CODEWITHSUNDEEP
node.jsfilestream
君之蘭
君之蘭

Reputation: 138

how to write a chunk data to a file

When client posts a chunk data(part of file), then server side should insert the chunk to file. But fs.open will truncate the file. So I cant use empty fd to write. Now this is what I am using it reads all buffer and changes the chunk range value in the buffer.

    //badly code
fs.open(getFilePath(fileId),"r+",function(err,fd){
    var bytes = new Buffer(metadata.fileSize);
    fs.read(fd,bytes,0,bytes.length,0,function(){
        for(var i=0;i<bytes.length;i++){
            if(i>=start && i <= end){
                bytes[i] = buffer[i-start];
            }
        }
        //console.log(bytes);
        fs.write(fd,bytes,0,bytes.length,0,function(err){
            if(err) throw err;

            fs.close(fd,function(){
                metadata.addChunk(start,end);
                metadata.save(callback);
            });
        });
    });
});

Is there a better method to do this? Please tell me,thank you very much.

Upvotes: 2

Views: 8997

Answers (2)

xhallix
xhallix

Reputation: 3011

I know this question might be a bit outdated but I faced the same problem, while trying to get source code to a file To solve this I did not use write file but append, for example:

  res.on('data', function (chunk) {
      fs.appendFile('body.txt', chunk, function (err) {
          if(err) throw err;
      });

This worked pretty fine for me

Upvotes: 5

generalhenry
generalhenry

Reputation: 17319

Sounds like you want to append http requests to a file.

Open an appending write stream.

var writeStream = fs.createWriteStream(path, {flags: 'a'});

Then in your http handler

function (req, res) {
  req.pipe(writeStream, {end: false});
  req.on('end', function () {
    res.end('chunk received');
  });
};

Upvotes: 3

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