Node.js fs.accessSync() Method
The fs.accessSync() method is used to synchronously test the permissions of a given file or directory. The permissions to be checked can be specified as a parameter using file access constants. It is also possible to check multiple file permissions by using the bitwise OR operator to create a mask with more than one file constant.
Syntax:
fs.accessSync( path, mode )
Parameters: This method accepts two parameters as mentioned above and described below:
- path: It is a String, Buffer or URL which denotes the path of the file or directory for which the permission has to be tested.
- mode: It is an integer value that denotes the permission to be tested for. The logical OR operator can be used to separate multiple permission. It can have the values
fs.constants.F_OK
,fs.constants.R_OK
,fs.constants.W_OK
andfs.constants.X_OK
. It is an optional parameter. The default value isfs.constants.F_OK
.
Below examples illustrate the fs.accessSync() method in Node.js:
Example 1: This example shows the testing of the read and write permission of a file.
// Node.js program to demonstrate the // fs.accessSync() method // Import the filesystem module const fs = require( 'fs' ); // Allowing only read permission console.log( "Giving only read permission to user" ); fs.chmodSync( "example.txt" , fs.constants.S_IRUSR); // Test the read permission console.log( '\n> Checking Permission for reading the file' ); try { fs.accessSync( 'example.txt' , fs.constants.R_OK); console.log( 'File can be read' ); } catch (err) { console.error( 'No Read access' ); } // Test both the read and write permission console.log( '\n> Checking Permission for reading and writing to file' ); try { fs.accessSync( 'example.txt' , fs.constants.R_OK | fs.constants.W_OK); console.log( 'File can be read and written' ); } catch (err) { console.error( 'No Read and Write access' ); } |
Output:
Giving only read permission to user > Checking Permission for reading the file File can be read > Checking Permission for reading and writing to file No Read and Write access
Example 2: This example shows the testing of a file if it exists.
// Node.js program to demonstrate the // fs.accessSync() method // Import the filesystem module const fs = require( 'fs' ); // Test the if the file exists console.log( '\n> Checking if the file exists' ); try { fs.accessSync( 'example.txt' , fs.constants.F_OK); console.log( 'File does exist' ); } catch (err) { console.error( 'File does not exist' ); } console.log( '\nCreating the file' ); fs.writeFileSync( "example.txt" , "Test File" ); // Test the if the file exists again console.log( '\n> Checking if the file exists' ); try { fs.accessSync( 'example.txt' , fs.constants.F_OK); console.log( 'File does exist' ); } catch (err) { console.error( 'File does not exist' ); } |
Output:
> Checking if the file exists File does not exist Creating the file > Checking if the file exists File does exist
Reference: https://nodejs.org/api/fs.html#fs_fs_accesssync_path_mode