Crate horrorshow [−] [src]

Horrorshow

An html templating library.

Example:

use horrorshow::prelude::*;
let actual = html! {
    html {
        head {
            title { : "Hello world!" }
        }
        body {
            // attributes
            h1(id="heading") {
                // Insert escaped text
                : "Hello! This is <html />"
            }
            p {
                // Insert raw text (unescaped)
                : raw!("Let's <i>count</i> to 10!")
            }
            ol(id="count") {
                // run some inline code...
                |mut tmpl| for i in 0..10 {
                    // append to the current template.
                    // store output because rust bug #25753
                    tmpl = tmpl << html! {
                        li {
                            // format some text
                            #{"{}", i+1 }
                        }
                    };
                }
            }
            // You need semi-colons for tags without children.
            br; br;
            p {
                : "Easy!"
            }
        }
    }
}.into_string();

let expected = "<html><head><title>Hello world!</title></head><body><h1 id=\"heading\">Hello! This is &lt;html /&gt;</h1><p>Let's <i>count</i> to 10!</p><ol id=\"count\"><li>1</li><li>2</li><li>3</li><li>4</li><li>5</li><li>6</li><li>7</li><li>8</li><li>9</li><li>10</li></ol><br /><br /><p>Easy!</p></body></html>";
assert_eq!(expected, actual);

Or cleaned up:

<html>
  <head>
    <title>Hello world!</title>
  </head>
  <body>
    <h1 id="heading">Hello!</h1>
    <p>Let's count to 10!</p>
    <ol id="count">
      <li>1</li>
      <li>2</li>
      <li>3</li>
      <li>4</li>
      <li>5</li>
      <li>6</li>
      <li>7</li>
      <li>8</li>
      <li>9</li>
      <li>10</li>
    </ol>
    <br /><br />
    <p>Easy!</p>
  </body>
</html>

Usage

Inside an html template, the following expressions are valid:

  • some_tag; -- Insert a the tag some_tag.

  • some_tag(attr=rust_expresion,...); -- Insert a the tag some_tag with the specified attributes. The attribute values will be evaluated as rust expressions at runtime.

  • some_tag { ... } -- Insert the tag some_tag and recursively evaluate the ....

  • some_tag(...) { ... } -- Same as above but with custom attributes.

  • : rust_expression, : { rust_code } -- Evaluate the expression or block and insert result current position. To insert literal html, mark it as raw with the raw! macro.

  • #{"format_str", rust_expressions... } -- Format the arguments according to format_str and insert the result at the current position.

  • |tmpl| rust_expression, |tmpl| { rust_code } -- Evaluate the expression or block. This is actually a closure so the block/expression can append to the current template through tmpl (of type &mut TemplateBuilder).

Traits, traits oh-my!

You will likely notice that there are four render traits:

  1. RenderOnce
  2. RenderMut
  3. Render
  4. RenderBox

These three traits map to the four Fn traits and reflect the fact that some templates need exclusive access (RenderMut) in order to be rendered and others might even consume their environment (RenderOnce).

In general, just import Template into your environment (or import the prelude).

Error Handling

IO errors (writing to the buffer) are handled in the background. If an io (or fmt) error occurs, template rendering will continue but no more data will be written and the original write_to_fmt/write_to_io call will return the error when rendering terminates.

There is no way to abort template rendering other than panicing. Try to do everything that can fail before rendering a template.

Modules

prelude

Traits that should always be imported.

Macros

box_html!

Crate a new owned html template.
html!

Crate a new html template
raw!

Mark a string as a raw. The string will not be rendered.

Structs

Raw

Raw content marker.
Renderer

A template renderer. The html! {} macro returns a Renderer.
TemplateBuilder

A template builder. This is the type that gets passed to closures inside templates.

Traits

Render

Something that can be rendered by reference.
RenderBox

Something that can be rendered once out of a box.
RenderMut

Something that can be rendered by mutable reference.
RenderOnce

Something that can be rendered once.
Template

A template that can be rendered into something.