From ba0f0bd513f368c8833491df936813f851d247f0 Mon Sep 17 00:00:00 2001
From: David Pedrosa <davidpedrosa@users.noreply.github.com>
Date: Thu, 25 Mar 2021 21:22:36 +0100
Subject: [PATCH] Improve dynamodb query case sensitivity (#3799) (#3800)

* between clause is not case-sensitive anymore

* begins_with will raise an exception unless lower-case is used

Co-authored-by: David Pedrosa <d.pedrosa@indizen.com>
---
 moto/dynamodb2/responses.py                   | 14 +++-
 .../test_dynamodb_table_with_range_key.py     | 66 +++++++++++++++++++
 2 files changed, 79 insertions(+), 1 deletion(-)

diff --git a/moto/dynamodb2/responses.py b/moto/dynamodb2/responses.py
index 5958a38c9..8ca9417aa 100644
--- a/moto/dynamodb2/responses.py
+++ b/moto/dynamodb2/responses.py
@@ -510,7 +510,7 @@ class DynamoHandler(BaseResponse):
                 range_key_expression_components = range_key_expression.split()
                 range_comparison = range_key_expression_components[1]
 
-                if "AND" in range_key_expression:
+                if " and " in range_key_expression.lower():
                     range_comparison = "BETWEEN"
                     range_values = [
                         value_alias_map[range_key_expression_components[2]],
@@ -521,6 +521,18 @@ class DynamoHandler(BaseResponse):
                     range_values = [
                         value_alias_map[range_key_expression_components[-1]]
                     ]
+                elif "begins_with" in range_key_expression.lower():
+                    function_used = range_key_expression[
+                        range_key_expression.lower().index("begins_with") : len(
+                            "begins_with"
+                        )
+                    ]
+                    return self.error(
+                        "com.amazonaws.dynamodb.v20111205#ValidationException",
+                        "Invalid KeyConditionExpression: Invalid function name; function: {}".format(
+                            function_used
+                        ),
+                    )
                 else:
                     range_values = [value_alias_map[range_key_expression_components[2]]]
             else:
diff --git a/tests/test_dynamodb2/test_dynamodb_table_with_range_key.py b/tests/test_dynamodb2/test_dynamodb_table_with_range_key.py
index 1c8c12110..845c0587d 100644
--- a/tests/test_dynamodb2/test_dynamodb_table_with_range_key.py
+++ b/tests/test_dynamodb2/test_dynamodb_table_with_range_key.py
@@ -1082,6 +1082,72 @@ def test_boto3_conditions():
     results["Count"].should.equal(1)
 
 
+@mock_dynamodb2
+def test_boto3_conditions_ignorecase():
+    dynamodb = boto3.client("dynamodb", region_name="us-east-1")
+
+    # Create the DynamoDB table.
+    dynamodb.create_table(
+        TableName="users",
+        KeySchema=[
+            {"AttributeName": "forum_name", "KeyType": "HASH"},
+            {"AttributeName": "subject", "KeyType": "RANGE"},
+        ],
+        AttributeDefinitions=[
+            {"AttributeName": "forum_name", "AttributeType": "S"},
+            {"AttributeName": "subject", "AttributeType": "S"},
+        ],
+        ProvisionedThroughput={"ReadCapacityUnits": 5, "WriteCapacityUnits": 5},
+    )
+
+    dynamodb.put_item(
+        TableName="users",
+        Item={"forum_name": {"S": "the-key"}, "subject": {"S": "100"}},
+    )
+    dynamodb.put_item(
+        TableName="users",
+        Item={"forum_name": {"S": "the-key"}, "subject": {"S": "199"}},
+    )
+    dynamodb.put_item(
+        TableName="users",
+        Item={"forum_name": {"S": "the-key"}, "subject": {"S": "250"}},
+    )
+
+    between_expressions = [
+        "BETWEEN :start  AND  :end",
+        "between :start  and  :end",
+        "Between :start  and  :end",
+        "between :start  AnD  :end",
+    ]
+    for expr in between_expressions:
+        results = dynamodb.query(
+            TableName="users",
+            KeyConditionExpression="forum_name = :forum_name and subject {}".format(
+                expr
+            ),
+            ExpressionAttributeValues={
+                ":forum_name": {"S": "the-key"},
+                ":start": {"S": "100"},
+                ":end": {"S": "200"},
+            },
+        )
+        results["Count"].should.equal(2)
+
+    with pytest.raises(ClientError) as ex:
+        dynamodb.query(
+            TableName="users",
+            KeyConditionExpression="forum_name = :forum_name and BegIns_WiTh(subject, :subject )",
+            ExpressionAttributeValues={
+                ":forum_name": {"S": "the-key"},
+                ":subject": {"S": "1"},
+            },
+        )
+    ex.value.response["Error"]["Code"].should.equal("ValidationException")
+    ex.value.response["Error"]["Message"].should.equal(
+        "Invalid KeyConditionExpression: Invalid function name; function: BegIns_WiTh"
+    )
+
+
 @mock_dynamodb2
 def test_boto3_put_item_with_conditions():
     import botocore