extension-file-save

A cross-platform OpenFL/Lime native extension for native OS file pickers — saving (desktop direct-path write, mobile copy-to-destination) and, on desktop, opening.

Platform Support

Platform	Save	Open
macOS	NSSavePanel (security-scoped URL)	NSOpenPanel
Windows	Lime FileDialog wrapper	Lime FileDialog wrapper
Linux	Lime FileDialog wrapper	Lime FileDialog wrapper
iOS	UIDocumentPickerViewController	not supported
Android	ACTION_CREATE_DOCUMENT Intent	not supported

On macOS both panels are shown as a sheet attached to the app window (beginSheetModalForWindow:), so the dialog cannot end up behind the window or on another Space, and the completion handler always fires. Where a platform does not support an operation, its function calls the cancel/failure callback immediately rather than doing nothing.

Installation

haxelib dev extension-file-save path/to/extension-file-save

Add to project.xml:

<haxelib name="extension-file-save" />

API

Desktop — requestSavePath / releasePath

The user picks a save location; your code writes directly to that path. On macOS the extension holds a security-scoped bookmark until releasePath() is called.

// Ask the user where to save, then write directly to the returned path
FileSave.requestSavePath('animation.mp4', 'video/mp4', (path:String) -> {
    beginEncoding(path, () -> {
        FileSave.releasePath(); // Release security-scoped access (macOS sandbox)
    });
}, () -> {
    trace('User cancelled');
});

Desktop — requestOpenPath

The user picks an existing file; your code reads it directly from the returned path. extensions is a comma-separated list without dots (empty = any file), defaultPath is the directory to start in (empty = system default), title labels the dialog (empty = none — the panel header on macOS, the window title on Windows/Linux).

FileSave.requestOpenPath('gif,jpg,jpeg,png', '', 'Select an image', (path:String) -> {
    final bytes:Bytes = sys.io.File.getBytes(path);
    // ...
}, () -> {
    trace('User cancelled');
});

Read the file inside the callback: on macOS the extension holds sandbox access to the chosen file only for the duration of that call. Do NOT call releasePath() afterwards — it belongs to requestSavePath and would release that panel's URL instead.

Mobile — saveFile

Copies an existing file to a user-chosen location via the native picker.

FileSave.saveFile('/tmp/output.mp4', 'animation.mp4', 'video/mp4', (success:Bool) -> {
    if (success) trace('Saved');
});

Building the Native Library

lime rebuild . <target> -release

Or directly via hxcpp — run it from project/, not from the repository root:

cd project
haxelib run hxcpp Build.xml -D<platform> -DHXCPP_ARM64

Build.xml declares <outdir name="../ndll/${BINDIR}" />, and a relative outdir is resolved against the current working directory, not the Build.xml location. Invoked from the repository root it writes to ../ndll/ above the repository while still printing Link: ../ndll/… and exiting 0 — the build looks fine and the app keeps linking the old library. lime rebuild handles the directory itself, so it is the safer entry point.

Target	lime rebuild	hxcpp flags (from project/)
macOS	lime rebuild . macos -release	-Dmacos -DHXCPP_ARM64
macOS	lime rebuild . macos -64 -release	-Dmacos -DHXCPP_M64
iOS	lime rebuild . ios -release	-Diphoneos -DHXCPP_ARM64
Android	Built automatically by Gradle

macOS ships as a universal binary, so both architectures must be built before a release. Verify a rebuild landed by checking the artifact rather than the exit status:

nm -gU ndll/MacArm64/extension_file_save.ndll | grep fs_request

Windows and Linux use Lime's built-in FileDialog and do not require a native library build.

macOS Sandbox Note

requestSavePath calls NSSavePanel and retains a security-scoped URL for the chosen file. This keeps sandbox access open while your code writes to the path. Call releasePath() as soon as writing is complete to release the resource.

requestOpenPath calls NSOpenPanel and holds access only for the duration of its own callback — nothing is retained, and releasePath() must not be called for it. A sandboxed app needs com.apple.security.files.user-selected.read-write (or read-only if it never writes); the panel itself runs out-of-process in the powerbox, which is what extends the sandbox to the file the user picked.

This is also why a sandboxed app must not fall back to Lime's FileDialog on macOS: that path goes through tinyfiledialogs, which shells out to osascript via popen, and the sandbox denies executing binaries outside the app bundle.

License

MIT