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jekyll-imgproxy-tag

jekyll-imgproxy-tag is a jekyll plugin that provides a Liquid tag that generates a fully secure, fully qualified url to an image asset stored on Amazon S3, and served via the imgproxy tool.

Example tag:

{% imgproxy_url path: "/path/to/image.jpg", resizing_type: 'fill', width: 800, format: "webp" %}

What's imgproxy?

"imgproxy is the blazing fast and secure image processing tool".

It is an image optimizer written in Go that you can self-host as an alternative to the larger commercial image optimization services like Imgix, Filestack, Cloudinary, et al.

More information can be found on the imgproxy website.

Ok, how do I start with this?

Step 1: have imgproxy running somewhere. For now, this library assumes you are generating secure addresses to the images you are serving, so you will need to take note of the salt and key that you are setting for your imgproxy instance. Typically these are ENV's set with the IMGPROXY_KEY and IMGPROXY_SALT keys.

Cool. I wrote those down. Now what?

In your Gemfile, add this gem:

gem 'jekyll-imgproxy-tag'

And do the bundle install dance.

Add the plugin to Jekyll's _config.yml file:

plugins:
  - jekyll-imgproxy-tag

ALSO add some required imgproxy config to that same _config.yml file:

imgproxy:
  base_url: https://url-to-your-imageproxy-server.com
  key: the-very-long-KEY-that-is-set-in-your-imgproxy-instance
  salt: the-very-long-SALT-that-is-set-in-your-imgproxy-instance
  aws_bucket: your-s3-bucket-name

If you're checking that config file into source control then you might not want to save that sort of sensitive information in your repo. As a result, this plugin supports fetching environment variables by prepending ENV_ in the values before the name of your ENV's. If you use something like Netlify this is pretty handy.

imgproxy:
  base_url: https://url-to-your-imageproxy-server.com
  key: ENV_IMGPROXY_KEY
  salt: ENV_IMGPROXY_SALT
  aws_bucket: ENV_AWS_BUCKET

Ok. Now ... how do I USE this?

Now you're ready to use this in your pages and/or posts. The most base liquid tag usage is {% imgproxy_url path: '/path/AFTER/your/bucket/dot.jpg' %}. If the sample object is in S3 bucket at s3://my-bucket/images/photos/puppy.jpg then your path would be /images/photos/puppy.jpg. Woof 🐶.

The options you may pass in to transform and optimize your image, and the corresponding information on their significance in imgproxy's docs, are as follows:

• resizing_type
  • example: {% imgproxy_url path: '/path/image.jpg', resizing_type: 'fill' %}
  • Sample resizing types: fit, fill, fill-down, force, auto. Refer to the ...
  • imgproxy docs
• width
  • example: {% imgproxy_url path: '/path/image.jpg', width: 960 %}
  • imgproxy docs
• height
  • example: {% imgproxy_url path: '/path/image.jpg', height: 400 %}
  • imgproxy docs
• gravity
  • example: {% imgproxy_url path: '/path/image.jpg', gravity: 'sm' %}
  • Note, there are many options. Provided option, sm, means "smart gravity".
  • Please refer to the imgproxy docs
• quality
  • example: {% imgproxy_url path: '/path/image.jpg', quality: '85' %}
  • Note, this the resulting quality represented in percentage, from 0 to 100.
  • imgproxy docs
• max_bytes
  • example: {% imgproxy_url path: '/path/image.jpg', max_bytes: '100000' %}
  • Note, these are BYTES, not Kilobytes. (100000 bytes == 100kB)
  • imgproxy docs
• cache_buster
  • example: {% imgproxy_url path: '/path/image.jpg', cache_buster: 'string' %}
  • imgproxy docs
• format
  • example: {% imgproxy_url path: '/path/image.jpg', format: 'webp' %}
  • Sample formats: png, jpg, webp, avif, gif, etc. More info at ...
  • imgproxy docs

Are there any gotchas?

Hey, I'm glad you asked. There are!

1. Currently this plugin only works with assets that exist in Amazon S3. Imgproxy needs to be set up to access.
2. Ensure that your instance of imgproxy has sufficient (IAM) access to your S3 bucket(s) via the aws key and secret.
3. If you're serving very large images, you may run into some issues. You can increase the max source image resolution via an environemt variable at your running imgproxy instance. For example IMGPROXY_MAX_SRC_RESOLUTION=22.0 would allow for up to 22 megapixels. If it helps, there's an online megapixels calculator here.
4. Setting IMGPROXY_DEVELOPMENT_ERRORS_MODE=1 on your imgproxy instance will provide more detailed error messages.

For those of you setting up imgproxy yourself there are many facets for configuration.

Development

1. Clone this repo
2. bundle
3. bundle exec rake
4. New features should be paired with appropriate test coverage. (Please, and thank you.)

Currently not implemented but I would be thrilled to receive PR's or feedback on:

• Support for plain source URL's.
• Support for unsafe (unsigned) paths.
• Support for serving local files.

And, I'm always open for feedback - @jayroh 🐦.