⬜ Select file

The File selection block allows you to trigger the opening of the system file explorer (browser or native OS) to allow the user to import a file from their local device to the Celestory graph.

This component is essential for document import features, such as sending resumes, attachments, backups or media.

📥 Entries

• extension_filter (Text, optional): Allows you to restrict the types of files accepted (eg: .pdf, .jpg). If not specified, all file types are allowed.
• No entry required: The block is activated via the current flow and uses system parameters to initiate the selection.

📤 Outings

• file (File/Image Resource): Object representing the file selected by the user, usable in the graph.
• completed (Stream): Signal indicating that the selection and loading of the file are finalized, allowing the stream to continue safely.

💡 Example of use

Scenario: Importing a user profile photo

1. The app displays a screen asking the user to choose a profile photo.
2. A "Select Image" button is clicked, triggering the flow to pass to the File Selection block.
3. The system file explorer opens, allowing the user to browse and choose a file (eg: profile.jpg).
4. Once the file is selected, the block generates the output file containing the resource, and the output finished signals the end of the process.
5. The flow continues to an image processing block (eg: resizing) or recording in a database.

⚙️ Technical Details

• Security constraints: The block must be triggered by an explicit user action (eg: click on a button) to avoid blocks by browsers or CORS policies.
• Error handling: If the user cancels the selection, the flow can be redirected to an alternative (eg: error message or rollback).
• MIME types: The extension filter uses MIME types to validate accepted files (eg: application/pdf for PDFs).

Updated on: 04/03/2026