Crate dojang

Dojang, a EJS inspired HTML template engine.

Dojang is a html template engine, which aims to be an drop-in replacement for the EJS html template engine. It follows the syntax of the EJS and follows the javascript syntax within the template. Dojang also provides the strong integration with Rust.

Dojang is pronounced as doe-jang, and it means a “stamp” in Korean (도장).

Quick Start

Every template files are parsed once during the construction of the Dojang object. Dojang owns and manages every template file provided. To provide the template files to Dojang, you can either specify the directory of the template files using load or you can manually provide the template as string using add method.

use dojang::dojang::Dojang;

fn main() {
  let mut dj = Dojang::new();

  // Load files as template under /template/files/path.
  dj.load("/template/files/path");

  // Register "template_file.html" which have "<%= data %>" as a template.
  dj.add("template_file.html".to_string(), "<%= data %>".to_string());

  // "hello" will be rendered.
  assert_eq!(dj.render("template_file.html", serde_json::json!({"data" : "hello"})).unwrap(), "hello");
}

Those template can be rendered by the either the name of the template file (when registered by load) or the name provided (when reigstered by add).

To render the template, use render method of Dojang. You should provide the name of the template to render and the context to render. Context is simply a json data. Use serde_json to either construct json data or parse the json string. You can even provide your custom struct if you define Serialize trait of serde.

Use Custom Functions

One powerful feature is that you can use Rust functions inside of the template file. For example,

use dojang::dojang::Dojang;

fn add(a: i64, b: i64) -> i64 {
  a + b
}

fn main() {
  let mut dj = Dojang::new();

  // Register our add function as "add_func". You can call add_func inside of the template now.
  dj.add_function_2("add_func".to_string(), add);

  dj.add("template_file.html".to_string(), "<%= add_func(1, 2) %>".to_string());

  // "3" will be rendered.
  assert_eq!(dj.render("template_file.html", serde_json::json!({})).unwrap(), "3");
}

You have to choose add_function_* based on the number of parameters that the function has. We provde add_function_1 to add_function_4.

Also, the type of the function parameter must be non-reference, and should be one of i64, f64, u64, String, bool.

Supported Javascript syntax.

Most of the basic Javascript syntax is supported. Still, any complex javascript usage is not recommended.

• if, else, for .. in, else is supported.

<% for i in vec1 { %>
<%   if i == 1 { %>
  <p>i is one</p>
<%   } else { <%>
  <p><%= i + 3 %></p>
<%   } %>
<% } %>

If vec1 is provided as [1,2,3], then the above will render

<p>i is one</p>
<p>5</p>
<p>6</p>

• break and continue keywords are supported.
• Property accessing using . and [..] are supported
• Calling registered function is supported.
• Local variables can be introduced but it does not have a scope (every introduced local variables are global). It should be used with care. For example,

<%# Sets the value of a as 3. %>
<%= a = 3 %>
<% a %><%# This will print 3 %>

Re-exports

pub use crate::dojang::Dojang;

Modules

dojang

func_helper

Enums

FunctionContainer