cdk-npubcash

Rust client SDK for the NpubCash v2 API.

Features

• HTTP Client: Fetch quotes with automatic pagination
• NIP-98 Authentication: Sign requests using Nostr keys
• JWT Token Caching: Automatic token refresh and caching
• Quote Polling: Subscribe to quote updates via polling
• Settings Management: Configure mint URL

Usage

use cdk_npubcash::{NpubCashClient, JwtAuthProvider};
use nostr_sdk::Keys;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let base_url = "https://npubx.cash".to_string();
    let keys = Keys::generate();
    
    let auth_provider = JwtAuthProvider::new(base_url.clone(), keys);
    let client = NpubCashClient::new(base_url, std::sync::Arc::new(auth_provider));

    // Fetch all quotes
    let quotes = client.get_quotes(None).await?;
    println!("Found {} quotes", quotes.len());

    // Fetch quotes since timestamp
    let recent_quotes = client.get_quotes(Some(1234567890)).await?;

    // Update mint URL setting
    client.set_mint_url("https://example-mint.tld").await?;
    
    Ok(())
}

Examples

The SDK includes several examples to help you get started:

• basic_usage.rs - Demonstrates fetching quotes and basic client usage
• manage_settings.rs - Illustrates settings management (mint URL)
• create_and_wait_payment.rs - Demonstrates creating a npub.cash address and monitoring for payments

Note: Quotes are always locked by default on the NPubCash server for security. The ability to toggle quote locking has been removed from the SDK.

Run an example with:

cargo run --example basic_usage

Set environment variables to customize behavior:

export NPUBCASH_URL=https://npubx.cash
export NOSTR_NSEC=nsec1...  # Optional: use specific Nostr keys
cargo run --example create_and_wait_payment

Authentication

The SDK uses NIP-98 (Nostr HTTP Auth) to authenticate with the NpubCash service:

1. Creates a NIP-98 signed event with the request URL and method
2. Exchanges the NIP-98 token for a JWT token
3. Caches the JWT token for subsequent requests
4. Automatically refreshes the token when it expires

License

MIT