pelican-plugin-image-preview-thumbnailer 1.0.8

Description:

pelicanpluginimagepreviewthumbnailer 1.0.8

Pelican plugin that insert thumbnails along image links.
Demo page
https://chezsoi.org/lucas/blog/pages/images-libres-de-droits.html#fonts
Source Markdown: pages/images-libres-de-droits.md
Usage instructions
To enable this plugin:

Install the package from Pypi: pip install pelican-plugin-image-preview-thumbnailer
Add the plugin to your pelicanconf.py:

PLUGINS = [..., 'image_preview_thumbnailer']


Enable it on the article / pages you wish by inserting this piece of metadata:

Image-preview-thumbnailer: $selector

$selector is a CSS selector to target HTML elements this plugin will parse and look for <a> hyperlinks.
It can be for example article if your Pelican template place your pages content in <article> tags,
or just body to select the whole page.
Several comma-separated values can be provided as CSS selectors to Image-preview-thumbnailer.
Supported link formats
Currently this plugin support preview of the following links:

"raw" links to GIF/JPEG/PNG images
links to Wikipedia/Wikimedia images
links to ArtStation artwork pages
links to Behance artwork pages
links to Dafont font pages
links to FreeSVG.org vector images
links to Pixabay images
links to pages with a <meta property="og:image"> or <meta property="twitter:image"> properties,
like DeviantArt artworks, Flickr photos, https://itch.io pages,
OpenGameArt assets or WikiArt pages

Feel free to submit PRs to add support for more image hosting websites.
Only displaying thumbnails on hover
The initial idea for this plugin was to just add 🖼️ icons after links to images,
and then only display thumbnails when hovering on those icons.
To configure this plugin to behave like this, defines the following in your pelicanconf.py:
IMAGE_PREVIEW_THUMBNAILER_INSERTED_HTML = '<span class="previewable"> 🖼️</span><img src="{thumb}" class="preview-thumbnail">'

And insert those CSS rules:
.preview-thumbnail { display: none; }
.previewable:hover + .preview-thumbnail { display: block; }

Usage with images lazyloading
There are various Javascript libraries that can provide images lazyloading.
If your Pelican template make use of one, you can customize IMAGE_PREVIEW_THUMBNAILER_INSERTED_HTML in order to benefit from it.
For example, to do so using lazysizes, defines the following in your pelicanconf.py:
IMAGE_PREVIEW_THUMBNAILER_INSERTED_HTML = '''<a href="{link}" target="_blank">
<div class="lazyload" data-noscript=""><noscript><img src="{thumb}" alt=""></noscript></div>
</a>'''

Configuration
Available pelicanconf.py options:

IMAGE_PREVIEW_THUMBNAILER_INSERTED_HTML (optional, default: <a href="{link}" target="_blank" class="preview-thumbnail"><img src="{thumb}" class="preview-thumbnail"></a>) :
the HTML code to be inserted after every link (<a>) to an image, in order to preview it
IMAGE_PREVIEW_THUMBNAILER_IGNORE_404 (optional, default: False) :
avoid raising exceptions that abort Pelican when links are found, pointing to images, but they end up in HTTP 404 errors
SILENT_HTTP_ERRORS (optional, default: True) :
avoid raising exceptions that abort Pelican when links are found, pointing to images, but they end up with an HTTP error, of any kind. An error log message is still produced.
IMAGE_PREVIEW_THUMBNAILER_DIR (optional, default: thumbnails) :
directory where thumbnail images are stored
IMAGE_PREVIEW_THUMBNAILER_EXCEPT_URLS (optional) :
comma-separated list of regex patterns of URLs to ignore
IMAGE_PREVIEW_THUMBNAILER_THUMB_SIZE (optional, default: 300) :
size in pixel of the generated thumbnails.
IMAGE_PREVIEW_THUMBNAILER_ENCODING (optional, default: utf-8) :
encoding to use to parse HTML files
IMAGE_PREVIEW_THUMBNAILER_HTML_PARSER (optional, default: html.parser) :
parse that BEautifulSoup will use to parse HTML files
IMAGE_PREVIEW_THUMBNAILER_CERT_VERIFY (optional, default: False) :
enforce HTTPS certificates verification when sending linkbacks
IMAGE_PREVIEW_THUMBNAILER_REQUEST_TIMEOUT (optional, in seconds, default: 3) :
time in seconds allowed for each HTTP linkback request before abandon
IMAGE_PREVIEW_THUMBNAILER_SELECTOR (optional, default: body) :
CSS selector to target HTML elements this plugin will parse and look for <a> hyperlinks.
IMAGE_PREVIEW_THUMBNAILER_USERAGENT (optional, default: pelican-plugin-image-preview-thumbnailer) :
the User-Agent HTTP header to use while sending notifications.
IMAGE_PREVIEW_THUMBNAILER (optional, default: False) :
enable the plugin on all your pages

Available metadata entries:
image-preview-thumbnailer: $selector or just true
image-preview-thumbnailer-except-urls: same as IMAGE_PREVIEW_THUMBNAILER_EXCEPT_URLS
image-preview-thumbnailer-ignore-404: same as IMAGE_PREVIEW_THUMBNAILER_IGNORE_404
image-preview-thumbnailer-inserted-html: same as IMAGE_PREVIEW_THUMBNAILER_INSERTED_HTML
image-preview-thumbnailer-thumb-size: same as IMAGE_PREVIEW_THUMBNAILER_THUMB_SIZE

You will also have to define a $PIXABAY_API_KEY environment variable
to download images from Pixabay.
Release notes
cf. CHANGELOG.md
Contributing
Contributions are welcome and much appreciated. Every little bit helps. You can contribute by improving the documentation,
adding missing features, and fixing bugs. You can also help out by reviewing and commenting on existing issues.
To start contributing to this plugin, review the Contributing to Pelican documentation,
beginning with the Contributing Code section.
Releasing a new version
With a valid ~/.pypirc:

update CHANGELOG.md
bump version in pyproject.toml
poetry build && poetry publish
perform a release on GitGub, including the description added to CHANGELOG.md

Linter & tests
To execute them:
pylint *.py
pytest