ballerina/file

Overview

This module provides APIs to create, delete, rename the file/directory, retrieve metadata of the given file, and manipulate the file paths in a way that is compatible with the operating system, and a Directory Listener, which is used to listen to the file changes in a directory in the local file system.

This also provides the following separators which are widely used in file path creation:

• file:pathSeparator: It is a character used to separate the parent directories that make up the path to a specific location. For windows, it’s ‘\’ and for UNIX it’s ‘/’
• file:pathListSeparator: It is a character commonly used by the operating system to separate paths in the path list. For windows, it’s ‘;‘ and for UNIX it’s ‘:’

Directory listener

The file:Listener is used to monitor all the files and subdirectories inside the specified directory.

A Listener endpoint can be defined using the mandatory path parameter and the optional recursive parameter as follows.

If the listener needs to monitor subdirectories of the given directory, recursive needs to be set to true. The default value of this is false.

A Service has the defined remote methods with the file:FileEvent and can be exposed via a Listener endpoint. When there are changes in the listening directory, the file:FileEvent will be triggered with the action of the file such as creating, modifying, or deleting.

The remote methods supported by the Service are as follows.

onCreate: This method is invoked once a new file is created in the listening directory.

onDelete: This method is invoked once an existing file is deleted from the listening directory.

onModify: This method is invoked once an existing file is modified in the listening directory.

The following code sample shows how to create a Service with the onCreate remote method and attach it to the above Listener endpoint:

For information on the operations, which you can perform with the file module, see the below Functions.