mirror of
https://github.com/wezm/wezm.net.git
synced 2024-12-21 03:39:54 +00:00
104 lines
3.3 KiB
Markdown
104 lines
3.3 KiB
Markdown
+++
|
|
title = "Generate a JSON Feed for a Zola Website"
|
|
date = 2024-09-28T20:50:30+10:00
|
|
|
|
[extra]
|
|
updated = 2024-09-30T09:08:57+10:00
|
|
+++
|
|
|
|
[JSON Feed] is a specification for representing an RSS-style feed in JSON. I
|
|
wanted to add one as an alternative alongside the Atom feed on a new website
|
|
I'm building. The website is built with [Zola], which unfortunately [doesn't
|
|
support the format][zola-issue], so this is how I went about adding one.
|
|
|
|
<!-- more -->
|
|
|
|
My first idea was to add a Tera template `json.feed` and try to generate JSON
|
|
in the template. This was foiled on multiple fronts:
|
|
|
|
1. Zola only loads files matching `*.{*ml,md}` and `robots.txt` as templates,
|
|
so it didn't render my `json.feed` template.
|
|
2. Tera has a `json_encode` filter but [does not support object literals][tera-issue],
|
|
which makes building well formed JSON tricky.
|
|
|
|
My next thought was to write a tool to convert the Atom feed to JSON. Rust is
|
|
my scripting language of choice these days (only a tiny bit joking) but I
|
|
didn't feel like adding a Rust project and build step for this. I then wondered
|
|
if it could be done with [jq], or in my case [jaq]—a `jq` implementation in
|
|
Rust. Short answer it can. Here's what I came up with:
|
|
|
|
I created `templates/dump.xml` with these contents:
|
|
|
|
```tera
|
|
{{ __tera_context }}
|
|
```
|
|
|
|
This dumps the whole Tera context as JSON when rendered into `public/dump.xml`.
|
|
It's `.xml` so that Zola will render it as a template. I added it to
|
|
`feed_filenames` in the Zola `config.toml`:
|
|
|
|
```toml
|
|
feed_filenames = [
|
|
"atom.xml",
|
|
"dump.xml", # HACK: This just dumps the Tera context as JSON
|
|
]
|
|
```
|
|
|
|
Then I wrote this `jaq` filter (`json-feed.jaq`) to generate a JSON Feed
|
|
`feed.json` from the rendered version of the template.
|
|
|
|
```jq
|
|
# vim: ft=jq
|
|
# Generate a JSON feed from context of a Zola feed template
|
|
{
|
|
"version": "https://jsonfeed.org/version/1.1",
|
|
"title": .config.title,
|
|
"home_page_url": .config.base_url,
|
|
"feed_url": .feed_url | sub("dump\\.xml$"; "feed.json"),
|
|
"authors": [ { "name": .config.author } ],
|
|
"language": "en-AU",
|
|
"items": .pages | map({
|
|
"id": .permalink,
|
|
"url": .permalink,
|
|
"title": .title,
|
|
"content_html": .content,
|
|
"date_published": .date,
|
|
"tags": .taxonomies.tags,
|
|
} + if .updated then {"date_modified": .updated} else {} end
|
|
+ if .extra.link then {"external_url": .extra.link} else {} end)
|
|
}
|
|
```
|
|
|
|
It turned out quite nice. The main challenge with the `jaq` filter was working
|
|
out how to conditionally include a key only if the value was non-null. I ended
|
|
up with the trailing [if-then-else-end] expressions. If there's a better way
|
|
I'd be keen to hear about it.
|
|
|
|
Finally, to coordinate all this I added a `Makefile` that deletes `dump.xml`
|
|
afterwards:
|
|
|
|
```make
|
|
help:
|
|
@echo "Available tasks:"
|
|
@echo
|
|
@echo "- build"
|
|
@echo "- deploy"
|
|
|
|
build:
|
|
zola build
|
|
jaq --from-file json-feed.jaq public/dump.xml > public/feed.json
|
|
rm public/dump.xml
|
|
|
|
deploy:
|
|
@echo todo
|
|
|
|
.PHONY: build depoly
|
|
```
|
|
|
|
[JSON Feed]: https://www.jsonfeed.org/
|
|
[tera-issue]: https://github.com/Keats/tera/issues/898
|
|
[zola-issue]: https://github.com/getzola/zola/issues/311
|
|
[Zola]: https://www.getzola.org/
|
|
[jq]: https://jqlang.github.io/jq/
|
|
[jaq]: https://github.com/01mf02/jaq
|
|
[if-then-else-end]: https://jqlang.github.io/jq/manual/#if-then-else-end
|