Add retry counter to work around implementations repeatedly sending challenge responses

Author: Yepoleb

a2s/defaults.py

@@ -1,2 +1,3 @@
 DEFAULT_TIMEOUT = 3.0
 DEFAULT_ENCODING = "utf-8"
+DEFAULT_RETRIES = 5

a2s/players.py

@@ -2,7 +2,8 @@
 from typing import List
 
 from a2s.exceptions import BrokenMessageError
-from a2s.defaults import DEFAULT_TIMEOUT, DEFAULT_ENCODING
+from a2s.defaults import DEFAULT_TIMEOUT, DEFAULT_ENCODING, \
+    DEFAULT_RETRIES
 from a2s.a2sstream import request
 from a2s.byteio import ByteReader
 from a2s.datacls import DataclsMeta
@@ -29,19 +30,20 @@ def players(address, timeout=DEFAULT_TIMEOUT,
             encoding=DEFAULT_ENCODING):
     return players_impl(address, timeout, encoding)
 
-def players_impl(address, timeout, encoding, challenge=0):
+def players_impl(address, timeout, encoding, challenge=0, retries=0):
     resp_data = request(
         address, b"\x55" + challenge.to_bytes(4, "little"), timeout)
     reader = ByteReader(
         io.BytesIO(resp_data), endian="<", encoding=encoding)
 
     response_type = reader.read_uint8()
     if response_type == A2S_CHALLENGE_RESPONSE:
-        if challenge != 0:
+        if retries >= DEFAULT_RETRIES:
             raise BrokenMessageError(
                 "Server keeps sending challenge responses")
-        challenge = reader.read_int32()
-        return players_impl(address, timeout, encoding, challenge)
+        challenge = reader.read_uint32()
+        return players_impl(
+            address, timeout, encoding, challenge, retries + 1)
 
     if response_type != A2S_PLAYER_RESPONSE:
         raise BrokenMessageError(

a2s/rules.py

@@ -1,7 +1,8 @@
 import io
 
 from a2s.exceptions import BrokenMessageError
-from a2s.defaults import DEFAULT_TIMEOUT, DEFAULT_ENCODING
+from a2s.defaults import DEFAULT_TIMEOUT, DEFAULT_ENCODING, \
+    DEFAULT_RETRIES
 from a2s.a2sstream import request
 from a2s.byteio import ByteReader
 
@@ -13,7 +14,7 @@
 def rules(address, timeout=DEFAULT_TIMEOUT, encoding=DEFAULT_ENCODING):
     return rules_impl(address, timeout, encoding)
 
-def rules_impl(address, timeout, encoding, challenge=0):
+def rules_impl(address, timeout, encoding, challenge=0, retries=0):
     resp_data = request(
         address, b"\x56" + challenge.to_bytes(4, "little"), timeout)
     reader = ByteReader(
@@ -31,11 +32,12 @@ def rules_impl(address, timeout, encoding, challenge=0):
 
     response_type = reader.read_uint8()
     if response_type == A2S_CHALLENGE_RESPONSE:
-        if challenge != 0:
+        if retries >= DEFAULT_RETRIES:
             raise BrokenMessageError(
                 "Server keeps sending challenge responses")
-        challenge = reader.read_int32()
-        return rules_impl(address, timeout, encoding, challenge)
+        challenge = reader.read_uint32()
+        return rules_impl(
+            address, timeout, encoding, challenge, retries + 1)
 
     if response_type != A2S_RULES_RESPONSE:
         raise BrokenMessageError(