Rust Templating Crates: A Comprehensive Guide
Choosing the Right Templating Crate for Your Rust Project
Rust offers a diverse range of templating crates, each with its unique features and strengths. In this article, we’ll explore three of the most popular templating crates, highlighting their capabilities, and providing guidance on how to get started with each.
1. Handlebars: A Minimal yet Powerful Templating System
Handlebars, originally developed for JavaScript, has been ported to Rust, offering a minimal yet powerful templating system. This crate is widely used, including by rust-lang.org, and is considered one of the most production-ready templating crates for Rust.
To use Handlebars, add it to your dependencies and create a new project with Cargo. Register a template using a string and supply the required data as a key-value pair in a HashMap. You can also enable strict mode to produce a RenderError when trying to access fields that don’t exist.
Loading Templates
For longer templates, consider moving them into their own files using the include_str macro. This macro includes the content of the file at compile time, yielding a &’static str. Alternatively, you can load templates at runtime using Handlebars’ utility functions.
2. Tera: A Feature-Rich Templating Language
Tera, inspired by Jinja2 and the Django template language, offers a more feature-rich templating language than Handlebars. Unlike Handlebars, Tera allows for complex logic within templates and is more flexible.
To get started with Tera, add the dependency to your Cargo.toml file. Register a template string, define some data context, and render an output string using the template and data. Tera’s templating language supports math, comparisons, conditional control structures, and more.
Using Filters and Loops
Tera includes filters that can be used to modify data from within a template. You can also register your own custom filters. For iterating over arrays and structs, Tera provides for loops. Additionally, you can compose templates using the include function.
3. Liquid: A Port of the Popular Liquid Template Language
Liquid, originally written in Ruby, has been ported to Rust, offering 100% compatibility with Shopify/liquid. This crate allows you to create templates with a similar syntax to Tera.
To use Liquid, add it to your dependencies and create a single template struct at a time. Define your data using the liquid::object macro or work with the liquid::Object type directly. Liquid templates have many similarities to Tera templates, including delimiters for expressions and statements, and filters with a similar syntax.
Conclusion
Rust offers excellent support for templating, with Handlebars and Tera being stable, production-ready crates. While Liquid may not be at the same level yet, it’s still a solid choice. With these crates, you can reap the performance and reliability benefits of writing web applications in Rust.