Read misc.tld from the IANA Root Zone Database, and file the .eh no root zone holds

data-import/tld.py

@@ -0,0 +1,68 @@
+#!/usr/bin/env python3
+"""Rebuild data/misc/tld.tsv from the IANA Root Zone Database.
+
+    data-import/tld.py [--source URL_OR_FILE] [--zone URL_OR_FILE] [--cache DIR] [--out FILE]
+
+A TLD ships when the database names a manager for it; one it marks "Not assigned" is a
+delegation the root zone no longer holds, and the zone file is fetched to prove the two
+agree. The key is the A-label the root zone holds; `unicode` is the form the database
+displays, less the bidi marks it wraps a right-to-left label in, and proved to punycode
+back to the key.
+"""
+import argparse
+import html
+import re
+import sys
+from pathlib import Path
+
+import source
+import tsv
+
+SOURCE = "https://www.iana.org/domains/root/db"
+ZONE = "https://data.iana.org/TLD/tlds-alpha-by-domain.txt"
+OUT = Path(__file__).resolve().parent.parent / "data" / "misc" / "tld.tsv"
+CACHE = Path(__file__).resolve().parent / "cache"
+COLUMNS = ["tld", "type", "unicode"]
+TYPES = ("country-code", "generic", "generic-restricted", "infrastructure", "sponsored")
+BIDI = {0x200E: None, 0x200F: None}
+ROW = re.compile(r'<a href="/domains/root/db/([^"]+)\.html">([^<]+)</a>.*?</td>\s*<td>([^<]*)</td>\s*<td>(.*?)</td>', re.S)
+
+
+def rows(page):
+    for a_label, shown, kind, manager in ROW.findall(page):
+        if "Not assigned" in manager:
+            continue
+        kind = kind.strip()
+        if kind not in TYPES:
+            sys.exit(f"{a_label}: the database types it {kind!r}, which is none of {TYPES}")
+        yield {"tld": "." + a_label, "type": kind, "unicode": html.unescape(shown).strip().translate(BIDI)}
+
+
+def prove_each_unicode_form_is_its_key(table):
+    """The displayed form is the key's own spelling, which punycode encodes back to."""
+    for r in table:
+        label = r["unicode"][1:]
+        encoded = label if label.isascii() else "xn--" + label.encode("punycode").decode("ascii")
+        if "." + encoded != r["tld"]:
+            sys.exit(f"{r['tld']}: the database displays {r['unicode']!r}, which is no spelling of it")
+
+
+def main():
+    p = argparse.ArgumentParser(description=__doc__.splitlines()[0])
+    p.add_argument("--cache", default=str(CACHE))
+    p.add_argument("--source", default=SOURCE)
+    p.add_argument("--zone", default=ZONE)
+    p.add_argument("--out", default=str(OUT))
+    a = p.parse_args()
+    table = sorted(rows(source.fetch(a.source, a.cache, "root-db.html").decode("utf-8")), key=lambda r: r["tld"])
+    prove_each_unicode_form_is_its_key(table)
+    listing = source.fetch(a.zone, a.cache, "tlds-alpha-by-domain.txt").decode("utf-8")
+    delegated = {"." + line.strip().lower() for line in listing.splitlines() if line.strip() and not line.startswith("#")}
+    shipped = {r["tld"] for r in table}
+    if len(table) != len(delegated) or shipped != delegated:
+        sys.exit(f"the database assigns {len(table)} rows where the root zone holds {len(delegated)} TLDs: {sorted(shipped ^ delegated)[:10]}")
+    tsv.write(a.out, COLUMNS, table)
+
+
+if __name__ == "__main__":
+    main()