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|
#+TITLE: ~soupault~
#+SERIES: ../cleopatra.html
#+SERIES_PREV: ./theme.html
#+SERIES_NEXT: ./commands.html
We use ~soupault~ to build this website[fn::~soupault~ is an awesome
free software project, with a unique approach to static website
generation. You should definitely [[https://soupault.app][check out their website]]!].
#+begin_export html
<nav id="generate-toc"></nav>
#+end_export
* Installation
We install ~soupault~ in a local switch. We use a witness file
~_opam/.init~ to determine whether or not our switch has always been
created during a previous invocation of *~cleopatra~*.
#+begin_src makefile :tangle soupault.mk
OCAML_VERSION := 4.11.2
OCAML := ocaml-base-compiler.${OCAML_VERSION}
CONFIGURE += _opam rss.json
ARTIFACTS += out
soupault-prebuild : _opam/init
#+end_src
Using ~soupault~ is as simple as calling it, without any particular
command-line arguments.
#+begin_src makefile :tangle soupault.mk
soupault-build : package-lock.json style.min.css
@cleopatra echo "Executing" "soupault"
@soupault
#+end_src
We now describe our configuration file for ~soupault~.
* Configuration
#+name: base-dir
#+begin_src verbatim :noweb yes :exports none
~lthms
#+end_src
** Global Settings
The options of the ~[settings]~ section of a ~soupault~
configuration are often self-explanatory, and we do not spend too
much time to detaul them.
#+begin_src toml :tangle soupault.conf :noweb yes
[settings]
strict = true
site_dir = "site"
build_dir = "out/<<base-dir>>"
doctype = "<!DOCTYPE html>"
clean_urls = false
generator_mode = true
complete_page_selector = "html"
default_content_selector = "main"
page_file_extensions = ["html"]
ignore_extensions = [
"v", "vo", "vok", "vos", "glob",
"html~", "org"
]
default_template_file = "templates/main.html"
pretty_print_html = false
#+end_src
** Setting Page Title
We use the “page title” widget to set the title of the webpage
based on the first (and hopefully the only) ~<h1>~ tag of the
page.
#+begin_src toml :tangle soupault.conf
[widgets.page-title]
widget = "title"
selector = "h1"
default = "~lthms"
prepend = "~lthms: "
#+end_src
** Acknowledging ~soupault~
When creating a new ~soupault~ project (using ~soupault --init~),
the default configuration file suggests advertising the use of
~soupault~. Rather than hard-coding the used version of ~soupault~
(which is error-prone), we rather determine the version of
~soupault~ with the following script.
#+NAME: soupault-version
#+begin_src bash :results verbatim output
soupault --version | head -n 1 | tr -d '\n'
#+end_src
The configuration of the widget ---initially provided by
~soupault~--- becomes less subject to the obsolescence[fn::That
is, as long as ~soupault~ does not change the output of its
~--version~ option.].
#+begin_src toml :tangle soupault.conf :noweb yes
[widgets.generator-meta]
widget = "insert_html"
html = """<meta name="generator" content="<<soupault-version()>>">"""
selector = "head"
#+end_src
** Prefixing Internal URLs
On the one hand, internal links can be absolute, meaning they
start with a leading ~/~, and therefore are relative to the
website root. On the other hand, website (especially static
website) can be placed in larger context. For instance, my
personal website lives inside the ~~lthms~ directory of the
~soap.coffee~ domain[fn::To my experience in hosting webapps and
websites, this set-up is way harder to get right than I initially
expect.].
The purpose of this plugin is to rewrite internal URLs which are relative to the
root, in order to properly prefix them.
From a high-level perspective, the plugin structure is the following.
First, we validate the widget configuration.
#+BEGIN_SRC lua :tangle plugins/urls-rewriting.lua
prefix_url = config["prefix_url"]
if not prefix_url then
Plugin.fail("Missing mandatory field: `prefix_url'")
end
if not Regex.match(prefix_url, "^/(.*)") then
prefix_url = "/" .. prefix_url
end
if not Regex.match(prefix_url, "(.*)/$") then
prefix_url = prefix_url .. "/"
end
#+END_SRC
Then, we propose a generic function to enumerate and rewrite tags
which can have.
#+BEGIN_SRC lua :tangle plugins/urls-rewriting.lua
function prefix_urls (links, attr, prefix_url)
index, link = next(links)
while index do
href = HTML.get_attribute(link, attr)
if href then
if Regex.match(href, "^/") then
href = Regex.replace(href, "^/*", "")
href = prefix_url .. href
end
HTML.set_attribute(link, attr, href)
end
index, link = next(links, index)
end
end
#+END_SRC
Finally, we use this generic function for relevant tags.
#+BEGIN_SRC lua :tangle plugins/urls-rewriting.lua
prefix_urls(HTML.select(page, "a"), "href", prefix_url)
prefix_urls(HTML.select(page, "link"), "href", prefix_url)
prefix_urls(HTML.select(page, "img"), "src", prefix_url)
prefix_urls(HTML.select(page, "script"), "src", prefix_url)
prefix_urls(HTML.select(page, "use"), "href", prefix_url)
#+END_SRC
Again, configuring soupault to use this plugin is relatively
straightforward.
#+BEGIN_SRC toml :tangle soupault.conf :noweb yes
[widgets.urls-rewriting]
widget = "urls-rewriting"
prefix_url = "<<base-dir>>"
after = "mark-external-urls"
#+END_SRC
** Marking External Links
#+BEGIN_SRC lua :tangle plugins/external-urls.lua
function mark(name)
return '<span class="icon"><svg><use href="/img/icons.svg#'
.. name ..
'"></use></svg></span>'
end
links = HTML.select(page, "a")
index, link = next(links)
while index do
href = HTML.get_attribute(link, "href")
if href then
if Regex.match(href, "^https?://github.com") then
icon = HTML.parse(mark("github"))
HTML.append_child(link, icon)
elseif Regex.match(href, "^https?://") then
icon = HTML.parse(mark("external-link"))
HTML.append_child(link, icon)
end
end
index, link = next(links, index)
end
#+END_SRC
#+BEGIN_SRC toml :tangle soupault.conf
[widgets.mark-external-urls]
after = "generate-history"
widget = "external-urls"
#+END_SRC
** Generating a Table of Contents
The ~toc~ widget allows for generating a table of contents for
HTML files which contains a node matching a given ~selector~ (in
the case of this document, ~#generate-toc~).
#+begin_src toml :tangle soupault.conf
[widgets.table-of-contents]
widget = "toc"
selector = "#generate-toc"
action = "replace_content"
valid_html = true
min_level = 2
max_level = 3
numbered_list = false
heading_links = true
heading_link_text = " §"
heading_links_append = true
heading_link_class = "anchor-link"
[widgets.append-toc-title]
widget = "preprocess_element"
selector = "#generate-toc"
command = 'echo "<h2>Table of Contents</h2> $(cat)"'
after = "table-of-contents"
#+end_src
** Generating Per-File Revisions Tables
*** Users Instructions
This widgets allows to generate a so-called “revisions table” of
the filename contained in a DOM element of id ~history~, based on
its history. Paths should be relative to the directory from which
you start the build process (typically, the root of your
repository). The revisions table notably provides hyperlinks to a
~git~ webview for each commit.
For instance, considering the following HTML snippet
#+begin_src html
<div id="history">
site/posts/FooBar.org
</div>
#+end_src
This plugin will replace the content of this ~<div>~ with the
revisions table of ~site/posts/FooBar.org~.
*** Customization
The base of the URL webview for the document you are currently
reading is src_verbatim[:noweb yes :exports code]{<<repo>>}.
#+name: repo
#+begin_src verbatim :exports none
https://code.soap.coffee/writing/lthms.git
#+end_src
The template used to generate the revision table is the following.
#+begin_src html :tangle templates/history.html :noweb yes
<details id="history">
<summary>Revisions</summary>
<p>
This revisions table has been automatically generated
from <a href="<<repo>>">the
<code>git</code> history of this website repository</a>, and the
change descriptions may not always be as useful as they should.
</p>
<p>
You can consult the source of this file in its current version
<a href="<<repo>>/tree/{{file}}">here</a>.
</p>
<table class="fullwidth">
{{#history}}
<tr>
<td class="date"
{{#created}}
id="created-at"
{{/created}}
{{#modified}}
id="modified-at"
{{/modified}}
>{{date}}</td>
<td class="subject">{{subject}}</td>
<td class="commit">
<a href="<<repo>>/commit/{{filename}}/?id={{hash}}">{{abbr_hash}}</a>
</td>
</tr>
{{/history}}
</table>
</details>
#+end_src
*** Implementation
We use the built-in [[https://soupault.neocities.org/reference-manual/#widgets-preprocess-element][=preprocess_element=]] to implement, which
means we need a script which gets its input from the standard
input, and echoes its output to the standard input.
#+begin_src toml :tangle soupault.conf
[widgets.generate-history]
widget = "preprocess_element"
selector = "#history"
command = 'scripts/history.sh templates/history.html'
action = "replace_element"
#+end_src
This plugin proceeds as follows:
1. Using an ad-hoc script, it generates a JSON containing for each revision
- The subject, date, hash, and abbreviated hash of the related commit
- The name of the file at the time of this commit
2. This JSON is passed to a mustache engine (~haskell-mustache~) with a
proper template
3. The content of the selected DOM element is replaced with the output of
~haskell-mustache~
This translates in Bash like this.
#+begin_src bash :tangle scripts/history.sh :shebang "#!/usr/bin/bash"
function main () {
local file="${1}"
local template="${2}"
tmp_file=$(mktemp)
generate_json ${file} > ${tmp_file}
haskell-mustache ${template} ${tmp_file}
rm ${tmp_file}
}
#+end_src
Generating the expected JSON is therefore as simple as:
- Fetching the logs
- Reading 8 line from the logs, parse the filename from the 6th
line
- Outputing the JSON
We will use ~git~ to get the information we need. By default,
~git~ subcommands use a pager when its output is likely to be
long. This typically includes ~git-log~. To disable this
behavior, ~git~ exposes the ~--no-pager~ command. Besides, we
also need ~--follow~ and ~--stat~ to deal with file
renaming. Without this option, ~git-log~ stops when the file
first appears in the repository, even if this “creation” is
actually a renaming. Therefore, the ~git~ command line we use to
collect our history is
#+name: gitlog
#+begin_src bash :tangle scripts/history.sh :noweb yes
function gitlog () {
local file="${1}"
git --no-pager log \
--follow \
--stat=10000 \
--pretty=format:'%s%n%h%n%H%n%cs%n' \
"${file}"
}
#+end_src
This function will generate a sequence of 8 lines containing all
the relevant information we are looking for, for each commit,
namely:
- Subject
- Abbreviated hash
- Full hash
- Date
- Empty line
- Change summary
- Shortlog
- Empty line
For instance, the =gitlog= function will output the following
lines for the last commit of this very file:
#+begin_src bash :results verbatim :exports results :noweb yes
<<gitlog>>
gitlog "soupault.org" | head -n8
#+end_src
Among other things, the 6th line contains the filename. We need
to extract it, and we do that with ~sed~. In case of file
renaming, we need to parse something of the form ~both/to/{old =>
new}~.
#+begin_src bash :tangle scripts/history.sh :noweb yes
function parse_filename () {
local line="${1}"
local shrink='s/ *\(.*\) \+|.*/\1/'
local unfold='s/\(.*\){\(.*\) => \(.*\)}/\1\3/'
echo ${line} | sed -e "${shrink}" | sed -e "${unfold}"
}
#+end_src
The next step is to process the logs to generate the expected
JSON. We have to deal with the fact that JSON does not allow the
last item of an array to be concluded by ",". Besides, we also
want to indicate which commit is responsible for the creation of
the file. To do that, we use two variables: =idx= and
=last_entry=. When =idx= is equal to 0, we know it is the latest
commit. When =idx= is equal to =last_entry=, we know we are
looking at the oldest commit for that file.
#+begin_src bash :tangle scripts/history.sh :noweb yes
function generate_json () {
local input="${1}"
local logs="$(gitlog ${input})"
if [ ! $? -eq 0 ]; then
exit 1
fi
let "idx=0"
let "last_entry=$(echo "${logs}" | wc -l) / 8"
local subject=""
local abbr_hash=""
local hash=""
local date=""
local file=""
local created="true"
local modified="false"
echo -n "{"
echo -n "\"file\": \"${input}\""
echo -n ",\"history\": ["
while read -r subject; do
read -r abbr_hash
read -r hash
read -r date
read -r # empty line
read -r file
read -r # short log
read -r # empty line
if [ ${idx} -ne 0 ]; then
echo -n ","
fi
if [ ${idx} -eq ${last_entry} ]; then
created="true"
modified="false"
else
created="false"
modified="true"
fi
output_json_entry "${subject}" \
"${abbr_hash}" \
"${hash}" \
"${date}" \
"$(parse_filename "${file}")" \
"${created}" \
"${modified}"
let idx++
done < <(echo "${logs}")
echo -n "]}"
}
#+end_src
Generating the JSON object for a given commit is as simple as
#+begin_src bash :tangle scripts/history.sh :noweb yes
function output_json_entry () {
local subject="${1}"
local abbr_hash="${2}"
local hash="${3}"
local date="${4}"
local file="${5}"
local created="${6}"
local last_entry="${7}"
echo -n "{\"subject\": \"${subject}\""
echo -n ",\"created\":${created}"
echo -n ",\"modified\":${modified}"
echo -n ",\"abbr_hash\":\"${abbr_hash}\""
echo -n ",\"hash\":\"${hash}\""
echo -n ",\"date\":\"${date}\""
echo -n ",\"filename\":\"${file}\""
echo -n "}"
}
#+end_src
And we are done! We can safely call the =main= function to generate
our revisions table.
#+begin_src bash :tangle scripts/history.sh
main "$(cat)" "${1}"
#+end_src
** Rendering Equations Offline
*** Users instructions
Inline equations written in the DOM under the class
src_css{.imath} and using the \im \LaTeX \mi syntax can be
rendered once and for all by ~soupault~. User For instance,
~<span class="imath">\LaTeX</span>~ is rendered \im \LaTeX \mi as
expected.
Using this widgets requires being able to inject raw HTML in
input files.
*** Implementation
#+begin_src js :tangle scripts/render-equations.js
var katex = require("katex");
var fs = require("fs");
var input = fs.readFileSync(0);
var displayMode = process.env.DISPLAY != undefined;
var html = katex.renderToString(String.raw`${input}`, {
throwOnError : false,
displayModed : displayMode
});
console.log(html)
#+end_src
We reuse once again the =preprocess_element= widget. The selector
is ~.imath~ (~i~ stands for inline in this context), and we
replace the previous content with the result of our script.
#+begin_src toml :tangle soupault.conf
[widgets.inline-math]
widget = "preprocess_element"
selector = ".imath"
command = "node scripts/render-equations.js"
action = "replace_content"
[widgets.display-math]
widget = "preprocess_element"
selector = ".dmath"
command = "DISPLAY=1 node scripts/render-equations.js"
action = "replace_content"
#+end_src
** RSS Feed
#+begin_src toml :tangle soupault.conf
[index]
index = true
dump_json = "rss.json"
extract_after_widgets = ["urls-rewriting"]
[index.fields]
title = {
selector = ["h1"]
}
modified-at = {
selector = ["#modified-at"]
}
created-at = {
selector = ["#created-at"]
}
#+end_src
** Series Navigation
#+begin_src lua :tangle plugins/series.lua
function get_title_from_path (path)
if Sys.is_file(path) then
local content_raw = Sys.read_file(path)
local content_dom = HTML.parse(content_raw)
local title = HTML.select_one(content_dom, "h1")
if title then
return String.trim(HTML.inner_html(title))
else
Plugin.fail(path .. ' has no <h1> tag')
end
else
Plugin.fail(path .. ' is not a file')
end
end
#+end_src
#+begin_src lua :tangle plugins/series.lua
function generate_nav_item_from_title (title, url, template)
local env = {}
env["url"] = url
env["title"] = title
local new_content = String.render_template(template, env)
return HTML.parse(new_content)
end
#+end_src
#+begin_src lua :tangle plugins/series.lua
function generate_nav_items (cwd, cls, template)
local elements = HTML.select(page, cls)
local i = 1
while elements[i] do
local element = elements[i]
local url = HTML.strip_tags(element)
local path = Sys.join_path(cwd, url)
local title_str = get_title_from_path(path)
HTML.replace_content(
element,
generate_nav_item_from_title(title_str, url, template)
)
i = i + 1
end
end
#+end_src
#+begin_src lua :tangle plugins/series.lua
cwd = Sys.dirname(page_file)
home_template = 'This article is part of the series “<a href="{{ url }}">{{ title }}</a>.”'
nav_template = '<a href="{{ url }}">{{ title }}</a>'
generate_nav_items(cwd, ".series", home_template)
generate_nav_items(cwd, ".series-prev", nav_template)
generate_nav_items(cwd, ".series-next", nav_template)
#+end_src
#+begin_src toml :tangle soupault.conf
[widgets.series]
widget = "series"
#+end_src
** Injecting Minified CSS
#+begin_src lua :tangle plugins/css.lua
style = HTML.select_one(page, "style")
if style then
css = HTML.create_text(Sys.read_file("style.min.css"))
HTML.replace_content(style, css)
end
#+end_src
#+begin_src toml :tangle soupault.conf
[widgets.css]
widget = "css"
#+end_src
** Cleaning-up
#+begin_src lua :tangle plugins/clean-up.lua
function remove_if_empty(html)
if String.trim(HTML.inner_html(html)) == "" then
HTML.delete(html)
end
end
#+end_src
#+begin_src lua :tangle plugins/clean-up.lua
function remove_all_if_empty(cls)
local elements = HTML.select(page, cls)
local i = 1
while elements[i] do
local element = elements[i]
remove_if_empty(element)
i = i + 1
end
end
#+end_src
#+begin_src lua :tangle plugins/clean-up.lua
remove_all_if_empty("p") -- introduced by org-mode
remove_all_if_empty("div.code") -- introduced by coqdoc
#+end_src
#+begin_src toml :tangle soupault.conf
[widgets.clean-up]
widget = "clean-up"
#+end_src
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