Node.js Filesystem I/O Check Permissions of a File or Directory
Example
fs.access() determines whether a path exists and what permissions a user has to the file or directory at that path. fs.access doesn't return a result rather, if it doesn't return an error, the path exists and the user has the desired permissions.
The permission modes are available as a property on the fs object, fs.constants
fs.constants.F_OK- Has read/write/execute permissions (If no mode is provided, this is the default)fs.constants.R_OK- Has read permissionsfs.constants.W_OK- Has write permissionsfs.constants.X_OK- Has execute permissions (Works the same asfs.constants.F_OKon Windows)
Asynchronously
var fs = require('fs');
var path = '/path/to/check';
// checks execute permission
fs.access(path, fs.constants.X_OK, (err) => {
if (err) {
console.log("%s doesn't exist", path);
} else {
console.log('can execute %s', path);
}
});
// Check if we have read/write permissions
// When specifying multiple permission modes
// each mode is separated by a pipe : `|`
fs.access(path, fs.constants.R_OK | fs.constants.W_OK, (err) => {
if (err) {
console.log("%s doesn't exist", path);
} else {
console.log('can read/write %s', path);
}
});
Synchronously
fs.access also has a synchronous version fs.accessSync. When using fs.accessSync you must enclose it within a try/catch block.
// Check write permission
try {
fs.accessSync(path, fs.constants.W_OK);
console.log('can write %s', path);
}
catch (err) {
console.log("%s doesn't exist", path);
}
