Handle rate limiting

ia-cdx-search

@@ -6,6 +6,7 @@ import json
 import re
 import shlex
 import sys
+import time
 
 
 HOST = 'web.archive.org'
@@ -23,6 +24,11 @@ def fetch(url, tries, connection):
 			r = connection.getresponse()
 			status = r.status
 			print(f'{status} {url}', file = sys.stderr)
+			if status == 302 and r.getheader('Location') in ('https://web.archive.org/429.html', '/429.html'):
+				# The CDX API is stupid and doesn't return 429s directly...
+				print('Exceeded rate limit, waiting...', file = sys.stderr)
+				time.sleep(30)
+				raise RuntimeError(f'Rate-limited on {url}')
 			if status != 200:
 				raise RuntimeError(f'Could not fetch {url}')
 			data = r.read()