Contentful is a Hugo theme mainly targeted for personal and one-man-show blogs that focuses on being contentful by having the most minimal format maintaining readability;
beautiful sane defaults while using modern web standards and features in this day and age.
It understands that not all use cases are possible with this theme so it also aims to be easy to extend and modify implementing the feature that you want.
Oh right, this also applies as my first practical application for reading [Practical Typography](https://practicaltypography.com/) by Matthew Butterick.
The quickest way to describe Contentful in one go is a list.
The core feature of Contentful is to be easy to extend while providing sane and modern foundations, if you don't want to.
Here are the default features of the theme provides:
* Beautifully simple default layout while made to be easily modified and extensible.
* Provides a template for valid [RSS](https://cyber.harvard.edu/rss/rss.html), [Atom](https://tools.ietf.org/html/rfc4287), and [JSON](https://jsonfeed.org/) feeds.
* Dark mode toggle.
* Focus on web accessibility and search engine optimization (SEO) including [Twitter cards](https://dev.twitter.com/cards) and [Open Graph protocol](https://opengraphprotocol.org/).
If you're decided to use this theme and don't want to bother using the `--theme` option, just set it in your [site configuration](https://gohugo.io/getting-started/configuration/) with the `theme` field and you're done!
*`toc` accepts a boolean and if enabled, generates a table of contents for your posts (only works with Markdown files to be parsed under Hugo's builtin Markdown parser).
As for custom frontmatter fields for individual pages, Contentful checks the following keys aside from the default keys (e.g., `date`, `tags`, `categories`):
*`author` field accepts an array of dictionaries/objects simiar to the [site `author` field](https://gohugo.io/variables/site/#site-variables-list).
It could be handy for guest posts and co-authored papers with others.
*`hidden` (a boolean), if enabled, excludes the page from being included in [list templates](https://gohugo.io/templates/lists/) such as the homepage, categorial pages, and web feeds.
*`toc` field which only requires a boolean and overrides the global `toc` setting for that page.
* The `copyright` key, similar to the site config's `copyright`, is a plain-text string that gives information about the copyright (or copyleft) of the content.
You can have web syndication formats like RSS and Atom by setting [custom output formats](https://gohugo.io/templates/output-formats) to your site configurations.
I should point out that the web feeds prints the whole content instead of summaries.
Also, they all rely on an icon to be placed in `icon.png`.
For more accurate control regarding the icon paths, you can copy the templates (at `theme/contentful/layouts/_default/list.{rss,atom,json}`) to your own layout folder.
I've conveniently placed some key phrases to easily find them.
Just search for the phrase `ICON, AHOY!` and the icon is usually below it then make your desired changes.
[Multiple languages](https://gohugo.io/content-management/multilingual/) for your site is supported.
You can simply organize your content as described on [this blog post](https://regisphilibert.com/blog/2018/08/hugo-multilingual-part-1-managing-content-translation/).
The theme requires a language code based from [IANA Language Subtag Registry](https://www.iana.org/assignments/language-subtag-registry/language-subtag-registry) as defined from the [W3 documentation](https://www.w3.org/International/questions/qa-choosing-language-tags).
As of 2019-09-21, only English and Tagalog is supported.
Contributions through translations are appreciated.
The theme was made to be easy to modify (thus extend).
But first, a preview of the core file structure of the project that you'll surely some attention in the future:
```shell
hugo-theme-contentful
├── content/
├── i18n/
├── layouts/
├── static/
├── CHANGELOG.adoc*
├── LICENSE*
└── README.md*
```
This is simply the [Hugo's directory structure](https://gohugo.io/getting-started/directory-structure/).
If you're already familiar with this, it shouldn't be a problem.
If you want to store CSS and JavaScript files, it is preferred to store them in `static/` folder.
To edit the site CSS, simply copy the stylesheet located in `theme/contentful/static/css/main.css` to your own static folder (with the same folder structure) and override it with your own modifications.
If your own modification has gone to an extent where maintaining a single CSS file is reminiscent of r
The next folder you most likely want to pay attention is the `layouts/` directory where all of the well, layouts are stored.
There are some things that are already figured out for you such as the templates for RSS, Atom, and JSON feeds.
You can easily add in your own, if you want.
Some things you may want to be customized are the [404 page](./layouts/404.html), [`<head>` for your own scripts](./layouts/partials/head.html), [header](./layouts/partials/header.html), and the [footer](./layouts/partials/footer.html).
Since Contentful does not provide all features by default, you have to implement it yourself ala-[Suckless tools](https://suckless.org/).
(Unlike Suckless tools, it's not as hard, I swear.)
Still, I've provided some recipes for some of the common features I've would added in most Hugo themes (though this is only specific to Contentful).
The following implementation assumes you have the example configuration given from the [configuration section](#configuration) and you're in your own Hugo directory with Contentful installed as a theme.
You can see more recipes for certain features like in the [official documentation](https://gohugo.io/), [its community forum](https://discourse.gohugo.io/), and [other third-party sites](http://hugocodex.org/add-ons/).
One of the most useful example that I won't be listing here is the [breadcrumbs implementation](https://gohugo.io/content-management/sections/#example-breadcrumb-navigation) from the official docs.
### Customizing your `<head>`
Let's start with the most basic and perhaps most useful customization: modifying the `<head`>.
This is useful for adding your own CSS and JavaScript files, changing certain metadata, or adding icons.
First, copy the `head` partial from the theme (`theme/contentful/layouts/partials/head.html`) to your own (`layouts/partials/head.html`).
We're simply taking advantage of [Hugo's lookup order](https://gohugo.io/templates/lookup-order/) where we've override the `head` partial with our own copy.
Then, feel free to add your own (or others') scripts and stylesheets, [icons and other metadata](https://developer.mozilla.org/en-US/docs/Learn/HTML/Introduction_to_HTML/The_head_metadata_in_HTML), or whatever suitable things.
In my case, I often use certain JavaScript libraries like [MathJax](https://www.mathjax.org/) for mathematical typesetting, [Prism](https://prismjs.com/) for syntax highlighting, and [medium-zoom](https://github.com/francoischalifour/medium-zoom/) for interactive image zooms.
Since most of the JavaScript libraries used here are not really a requirement (except for MathJax for mathematical typesetting), I've set them to be loaded at the end of the page loading with [`defer` attribute](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script).
If you have an inline script, you can simply wrap it in an event listener for page loading (`window.addEventListener("load", your_function_goes_here)`).
If you want document-specific libraries, you have to pass some raw HTML through the parser of the document.
For Goldmark, the default Markdown parser starting [Hugo v0.60.0](https://gohugo.io/news/0.60.0-relnotes/), blocks raw HTML by default and you can disable it by setting `markup.goldmark.renderer.unsafe` to `true`.
For Blackfriday, it parses even the raw HTML just fine.
Though, you have to set it as the default Markdown parser.
For [Asciidoctor](https://asciidoctor.org/), you can use [passthroughs](https://asciidoctor.org/docs/user-manual/#passthroughs) to get raw HTML through.
### Twitter cards
This will add [Twitter cards](https://developer.twitter.com/en/docs/tweets/optimize-with-cards/guides/getting-started) for your webpages.
(Be sure to copy the `head` partial first in your own layout folder.)
Thankfully, Hugo already has [an internal template for Twitter cards](https://gohugo.io/templates/internal/#twitter-cards).
Simply add `{{- template "_internal/twitter_cards.html" . -}}` somewhere in your own copy.
(For reference, [here's the source code for the internal template](https://github.com/gohugoio/hugo/blob/25a6b33693992e8c6d9c35bc1e781ce3e2bca4be/tpl/tplimpl/embedded/templates/twitter_cards.html).)
You could also roll your own Twitter cards but I recommend to modify the internal template instead fitting your specific needs.
(Copy the internal template from the given link, create it as a partial in `layouts/partials/twitter_cards.html`, modify it, and insert the template with `{{- partial "twitter_cards.html" -}}`.)
### Open Graph protocol
Next up, we're implementing [Open Graph protocol](https://opengraphprotocol.org/) for our webpages.
Commonly used for making suitable format when sharing the content on certain sites like Facebook.
(Be sure to copy the `head` partial first in your own layout folder.)
Similar to Twitter cards, Hugo has [an internal template for this](https://gohugo.io/templates/internal/#open-graph).
Simply add `{{- template "_internal/opengraph.html" . -}}` somewhere in your own copy.
(For reference, [here's the source code for the internal template](https://github.com/gohugoio/hugo/blob/25a6b33693992e8c6d9c35bc1e781ce3e2bca4be/tpl/tplimpl/embedded/templates/opengraph.html).)
If you want more control and customized version of the output, I recommend to copy the internal template and create a partial (e.g., `layouts/partials/opengraph.html`) and modify it.
### An archive page
This will add an archive page similar to archive pages [like](https://davidtranscend.com/archives/) [these](https://lukesmith.xyz/blogindex.html).
```go
{{- define "main" -}}
<h1>{{ .Title }}</h1>
{{ .Content }}
<hr>
{{- /* Creating a section that lists out regular pages by year */ -}}
{{ range $.Site.RegularPages.GroupByPublishDate "2006" }}
{{- /* Skip regular pages with an invalid creation date string. */ -}}
{{- /* This is convenient if we want to exclude certain posts to be listed by giving no value to `date` in the frontmatter. */ -}}
{{- /* We will also exclude hidden pages. */ -}}
{{ if ne .Key "0001" }}
<sectiondata-year="{{ .Key }}">
<h2id="{{ .Key }}">{{ .Key }}</h2>
<ul>
{{- range where .Pages "Params.hidden" "!=" true -}}
We will simply add this as a layout in our customized theme.
Let's call it `archives` so we have to add a file in `layouts/_default/archives.html` then set a page of our project with the `layout` key in the frontmatter.
We want the archives page to be accessed at `$.Site.BaseURL/archives` so we'll simply create `archives.adoc` ([any valid content files with certain file extensions can do](https://gohugo.io/content-management/formats/#list-of-content-formats), I'm using [Asciidoctor](https://asciidoctor.org/)) with the following example content.
```asciidoctor
---
title: "Archives"
layout: "archive"
---
= Archives
This is the archives of the century.
```
### Configurable social media links
Most themes offer quick social media links with site configuration.
However, it is only limited to popular media sites such as Facebook, Twitter, Instagram, GitHub, etc.
To get around this, we'll make use of [data templates](https://gohugo.io/templates/data-templates/).
Let's create a quick game plan how does it work.
The data is a top-level dictionary/object with each key contains an object with the following fields.
*`url` is the... contact link itself and it is required to have it.
*`name` is the text to appear in the output.
Also required to have.
*`weight` is an integer similar to how Hugo sorts the pages with the lower weight having high precedence;
if this key is absent, it will be interpreted as 0.
And here's the data example in TOML which is placed in `data/contact.toml`.
```toml
[github]
name = "GitHub"
url = "https://github.com/foo-dogsquared"
[gitlab]
name = "Gitlab"
url = "https://gitlab.com/foo-dogsquared"
[keybase]
name = "Keybase"
url = "https://keybase.io/foo_dogsquared"
weight = -1
[twitter]
name = "Twitter"
url = "https://twitter.com/foo_dogsquared"
```
I want my Keybase profile to appear first than anything else for whatever reason so the `weight` key is set to -1.
With this data, we can then create a template out of it.
I've put the following template in a partial named `contacts` (i.e., `layouts/partials/contacts`).
```go
<address>
{{- range (sort $.Site.Data.contact "weight" "asc") -}}
| <arel="me"href="{{ .url }}">{{- .name -}}</a> |
{{- end -}}
</address>
```
A suggestion (and an exercise) for extending this is to create image links.
Maybe add another key named `image` that accepts either URL.
