Liquid Toolkit

Basics

Liquid Security Basics

Liquid Security Practices

Liquid security ensures safe input handling in Shopify themes.

Introduction to Liquid Security

Liquid is a templating language used in Shopify themes to display dynamic content. Ensuring security in Liquid templates is crucial to protect against vulnerabilities, such as cross-site scripting (XSS), which can lead to unauthorized data exposure and theme manipulation. This post covers essential practices for handling inputs securely in Liquid templates.

Understanding Variable Output

Liquid outputs variables using the syntax {{ variable }}. By default, Liquid escapes HTML entities to prevent XSS attacks. This means special characters are converted to their HTML entity equivalents, ensuring safe rendering in the browser.

Escaping Output Manually

While Liquid escapes HTML by default, there might be cases where you need to ensure extra safety or handle custom escaping. For manual escaping, you can use the | escape filter, which converts characters like <, >, and & to HTML-safe sequences.

Using Filters for Safe Display

Filters in Liquid transform output and can be used to ensure security. For instance, the | strip_html filter can remove all HTML tags from a variable, preventing any embedded scripts or styles from executing.

Sanitizing URLs

When dealing with URLs, it's important to ensure they are safe and well-formed. The | url_escape filter helps in encoding URLs, making them safe to use within templates.

Avoiding Unsafe Liquid Code

Be cautious when using the {% raw %} and {% endraw %} tags, as they disable Liquid parsing. This can lead to security issues if user input is not properly sanitized, as it allows raw HTML to be outputted directly.

Conclusion

Understanding and implementing Liquid security practices is vital for maintaining the integrity and safety of Shopify themes. By leveraging built-in filters and being mindful of how Liquid handles inputs, you can significantly reduce the risk of common security vulnerabilities.

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