NodeJS进程使用readline上传文件

Question

I'm getting a file the client uploads which I receive with the following route:

app.post('/upload', function(req, res){
    var file = req.files.file;

    //Process file inline
    funcs.Process(file, req).then((data)=>{
        //res.setHeader('Content-Length', stat.size);
        res.setHeader('Content-Type', 'text/plain');
        res.setHeader('Content-Disposition', 'attachment; filename=output.txt');
        res.write(data, 'binary');
        res.end();
    }).catch((err)=>{
        res.redirect('/?err='+err);
    });

});

This is the code for funcs.Process :

Process: function(file, req){


    return new Promise(function(resolve, reject){

        var lineReader = require('readline').createInterface({
            input: fs.createReadStream(file)
        });

        var output = "";

        lineReader.on('line', function (line) {
            //some checks
            ProcessLine(line).then((data)=>{
                output += data + "\n";
            }).catch((err)=>{
                reject(`Invalid line in file [${line}].`);
            });
        });

        lineReader.on('close', () => {
            resolve(output);
        });

    });

However, I am getting the following error:

TypeError: path must be a string or Buffer,

produced by the readline input: fs.createReadStream(file)

As this is an uploaded file, how do I use it in the readline createInterface ?

Answer 1

createReadStream accepts a string path.

You're passing it req.files.file , which is the file object created by express-fileupload .

You have two options:

1. Use the mv function ( req.files.file.mv('<path>', callbackFunc) ) to first move the file to a known path on your server. Then pass this known path to fs.createReadStream .

2. Create the read stream directly from the file data buffer exposed in req.files.file.data using streamifier or similar library.

var fileStream = require('streamifier').createReadStream(req.files.file.data)

This stream can then be passed to readline as input directly.