Processing HTTP GET input parameter on server side in python

Question

I wrote a simple HTTP client and server in Python for experimenting. The first code snippet below shows how I send an HTTP GET request with a parameter named imsi. In the second code snippet I show my do_Get function implementation in the server side. My question is how I can extract the imsi parameter in the server code and send a response back to the client in order to signal the client that imsi is valid.
Thanks.

P.S.: I verified that the client sends the request successfully.

CLIENT code snippet

    params = urllib.urlencode({'imsi': str(imsi)})
    conn = httplib.HTTPConnection(host + ':' + str(port))
    #conn.set_debuglevel(1)
    conn.request("GET", "/index.htm", 'imsi=' + str(imsi))
    r = conn.getresponse()

SERVER code snippet

import sys, string, cStringIO, cgi, time, datetime
from os import curdir, sep
from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer

class MyHandler(BaseHTTPRequestHandler):

# I want to extract the imsi parameter here and send a success response to 
# back to the client.
def do_GET(self):
    try:
        if self.path.endswith(".html"):
            #self.path has /index.htm
            f = open(curdir + sep + self.path)
            self.send_response(200)
            self.send_header('Content-type','text/html')
            self.end_headers()
            self.wfile.write("<h1>Device Static Content</h1>")
            self.wfile.write(f.read())
            f.close()
            return
        if self.path.endswith(".esp"):   #our dynamic content
            self.send_response(200)
            self.send_header('Content-type','text/html')
            self.end_headers()
            self.wfile.write("<h1>Dynamic Dynamic Content</h1>")
            self.wfile.write("Today is the " + str(time.localtime()[7]))
            self.wfile.write(" day in the year " + str(time.localtime()[0]))
            return

        # The root
        self.send_response(200)
        self.send_header('Content-type','text/html')
        self.end_headers()

        lst = list(sys.argv[1])
        n = lst[len(lst) - 1]
        now = datetime.datetime.now()

        output = cStringIO.StringIO()
        output.write("<html><head>")
        output.write("<style type="text/css">")
        output.write("h1 {color:blue;}")
        output.write("h2 {color:red;}")
        output.write("</style>")
        output.write("<h1>Device #" + n + " Root Content</h1>")
        output.write("<h2>Device Addr: " + sys.argv[1] + ":" + sys.argv[2] + "</h1>")
        output.write("<h2>Device Time: " + now.strftime("%Y-%m-%d %H:%M:%S") + "</h2>")
        output.write("</body>")
        output.write("</html>")

        self.wfile.write(output.getvalue())

        return

    except IOError:
        self.send_error(404,'File Not Found: %s' % self.path)

Asked By: F. Aydemir

||

Source

Answer 1

You can parse the query of a GET request using urlparse, then split the query string.

from urlparse import urlparse
query = urlparse(self.path).query
query_components = dict(qc.split("=") for qc in query.split("&"))
imsi = query_components["imsi"]
# query_components = { "imsi" : "Hello" }

# Or use the parse_qs method
from urlparse import urlparse, parse_qs
query_components = parse_qs(urlparse(self.path).query)
imsi = query_components["imsi"] 
# query_components = { "imsi" : ["Hello"] }

You can confirm this by using

 curl http://your.host/?imsi=Hello

Answered By: ib.lundgren

Answer 2

BaseHTTPServer is a pretty low-level server. Generally you want to use a real web framework that does this kind of grunt work for you, but since you asked…

First import a url parsing library. In Python 2,x it’s urlparse. (In Python3, you’d use urllib.parse)

import urlparse

Then, in your do_get method, parse the query string.

imsi = urlparse.parse_qs(urlparse.urlparse(self.path).query).get('imsi', None)
print imsi  # Prints None or the string value of imsi

Also, you could be using urllib in your client code and it would probably be a lot easier.

Answered By: Ken Kinder

Answer 3

cgi module contains FieldStorage class which is supposed to be used in CGI context, but seems to be easily used in your context as well.

Answered By: newtover

Answer 4

If you dont want to import additional libraries in most cases you can use:

i = self.path.index ( "?" ) + 1
params = dict ( [ tuple ( p.split("=") ) for p in self.path[i:].split ( "&" ) ] )

Answered By: BatRamboZPM

Processing HTTP GET input parameter on server side in python

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