find-bindist

#!/usr/bin/env python
#
# Return the url for a GHC bindist.
#
# Examples:
#   find-bindist apple
#   find-bindist deb8 64
#   find-bindist i3 ming
#   find-bindist apple 7.10.2
#   find-bindist               -- shows all bin dists

import requests
import re
import os
import sys

BASE_URL = "http://downloads.haskell.org/~ghc"
DEFAULT_GHC_VERSION = "8.0.1"

def list_bin_dists(url):
  r = requests.get(url)
  contents = r.text
  return re.findall('a href="(ghc-.*?.tar.xz)"', contents)

def has_words(words, m):
  for w in words:
    if not (w in m):
      return False
  return True

def is_ghc_vers(arg):
  return re.match("(\d+)\.(\d+)\.(\d+)\Z", arg)

def process_args(args):
  versions = []
  others = []
  for arg in args:
    if is_ghc_vers(arg):
      versions.append(arg)
    else:
      others.append(arg)
  return versions, others

def main():
  args = sys.argv[1:]

  versions, words = process_args(sys.argv[1:])
  if not versions:
    versions.append(DEFAULT_GHC_VERSION)

  ghc_vers = versions[0]

  url = BASE_URL + "/" + ghc_vers + "/"
  matches = [ m for m in list_bin_dists(url) if has_words(words, m) ]
  if not matches:
    if words:
      msg = " contain the words: " + ", ".join(words)
    else:
      msg = ""
    print "no bindists for version " + ghc_vers + msg
  elif len(matches) == 1:
    print url + matches[0]
  else:
    print "Multiple matching bindists:"
    for m in matches:
      print "  ", url + m

main()