Simple Python server to process GET and POST requests with JSON

Question

I'm trying to create a simple Python server in order to test my frontend. It should be able to handle GET and POST requests. The data should be always in JSON format until they are translated to HTTP request/response. A script with corresponding name should be called to handle each request.

server.py

#!/usr/bin/env python

from BaseHTTPServer import BaseHTTPRequestHandler, HTTPServer
import SocketServer
import json
import urlparse
import subprocess

class S(BaseHTTPRequestHandler):
    def _set_headers(self):
        self.send_response(200)
        self.send_header('Content-type', 'application/json')
        self.end_headers()

    def do_GET(self):
        self._set_headers()
        parsed_path = urlparse.urlparse(self.path)
        request_id = parsed_path.path
        response = subprocess.check_output(["python", request_id])
        self.wfile.write(json.dumps(response))

    def do_POST(self):
        self._set_headers()
        parsed_path = urlparse.urlparse(self.path)
        request_id = parsed_path.path
        response = subprocess.check_output(["python", request_id])
        self.wfile.write(json.dumps(response))

    def do_HEAD(self):
        self._set_headers()

def run(server_class=HTTPServer, handler_class=S, port=8000):
    server_address = ('', port)
    httpd = server_class(server_address, handler_class)
    print 'Starting httpd...'
    httpd.serve_forever()

if __name__ == "__main__":
    from sys import argv

    if len(argv) == 2:
        run(port=int(argv[1]))
    else:
        run()

Example of testscript.py for handling requests, which in this case just returns a JSON object.

#!/usr/bin/env python
return {'4': 5, '6': 7}

The server should for example return {'4': 5, '6': 7} for a response in format http://www.domainname.com:8000/testscript.

My problem is that I can't figure out how to pass variables in between and I need help to make it work.

Answer 1

Here is an example of server client in python. I am using bottle library to handle requests to server and create server.

Server Code

import subprocess
from bottle import run, post, request, response, get, route

@route('/<path>',method = 'POST')
def process(path):
    return subprocess.check_output(['python',path+'.py'],shell=True)

run(host='localhost', port=8080, debug=True)

It starts server on localhost:8080. You can pass file name you want to run run. Make sure that file is in the same path for above code to work or change path appropriately to run from different directory. Path corresponds to file name and it invokes process function when any path is given. If it cannot find file it raises exception Internal server error. You can call scripts from subdirectories too.

Client Code

import httplib, subprocess

c = httplib.HTTPConnection('localhost', 8080)
c.request('POST', '/return', '{}')
doc = c.getresponse().read()
print doc

It invokes a POST request to localhost:8080/return

return.py

def func():
    print {'4': 5, '6': 7}
func()

Make sure you print your output response as we are using subprocess.check_output() as it catches only print statements.

Use Popen in subprocess to open a continuous connection instead of check_output to pass arguments to function in server

Check this documentation on how to extract POST or GET values