pair client server example

example.script

Script started on Mon 05 Dec 2016 02:54:46 PM PST
[sfitzpa1@hills pair]$ ls   
example.script  users_client.py  users_service.py
[sfitzpa1@hills pair]$ echo "Run server in background by appending & to command" && ./users_service.py &
[1] 7158
[sfitzpa1@hills pair]$ Run server in background by appending & to command
running server:
echo "Communicate with server using client script" && ./users_client.py fitz boyd
Communicate with server using client script
127.0.0.1 - - [05/Dec/2016 14:55:41] "GET /?strings=fitz,boyd HTTP/1.1" 200 -
http://localhost:8889?strings=fitz,boyd
{'result': ['rfitzge5',
            'jfitzpa3',
            'jfitzge8',
            'sfitzpa1',
            'dfitzpa2',
            'gboyd',
            'gboyd02',
            'mboyd',
            'dboyd9']}
[sfitzpa1@hills pair]$ ./users_client.py sam
127.0.0.1 - - [05/Dec/2016 14:55:52] "GET /?strings=sam HTTP/1.1" 200 -
http://localhost:8889?strings=sam
{'result': ['lsamuel3',
            'ssamels',
            'csample',
            'msampso3',
            'hisamali',
            'asamir',
            'jsambran',
            'tonsaman',
            'gkassame',
            'lsamuel5',
            'asamson2',
            'jsample2']}
[sfitzpa1@hills pair]$ exit

Script done on Mon 05 Dec 2016 02:55:56 PM PST

users_client.py

#!/usr/bin/env python3
from argparse import ArgumentParser
from urllib.request import urlopen
from pprint import pprint
import json

parser = ArgumentParser(description=
                        """
                        A tool to query this Linux machine's /etc/passwd usernames.

                        The path to the server is /students/sfitzpa1/cs232/pair/users_client.py
                        """
                        )

parser.add_argument('strings', nargs='+', help="strings to search this Linux system's users for (i.e: fitz, boyd)")

args = parser.parse_args()

url = "http://localhost:8889?strings={}".format(','.join(args.strings))

response = urlopen(url)

result = json.loads(response.read().decode())

print(url)
pprint(result)

users_service.py

#!/usr/bin/env python3
from functools import singledispatch, reduce
from urllib.parse import urlparse, parse_qs
from operator import add
import http.server
import json
import csv


def all_users():
    """Return a list of all users on the system"""
    with open('/etc/passwd') as fp:
        reader = csv.reader(fp, delimiter=':')
        users = [l[0] for l in reader]
    return users


@singledispatch
def get_users():
    print('requires a string or list of strings')


@get_users.register(str)
def _(substring):
    """Return a list of users on the system that contains the given substring."""
    return [u for u in all_users() if substring in u]


@get_users.register(list)
def _(substrings):
    """Return a list of users on the system with any of the given substrings."""
    return list(reduce(add, [get_users(s) for s in substrings]))


class Handler(http.server.BaseHTTPRequestHandler):
    def do_GET(self):
        query = urlparse(self.path).query
        params = parse_qs(query)

        if 'strings' in params:
            strings = params['strings'][0].split(',')
            result = get_users(strings)
            self.send_response(200)
            self.end_headers()
            self.wfile.write(json.dumps({'result': result}, indent=2).encode())


def run(server_class=http.server.HTTPServer, handler_class=http.server.BaseHTTPRequestHandler, port=8889):
    server_address = ('', port)
    httpd = server_class(server_address, handler_class)
    httpd.serve_forever()


if __name__ == "__main__":
    print('running server:')
    run(handler_class=Handler)