    // Output 
    bitRate: 128, 
    outSampleRate: 22050, 
    mode: lame.STEREO // STEREO (default), JOINTSTEREO, DUALCHANNEL or MONO 
}); 

encoder.on('data', function(data) { 
    stream.write(data); 
}); 

var server = net.createServer(function(socket) { 
    socket.on('data', function(data) { 

    // There is some logic here that will based on time if it's 
    // time to create a new file. When creating a new file it uses 
    // the following code. 
    stream = fs.createWriteStream(filename); 

    // This will write data through the encoder into the file. 
    encoder.write(data); 

    // Can't close the file here since it might try to write after 
    // it's closed. 
    }); 
}); 

server.listen(port, host); 

但是，如何在最後一個數據塊寫入後關閉文件？從技術上講，可以打開一個新文件，而前一個文件仍然需要完成寫入最後一個文件。

這種情況下，我該如何正確關閉文件？

[1] https://www.npmjs.com/package/lame

Answer 1

您需要然後使用socket.io流，以解決您的業務流程數據作爲只讀流。

var ss = require('socket.io-stream'); 

//encoder.on('data', function(data) { 
// stream.write(data); 
//}); 

var server = net.createServer(function(socket) { 
    ss(socket).on('data', function(stream) { 

     // There is some logic here that will based on time if it's 
     // time to create a new file. When creating a new file it uses 
     // the following code. 
     stream.pipe(encoder).pipe(fs.createWriteStream(filename)) 
    }); 
}); 

Answer 2

關閉流（文件）的所有寫操作完成後：

stream.end(); 

見documetation：https://nodejs.org/api/stream.html

writable.end([chunk][, encoding][, callback])# 

    * chunk String | Buffer Optional data to write 
    * encoding String The encoding, if chunk is a String 
    * callback Function Optional callback for when the stream is finished 

Call this method when no more data will be written to the stream. If supplied, the 
callback is attached as a listener on the finish event.