Made some changes for clarity, and added a web server feature available to user applications.

AppDarmon starts at system boot via command in /etc/rc.local. If you add the argument "WebDir=<some-directory>", the system will start a web server in that directory along with your application. Place an index.html in that directory and whatever support files you might need (index.css, index.js, favicon.ico), and these will be served on port 80 with your application.

This is a *simple* web server, based on the javascript html library, so it doesn't do sophisticated processing or security controls or .htaccess.

If you need full website functionality, install and use Apache.

But if you just need a simple page or two for your application, you can use the built-in one supplied with the AppDaemon.

Here's how you might modify rc.local to make use of this feature:

ConfigGPIO=4;       # Config switch WPi07, Connector pin  7, GPIO (command) BCM 04                                                                                                
LEDGPIO=19;         # Config LED    WPi24, Connector pin 35, GPIO (command) BCM 19                                                                                                

Verbose="-v"        # AppDaemon gets very talky                                                                                                                                   
#Verbose=           # AppDaemon shuts up                                                                                                                                          

nohup /root/AppDaemon/bin/AppDaemon $Verbose --config-gpio=$ConfigGPIO --led-gpio=$LEDGPIO  \
                                             --web-dir /home/pi/GPIOServer/public_html      \
                                             --user=pi /home/pi/GPIOServer/bin/GPIOServer &

And with that example, here are the files the application would need:

/home/pi/GPIOServer/public_html: l
favicon.ico  GPIOServer.css  GPIOServer.js  images  index.html  success.txt

For reference, here's the full command line documentation for the AppDaemon:

##  USAGE                                                                                                                                                                         
##                                                                                                                                                                                
##      AppDaemon [-v] --SSID=<name> --config-gpio=<gpio#> --led-gpio=<gpio#> --web-dir=<dir> --user=<user> App1 [App2 ... ]                                                      
##                                                                                                                                                                                
##      where:                                                                                                                                                                    
##                                                                                                                                                                                
##          --SSID=name             Name to show when in access point mode                                                                                                        
##                                                                                                                                                                                
##          --config-gpio=#         GPIO of button to enter config mode                                                                                                           
##                                                                                                                                                                                
##          --led-gpio=#            GPIO of LED (to blink when in AP mode)                                                                                                        
##                                                                                                                                                                                
##          --user=<user>           User to run applications as (ie - "pi" for raspberry pi default user)                                                                         
##                                                                                                                                                                                
##          App[n]                  Applications to run and monitor                                                                                                               
##                                                                                                                                                                                
##          --web-dir=<dir>         Spark a web server in this directory, in addition to any apps                                                                                 
##                                                                                                                                                                                
##          -verbose                Print out things as they happen                                                                                                               
##          -v                                                                                                                                                                    
##                                                                                                                                                                                
##          If ap-name is not given, will use the text in /etc/hostname. If this file is blank or                                                                                 
##            missing, will use the literal "RasPi"                                                                                                                               
##                                                                                                                                                                                
##          If led-gpio is not given, will not attempt to blink anything when entering config mode.                                                                               
##                                                                                                                                                                                
##          If config-gpio is not given, will not enter config/ap mode.                                                                                                           
##                                                                                                                                                                                
##          If user is not given, will use "pi"