The Liquid template language is a simple, expressive, and powerful templating language originally created by Shopify. It's designed to enable developers to embed dynamic content in static web pages, particularly in e-commerce sites, but it's also widely used in static site generators like Jekyll and other web applications.
### Key Features of Liquid:
1. **Simple Syntax**:
- Liquid uses a combination of tags, filters, and objects to embed logic and dynamic content within templates.
- Tags: Control the logic (e.g., `{% if %}`, `{% for %}`, `{% assign %}`).
- Objects: Output data from variables (e.g., `{{ product.title }}`).
- Filters: Modify the output of objects (e.g., `{{ product.title | upcase }}`).
2. **Safe and Secure**:
- Liquid ensures that template authors can't execute arbitrary code, providing a secure way to embed logic within templates.
3. **Designed for Performance**:
- It's optimized for speed and efficiency, making it suitable for high-traffic e-commerce sites.
4. **Extensible**:
- Liquid allows for custom filters and tags, enabling developers to extend its functionality as needed.
### Basic Syntax Examples:
1. **Variables**:
```liquid
{{ variable_name }}
```
2. **Tags**:
- Control structures, such as loops and conditionals:
```liquid
{% if product.available %}
This product is available.
{% else %}
This product is out of stock.
{% endif %}
```
- Iteration over collections:
```liquid
{% for product in products %}
{{ product.title }}
{% endfor %}
```
3. **Filters**:
- Used to modify output:
```liquid
{{ "hello world" | upcase }}
{{ product.price | divided_by: 100 }}
```
### Common Use Cases:
1. **E-commerce Sites**:
- Display product information, handle shopping cart logic, and render customer data dynamically.
2. **Static Site Generators**:
- Used in Jekyll to render dynamic content on static websites.
3. **Content Management Systems**:
- Integrates with CMS platforms to allow for dynamic content rendering.
### Example in an E-commerce Context:
```liquid
{{ page.title }}
{{ shop.name }}
{% for product in collections.frontpage.products %}
```
In this example, the Liquid template dynamically generates a list of products, displaying their title, description, and price.
### Conclusion
Liquid is a versatile and secure templating language well-suited for applications where dynamic content needs to be rendered safely and efficiently. Its straightforward syntax and extensive use in platforms like Shopify and Jekyll make it a popular choice among developers.