Nostr Scrolls

Self-contained WebAssembly programs packaged as Nostr events ("scrolls"). The binaries execute in a sandboxed environment inside a "host" (i.e., a proper Nostr client). Scrolls interact with Nostr exclusively through a minimal set of APIs provided by the host.

This SDK provides a safe, ergonomic wrapper around the host API, making scroll development straightforward. It includes the nostr_scrolls::main macro, which handles parameter deserialization from the host-supplied pointer and registers a panic handler that logs errors before termination.

Getting started

#![no_main]
#![no_std]

extern crate alloc;

use nostr_scrolls::{PublicKey, Filter, cb, display};

#[nostr_scrolls::main]
fn run(me: PublicKey) {
  let sub = Filter::new()
    .author(&me)
    .kind(1)
    .close_on_eose()
    .tag('t', "asknostr")
    .subscribe()
    .on_event(cb!(|event| display(&event)));
}

More examples can be found in the examples directory.

Features

debug-strings

This crate does not use .unwrap() or .expect() and by default the structs don't implement Debug nor Display traits. These functions and traits depend on core::fmt, and its instruction set is huge, it easily adds up 5~8KiB to your wasm program. Anyway, the runtime will not see those debug information, so they are disabled by default, if you need them just enable the feature

Relays check the nostr event size, they usually limit it to 16KiB, just make sure your program doesn't exceed this limit, core::fmt is useless in our case, make sure your program doesn't load it. You can check the program wat in debug and search for 4core3fmt. If it's there fix your program.

Global allocator

This crate creates a global bump allocator, so your std code or alloc will use it. The bump allocator is simple, you can find it in nostr-scrolls/src/allocator.rs. This allocator just pushes the WASM linear memory; it doesn't free memory, so don't overuse it.

Changelog

All notable changes to this library are documented in the CHANGELOG.md file.

State

This library is in an ALPHA state, things that are implemented generally work but the API will change in breaking ways.

Donations

rust-nostr is free and open-source. This means we do not earn any revenue by selling it. Instead, we rely on your financial support. If you actively use any of the rust-nostr libs/software/services, then please donate.

License

This project is distributed under the MIT software license - see the LICENSE file for details