Support dicts in parameter values. (#142)

* In dictionaries, keys need to _not_ be quoted.
* We process parameter values recursively, so that (nested) lists and dicts are handled.

Author: skieffer

redisgraph/graph.py

@@ -1,6 +1,6 @@
 import redis
 
-from redisgraph.util import random_string, quote_string
+from redisgraph.util import random_string, quote_string, stringify_param_value
 from redisgraph.query_result import QueryResult
 from redisgraph.exceptions import VersionMismatchException
 
@@ -162,13 +162,7 @@ def _build_params_header(self, params):
         # Header starts with "CYPHER"
         params_header = "CYPHER "
         for key, value in params.items():
-            # If value is string add quotation marks.
-            if isinstance(value, str):
-                value = quote_string(value)
-            # Value is None, replace with "null" string.
-            elif value is None:
-                value = "null"
-            params_header += str(key) + "=" + str(value) + " "
+            params_header += str(key) + "=" + stringify_param_value(value) + " "
         return params_header
 
     def query(self, q, params=None, timeout=None, read_only=False):

redisgraph/util.py

@@ -1,7 +1,7 @@
 import random
 import string
 
-__all__ = ['random_string', 'quote_string']
+__all__ = ['random_string', 'quote_string', 'stringify_param_value']
 
 
 def random_string(length=10):
@@ -28,3 +28,30 @@ def quote_string(v):
     v = v.replace('"', '\\"')
 
     return '"{}"'.format(v)
+
+
+def stringify_param_value(value):
+    """
+    Turn a parameter value into a string suitable for the params header of
+    a Cypher command.
+
+    You may pass any value that would be accepted by `json.dumps()`.
+
+    Ways in which output differs from that of `str()`:
+        * Strings are quoted.
+        * None --> "null".
+        * In dictionaries, keys are _not_ quoted.
+
+    :param value: The parameter value to be turned into a string.
+    :return: string
+    """
+    if isinstance(value, str):
+        return quote_string(value)
+    elif value is None:
+        return "null"
+    elif isinstance(value, (list, tuple)):
+        return f'[{",".join(map(stringify_param_value, value))}]'
+    elif isinstance(value, dict):
+        return f'{{{",".join(f"{k}:{stringify_param_value(v)}" for k, v in value.items())}}}'
+    else:
+        return str(value)

tests/unit/test_util.py

@@ -17,3 +17,28 @@ def test_quote_string(self):
         self.assertEqual(util.quote_string('\"'), '"\\\""')
         self.assertEqual(util.quote_string('"'), '"\\""')
         self.assertEqual(util.quote_string('a"a'), '"a\\"a"')
+
+    def test_stringify_param_value(self):
+        cases = [
+            [
+                "abc", '"abc"'
+            ],
+            [
+                None, "null"
+            ],
+            [
+                ["abc", 123, None],
+                '["abc",123,null]'
+            ],
+            [
+                {'age': 2, 'color': 'orange'},
+                '{age:2,color:"orange"}'
+            ],
+            [
+                [{'age': 2, 'color': 'orange'}, {'age': 7, 'color': 'gray'}, ],
+                '[{age:2,color:"orange"},{age:7,color:"gray"}]'
+            ],
+        ]
+        for param, expected in cases:
+            observed = util.stringify_param_value(param)
+            self.assertEqual(observed, expected)