JS: Node.js File System Module
Add File System Module:
var fs = require('fs');
Read File
s.readFile()
Example:
fs.readFile('demofile1.html', function(err, data) {
res.writeHead(200, {'Content-Type': 'text/html'});
res.write(data);
res.end();
});
Create Files
fs.appendFile()
The fs.appendFile() method appends specified content at the end of a file. If the file does not exist, the file will be created:
Example:
var fs = require('fs');
fs.appendFile('mynewfile1.txt', 'Hello content!', function (err) {
if (err) throw err;
console.log('Saved!');
});
fs.open()
The fs.open() method takes a “flag” as the second argument, if the flag is “w” for “writing”, the specified file is opened for writing. If the file does not exist, an empty file is created:
Example:
var fs = require('fs');
fs.open('mynewfile2.txt', 'w', function (err, file) {
if (err) throw err;
console.log('Saved!');
});
fs.writeFile()
The fs.writeFile() method replaces the specified file and content if it exists. If the file does not exist, a new file, containing the specified content, will be created:
Example:
var fs = require('fs');
fs.writeFile('mynewfile3.txt', 'Hello content!', function (err) {
if (err) throw err;
console.log('Saved!');
});
Update Files
fs.appendFile()
fs.writeFile()
Delete Files
fs.unlink()
Example:
var fs = require('fs');
fs.unlink('mynewfile2.txt', function (err) {
if (err) throw err;
console.log('File deleted!');
});
Rename Files
fs.rename()
var fs = require('fs');
fs.rename('mynewfile1.txt', 'myrenamedfile.txt', function (err) {
if (err) throw err;
console.log('File Renamed!');
});
Upload Files
var formidable = require(‘formidable’);
Exapmle:
var http = require('http');
var formidable = require('formidable');
var fs = require('fs');
http.createServer(function (req, res) {
if (req.url == '/fileupload') {
//upload file
var form = new formidable.IncomingForm();
form.parse(req, function (err, fields, files) {
var oldpath = files.filetoupload.path;
var newpath = 'C:/Users/Your Name/' + files.filetoupload.name;
//move file to current folder
fs.rename(oldpath, newpath, function (err) {
if (err) throw err;
//file palce on a temppory folder if without fs.rename()
res.write('File uploaded and moved!');
res.end();
});
});
} else {
//create upload form
res.writeHead(200, {'Content-Type': 'text/html'});
res.write('<form action="fileupload" method="post" enctype="multipart/form-data">');
res.write('<input type="file" name="filetoupload"><br>');
res.write('<input type="submit">');
res.write('</form>');
return res.end();
}
}).listen(8080);