Notes:
hello-web.py:
from webob import Request, Response class WebApp ( object ): def __call__ (self, environ, start_response): # capture the request (input) req = Request(environ) # get the name variable, # default value of 'World' if it is not set name = req.params.get( 'name' , 'World' ) # generate the HTML for the response (output) html = """
Hello %s!
""" # create and return the response resp = Response(html % name) return resp(environ, start_response) application = WebApp() # main program - the web server if __name__ == '__main__' : from wsgiref.simple_server import make_server port = 8080 httpd = make_server( '' , port, application) print ( 'Serving HTTP on port %s...' %port) httpd.serve_forever()Run this application in IDLE, then launch a web browser. Go to the URL “http://localhost:8080”. If you’re working from another computer available on the same network, change “localhost” to the IP address of your Raspberry Pi. Remember, you can find your IP address by typing “ifconfig” into the Terminal. You can stop the server by pressing Ctrl-C. Note that most web pages are normally served on port 80. In order to run on a port below 1024, your program must be run with “superuser” (root) privileges. We have used port 8080 with this program – this is commonly used by web applications that are run as a normal user. How does it work? The “name” variable is passed through to your program in the form of a “POST” request. This is generated using a form in HTML. The first time your page is viewed, the “name” variable is not set, so a default value of “World” is used.
Human-computer interfacing
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