11#!/usr/bin/env python3
22
3+ """
4+ short.py generates unique short URLs.
5+
6+ This script reads lines from stdin or files named as arguments, then:
7+
8+ 1. retrieves or creates new short URLs, taking into account existing RedirectTemp
9+ directives in custom.htacess or short.htacess;
10+ 2. appends RedirectTemp directives for newly created short URLs to short.htacess;
11+ 3. outputs the list of (short, long) URLs retrieved or created.
12+
13+ """
14+
15+ import fileinput
316import itertools
417from collections .abc import Iterator
18+ from time import strftime
519
20+ BASE_DOMAIN = 'fpy.li'
621
722def load_redirects ():
823redirects = {}
@@ -25,52 +40,55 @@ def load_redirects():
2540SDIGITS = '23456789abcdefghjkmnpqrstvwxyz'
2641
2742
28- def gen_short ()-> Iterator [str ]:
43+ def gen_short (start_len = 1 )-> Iterator [str ]:
2944"""
30- Generate every possible sequence of SDIGITS.
45+ Generate every possible sequence of SDIGITS, starting with start_len
3146 """
32- length = 1
47+ length = start_len
3348while True :
3449for short in itertools .product (SDIGITS ,repeat = length ):
3550yield '' .join (short )
3651length += 1
3752
3853
39- def gen_free_short (redirects :dict )-> Iterator [str ]:
54+ def gen_unused_short (redirects :dict )-> Iterator [str ]:
4055"""
41- Generate next available short URL.
56+ Generate next available short URL of len >= 2 .
4257 """
43- for short in gen_short ():
58+ for short in gen_short (2 ):
4459if short not in redirects :
4560yield short
4661
4762
4863def shorten (urls :list [str ],redirects :dict ,targets :dict )-> list [tuple [str ,str ]]:
49- """return (short, long) pairs,updating short.htaccess as needed""'
50- iter_short =gen_free_short (redirects)
64+ """return (short, long) pairs,appending directives to short.htaccess as needed"""
65+ iter_short = gen_unused_short (redirects )
5166pairs = []
67+ timestamp = strftime ('%Y-%m-%d %H:%M:%S' )
5268with open ('short.htaccess' ,'a' )as fp :
5369for long in urls :
54- assert'fpy.li' not in long, f"{long} is afpy.li URL"
70+ assert BASE_DOMAIN not in long ,f"{ long } { BASE_DOMAIN }
5571if long in targets :
5672short = targets [long ]
5773else :
5874short = next (iter_short )
59- redirects[short] = url
60- targets[url] = short
61- fp.write(f"RedirectTemp /{short} {url}\n ")
75+ redirects [short ]= long
76+ targets [long ]= short
77+ if timestamp :
78+ fp .write (f'\n # appended:{ timestamp } \n ' )
79+ timestamp = None
80+ fp .write (f'RedirectTemp /{ short } { long } \n ' )
6281pairs .append ((short ,long ))
6382
6483return pairs
6584
6685
6786def main ():
68- from random import randrange
69- urls = [f'https://example.com/{randrange(100000)}.html' for n in range(7)]
70-
87+ """read URLS from filename arguments or stdin"""
88+ urls = [line .strip ()for line in fileinput .input (encoding = "utf-8" )]
7189redirects ,targets = load_redirects ()
7290for short ,long in shorten (urls ,redirects ,targets ):
73- print(f'fpy.li /{short}\t {long }')
91+ print (f'{ BASE_DOMAIN } { short } \t { long } )
7492
7593
7694if __name__ == '__main__' :