# LnTip - your friendly lightning tipping widget

LnTip provides a Bitcoin lightning tipping widget that can easily be integrated into any website.  

It consistes of a small service written in Go that connects to a lnd node and exposes 
a simple HTTP JSON API to create and monitor invoices. This is a HTTP/REST proxy to the LND add and receive invoices API.

That API is consumed from a tiny JavaScript widget that can be integrated into any website. 

If [webln](https://github.com/wbobeirne/webln) is available the widget automatically use webln to request the payment; 
otherwise an overlay will be shown with the payment request and a QR code.


## Motivation

I wanted a simple tipping button for my website that uses my own lightning node and does not rely on external services (trusts external services with handling the payments).


## Installation

To use LnTip a running [LND node](https://github.com/lightningnetwork/lnd/blob/master/docs/INSTALL.md) 
is required.  

1. download the latest [release](https://github.com/bumi/lntip/releases)
2. run `invoices-proxy` to run it as systemd service have a look at the [systemd service example config](https://github.com/bumi/lntip/blob/master/examples/invoices-proxy.service)
3. integrate the widget on website

### Configuration

To connect to the lnd node the cert, macaroon and address of the lnd node has to be configured:

* address: Host and port of the lnd gRPC service. default: localhost:10009
* cert: Path to the lnd cert file. default: ~/.lnd/tls.cert
* macaroon: Path to the macaroon file. default: ~/.lnd/data/chain/bitcoin/mainnet/invoice.macaroon
* bind: Host and port to listen on. default: :1323 (localhost:1323)
* static-path: The proxy can serve files from a static folder (e.g. the JS/CSS files). Use this option to configure the path to a filder. (e.g. /home/bitcoin/lntip/assets) default: disabled
* disable-cors: Disable CORS headers. (default: false)

Example: 

    $ ./invoices_proxy --help
    $ ./invoices_proxy --address=lndhost.com:10009 --bind=localhost:4711


### JavaScript Widget integration

Load the JavaScript file in your HTML page and configure the `lntip-host` attribute 
to the host and port on which your lntip instance is running:

```html
<script lntip-host="https://your-lntip-host.com:1323" src="https://cdn.jsdelivr.net/gh/bumi/lntip/assets/lntip.js" id="lntip-script"></script>
```

#### Usage

To request a lightning payment simply call `request()` on a `new LnTip({value: value, memo: memo})`:

```js
new LnTip({ value: 1000, memo: 'high5' }).request()
```

Use it from a plain HTML link:
```html
  <a href="#" onclick="javascript:new LnTip({ value: 1000, memo: 'high5' }).request();return false;">Tip me</a>
```

##### More advanced JS API:

```js
let tip = new LnTip({ value: 1000, memo: 'high5' });

// get a new invoice and watch for a payment
// promise resolves if the invoice is settled
tip.requestPayment().then((invoice) => {
  alert('YAY, thanks!');
});

// create a new invoice
tip.addInvoice().then((invoice) => {
  console.log(invoice.PaymentRequest)
});

// periodically watch if an invoice is settled
tip.watchPayment().then((invoice) => {
  alert('YAY, thanks!');
});

```

## Development

Use `go run` to ron the service locally: 

    $ go run invoices_proxy.go --address=127.0.0.1:10009 --cert=/home/bitcoin/lightning/tls.cert --macaroon=/home/bitcoin/lightning/invoice.macaroon


## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/bumi/lntip

## License

Available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).