+++
title = "Zola"
description = "Zola is a static site generator"
date = 2025-05-01T18:00:00+00:00
updated = 2021-05-01T18:00:00+00:00
template = "section.html"
sort_by = "weight"
weight = 4
draft = false
+++

# Zola

[Zola](https://getzola.org) is a static site generator written in
[Rust](../rust). It builds an entire web page out of a structured markdown
collection and a collection of HTML templates. The templating language is called
[Tera](https://tera.netlify.app).

## Running Zola

- `zola init` - Starts a new Zola project. Not for the faint of heart.
- `zola serve` - Starts a localhost webserver to serve your content for demo
- `zola build` - Builds a Zola project into a collection of static HTML.

## Project layout

The following files and folders define a basic Zola project

- `config.toml`: A configuration file in the [TOML](https://toml.io/en/)
  configuration language. Can contain a lot of information that will be made
  available to *all* pages in the system.
- `content/`: The structured content folder.
- `sass/`: [Sass](../sass) is a CSS preprocessor language that makes CSS easier.
- `static/`: Static content such as images, fonts, and Javascript
- `templates`: The HTML templates (and includes, etc) that define the website's
  layouts
  
Note that if you want to use modern Javascript features such as a precompiler
like Typescript or a bundler like Webpack, that is outside the functionality of
Zola. You'll have to have a separate project for that, or a subfolder or git
submodule, and you'll have to have a separate build step for that.

It's also a bit of a shame that Tera is 100% an HTML play, and there's no HAML
or similar HTML templating involved.  That would be a nifty project.

## Tera

The Tera templating language looks a lot like Django's, or for that matter any
number of templating languages. Every page generated with Tera receives a
_context_, which can be thought of as a JSON object with which to populate the
page (it is, technically, a [Serde::Serializable](https://serde.rs/)). Zola
provides a large and complex context, which is explained further down.

Tera has the following syntax. Everything within these markers is processed by
Tera; everything outside is left untouched.

- `{{` and `}}` for expressions
- `{%` and `%}` for statements
- `{#` and `#}` for comments

Statements that have a dash as part of their delimeter remove all whitespace
from around the delimiter.  `{%-` says to eliminate all whitespace between this
statement and anything that came before it; `-%}` says to eliminate everything
that comes after it.

### Statements

#### `set`

Variables are set in a given scope with `set`:

```jinja2
{% set my_var = "hello" %}
```

Sets a variable `my_var`. Variables can contain booleans, floats, strings,
integers, and arrays. There is a special syntax, `set_global`, that can be used
to set variables one level up in scope when working inside `for` loops (i.e. in
the outer scope containing the loop, preserving its content between iterations).

#### `if`

Conditional statements are managed with `if/is ... else ... endif`

```jinja2
{% if my_var is ... %} ... {% endif %}
```

The list of `is` tests that are shipped with Zola are:

- `defined`: the given variable is defined.
- `undefined`: the given variable is undefined.
- `odd`: the given variable is an odd number.
- `even`: the given variable is an even number.
- `string`: the given variable is a string.
- `number`: the given variable is a number.
- `divisibleby`: the given expression is divisible by the arg given.
- `iterable`: Returns true if the given variable can be iterated over in Tera (i.e. is an array/tuple or an object).
- `object`: Returns true if the given variable is an object (i.e. can be iterated over key, value).
- `starting_with(string)`: Returns true if the given variable is a string and starts with the arg given.
- `ending_with(string)`: Returns true if the given variable is a string and ends with the arg given.
- `containing(val)`: Returns true if the given variable contains the arg given.
  - strings: is the arg a substring?
  - arrays: is the arg given one of the members of the array?
  - maps: is the arg given a key of the map?
- `matching(regexp)`: Returns true if the given variable is a string and matches the regex in the argument.

#### `for`

Arrays are iterated with the `for x in array/map ... endfor` syntax.

```jinja2
{% for name in users %}
Hello: {{ name }}
{% endfor %}
```

Maps will provide a key/value pair. The names of the two fields are arbitrary:

```jinja2
{% for name, label in options %}
<option value="{name}">{label}</option>
{% endfor %}
```

Array filters (see below) are invoked before the loop. The following will print
the list in reverse order.

```jinja2
{% for name in users | reverse %}{{ name }}{% endfor %}
```

#### `include`

Include other content into the current template being rendered. Include strings
cannot be built out of variables, but they _may_ be a list, in which case the
first filename found is rendered. If the include block has the phrase 'ignore
missing' at the end a missing file will not cause an error at build time.

```jinja2
{% include "header.html" %}
```

#### Macros

Macros are blocks of template that can be passed variables; they're basically
just big chunks of content that can be parameterized. Macros must be defined in
a file separate from the main content and imported with a distinct syntax from
`import`:

```jinja2
{% import "header.html" as header %}
```

The header macro can be invoked in that file like this:

```jinja2
{{ header::header("My Blog!") }}
```

And an example of this macro (again, in the `header.html` file) would look like this:

```jinja2
{% macro header(title) %}
<header class="header">
  <h1>{ title }</h1>
</header>
{% endmacro %}
  ```


```jinja2
{% raw %}Content {{ goes here }}{% endraw %}
```

Content within the `raw` block will not be processed.