File Import Export

High-level API

Device name: file_import_export

Provided by the file import/export card.

Exporting

Call beginExportFile() with a name, append the contents with writeExportFile(), then call finishExportFile(). Every user at the terminal is offered to save the file. Files are limited to 512 KiB.

Importing

Call requestImportFile() to prompt every user at the terminal for a file. Poll beginImportFile() until it returns the file's name and size; the first file a user picks wins, and the prompts on other clients are canceled. Then call readImportFile() until it returns nothing. reset() cancels either operation.

Methods fail with an error when called in the wrong order, or when the users canceled.

Methods

beginExportFile(name:string)

Begins exporting a file. Provide its contents with writeExportFile() and complete the export with finishExportFile(). Fails if the device is currently exporting or importing.

- name: the name of the file being exported.

beginImportFile():table

Checks whether a requested file has arrived and, if so, starts reading it. Poll this after requestImportFile(). Fails if no import was requested, or every user canceled.

- Returns a table with the file's name and size, or nothing while no file was picked yet.

finishExportFile()

Finishes the export and offers every user at the terminal to save the file. Fails if the device is not currently exporting.

readImportFile():string

Reads the next chunk of the file being imported. Fails if beginImportFile() did not succeed yet.

- Returns up to 4 KiB of data, or nothing once the whole file was read.

requestImportFile():boolean

Begins an import by prompting every user at the terminal to pick a file. Fails if the device is currently exporting or importing.

- Returns whether anyone was prompted; false when nobody is using the terminal.

reset()

Cancels any export or import in progress and returns the device to its idle state.

writeExportFile(data:string)

Appends data to the file being exported. Fails if the device is not currently exporting, or the file grows past 512 KiB.

- data: the data to append to the file being exported.