Version 1.0, fully working addon

 - English language provided
 - Addon finds NVIDIA GeForce NOW in it's default location if installed
 - Automatically stops any playback from Kodi
 - In settings user can input a custom location

script.kodi.geforcenow/addon.py

@@ -0,0 +1,104 @@
+import xbmc
+import xbmcaddon
+import xbmcgui
+
+import platform
+import os.path
+import subprocess
+
+
+# Getting addon constants
+ADDON = xbmcaddon.Addon('script.kodi.launches.steam')
+ADDON_ID = ADDON.getAddonInfo('id')
+ADDON_NAME = ADDON.getAddonInfo('name')
+ADDON_VERSION = ADDON.getAddonInfo('version')
+MSG = ADDON.getLocalizedString
+
+# Getting main settings
+useCustomExecutable = ADDON.getSetting('useCustomExecutable')
+
+
+####################### Defining common methods #######################
+
+# Method to print logs on a standard way
+def log(message, level=xbmc.LOGNOTICE):
+    xbmc.log("[{0}:v{1}] {2}".format(ADDON_ID, ADDON_VERSION, message), level)
+# log
+
+# Method to show when addon couldn't detect the executable in the default directory
+def showExecutableNotFoundDialog():
+    title = MSG(32003)
+    message = MSG(32004)
+    xbmcgui.Dialog().ok(title, message)
+    showOpenSettingsDialog()
+# showExecutableNotFoundDialog
+
+# Method to ask if user wants to open Addon Settings
+def showOpenSettingsDialog():
+    title = MSG(32005)
+    message = MSG(32006)
+    if xbmcgui.Dialog().yesno(title, message):
+        ADDON.openSettings()
+# showOpenSettingsDialog
+
+# Method to show when addon is launched on Linux / Mac (as only Windows is supported)
+def showWindowsNotDetected():
+    title = MSG(32007)
+    message = MSG(32008)
+    xbmcgui.Dialog().ok(title, message)
+# showWindowsNotDetected
+
+# Method to show when user has provided a custom executable path that doesn't exist
+def showCustomExecutableNotFoundDialog():
+    title = MSG(32009)
+    message = MSG(32010)
+    xbmcgui.Dialog().ok(title, message)
+    showOpenSettingsDialog()
+# showCustomExecutableNotFoundDialog
+
+# Method to stop media playback in Kodi
+def stopMediaPlayback():
+    player = xbmc.Player()
+    player.stop()
+# stopMediaPlayback
+
+# Method to execute GeForceNOW using provided executable
+def execute(executable):
+    parameters = ''
+    log('Calling executable: {0}  with parameters: {1}'.format(executable,parameters))
+    stopMediaPlayback()
+    subprocess.call([executable, parameters])
+# execute
+
+####################### Addon entrypoint #######################
+
+# Starting the Addon
+log("Starting Addon")
+
+# Calling custom executable (if it is activated on Addon Settings)
+if useCustomExecutable == 'true':
+    customExecutable = ADDON.getSetting('customExecutable')
+    if os.path.isfile(customExecutable):
+        execute(customExecutable)
+    else:
+        log('Executable not found on the custom location provided by user', xbmc.LOGERROR)
+        showCustomExecutableNotFoundDialog()
+
+# Finding default GeForceNOW executable location
+else:
+    executable = ''
+    executableTemp = ''
+
+    if platform.system() == 'Windows':
+        executableTemp = os.path.expandvars(r'%LOCALAPPDATA%\NVIDIA Corporation\GeForceNOW\CEF\GeForceNOW.exe')
+        if os.path.isfile(executableTemp):
+            executable = executableTemp
+        else:
+            log('Windows executable not found on default paths', xbmc.LOGERROR)
+            showExecutableNotFoundDialog()
+        if executable:
+            execute(executable)
+
+    else:
+        log('Platforms other than Windows are not supported now', xbmc.LOGERROR)
+        showWindowsNotDetected()

script.kodi.geforcenow/addon.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<addon id="script.kodi.geforcenow" name="GeForce NOW" version="1.0.0" provider-name="GanzeVA">
+	<requires>
+		<import addon="xbmc.python" version="2.25.0"/>
+	</requires>
+	<extension point="xbmc.python.script" library="addon.py">
+		<provides>executable</provides>
+	</extension>
+	<extension point="xbmc.addon.metadata">
+		<platform>windx</platform>
+		<summary lang="en">Kodi Addon for launching GeForce NOW</summary>
+		<description lang="en">Kodi Addon for launching NVIDIA GeForce NOW app.</description>
+		<license>GNU GENERAL PUBLIC LICENSE. Version 3, 29 June 2007</license>
+		<language>en</language>
+		<source>https://github.com/GanzeVA/Kodi-GeForceNOW</source>
+		<website>https://github.com/GanzeVA/Kodi-GeForceNOW</website>
+		<forum></forum>
+		<email>[email protected]</email>
+		<news></news>
+		<assets>
+			<icon>icon.png</icon>
+			<fanart>fanart.jpg</fanart>
+		</assets>
+	</extension>
+</addon>

script.kodi.geforcenow/changelog.txt

@@ -0,0 +1,6 @@
+v.1.0
+ - First Release
+ - English language provided
+ - Addon finds NVIDIA GeForce NOW in it's default location if installed
+ - Automatically stops any playback from Kodi
+ - In settings user can input a custom location

script.kodi.geforcenow/resources/language/English/strings.po

@@ -0,0 +1,61 @@
+# Kodi Media Center language file
+# Addon Name: Kodi GeForceNOW
+# Addon id: script.kodi.geforcenow
+# Addon Provider: iampeluca <[email protected]>
+msgid ""
+msgstr ""
+"Project-Id-Version: script.kodi.geforcenow\n"
+"Report-Msgid-Bugs-To: [email protected]\n"
+"POT-Creation-Date: 2020-03-02 15:30-0600\n"
+"PO-Revision-Date: 2020-03-02 15:30-0600\n"
+"Last-Translator: Szymon Zborowski <[email protected]>\n"
+"Language-Team: English <[email protected]>\n"
+"MIME-Version: 1.0\n"
+"Content-Type: text/plain; charset=UTF-8\n"
+"Content-Transfer-Encoding: 8bit\n"
+"Language: en\n"
+"Plural-Forms: nplurals=2; plural=(n != 1);f\n"
+
+msgctxt "#32000"
+msgid "General"
+msgstr ""
+
+msgctxt "#32001"
+msgid "Use custom executable:"
+msgstr ""
+
+msgctxt "#32002"
+msgid "Custom Executable:"
+msgstr ""
+
+msgctxt "#32003"
+msgid "Executable not found"
+msgstr ""
+
+msgctxt "#32004"
+msgid "The NVIDIA GeForceNOW executable was not found on your System on the expected locations."
+msgstr ""
+
+msgctxt "#32005"
+msgid "Addon Settings"
+msgstr ""
+
+msgctxt "#32006"
+msgid "Would you like to open the Addon Settings and specify the NVIDIA GeForceNOW location?"
+msgstr ""
+
+msgctxt "#32007"
+msgid "Windows Not Detected"
+msgstr ""
+
+msgctxt "#32008"
+msgid "This Addon currently works only on Windows platforms."
+msgstr ""
+
+msgctxt "#32009"
+msgid "Custom executable not found"
+msgstr ""
+
+msgctxt "#32010"
+msgid "The custom executable was not found. Please select a new location for it on the Addon Settings."
+msgstr ""

script.kodi.geforcenow/resources/settings.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="utf-8" standalone="yes"?>
+<settings>
+    <category label="32000">
+        <setting id="useCustomExecutable" label="32001" type="bool" default="false"/>
+        <setting id="customExecutable" label="32002" type="executable" default="" subsetting="true" enable="eq(-1,true)"/>
+    </category>
+</settings>