[plugin] 0.0.1 of donation plugin and invoice query service

contrib/plugins/donations/LICENSE

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+Note: the modules in the ccan/ directory have their own licenses, but
+the rest of the code is covered by the following (BSD-MIT) license:
+
+	Copyright Rene Pickhardt 2018.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.

contrib/plugins/donations/README.md

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+# Invoice Service (for Donations) plugin
+
+this plugin enables c-lightning nodes to start one or several small
+webserver via the command line on specified port. The webserver is
+based on flask and exposes the invoice API call.
+
+Therefor people can query for an invoice which they can use to pay
+
+run the plugin with:
+
+```
+lightningd --plugin=/path/to/lightning/contrib/plugins/donations/donations.py
+```
+
+Once the plugin is active you can run `lightning-cli help donationserver`
+to learn about the command line API:
+
+Starts a donationserver with {start/stop/restart/list} on {port}
+
+A Simple HTTP Server is created that can serve a donation webpage and allow to issue invoices.
+The plugin takes one of the following three commands {start/stop/restart} as the first agument
+By default the plugin starts the server on port 8088. This can however be changed with the
+port argument.
+
+this means after starting `lightningd` together with the plugin you can run: `lightning-cli donationserver start` and access the server at http://localhost:8088/donation (in case you run your lightning node at localhost)
+
+## About the plugin
+You can see a demo of the plugin on the authors website at:
+https://ln.rene-pickhardt.de/donation
+
+This plugin was created and is maintained by Rene Pickhardt. Thus Rene Pickhardt
+is the copyright owner of this plugin. It shall serve as an educational resource
+on his Youtube channel at: https://www.youtube.com/user/RenePickhardt
+
+The plugin is licensed like the rest of c-lightning with BSD-MIT license
+and comes without any warrenty.
+
+If you like my work feel free to support me on patreon:
+https://www.patreon.com/renepickhardt

contrib/plugins/donations/donations.py

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+#!/usr/bin/env python3
+""" A small donation service so that users can request ln invoices
+
+This plugin spins up a small flask server that provides a form to 
+users who wish to donate some money to the owner of the lightning
+node. The server can run on an arbitrary port and returns an invoice. 
+Also a list of previously paid invoices (only those that used this
+service) will be displayed. Displaying paid invoices could be made
+optionally in a future version. 
+
+Author: Rene Pickhardt (https://ln.rene-pickhardt.de)
+
+you can see a demo of the plugin (and leave a tip) directly at:
+       https://ln.rene-pickhardt.de/donation
+
+LICENSE: MIT / APACHE
+"""
+import base64
+import json
+import multiprocessing
+import qrcode
+import sys
+
+
+from flask import Flask, render_template
+from flask_bootstrap import Bootstrap
+from flask_wtf import FlaskForm
+from io import BytesIO
+from lightning.lightning import LightningRpc
+from os.path import join
+from random import random
+from time import time
+from wtforms import StringField,  SubmitField, IntegerField
+from wtforms.validators import Required, NumberRange
+
+# "FIXME: for debugging without plugin
+rpc_interface = LightningRpc("/tmp/spark-env/ln1/lightning-rpc")
+
+
+class DonationForm(FlaskForm):
+    """Form for donations """
+    amount = IntegerField("Enter how many Satoshis you want to donate!",
+                          validators=[Required(), NumberRange(min=1, max=16666666)])
+    description = StringField("Leave a comment (displayed publically)")
+    submit = SubmitField('Donate')
+
+
+def make_base64_qr_code(bolt11):
+    qr = qrcode.QRCode(
+        version=1,
+        error_correction=qrcode.constants.ERROR_CORRECT_H,
+        box_size=4,
+        border=4,
+    )
+
+    qr.add_data(bolt11)
+    qr.make(fit=True)
+    img = qr.make_image()
+
+    buffered = BytesIO()
+    img.save(buffered, format="PNG")
+    img_str = base64.b64encode(buffered.getvalue()).decode("utf-8")
+    return img_str
+
+
+def ajax(label):
+    msg = rpc_interface.listinvoices(label)["invoices"][0]
+    if msg["status"] == "paid":
+        return "Your donation has been received and is well appricated."
+    return "waiting"
+
+
+def donation_form():
+    form = DonationForm()
+    b11 = None
+    qr = None
+    label = None
+    if form.validate_on_submit():
+        amount = form.amount.data
+        description = form.description.data
+        label = "ln-plugin-donation-{}".format(random())
+        invoice = rpc_interface.invoice(
+            int(amount)*1000, label, description)
+        b11 = invoice["bolt11"]
+        qr = make_base64_qr_code(b11)
+
+    invoices = rpc_interface.listinvoices()["invoices"]
+    donations = []
+    for invoice in invoices:
+        if invoice["label"].startswith("ln-plugin-donation-"):
+            # FIXME: change to paid after debugging
+            if invoice["status"] == "paid":
+                bolt11 = rpc_interface.decodepay(invoice["bolt11"])
+                satoshis = int(bolt11["msatoshi"])//1000
+                description = bolt11["description"]
+                ts = bolt11["created_at"]
+                donations.append((ts, satoshis, description))
+
+    if b11 is not None:
+        return render_template("donation.html", donations=sorted(donations, reverse=True), form=form, bolt11=b11, qr=qr, label=label)
+    else:
+        return render_template("donation.html", donations=sorted(donations, reverse=True), form=form)
+
+
+def worker(port):
+    app = Flask(__name__)
+    # FIXME: use hexlified hsm secret or something else
+    app.config['SECRET_KEY'] = 'you-will-never-guess-this'
+    app.add_url_rule('/donation', 'donation',
+                     donation_form, methods=["GET", "POST"])
+    app.add_url_rule('/is_invoice_paid/<label>', 'ajax', ajax)
+    bootstrap = Bootstrap(app)
+    app.run("0.0.0.0", port=port)
+    return
+
+
+jobs = {}
+
+
+def start_server(port):
+    if port in jobs:
+        return False, "server already running"
+
+    p = multiprocessing.Process(
+        target=worker, args=[port], name="server on port {}".format(port))
+    p.daemon = True
+
+    jobs[port] = p
+    p.start()
+
+    return True
+
+
+def stop_server(port):
+    if port in jobs:
+        jobs[port].terminate()
+        del jobs[port]
+        return True
+    else:
+        return False
+
+
+def json_donation_server(request, command="start", port=8088):
+    commands = {"start", "stop", "restart", "list"}
+
+    # if command unknown make start our default command
+    if command not in commands:
+        command = "start"
+
+    # if port not an integer make 8088 as default
+    try:
+        port = int(port)
+    except:
+        port = 8088
+
+    if command == "list":
+        return "servers running on the following ports: {}".format(list(jobs.keys()))
+
+    if command == "start":
+        if port in jobs:
+            return "Server already running on port {}. Maybe restart the server?".format(port)
+        suc = start_server(port)
+        if suc:
+            return "started server successfully on port {}".format(port)
+        else:
+            return "Could not start server on port {}".format(port)
+
+    if command == "stop":
+        if stop_server(port):
+            return "stopped server on port{}".format(port)
+        else:
+            return "could not stop the server"
+
+    if command == "restart":
+        stop_server(port)
+        suc = start_server(port)
+        if suc:
+            return "started server successfully on port {}".format(port)
+        else:
+            return "Could not start server on port {}".format(port)
+
+
+def json_getmanifest(request):
+
+    verbose = """Starts a donationserver with {start/stop/restart} on {port}.
+
+A Simple HTTP Server is created that can serve a donation webpage and allow to issue invoices.
+The plugin takes one of the following three commands {start/stop/restart} as the first agument
+By default the plugin starts the server on port 8088. This can however be changed with the
+port argument.
+"""
+
+    return {
+        "options": [
+        ],
+        "rpcmethods": [
+            {
+                "name": "donationserver",
+                "description": "Starts a donationserver with {start/stop/restart} on {port}.",
+                "long_description": verbose
+            },
+        ]
+    }
+
+
+def json_init(request, options, configuration):
+    """The main daemon is telling us the relevant cli options
+    """
+    global rpc_interface
+
+    basedir = request['params']['configuration']['lightning-dir']
+    rpc_filename = request['params']['configuration']['rpc-filename']
+    path = join(basedir, rpc_filename)
+
+    rpc_interface = LightningRpc(path)
+
+    return "ok"
+
+
+methods = {
+    'getmanifest': json_getmanifest,
+    'init': json_init,
+    'donationserver': json_donation_server,
+
+
+}
+# FIXME: for debugging
+# start_server(8088)
+
+partial = ""
+for l in sys.stdin:
+    try:
+        partial += l
+        request = json.loads(partial)
+    except Exception:
+        continue
+
+    result = None
+    method = methods[request['method']]
+    params = request['params']
+    try:
+        if isinstance(params, dict):
+            result = method(request, **params)
+        else:
+            result = method(request, *params)
+        result = {
+            "jsonrpc": "2.0",
+            "result": result,
+            "id": request['id']
+        }
+    except Exception as e:
+        result = {
+            "jsonrpc": "2.0",
+            "error": "Error while processing {}".format(request['method']),
+            "id": request['id']
+        }
+
+    json.dump(result, fp=sys.stdout)
+    sys.stdout.write('\n')
+    sys.stdout.flush()
+    partial = ""