Prevent SQL Injection for Realm Database

In React Native, you can use the Realm database to store and retrieve data in a mobile application. To perform a filter query with a prepared statement, you can use the .filtered() method of the Realm database.

Understand SQL Injection for Realm

SQL injection attacks can occur when user-supplied data is used in a SQL query without proper validation or escaping. To prevent SQL injection attacks when using the Realm database in React Native, it’s important to properly validate and escape the user-supplied data before using it in a query.

Here are some steps you can take to prevent SQL injection attacks in a Realm database:

1. Validate user input: Ensure that the user-supplied data meets the expected format and range of values before using it in a query. For example, you can use regular expressions to validate that a string is a valid email address or that a number falls within a certain range.
2. Use prepared statements: Use the .filtered() method with prepared statements as described in my previous answer. This approach automatically escapes the values and prevents SQL injection attacks.
3. Avoid concatenating user-supplied data into the query string: Instead of concatenating user-supplied data into the query string, use the .filtered() method with prepared statements as described above.
4. Sanitize user-supplied data: If you need to concatenate user-supplied data into the query string, you should sanitize the data to remove any malicious characters. For example, you can use the escape() function in JavaScript to escape special characters in a string.

By following these steps, you can ensure that your Realm database is protected against SQL injection attacks in your React Native applications.

Example :

Here is an example of how you can retrieve all objects from the Person model that have a specific value in a certain property:

In this example, the filterValue variable represents the dynamic value that you want to use to filter the results. The .filtered() method takes a string argument that specifies the condition for the filter, and an array of values that will be used to replace placeholders in the string. In this case, we're using the placeholder $0 in the filter condition, and passing filterValue as the first item in the array of values.

This approach provides a secure way to use dynamic values in the filter condition, as it automatically escapes the values and prevents SQL injection attacks.