diff --git a/src/galaxy/api/jsonrpc.py b/src/galaxy/api/jsonrpc.py
index e491c3f..eb40ab3 100644
--- a/src/galaxy/api/jsonrpc.py
+++ b/src/galaxy/api/jsonrpc.py
@@ -74,7 +74,7 @@ class Server():
         self._notifications = {}
         self._eof_listeners = []
         self._input_buffer = bytes()
-        self._input_buffer_it = 0
+        self._processed_input_buffer_it = 0
 
     def register_method(self, name, callback, internal, sensitive_params=False):
         """
@@ -120,18 +120,21 @@ class Server():
     async def _readline(self):
         """Like StreamReader.readline but without limit"""
         while True:
-            chunk = await self._reader.read(1024)
-            self._input_buffer += chunk
-            it = self._input_buffer.find(b"\n", self._input_buffer_it)
-            if it < 0:
+            # check if there is no unprocessed data in the buffer
+            if not self._input_buffer or self._processed_input_buffer_it != 0:
+                chunk = await self._reader.read(1024)
                 if not chunk:
                     return bytes() # EOF
-                else:
-                    self._input_buffer_it = len(self._input_buffer)
-                    continue
+                self._input_buffer += chunk
+
+            it = self._input_buffer.find(b"\n", self._processed_input_buffer_it)
+            if it < 0:
+                self._processed_input_buffer_it = len(self._input_buffer)
+                continue
+
             line = self._input_buffer[:it]
             self._input_buffer = self._input_buffer[it+1:]
-            self._input_buffer_it = 0
+            self._processed_input_buffer_it = 0
             return line
 
     def stop(self):