Fix hanging when a connection is closed without an MRD header

Author: kspaceKelvin

connection.py

@@ -202,6 +202,8 @@ def read_config_text(self):
         config = self.read(length)
         config = config.split(b'\x00',1)[0].decode('utf-8')  # Strip off null teminator
 
+        logging.debug("    " + config)
+
         if self.savedata is True:
             if self.dset is None:
                 self.create_save_file()

server.py

@@ -77,6 +77,12 @@ def handle(self, sock):
 
             # Second messages is the metadata (text)
             metadata_xml = next(connection)
+
+            # Break if no MRD header was received before a close message (e.g. Gadgetron dependency query)
+            if ((metadata_xml is None) & (connection.is_exhausted is True)):
+                logging.info("Connection closed without an MRD header received")
+                return
+
             logging.debug("XML Metadata: %s", metadata_xml)
             try:
                 metadata = ismrmrd.xsd.CreateFromDocument(metadata_xml)