Fixing starttls for mailservers

get_cert.py

@@ -15,29 +15,26 @@ logging.basicConfig(level=logging.INFO,
 logger = logging.getLogger('certo')
 
 
-# The following two functions from
+# The following inspired by:
 # https://stackoverflow.com/questions/17667903/python-socket-receive-large-amount-of-data
+# https://www.binarytides.com/receive-full-data-with-the-recv-socket-function-in-python/
 def recv_msg(sock, timeout):
     # Read message length and unpack it into an integer
-    raw_msglen = recvall(sock, 1024, timeout)
-    if not raw_msglen:
-        return None
-    msglen = struct.unpack('>I', raw_msglen)[0]
-    # Read the message data
-    return recvall(sock, msglen, timeout)
-
-
-def recvall(sock, n, timeout):
-    # Helper function to recv n bytes or return None if EOF is hit
     data = b''
     begin = time.time()
-    while len(data) < n:
-        packet = sock.recv(n - len(data))
-        if not packet:
-            return None
-        data += packet
-        if time.time() - begin > timeout:
+    n = 1024
+    while len(data) < n or time.time() - begin < timeout:
+        try:
+            data += sock.recv(n - len(data))
+            logger.debug("Partial: %r" % data)
+        except socket.timeout:
+            pass
+        if b'Ready to start TLS\r\n' in data:
             break
+        time.sleep(0.1)
+    if len(data) == 0:
+        return None
+    logger.debug("Data: %r" % data)
     return data