Creating a Hugo Theme From Scratch

Jan 25, 2020 software tools

In this post I will show you how to build a minimalist theme for Hugo.

Pre-requisites

A basic understanding of Hugo templating and folder structure
Having installed Hugo locally https://gohugo.io/getting-started/installing/

Hugo is written in Go, but you do not need to install it for now.

Getting started

Create a new Hugo site
```
hugo new site example
```
Go into the newly created folder
```
cd example
```
Create a new theme
```
hugo new theme exampleTheme
```

This will have created a themes folder with a exampleTheme subfolder, the folder structure should look like this

.
├── archetypes
│   └── default.md
├── config.toml
├── content
├── data
├── layouts
├── resources
│   └── _gen
│       ├── assets
│       └── images
├── static
└── themes
    └── exampleTheme
        ├── LICENSE
        ├── archetypes
        │   └── default.md
        ├── layouts
        │   ├── 404.html
        │   ├── _default
        │   │   ├── baseof.html
        │   │   ├── list.html
        │   │   └── single.html
        │   ├── index.html
        │   └── partials
        │       ├── footer.html
        │       ├── head.html
        │       └── header.html
        ├── static
        │   ├── css
        │   └── js
        └── theme.toml

Check that everything is working fine by starting the server
```
hugo server
```
Navigate to http://localhost:1313, and check there are no errors in the developer console (Chrome) or equivalent in your browser of choice

Check the config.toml file and make sure it looks like this

baseURL = "http://example.org/"
languageCode = "en-us"
title = "My New Hugo Site"

I will be using this for the rest of the post, but feel free to customise it

Partials

Partials are small, context-aware components that can be used economically to keep your templating DRY.

Head

Open example/themes/exampleTheme/layouts/partials/head.html in a text editor
This will be the place for metadata like the document title, character set, styles, scripts, and other meta information

Paste the following

<head>
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1">
    <link rel="stylesheet" type="text/css" href="/css/bootstrap.min.css">
    <link rel="stylesheet" type="text/css" href="/css/style.css">
    {{ $title := print .Site.Title " | " .Title }}
    {{ if .IsHome }}{{ $title = .Site.Title }}{{ end }}
    <title>{{ $title }}</title>
</head>

Here we are specifying the charset that our document will use, utf-8 in this case, the viewport information and couple of stylesheets
Let’s go ahead and add the missing CSS files
Go to example/themes/exampleTheme/static/css and create a file called style.css, we will place our custom CSS here later on
Go to https://getbootstrap.com/ and download the latest version of Bootstrap (v4.4.1 at the time of writing)
Extract the ZIP file and copy bootstrap.min.css to example/themes/exampleTheme/static/css
Finally, for the title, we will render the site title as it appears in config.toml when we are at the homepage and we will concatenate the section name when we are in a section page e.g. My New Hugo Site | Posts

Script

In addition to Bootstrap, we are going to use Feather icons to display icons on our site
Go to https://github.com/feathericons/feather#client-side-javascript and download feather.min.js into example/themes/exampleTheme/static/js
Create a file example/themes/exampleTheme/layouts/partials/script.html and paste the following
```
<script src="/js/feather.min.js"></script>
<script>
  feather.replace()
</script>
```

Header and footer

Let’s add a nav to the header so that we can navigate between the different sections of our site

Open example/themes/exampleTheme/layouts/partials/header.html and paste the following

<div id="nav-border" class="container">
    <nav id="nav" class="nav justify-content-center">
        {{ range .Site.Menus.main }}
        <a class="nav-link" href="{{ .URL }}">
        {{ if .Pre }}
        {{ $icon := printf "<i data-feather=\"%s\"></i> " .Pre | safeHTML }}
        {{ $icon }}
        {{ end }}
        {{ $text := print .Name | safeHTML }}
        {{ $text }}
        </a>
        {{ end }}
    </nav>
</div>

Here we are creating a nav menu that will be centred at the top of each page
Each menu item will have a link and also an icon if we configure it as a pre property in config.toml, more on that later

For the footer let’s just add a basic copyright disclaimer

<p class="footer text-center">Copyright (c) {{ now.Format "2006"}} John Doe</p>

You can replace John Doe with your name
The current year will be displayed as well
If you are wondering why “2006”, you can find out more about it here

Metadata

Let’s create one more partial to display metadata about each post e.g. date and tags

Create a new file example/themes/exampleTheme/layouts/partials/metadata.html

{{ $dateTime := .PublishDate.Format "2006-01-02" }}
{{ $dateFormat := .Site.Params.dateFormat | default "Jan 2, 2006" }}
<i data-feather="calendar"></i>
<time datetime="{{ $dateTime }}">{{ .PublishDate.Format $dateFormat }}</time>
{{ with .Params.tags }}
<i data-feather="tag"></i>
{{ range . }}
{{ $href := print (absURL "tags/") (urlize .) }}
<a class="btn btn-sm btn-outline-dark tag-btn" href="{{ $href }}">{{ . }}</a>
{{ end }}
{{ end }}

We are using Feather icons to spice things up a little, but in fact we are just rendering the publication date and the tags
Tags will be passed in as parameters from the post itself in the front matter, more information here
```
---
author: "John Doe"
title: "My First Post"
date: "2006-02-01"
tags: ["foo", "bar"]
---
```

Default layouts

Now we have all the basic ingredients to work on the layouts
These are placed under example/themes/exampleTheme/layouts/_default and, at least, consist of
- baseof
- list
- single

Baseof

This will be the base template for all pages, and should reference the different partials we edited above.

Open example/themes/exampleTheme/layouts/_default/baseof.html, it should look like this

<!DOCTYPE html>
<html>
    {{- partial "head.html" . -}}
    <body>
        {{- partial "header.html" . -}}
        <div id="content">
        {{- block "main" . }}{{- end }}
        </div>
        {{- partial "footer.html" . -}}
    </body>
</html>

Let’s also include the script.html partial with our Feather icons

<!DOCTYPE html>
<html>
    {{- partial "head.html" . -}}
    <body>
        {{- partial "header.html" . -}}
        <div id="content">
        {{- block "main" . }}{{- end }}
        </div>
        {{- partial "footer.html" . -}}
        {{- partial "script.html" . -}}
    </body>
</html>

It’s good practice to place our scripts at the end of the HTML code so that it doesn’t block rendering the page

List

This layout will be used to display the list of posts on our site.

Open example/themes/exampleTheme/layouts/_default/list.html

We will define the main section of the baseof layout like this

{{ define "main" }}
<h1>{{ .Title }}</h1>
{{ range .Pages.ByPublishDate.Reverse }}
<p>
    <h3><a class="title" href="{{ .RelPermalink }}">{{ .Title }}</a></h3>
    {{ partial "metadata.html" . }}
    <a class="summary" href="{{ .RelPermalink }}">
        <p>{{ .Summary }}</p>
    </a>
</p>
{{ end }}
{{ end }}

We are displaying the metadata i.e. publication date and tags, and the summary of the post
We are also sorting posts by publication date in reverse order, most recent first

Single

This layout will be used to display a single post.

Open example/themes/exampleTheme/layouts/_default/single.html

Similarly to what we did above, let’s define the main section

{{ define "main" }}
<h1>{{ .Title }}</h1>
{{ partial "metadata.html" . }}
<br><br>
{{ .Content }}
{{ end }}

Like before, we will display the metadata, but in this case, we will display the full content instead of the summary

Homepage

This will be the landing page at the root of our site.

Open example/themes/exampleTheme/layouts/index.html in a text editor
With Bootstrap in place, we can now use the Jumbotron component to render a hero section

Paste the following

{{ define "main" }}
<div id="home-jumbotron" class="jumbotron text-center">
  <h1 class="title">{{ .Site.Title }}</h1>
</div>
{{ end }}

404

This is used to customise an error message for when a link is broken. However, Hugo comes with a default one, so let’s delete it for now.

Feel free to play with the contents of the file if you want to customise your error messages.

Configuration

We have created the template, now we need to tell Hugo to use it for our site.

Open example/config.toml and add a line to select the theme like this
```
theme = "exampleTheme"
```

We’ll also need a menu to navigate to the different sections, let’s add it

[menu]
  [[menu.main]]
    name = "Home"
    pre = "home"
    url = "/"
    weight = 1
  [[menu.main]]
    name = "Posts"
    pre = "pen-tool"
    url = "/posts/"
    weight = 2
  [[menu.main]]
    name = "Tags"
    pre = "tag"
    url = "/tags/"
    weight = 3

Here we are defining a menu, and referencing it with the name main to match our header (.Site.Menus.main)
In Hugo there is another way to create a menu quickly, and that is by adding this line to your config.toml file instead, more information here
```
sectionPagesMenu = "main"
```
However we want to be able to customise our nav menu and add icons, therefore we’ll go with the manual approach

Write your first post

The real value of a website is its content. Let’s create a post before we have a look at the final result.

Open a terminal and use the following command from the root of your site to create a post
```
hugo new posts/my-first-post.md
```
Open the newly created example/content/posts/my-first-post.md
Add some tags to the front matter
```
tags: ["foo", "bar"]
```
Add some content under the front matter
Hugo automatically takes the first 70 words of your content as its summary and stores it into the .Summary variable
Instead, you can manually define where the summary ends with a  divider
Alternatively, you can add a summary to the front matter if you don’t want your summary to be the beginning of your post

The final result should look similar to this

---
title: "My First Post"
date: 2020-01-26T23:11:13Z
draft: true
tags: ["foo", "bar"]
---
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor 
incididunt ut labore et dolore magna aliqua. Pellentesque eu tincidunt tortor 
aliquam nulla facilisi cras fermentum odio. A erat nam at lectus urna duis. 
Sed velit dignissim sodales ut eu sem. Lectus urna duis convallis convallis 
tellus. Diam sit amet nisl suscipit adipiscing bibendum est. Sed felis eget 
velit aliquet sagittis id consectetur. Vulputate dignissim suspendisse in est 
ante in nibh mauris cursus. Morbi quis commodo odio aenean. Mollis nunc sed id 
semper risus in hendrerit gravida rutrum.

<!--more-->

Ac ut consequat semper viverra nam. Hac habitasse platea dictumst vestibulum 
rhoncus. Amet porttitor eget dolor morbi non. Justo eget magna fermentum 
iaculis eu non. Id eu nisl nunc mi ipsum faucibus vitae aliquet nec. Aliquam 
id diam maecenas ultricies. Non sodales neque sodales ut etiam. Amet massa 
vitae tortor condimentum lacinia quis. Erat imperdiet sed euismod nisi porta. 
Nisl suscipit adipiscing bibendum est ultricies integer quis auctor. Viverra 
suspendisse potenti nullam ac. Tincidunt id aliquet risus feugiat in. Varius 
quam quisque id diam vel. Egestas erat imperdiet sed euismod nisi. Scelerisque 
felis imperdiet proin fermentum leo vel orci porta non. Ut faucibus pulvinar 
elementum integer. Fermentum odio eu feugiat pretium nibh ipsum consequat nisl.

Trying it out

Open a terminal and run the following from the root folder of your site
```
hugo server -D
```
The -D option means to include content marked as draft
Alternatively, edit the front matter of your post and change this line draft: true to draft: false
Navigate to http://localhost:1313
You should see something like this

Final thoughts

In this post I’ve showed how to create a simple template and apply it to a new Hugo site. From here, you can customise the look and feel with the style.css file and modify the template to add more features.

In future posts I will show how to add share buttons and analytics to our site.

If you want to jump ahead and see the final template that I use for my site, you can find it in GitHub here.

Thanks for reading!