Discover DIAL device and request DIAL REST API

dial.py

#!/usr/bin/env python3
from urllib.request import *
import xml.etree.ElementTree as ET

headers = {'Origin': 'package:dial.py'}


class Dial:
    appUrl = ''
    appName = ''
    ns = {'role': 'urn:dial-multiscreen-org:schemas:dial'}

    def __init__(self, appUrl, appName):
        self.appUrl = appUrl
        self.appName = appName

    def getInfo(self):
        url = self.appUrl + self.appName
        req = Request(url=url, headers=headers, method='GET')
        data = {'url': req.full_url}
        try:
            with urlopen(req) as res:
                body = res.read().decode()
                service = ET.fromstring(body)
                data['name'] = service.find('./role:name', self.ns).text
                data['state'] = service.find('./role:state', self.ns).text
                data['allowStop'] = service.find('./role:options[@allowStop]', self.ns).attrib['allowStop']
                data['resourceName'] = service.find("./role:link[@rel='run']", self.ns).attrib['href']
        except:
            pass
        return data

    def launch(self):
        info = self.getInfo()
        if info['state'] == 'running':
            return None
        url = info['url']
        req = Request(url=url, headers=headers, method='POST')
        try:
            with urlopen(req):
                return True
        except:
            return False

    def stop(self):
        info = self.getInfo()
        if info['state'] != 'running':
            return None
        url = info['url'] + '/' + info['resourceName']
        req = Request(url=url, headers=headers, method='DELETE')
        try:
            with urlopen(req):
                return True
        except:
            return False

    def hide(self):
        info = self.getInfo()
        if info['state'] != 'running':
            return None
        url = info['url'] + '/' + info['resourceName'] + '/hide'
        req = Request(url=url, headers=headers, method='POST')
        try:
            with urlopen(req):
                return True
        except:
            return False


def main():
    import argparse
    import sys
    parser = argparse.ArgumentParser()
    parser.add_argument('action', help='Action (state/launch/stop/hide)')
    parser.add_argument('-u', '--url', required=True, help='Application URL')
    parser.add_argument('-n', '--name', required=True, help='Application Name')
    args = parser.parse_args()

    ret = True
    dial = Dial(args.url, args.name)
    if args.action == 'state':
        info = dial.getInfo()
        print(info['state'])
    elif args.action == 'launch':
        ret = dial.launch()
    elif args.action == 'stop':
        ret = dial.stop()
    elif args.action == 'hide':
        ret = dial.hide()
    else:
        print('Invalid action: %s' % args.action)
        parser.print_help()
        ret = False
    sys.exit(1 - int(ret or '0'))


if __name__ == '__main__':
    # e.g. python3 dial.py -u http://192.168.181.222:56789/apps/ -n YouTube launch
    main()

discover-dial.py

#!/usr/bin/env python3
import socket
from random import randrange

body = """
M-SEARCH * HTTP/1.1
HOST: 239.255.255.250:1900
MAN: "ssdp:discover"
MX: 1
ST: urn:dial-multiscreen-org:service:dial:1

""".replace('\n', '\r\n').encode('utf-8')

s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
s.settimeout(5)
s.bind((socket.gethostname(), randrange(50000, 60000)))
s.sendto(body, ('239.255.255.250', 1900))

while True:
    try:
        buf, _ = s.recvfrom(1024)
        print(buf.decode('utf-8'))
    except:
        break

s.close()

launch_dial.js

globalThis.cast = globalThis.cast || {};

const nop = () => {};
const errorLog = (text) => (err) => console.log(text, err);
const launchApp = function (dialAppName = "AmazonInstantVideo") {
  const sessionRequest = new chrome.cast.SessionRequest(
    chrome.cast.media.DEFAULT_MEDIA_RECEIVER_APP_ID
  );
  sessionRequest.dialRequest = new chrome.cast.DialRequest(dialAppName);

  chrome.cast.requestSession(
    (session) => (cast.session = session),
    errorLog("requestSession failed"),
    sessionRequest
  );
};

const stopApp = function () {
  if (cast.session) {
    cast.session.stop(nop, errorLog("stop failed"));
    const status = document.getElementById("dial-status");
    if (status) {
      status.innerText = "Disconnected.";
    }
  }
};

initializeCastApiLegacy = function () {
  const sessionRequest = new chrome.cast.SessionRequest(
    chrome.cast.media.DEFAULT_MEDIA_RECEIVER_APP_ID
  );
  const apiConfig = new chrome.cast.ApiConfig(sessionRequest, nop, nop);
  apiConfig.customDialLaunchCallback = async (dialInfo) => {
    console.log("dialCallback", dialInfo.receiver.friendlyName, dialInfo);
    const status = document.getElementById("dial-status");
    if (status) {
      status.innerText = `Connected: ${dialInfo.receiver.friendlyName}[${dialInfo.receiver.ipAddress}]`;
    }
  };

  chrome.cast.initialize(
    apiConfig,
    () => console.log("Initialized."),
    errorLog("initialize failed")
  );
};

window["__onGCastApiAvailable"] = function (loaded, _errorInfo) {
  if (loaded) {
    initializeCastApiLegacy();
  }
};

launchDial.html

<!DOCTYPE html>
<html>
<head>
  <meta charset="UTF-8">
  <title>LaunchDial</title>
  <script src="https://www.gstatic.com/cv/js/sender/v1/cast_sender.js"></script>
  <script src="launch_dial.js"></script>
</head>
<body>
  <button onclick="launchApp('AmazonInstantVideo')">Launch Prime Video</button>
  <button onclick="stopApp()">Stop</button>
  <div id="dial-status">Waiting to connect.</div>
</body>
</html>