Expose plaintext `description` to pages/posts

[holyjak]

so that they can use it in <meta name=description ..> and for previews on Fb/Slack/.. e.g. via <meta property=og:description ...>.

The new post/page :description is derived from the HTML previews, by default including text from p and hN tags.

You want to use it as {{post.description}} in a template.

Updating templates

When this is merged, we should update templates as follows:

<!-- base.html: -->
...
       <title>{{title}}{% block subtitle %}{% endblock %}</title>
        {% block meta %}
        <meta name="description" content="{{description}}">
        <meta name="keywords" content="">
        {% endblock %}
...
<!-- post.html: -->
{% extends "/html/base.html" %}
{%block subtitle %}: {{post.title}}{% endblock %}
{% block meta %}
<meta name="keywords" content="{% for tag in tags %}{{tag.name}}{% if not forloop.last %},{% endif %}{% endfor %}">
{% if post.description %}
<meta name="description" content="{{post.description}}">

{% comment %}{# OpenGraph tags #}{% endcomment %}
<meta property="og:url" content="{{site-url}}{{uri}}" />
<meta property="og:title" content="{{post.title}}" />
<meta property="og:description" content="{{post.description}}">
<meta property="og:type" content="article" />
{% endif %}
{% endblock %}
{% endblock %}
...
<!-- page.html: -->
{% extends "/html/base.html" %}
{% block subtitle %}: {{page.title}}{% endblock %}
{% block meta %}
{% if page.description %}
<meta name="description" content="{{page.description}}">

{% comment %}{# OpenGraph tags #}{% endcomment %}
<meta property="og:url" content="{{site-url}}{{uri}}" />
<meta property="og:title" content="{{page.title}}" />
<meta property="og:description" content="{{page.description}}">
<meta property="og:type" content="article" />
{% endblock %}
...

Updating docs

We need to update the docs to mention that the :post|:page :description is available, to document the config option description-include-elements and its default of #{:p :h1 :h2 :h3 :h4 :h5 :h6}, and to document that you can specify a custom :description in the page metadata block or :description false to disable it.

[lacarmen]

LGTM. Will you be doing the template and doc updates as well? I'm happy to merge this in now, but want to hold off on publishing to clojars until we get those two things done.

[holyjak]

The docs and templates PRs 👆