Soupault 1.6 release

Estimated reading time: 3 minutes.


Soupault 1.6 is now available for download. The first big improvement is a built-in index generator that supports mustache templates, so you can make blog feeds and lists of pages without any external scripts now. The second improvement is a bunch of new plugin API functions that should make writing plugins easier and add more capabilities.

Built-in index generator with mustache templates

Older versions used to include a mostly useless built-in index generator that would just copy elements unchanged, with all their original tags. That would produce a very odd-looking index.

My assumption was that everyone will use an external script anyway, but for many people, especially on Windows or those without programming experience, an external script is a much bigger headache than for a programmer on a UNIX-like system.

There’s no sensible default for the index. One person will want a simple list of pages, someone else will want a blog feed, or something else entirely.

So I went for adding support for mustache templates. It’s a simple and lightweight, logicless template language that should cover the basic needs without bloating the executable too much (the library I used only adds about 200 kbytes to the executable).

This is what settings for a simple blog feed may look like now:

  index = true
  # Insert into a <div id="blog-index">
  index_selector = "div#blog-index"

  index_title_selector = "h1"
  index_date_selector = ["time#post-date", "time"]
  index_excerpt_selector = ["p#post-excerpt", "p"]

  newest_entries_first = true

  index_item_template = """
    <h2><a href="{{url}}">{{title}}</a></h2>
    <p><strong>Last update:</strong> {{date}}.</p>
    <a href="{{url}}">Read more</a>

Of course, support for external index generators is not going anywhere. If you want something advanced, you can get the index data in JSON and process it as you want.

strip_tags option for ToC headings and index data

Soupault, generally, makes a point to preserve the original HTML whenever possible. However, sometimes you may not want to preserve it.

Now the toc widget and the [index] section offer a strip_tags option. In the ToC widget, it removes all HTML tags from the ToC headings. In the index generator, it removes tags from all index data, including titles and excerpts.


  widget = "toc"
  strip_tags = true

  index = true
  strip_tags = true

That’s an easy way to prevent tags inserted by other widgets, like footnotes, from polluting the blog feed etc.

Sometimes, however, the situation is more nuanced. You may want to keep HTML that originally was there, but prevent widgets from inserting new tags before index data extraction is complete. Now it’s possible too.

Metadata extraction scheduling

In pre-1.6 versions, the metadata used for site index used to be extracted after all widgets have run. It could cause unfortunate interactions with some widgets. For example, the ToC widget adds section links to all headings if the heading_links option is true. In a blog feed, those links make no sense.

A simple solution would be to just do metadata extraction before any widgets had a chance to modify the page. However, that would make certain workflows impossible. For example, if you want to insert “last modified” data into pages from VCS revision history using an exec widget, and then use it as a post date in your blog feed, you need to schedule metadata extraction after the widget that inserts it.

It’s clear that running them after all widgets is a bad idea, so since 1.6, by default it’s done before any widgets.

However, you also have some control over it. Using the extract_after_widgets option, you can specify a list of widgets that must run before index data is extracted. Here’s an example for the page date in git situation:

  widget = "exec"
  selector = "#git-timestamp"
  command = "git log -n 1 --pretty=format:%ad --date=format:%Y-%m-%d -- $PAGE_FILE"

  extract_after_widgets = ["last-modified"]
  date_selector = "#git-timestamp"

If you have debug = true in the settings section, it will display the lists of widgets that will run before and after that step.

Note that it has no effect on the widget processing order. It only means that when all widgets specified in extract_after_widgets have run, soupault stops to extract the metadata and continues running widgets as usual.

This means you can still run into adverse interactions if you aren’t careful. When widgets don’t have any dependencies specified, their processing order is arbitrary. To make sure a widget only runs after metadata is extracted, you should add all widgets that from the extract_after_widgets option to its dependencies.

New plugin APIs

First, it’s not possible to exit early. The Plugin.exit function exists normally, while causes an error.

if not config["selector"] then"Missing required option selector")

target_element =, config
if not target_element then
  Plugin.exit("Could not find the target element, nothing to do")


There’s also a Regex.split option for splitting strings. Example:

The HTML module has two additions: HTML.create_text and HTML.strip_tags. The HTML.create_text function creates a text node that can be used with HTML.append_child and similar functions. This is handy if you want to insert raw text into the page.

The HTML.strip_tags is similar to HTML.inner_html, but it returns a string representation of an element content with all tags removed.

With Sys.read_file function, you can read a file into a string in one step, without having to keep track of any file handles. There’s also Sys.join_path for easily concatenating file paths without having to deal with separators by hand (it takes two strings, not a list).

There’s also page_url variable now that holds the relative URL like /about or /about.html, depending on whether clean URLs are used or not.

Last but not least, you can now pass integer options to plugins through the config. You can also pass booleans, but they are converted to strings "true" and "false".

Bug fixes and improvements