loki-file-access

Cross-platform, frontend-agnostic file picker and capability-based file access for Rust applications.

This crate provides a unified API for presenting native file-picker dialogs and accessing user-selected files across all major platforms:

• Desktop (Windows, macOS, Linux, BSD) — via the rfd crate
• Android — via the Storage Access Framework with persistable URI permissions
• iOS — via UIDocumentPickerViewController with security-scoped bookmarks
• WASM — via <input type="file"> with in-memory file buffers

Zero UI Framework Dependencies

loki-file-access has no UI framework dependencies. It returns standard [Future] values implemented with only std primitives (no Tokio, no async-std required). It is usable from Dioxus, egui, Iced, Xilem, pollster::block_on, or any other async or sync Rust context.

Quick Start

use loki_file_access::{FilePicker, PickOptions};
use std::io::Read;

# async fn example() -> Result<(), Box<dyn std::error::Error>> {
let picker = FilePicker::new();

// Pick a file to open
let token = picker
    .pick_file_to_open(PickOptions {
        mime_types: vec!["text/plain".into()],
        ..Default::default()
    })
    .await?;

if let Some(token) = token {
    let mut reader = token.open_read()?;
    let mut contents = String::new();
    reader.read_to_string(&mut contents)?;
    println!("File contents: {contents}");

    // Serialize the token for later use
    let stored = token.serialize();
    println!("Token: {stored}");
}
# Ok(())
# }

Capability Tokens

Every picker operation returns a [FileAccessToken] — a serializable capability that encapsulates all platform-specific state needed to re-open the file. Tokens can be serialized to a URL-safe string for storage in a recent-files list and deserialized to re-open files across app restarts.

On Android, the token holds a content URI with a persistable permission grant. On iOS, it holds a security-scoped bookmark. On desktop, it holds a filesystem path. On WASM, it holds the file data in memory.