# Jekyll::Linkpreview

Jekyll plugin to generate link preview by `{% linkpreview %}` tag. The plugin fetches [Open Graph protocols](http://ogp.me/) of the designated page to generate preview. The og properties are saved as JSON for caching and it is used when rebuilding the site.

You can pass url directly to the tag, 

```
{% linkpreview https://github.com %}
```

or, can pass a url variable.

```
{% assign github_toppage = 'https://github.com'%}
{% linkpreview github_toppage %}
```

The tag above generates following HTML when you run `jekyll build`,

```html
<div class="jekyll-linkpreview-wrapper">
  <p><a href="https://github.com" target="_blank">https://github.com</a></p>
  <div class="jekyll-linkpreview-wrapper-inner">
    <div class="jekyll-linkpreview-content">
      <div class="jekyll-linkpreview-image">
        <a href="https://github.com" target="_blank">
          <img src="https://github.githubassets.com/images/modules/open_graph/github-logo.png" />
        </a>
      </div>
      <div class="jekyll-linkpreview-body">
        <h2 class="jekyll-linkpreview-title">
          <a href="https://github.com" target="_blank">Build software better, together</a>
        </h2>
        <div class="jekyll-linkpreview-description">GitHub is where people build software. More than 31 million people use GitHub to discover, fork, and contribute to over 100 million projects.</div>
      </div>
    </div>
    <div class="jekyll-linkpreview-footer">
      <a href="https://github.com" target="_blank">github.com</a>
    </div>
  </div>
</div>
```

Applying appropriate CSS, the link preview will be like this.

<img width="613" alt="スクリーンショット 2019-04-03 20 52 50" src="https://user-images.githubusercontent.com/3449164/55479970-35baf100-565a-11e9-8c5d-709213917f74.png">

## Installation

See https://jekyllrb.com/docs/plugins/installation/ .

## Usage

1. Create `_cache` directory where you run `jekyll build` or `jekyll serve`.

1. Embed [linkpreview.css](assets/css/linkpreview.css) into your Website.

1. Use `{% linkpreview %}` tag.

1. Run `jekyll build` or `jekyll serve`.

## Development

After checking out the repo, run `bin/setup` to install dependencies. Then, run `rake spec` to run the tests. You can also run `bin/console` for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).

## Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/ysk24ok/jekyll-linkpreview.

## License

The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).