ip_server_open() and URL parameters
annuello
Posts: 294
Gday all,
I'm trying to write a server module which does different actions depending on the parameters in the URL. I've been able to open a server port, listen for connections, and serve basic replies. Where does the parameter information get stored so I can act on the parameter values?
E.g. http://my.master.com:12345/?param1=hello¶m2=world
So far I am handling everything in the online event of the port. I expect that I will have to parse the parameters to get each individual value, but how do I obtain the parameters in the first place? I'm looking for a non-Duet solution if there is one, since I want it to run on my NXC-ME at home.
Yours,
Roger McLean
Swinburne University
I'm trying to write a server module which does different actions depending on the parameters in the URL. I've been able to open a server port, listen for connections, and serve basic replies. Where does the parameter information get stored so I can act on the parameter values?
E.g. http://my.master.com:12345/?param1=hello¶m2=world
So far I am handling everything in the online event of the port. I expect that I will have to parse the parameters to get each individual value, but how do I obtain the parameters in the first place? I'm looking for a non-Duet solution if there is one, since I want it to run on my NXC-ME at home.
DEFINE_DEVICE
vdvIpPort = 0:4:0
DEFINE_CONSTANT
integer iHTTPPort = 12345
char crlf[2] = {13,10}
DEFINE_FUNCTION WaitForConnection(){
stack_var slong theResult
theResult = ip_server_open(vdvIpPort.port,iHTTPPort,ip_tcp)
select{
active(theResult == -1):{ send_string 0, 'ip_server_open() failed -1 invalid server port' }
active(theResult == -2):{ send_string 0, 'ip_server_open() failed -2 invalid value for protocol' }
active(theResult == -3):{ send_string 0, 'ip_server_open() failed -3 unable to open communication port' }
}
}
DEFINE_EVENT
data_event[vdvIpPort]{
online:{
send_string vdvIpPort, "'Connected', crlf"
send_string vdvIpPort, "'Parameters = '"
//How to I access the parameters? For debugging I'd like to send_string them back to the browser.
//e.g. param1=hello, param2=world
ip_server_close(vdvIpPort.port) //Tells browser that all data has been sent
WaitForConnection() //Reopen to listen for new connections
}
}
data_event[vdvIpPort]{
online:{
wait 50
WaitForConnection() //Start initial listening
}
}
Yours,
Roger McLean
Swinburne University
0
Comments
In my implementations, I use PHP to open the connection with the controller and send just the data, so I don't have full URLs with name/value pairs. I just connect, then send the data in a fixed format separated by periods; i.e. "zone.device.command.value<CR>". The STRING handler looks for the <CR> in the string, and when found, uses remove_string() to grab everything up to that <CR> and pass it to a parsing function.
Using full URLS and name/value pairs allows you to get by without PHP programming to handle controller communications, and is certainly more flexible in the long run, but you're gonna have to write more parsing code to handle the URLS.
Does the application that submits the URLS to the controller need device state feedback?
Yes, the app will require state feedback. Since it will be access via a web browser, I've had a quick play with some auto-refrshing HTML. It seems to work okay, though I'm not a huge fan of the "continuous hits" approach. If I were using a purpose-written client which keeps the connection open, I don't think I'd have such issues. If the continuous hits become a problem I may have to investigate the XMLHttpRequest object to see if that can help me out. What a good compliment to my insomnia! At leat this is all for a home-project, and not work.
Roger McLean
Good luck!