clamd in Python, accepting long commands on standard input

clams.py

#!/usr/bin/python
from __future__ import print_function
import base64, httplib, json, string, sys, re

USER = 'user'; PASS = 'pass'; HOST = '127.0.0.1'; PORT = 30174

class RPC:
    def __init__(self, host, port, username, password):
        self.authhdr = "Basic %s" % (base64.b64encode("%s:%s" % (username, password)))
        self.conn = httplib.HTTPConnection(host, port, False, 30)

    def execute(self, obj, params):
        self.conn.request('POST', '/', json.dumps(obj).replace('"'+magic_random_string+'"', params),
                          {'Authorization':self.authhdr, 'Content-type':'application/json' })
        resp = self.conn.getresponse()
        if resp is None:
            print("JSON-RPC: no response", file=sys.stderr)
            return None
        return json.loads(resp.read())

def run_line(line):
    decoder, pos, j, params = json.JSONDecoder(), 0, string.join(line[1:]), ''
    while True: # use the JSON decoder to separate the parameters, but keep them in their original string form
        matched = nonspace.search(j, pos)
        if not matched: break
        try:
            decoded, pos = decoder.raw_decode(j, matched.start())
        except:
            return print('JSON-RPC: parse error in object starting "%s[...]"' % (j[matched.start():matched.start()+30]), file=sys.stderr)
        params += j[matched.start():pos] + ','
    params = '[%s]' % params[:-1]

    # magic_random_string hackery because the JSON isn't always valid, eg. duplicate keys in {a1:v1, a1:v2}
    resp = rpc.execute({'version':'1.1', 'method':line[0], 'id':0, 'params':magic_random_string}, params)
    if 'error' in resp and resp['error'] is not None: print('JSON-RPC: error: ', json.dumps(resp['error']), file=sys.stderr)
    else: print(json.dumps(resp['result'], indent=2))

def prompt():
    if sys.stdin.isatty(): sys.stderr.write("> ")
    return sys.stdin.readline()

rpc = RPC(HOST, PORT, USER, PASS);
magic_random_string = 'woefh3oifg38hg27gdygf3oirgjowihfiouwh'
nonspace = re.compile(r'\S')
line = prompt()
while line:
    split = line[:-1].split()
    if len(split): run_line(split)
    line = prompt()