Add support for read_only queries (#101)

* add support for read_only queries

* add test for RO_QUERY

* Update test.py

* Update test.py

Co-authored-by: Roi Lipman <swilly22@users.noreply.github.com>

Author: gkorland

redisgraph/graph.py

@@ -141,7 +141,7 @@ def build_params_header(self, params):
             params_header += str(key) + "=" + str(value) + " "
         return params_header
 
-    def query(self, q, params=None, timeout=None):
+    def query(self, q, params=None, timeout=None, read_only=False):
         """
         Executes a query against the graph.
         """
@@ -156,7 +156,7 @@ def query(self, q, params=None, timeout=None):
         # construct query command
         # ask for compact result-set format
         # specify known graph version
-        command = ["GRAPH.QUERY", self.name, query, "--compact", "version", self.version]
+        command = [("GRAPH.QUERY","GRAPH.RO_QUERY")[read_only], self.name, query, "--compact", "version", self.version]
 
         # include timeout is specified
         if timeout:

test.py

@@ -207,6 +207,7 @@ def test_execution_plan(self):
 
         redis_graph.delete()
 
+
     def test_query_timeout(self):
         redis_graph = Graph('timeout', self.r)
         # Build a sample graph with 1000 nodes.
@@ -228,6 +229,19 @@ def test_query_timeout(self):
             # Expecting an error.
             pass
 
+
+    def test_read_only_query(self):
+        redis_graph = Graph('read_only', self.r)
+
+        try:
+            # Issue a write query, specifying read-only true, this call should fail.
+            redis_graph.query("CREATE (p:person {name:'a'})", read_only=True)
+            assert(False)
+        except Exception as e:
+            # Expecting an error.
+            pass
+
+
     def test_cache_sync(self):
         # This test verifies that client internal graph schema cache stays
         # in sync with the graph schema