reading a file using node.js

Question

trying to read a file using node.js

    var fs = require('fs');
    fs.readFile("details.txt",'utf8',function(err,data)
    {
        if(err)
        {
            return console.log(err);
        }
        response.write(data);
    });

there is a file alredy with some text in the same directory.

Error im getting is :

response.write(data); ^ ReferenceError: data is not defined

I can't think of any reason why `err` would be false but `data` undefined. — Quentin, Apr 17 '16 at 14:10
./ refers to the working directory. Juat trying to ensure it is looking in the right place. — mcgraphix, Apr 17 '16 at 14:15
i changed the code to this var fs = require('fs'); fs.readFile("./details.txt",'',function(err,data) { if(!err) { return console.log(err); } response.writeHead(200, {"Content-Type":"text/html"}); response.write(data); }); now im getting a error in console "null" which is in the if statement — Asanka, Apr 17 '16 at 14:36

Michael Seltene · Accepted Answer · 2016-04-17T15:13:18.287

File order

Above img shows my File order. Note: I'm using IntelliJ IDEA. You will have to find the file "details.txt" in your system.

//Instead of using hard coded path, use: the following code to get the path in Node.js
//var path = require('path');
//console.log(path.join(__dirname, '../details.txt'));

//require file system
var fs = require('fs');

//read file
fs.readFile("details.txt",'utf8',function(err,data){

  //if error, log error and return
  if(err) { return console.error('Error: ' + err); }


  //check if there is data in the file
  if(data) {

     //EDITED to include line break
    //write response
    //response.write('<div style="color:green">' + data + '</div>');

    //write response with <br>
    response.write('<div style="color:green">' + data.split('\n').join('<br>') + '</div>');

    //end the response
    response.end();


  //if no data on the file, do the following
  }else{
    //error variable
    var error = "Error: file is empty: " + data.length + " bytes.";

    //log error
    // console.error(error);

    //write response
    response.write('<div style="color:red">' + error + '</div>');

    //end response
    response.end();
  }
});

Yes!!! It's worked. Thanks so much!!!! Any tips of retrieving the output line by line ? at the moment it is displaying all the details in one line. — Asanka, Apr 17 '16 at 14:58
@CJM You can use readLine function instead. http://stackoverflow.com/a/32599033/3359432 — Nidhin David, Apr 17 '16 at 15:05
Ok, I have edited the code for write data to. data.split('\n').join('
') — Michael Seltene, Apr 17 '16 at 15:13

Gary Stafford · Answer 2 · 2016-04-17T14:21:24.050

0

Try using the full path to 'details.txt' (i.e. '/etc/hosts'). And, send it to console.log just to confirm it works.

edited Apr 17 '16 at 14:21

answered Apr 17 '16 at 14:11

Gary Stafford

331
3
10

it is in the home directory where all the other files are server.js, router.js – Asanka Apr 17 '16 at 14:22
I can write into the file but only when im reading it gives me that error. – Asanka Apr 17 '16 at 14:23

score 0 · Answer 3 · answered Apr 17 '16 at 14:21

0

   var fs = require('fs');
    fs.readFile("details.txt",'utf8',function(err,data)
    {
        if(err)
        {
            return console.log(err);
        }
        console.log(data);
    });

the error is

response.write(data)

answered Apr 17 '16 at 14:21

Muhammad F. Musad

869
8
17

reading a file using node.js

3 Answers3