More specific error messages on Payload Too Large.

sanic/http.py

@@ -116,7 +116,7 @@ class Http:
                 break
             await self._receive_more()
         if pos >= self.request_max_size:
-            raise PayloadTooLarge("Payload Too Large")
+            raise PayloadTooLarge("Request header too large")
         # Parse header content
         try:
             reqline, *raw_headers = buf[:pos].decode().split("\r\n")
@@ -347,7 +347,7 @@ class Http:
         # Request size limit
         if self.request_bytes > self.request_max_size:
             self.keep_alive = False
-            raise PayloadTooLarge("Payload Too Large")
+            raise PayloadTooLarge("Request body too large")
         # End of request body?
         if not self.request_bytes_left:
             self.request_body = None

tests/test_payload_too_large.py

@@ -27,7 +27,7 @@ def test_payload_too_large_at_data_received_default(app):
 
     response = app.test_client.get("/1", gather_request=False)
     assert response.status == 413
-    assert "Payload Too Large" in response.text
+    assert "Request header" in response.text
 
 
 def test_payload_too_large_at_on_header_default(app):
@@ -40,4 +40,4 @@ def test_payload_too_large_at_on_header_default(app):
     data = "a" * 1000
     response = app.test_client.post("/1", gather_request=False, data=data)
     assert response.status == 413
-    assert "Payload Too Large" in response.text
+    assert "Request body" in response.text