crate

#! /usr/bin/python
# Usage: crate <from> <to> <api_key>
#
# Uses the API at http://currency-api.appspot.com to get a currency
# comparison rate between the two currency codes specified, e.g.
#   crate HKD NZD kkkkkkkkkk
# This will show how many NZD you wil get for 1 HKD.
#
# (kkkkkkkkkk should be replaced with your API key, which you can get from the
# website)
#
# Note that this script doesn't do conversions because the rates are only
# updated daily and one fetch per conversion would be inefficient.

import sys
import urllib
import json

program_name = "crate"

def help():
    print >>sys.stderr, "Usage: crate <from> <to> <api_key>"


# *** MAINLINE ***
# == initialisation ==
settings = {}

# == Command-line parsing ==
import getopt

# -- defaults --
settings['quiet'] = False

# -- option handling --
try:
    (opts, args) = getopt.getopt(sys.argv[1:], "qh", ['help'])
except getopt.GetoptError, e:
    print >> sys.stderr, program_name + ":", e
    sys.exit(1)

for optpair in opts:
    if optpair[0] == "-q":
        settings['quiet'] = True
    elif optpair[0] == "--help" or optpair[0] == "-h":
        help()
        sys.exit(0)

# -- pre-preparation --
if len(args) != 3:
    help()
    sys.exit(1)

# -- argument handling --
c_from = args[0]
c_to   = args[1]
api_key = args[2]

# == preparation ==

# == sanity checking ==

# == processing ==
url = "http://currency-api.appspot.com/api/%s/%s.json?key=%s" % (c_from, c_to, api_key)

url = urllib.urlopen(url)
result = url.read()
url.close()
## print result
## exit(99)

decoded_result = json.loads(result)

if decoded_result['success']:
    if settings['quiet']:
        print decoded_result['rate']
    else:
        print "1 %s is worth %f %s" % (c_from, decoded_result['rate'], c_to)