AWS Application Composer and the File System Access API

To use the AWS Application Composer local sync mode, a web browser that supports the File System Access API is required.

What is the File System Access API?

The File System Access API lets web pages gain access to your local file system in order to read, write, or save files. This feature is off by default and requires your permission through a visual prompt to allow it. Once granted, this access remains for the duration of your web page’s browser session.

To learn more about the File System Access API, see:

• File System Access API in the mdn web docs.

• The File System Access API: simplifying access to local files in the web.dev website.

What is the local sync mode?

Local sync mode lets you automatically sync and save your template files and project folders locally as you design in Application Composer. To use this feature, a web browser that supports the File System Access API is required.

What web browsers are supported?

Any recent version of Google Chrome and Microsoft Edge support all capabilities of the File System Access API and can be used with local sync mode in Application Composer.

What does Application Composer gain access to?

Application Composer gains read and write access to the project folder you allow, along with any child folders of that project folder. This access is used to create, update, and save any template files, project folders, and backup directories that are generated as you design. Data accessed by Application Composer is not used for any other purpose and is not stored anywhere beyond your local file system.

Access to sensitive data

The File System Access API excludes or limits access to specific directories that may contain sensitive data. An error will occur if you select one of these directories to use with Application Composer local sync mode. You can choose another local directory to connect with or use Application Composer in its default mode with local sync deactivated.

For more information, including examples of sensitive directories, see Users giving access to more, or more sensitive files than they intended in the File System Access W3C Draft Community Group Report.

If you use Windows Subsystem for Linux (WSL), the File System Access API excludes access to the entire Linux directory because of its location within your Windows system. You can use Application Composer with local sync deactivated or configure a solution to sync project files from your WSL directory to a working directory in Windows. Then, use Application Composer local sync mode with your Windows directory.