gerador de URLs curtas

links/short.py

@@ -0,0 +1,81 @@
+#!/usr/bin/env python3
+
+import itertools
+from collections.abc import Iterator
+
+
+def load_redirects():
+    redirects = {}
+    targets = {}
+    for filename in ('custom.htaccess', 'short.htaccess'):
+        with open(filename) as fp:
+            for line in fp:
+                if line.startswith('RedirectTemp'):
+                    _, short, long = line.split()
+                    short = short[1:]  # Remove leading slash
+                    assert short not in redirects, f"{filename}: duplicate redirect from {short}"
+                    # custom is live since 2022, we cannot change it remove duplicate targets
+                    if not filename.startswith('custom'):
+                        assert long not in targets, f"{filename}: Duplicate redirect to {long}"
+                    redirects[short] = long
+                    targets[long] = short
+    return redirects, targets
+
+
+SDIGITS = '23456789abcdefghjkmnpqrstvwxyz'
+
+
+def gen_short() -> Iterator[str]:
+    """
+    Generate every possible sequence of SDIGITS.
+    """
+    length = 1
+    while True:
+        for short in itertools.product(SDIGITS, repeat=length):
+            yield ''.join(short)
+        length += 1
+
+
+def shorten(n: int) -> str:
+    """
+    Get Nth short URL made from SDIGITS, where 0 is the first.
+    """
+    iter_short = gen_short()
+    for i in range(n+1):
+        short = next(iter_short)
+        if i == n:
+            return short
+
+
+def gen_free_short(redirects: dict) -> Iterator[str]:
+    """
+    Generate next available short URL.
+    """
+    for short in gen_short():
+        if short not in redirects:
+            yield short
+
+
+def new_urls(urls: list[str], redirects: dict, targets: dict) -> None:
+    iter_short = gen_free_short(redirects)
+    with open('short.htaccess', 'a') as fp:
+        for url in urls:
+            assert 'fpy.li' not in url, f"{url} is a fpy.li URL"
+            if url in targets:
+                continue
+            short = next(iter_short)
+            redirects[short] = url
+            targets[url] = short
+            fp.write(f"RedirectTemp /{short} {url}\n")
+
+
+def main():
+    from random import randrange
+    urls = [f'https://example.com/{randrange(100000)}.html' for n in range(7)]
+
+    redirects, targets = load_redirects()
+    new_urls(urls, redirects, targets)
+
+
+if __name__ == '__main__':
+    main()