This README is the one indexed from the repository at its latest ref, not from the tag for this version.

captcha

Crystal library that generates image CAPTCHAs.

Installation

1. Add the dependency to your shard.yml:

   dependencies:
     captcha:
       github: crystal-china/captcha

2. Run shards install

Usage

require "captcha"

captcha = CaptchaGenerator.new(length: 6)

# Return image as base64 string.
captcha.base64

# An <img> tag string that embeds the image for use in an HTML page.
captcha.img_tag # <img src="data:image/webp;base64,BASE64_ENCODED_IMAGE_DATA" />

# You can set image height or width like this: 
captcha.img_tag(height: "50px", width: "100px")

# You can use #write_html_file to preview how the captcha looks in an HTML file.
captcha.write_html_file("test.html")

# return the underlying captcha code
captcha.code # nh8S8G

More usage, check spec

You should use this shard with a memory cache.

Refer to the links below for a production use case with Lucky.

create a cache.

config/application.cr

Generate a random unique signup_captcha_id and save to cookie.

Then use this random id as key, save the captcha code into cache and render the img_tag

src/actions/htmx/captcha.cr

get the captcha code from cache use cookie.

Get the captcha_id from the cookie, then retrieve the captcha code from the cache and compare them.

src/actions/sign_ups/create.cr

limit

You can't create a fully static Crystal binary because it relies on libvips as a dependency. If that’s an issue for you, you might want to check out simple_captcha.

These two libraries should work interchangeably, so you shouldn’t need to change your code.

Contributing

1. Fork it (https://github.com/crystal-china/captcha/fork)
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create a new Pull Request

Contributors

• Ali Naqvi creator and maintainer
• Billy.Zheng - maintainer