A collection of useful things to help make it easier to integrate Contentful into your Rails app.

This is a work in progress. It relies on the contentful_model gem (http://github.com/errorstudio/contentful_model)

ContentfulRails accepts a block for configuration. Best done in a Rails initializer.

ContentfulRails.configure do |config|
  config.authenticate_webhooks = true # false here would allow the webhooks to process without basic auth
  config.webhooks_username = "a basic auth username"
  config.webhooks_password = "a basic auth password"
  config.access_token = "your access token"
  config.preview_access_token = "your preview access token"
  config.space = "your space ID"
  config.options = "hash of options"
end

Note that you don't have to separately configure ContentfulModel - adding the access tokens / space ID / options here will pass to ContentfulModel in an initializer in the Rails engine.

The default is to authenticate the webhooks; probably a smart move to host on an HTTPS endpoint too.

The issue with 'Russian Doll' caching in Rails is that it requires a hit on the database to check the updated_at timestamp of an object.

This is obviously expensive when the object is called over an API. So this gem wraps caches updated_at locally, and checks that first on subsequent calls.

Foo.updated_at #returns a timestamp from cache, or from the API if no cache exists

If there's a new version of an entry we need to expire the timestamp from the cache.

This gem includes a controller endpoint for Contentful to POST back to.

To make use of this in your app:

Mount the ContentfulRails engine at your preferred url:

mount ContentfulRails::Engine => '/contentful' #feel free to choose a different endpoint name

This will give you 2 routes:

/contentful/webhooks - the URL for contentful to post back to. /contentful/webhooks/debug - a development-only URL to check you have mounted the engine properly :-)

At the moment all this does is delete the timestamp cache entry, which means that a subsequent call to updated_at calls the API.

Contentful has a really nice url-based image manipulation API.

To take advantage of this, there's a custom Redcarpet renderer which allows you to pass the image parameters you want into the call to a parse_markdown() method.

In your application_controller.rb:

helper ContentfulRails::MarkdownHelper

This allows you to call parse_markdown(@your_markdown) and get HTML. Note that out of the box, the parse_markdown() is really permissive and allows you to put HTML in the Contentful markdown fields. This might not be what you want.

To manipulate images which are referenced in your markdown, you can pass the following into the parse_markdown() call.

parse_markdown(@your_markdown, image_options: {width: 1024, height: 1024})

The image_options parameter takes the following options (some are mutually exclusive. Read the instructions here):

• :width
• :height
• :fit
• :focus
• :corner_radius
• :quality

Sometimes you might want to apply some specific class, markup or similar to an html entity when it's being processed. With RedCarpet that's dead easy.

Just subclass the ContentfulRails::MarkdownRenderer class, and call any methods you need.

class MyRenderer < ContentfulRails::MarkdownRenderer
      # If you want to pass options into your renderer, you need to overload initialize()
      def initialize(opts)
        @options = opts
        super
      end

      # If you want to do something special with links:
      def link(link,title,content)
        # Add a class name to all links, for example
        class_name = "my-link-class-name"
        content_tag(:a, content, href: link, title: title, class: class_name)
      end
end

You can overload any methods exposed in RedCarpet.

Some things would be nice to do:

• Tests :-)
• Make caching the timestamp optional in the configuration
• Implement a method on ContentfulModel to simulate a parent-child relationship, so we can invalidate caches for parent items

Licence is MIT. Please see MIT-LICENCE in this repo.

Please feel free to contribute!

• Fork this repo
• Make your changes
• Commit
• Create a PR