Kontent.ai Delivery Ruby SDK

The Delivery Ruby SDK can be used in Ruby/Rails projects to retrieve content from Kontent.ai. This is a community project and not an official Kontent.ai SDK. If you find a bug in the SDK or have a feature request, please submit a GitHub issue.

See How to setup a development environment on Windows for local development, and check out the Kontent.ai Blog for a tutorial on creating a Rails application.

Table of contents

• Kontent.ai Delivery Ruby SDK
  • Table of contents
  • Installation
  • Creating a client
    • Previewing unpublished content
    • Making secure requests
    • Retry policy
    • Custom URLs
  • Listing items
    • Filtering
    • Parameters
    • Responses
    • Requesting the latest content
    • Providing custom headers
    • Pagination
  • Working with content items
    • Assets
    • Linked items
    • Resolving links
    • Resolving inline content
  • Items feed
  • Retrieving content types
  • Retrieving taxonomy
  • Retrieving content type elements
  • Retrieving languages
  • Image transformation
  • Feedback & Contributing
  • License
  • Code of Conduct
  • Wall of Fame

Installation

To use the SDK in your own project, add the gem to your Gemfile:

gem 'kontent-ai-delivery'

Then run bundle install. You can also download the gem from RubyGems.org. To use the SDK in an .rb file, you need to require it:

require 'kontent-ai-delivery'

Creating a client

You will use Kontent::Ai::Delivery::DeliveryClient to obtain content from Kontent.ai. Create an instance of the client and pass your project ID:

delivery_client = Kontent::Ai::Delivery::DeliveryClient.new project_id: '<your-project-id>'

💎 Pro tip: You can alias namespaces to make them shorter, e.g.

KA = Kontent::Ai::Delivery
delivery_client = KA::DeliveryClient.new project_id: '<your-project-id>'

Previewing unpublished content

To enable preview, pass the Preview API Key to the constructor:

delivery_client = Kontent::Ai::Delivery::DeliveryClient.new project_id: '<your-project-id>',
                                                                 preview_key: '<your-preview-key>'

This enables preview, but you can toggle preview at any time by setting the use_preview attribute of DeliveryClient which is propagated to all queries created by the client, or per-query by setting its use_preview attribute:

# For all queries created by client
delivery_client.use_preview = false

# Per-query
query = delivery_client.items
query.use_preview = false
query.execute do |response|
  # Do something
end

Making secure requests

If you've secured access to your project, you need to provide the DeliveryClient with either the primary or secondary key:

Kontent::Ai::Delivery::DeliveryClient.new project_id: '<your-project-id>',
                                               secure_key: '<your-secure-key>'

You can then securely request published content in your project. Be sure to not expose the key if the file(s) it appears in are publicly available.

Retry policy

By default, the SDK uses a retry policy, asking for requested content again in case of an error. The default policy retries the HTTP request if the following status codes are returned:

• 408 - RequestTimeout
• 429 - TooManyRequests
• 500 - InternalServerError
• 502 - BadGateway
• 503 - ServiceUnavailable
• 504 - GatewayTimeout

The SDK will perform a total of 6 attempts at a maximum of 30 seconds to retrieve content before returning a ResponseBase object containing the error. The consecutive attempts are delayed with exponential backoff and jitter.

To disable the retry policy, you can use the with_retry_policy argument:

Kontent::Ai::Delivery::DeliveryClient.new project_id: '<your-project-id>',
                                               secure_key: '<your-secure-key>',
                                               with_retry_policy: false

Custom URLs

When you have a URL (i.e. next_page for paging, for testing purposes, or if you prefer to build it on your own) and still want to leverage SDK functionality such as rich text resolving, use the .url method:

delivery_client.items
  .url('https://deliver.kontent.ai/<your-project-id>/items?system.type=grinder')
  .execute do |response|
    # Do something
  end

Listing items

Use .item or .items to create a Kontent::Ai::Delivery::DeliveryQuery, then call .execute to perform the request.

delivery_client.items.execute do |response|
  response.items.each do |item|
    # Do something
  end
end

You can also execute the query without a block and just get the response:

response = delivery_client.items.execute

Filtering

You can use filtering to retrieve particular items. The filtering methods are applied directly to a string and the available methods are:

You can pass a single filter or multiple filters in the DeliveryClient methods. For example:

# Single filter
delivery_client.items('elements.price'.gt 20)

# Multiple filters
delivery_client.items [
  ('elements.price'.gt 20),
  ('system.type'.eq 'grinder')
]

Parameters

The .item and .items methods return a Kontent::Ai::Delivery::DeliveryQuery object which you can further configure before executing. The methods you can call are:

For example:

delivery_client.items('system.type'.eq 'coffee')
  .depth(0)
  .limit(5)
  .elements(%W[price product_name])
  .execute do |response|
    # Do something
  end

Responses

All responses from the .execute method will be/extend the Kontent::Ai::Delivery::Responses::ResponseBase class which contains the following attributes:

• http_code: The HTTP status code of the response
• headers: The headers of the response
• json: The full JSON body of the response

You can check the response code to determine if the request was successful:

delivery_client.items.execute do |response|
  case response.http_code
  when 200
    # Success!
  when 401
    # Did you forget the secure key?
  else
    # to_s displays a friendly message with details of the response
    puts response.to_s
  end
end

For successful content item queries, you will get either DeliveryItemResponse for single item queries, or DeliveryItemListingResponse for multiple item queries. You can access the returned content item(s) at .item or .items respectively.

The ContentItem object gives you access to all system elements and content type elements at the .system and .elements properies. These are dynamic objects, so you can simply type the name of the element you need:

price = response.item.elements.price.value

Requesting the latest content

Kontent.ai caches content using Fastly, so requests made to Kontent.ai may not be up-to-date. In some cases, such as when reacting to webhook notifications, you might want to request the latest content from your Kontent.ai project.

You can check the headers of the response for the X-Stale-Content header to check if the response was served from cache:

delivery_client.item('about_us').execute do |response|
  if response.headers[:x_stale_content].eq 1
    ## Content is stale
  end
end

You can bypass the cache and get the latest content using request_latest_content

delivery_client.item('about_us')
  .request_latest_content
  .execute

Providing custom headers

If you want to pass custom headers in the request, you can use custom_headers. This could be useful when you are developing your package on top of the SDK.

Note that you can not override internal headers such as Authorization. If headers with an existing key are passed into the method, they will be ignored.

delivery_client.items
  .custom_headers({ 'MY-HEADER' => 'HEADER VALUE' })
  .execute

Pagination

Most responses also contain a pagination attribute to access the paging data for the Delivery query. This object contains the following attributes:

• skip
• limit
• count
• next_page
• total_count (only if include_total_count is called)

For example, to access the next page URL you can use:

delivery_client.items
    .skip(0)
    .limit(5)
    .include_total_count
    .execute do |response|
      next_page_url = response.pagination.next_page
    end

⚠️ Note that using the include_total_count method may increase the response time and should only be used if necessary.

Working with content items

Assets

You can use .get_assets(code_name) to get one or more assets from the specified element. This method will always return an array, so use .first to get the first asset:

url = response.item.get_assets('teaser_image').first.url

Linked items

You can get a simple array of code names by accessing the element's value:

links = response.item.elements.facts.value

The .get_links(element) method will return an array of ContentItems instead:

response.item.get_links('facts').each do |link|
  title = link.elements.title.value
end

Resolving links

If a rich text element contains links to other content items, you will need to generate the URLs to those items. You can do this by registering a Kontent::Ai::Delivery::Resolvers::ContentLinkResolver when you instantiate the DeliveryClient. When you create a ContentLinkResolver, you must pass a method that will return the URL, and you may pass another method that will be called if the content contains a link, but the content item is not present in the response:

link_resolver = Kontent::Ai::Delivery::Resolvers::ContentLinkResolver.new(lambda do |link|
        # Link valid
        return "/coffees/#{link.url_slug}" if link.type.eql? 'coffee'
        return "/brewers/#{link.url_slug}" if link.type.eql? 'brewer'
      end, lambda do |id|
        # Link broken
        return "/notfound?id=#{id}"
      end)
delivery_client = Kontent::Ai::Delivery::DeliveryClient.new project_id: '<your-project-id>',
                                                             content_link_url_resolver: link_resolver

You can also build the logic for your resolver in a separate class and register an instance of that class in the DeliveryClient. The class must extend Kontent::Ai::Delivery::Resolvers::ContentLinkResolver and contain a resolve_link(link) method, as well as the resolve_404(id) method for broken links. For example, you can create MyLinkResolver.rb:

class MyLinkResolver < Kontent::Ai::Delivery::Resolvers::ContentLinkResolver
  def resolve_link(link)
    return "/coffees/#{link.url_slug}" if link.type.eql? 'coffee'
    return "/brewers/#{link.url_slug}" if link.type.eql? 'brewer'
  end

  def resolve_404(id)
    "/notfound?id=#{id}"
  end
end

Then create an object of this class when instantiating the DeliveryClient:

delivery_client = Kontent::Ai::Delivery::DeliveryClient.new project_id: '<your-project-id>',
                                                             content_link_url_resolver: MyLinkResolver.new

You can pass a ContentLinkResolver to the DeliveryQuery instead of the client if you only want to resolve links for that query, or they should be resolved differently:

delivery_client = Kontent::Ai::Delivery::DeliveryClient.new project_id: '<your-project-id>'
# Client doesn't use ContentLinkResolver, but query below will
delivery_client.items
               .with_link_resolver MyLinkResolver.new

The ContentLink object that is passed to your resolver contains the following attributes:

• id: the system.id of the linked content item
• code_name: the system.codename of the linked content item
• type: the content type of the linked content item
• url_slug: the URL slug of the linked content item, or nil if there is none

To resolve links in rich text elements, you must retrieve the text using get_string:

item_resolver = Kontent::Ai::Delivery::Resolvers::ContentLinkResolver.new(lambda do |link|
  return "/coffees/#{link.url_slug}" if link.type.eql? 'coffee'
  return "/brewers/#{link.url_slug}" if link.type.eql? 'brewer'
end)
delivery_client = Kontent::Ai::Delivery::DeliveryClient.new project_id: '<your-project-id>',
                                                             content_link_url_resolver: item_resolver
delivery_client.item('coffee_processing_techniques').execute do |response|
  text = response.item.get_string 'body_copy'
end

Resolving inline content

Existing content items can be inserted into a rich text element, or you can create new content items as components. You need to resolve these in your application just as with content links. You can register a resolver when you instantiate the client by passing it with the hash key inline_content_item_resolver:

item_resolver = Kontent::Ai::Delivery::Resolvers::InlineContentItemResolver.new(lambda do |item|
      return "<h1>#{item.elements.zip_code.value}</h1>" if item.system.type.eql? 'cafe'
      return "<div>$#{item.elements.price.value}</div>" if item.system.type.eql? 'brewer'
    end)
delivery_client = Kontent::Ai::Delivery::DeliveryClient.new project_id: '<your-project-id>',
                                                             inline_content_item_resolver: item_resolver

The object passed to the resolving method is a complete ContentItem. Similar to content link resolvers, you can create your own class which extends Kontent::Ai::Delivery::Resolvers::InlineContentItemResolver and implements the resolve_item method:

class MyItemResolver < Kontent::Ai::Delivery::Resolvers::InlineContentItemResolver
  def resolve_item(item)
    return "<h1>#{item.elements.zip_code.value}</h1>" if item.system.type.eql? 'cafe'
    return "<div>$#{item.elements.price.value}</div>" if item.system.type.eql? 'brewer'
  end
end

You can also set the inline content resolver per-query:

delivery_client = Kontent::Ai::Delivery::DeliveryClient.new project_id: '<your-project-id>'
# Client doesn't use InlineContentItemResolver, but query below will
delivery_client.items
               .with_inline_content_item_resolver MyItemResolver.new

To resolve inline content in elements, you must call get_string similar to content item links:

item_resolver = Kontent::Ai::Delivery::Resolvers::InlineContentItemResolver.new(lambda do |item|
  return "<div>$#{item.elements.price.value}</div>" if item.system.type.eql? 'brewer'
end)
delivery_client = Kontent::Ai::Delivery::DeliveryClient.new project_id: PROJECT_ID,
                                                            inline_content_item_resolver: item_resolver
delivery_client.item('our_brewers').execute do |response|
  text = response.item.get_string 'body_copy'
end

Items feed

Use the items_feed method to retrieve a dynamically paginated list of content items in your project. The result will have a more_results? method which indicates that more items can be retrieved from the feed, using the next_result method.

This method accepts all filtering and parameters except depth, skip, and limit. You can read more about the /items-feed endpoint in the Delivery API reference

Below is an example that will load all content items of a project into a single array:

result = delivery_client.items_feed.execute
items = result.items
if result.more_results?
  loop do
    result = result.next_result
    items.push *result.items
    break unless result.more_results?
  end
end

Retrieving content types

You can use the .type and .types methods to request your content types from Kontent.ai:

delivery_client.types.execute do |response|
  # Do something
end
delivery_client.type('coffee').execute do |response|
  # Do something
end

As with content item queries, all content type queries will return a Kontent::Ai::Delivery::Responses::ResponseBase of the class DeliveryTypeResponse or DeliveryTypeListingResponse for single and multiple type queries, respectively.

For multiple type queries, you can access the array of ContentType objects at .types, and at .type for singe type queries. You can access information about the type(s) dynamically:

delivery_client.type('coffee').execute do |response|
  field_type = response.type.elements.product_status.type # taxonomy
end

The DeliveryTypeListingResponse also contains pagination data, similar to DeliveryItemListingResponse.

Retrieving taxonomy

Use the .taxonomies and .taxonomy(code_name) endpoints to get information about the taxonomy in your project:

# Get all taxonomies
delivery_client.taxonomies.execute do |response|
  response.taxonomies.each do |tax|
    puts "#{tax.system.name} (#{tax.terms.length})"
  end
end

# Get terms of specific taxonomy
delivery_client.taxonomy('personas').execute do |response|
  puts response.taxonomy.terms.length
end

Each response will return either a single Kontent::Ai::Delivery::TaxonomyGroup or an array of groups. The taxonomy group(s) are accessible at .taxonomy and .taxonomies for single and multiple queries, respectively.

The TaxonomyGroup object contains two attributes .system and .terms which are dynamic OStruct objects containing the same elements as a standard JSON reponse. For example, given a successful query you could access information about the first term of a group using:

taxonomy_group.terms[0].codename

Note that the terms of a taxonomy group may also contain terms, for example in Dancing Goat's Personas taxonomy group, which looks like this:

• Coffee expert
  • Barista
  • Cafe owner
• Coffee enthusiast
  • Coffee lover
  • Coffee blogger

To get the code name of the first term under the "Coffee expert" term, you could do this:

delivery_client.taxonomy('personas').execute do |response|
  puts response.taxonomy.terms[0].terms[0].codename
end

Retrieving content type elements

Kontent.ai provides an endpoint for obtaining details about a specific element of a content type. In the Ruby SDK, you can use the .element method:

delivery_client.element('brewer', 'product_status').execute do |response|
  puts response.element.type # taxonomy
end

This returns a Kontent::Ai::Delivery::Responses::DeliveryElementResponse where the element attribute is a dynamic OStruct representation of the JSON response. This means that you can access any property of the element by simply typing the name as in the above example.

The element will always contain codename, type, and name, but multiple choice elements will also contain options and taxonomy elements will contain taxonomy_group. The Ruby SDK fully supports obtaining custom elements using this approach and any other methods.

Retrieving languages

Use the .languages method to list all of the languages in the project:

delivery_client.languages.execute do |response|
  puts response.languages.length # number of languages
end

The response is a Kontent::Ai::Delivery::Responses::DeliveryLanguageListingResponse where languages is an array of all langauges. You can access the system properties of each language as they are returned by Kontent:

delivery_client.languages.execute do |response|
  puts response.languages[0].system.codename # en-us
end

Image transformation

When you've obtained the URL for an asset, you can use our Image Transformation API to make on-the-fly modifications to the image. To do this, use the static .transform method of Kontent::Ai::Delivery::Builders::ImageTransformationBuilder, then call the transformation methods. When you're done, call the .url method to get the new URL:

url = response.item.get_assets('teaser_image').first.url
url = Kontent::Ai::Delivery::Builders::ImageTransformationBuilder.transform(url)
                                                                      # methods...
                                                                      .url

The available methods are:

Feedback & Contributing

Check out the contributing page to see the best places to file issues, start discussions, and begin contributing.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the Delivery project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.

Wall of Fame

We would like to express our thanks to the following people who contributed and made the project possible:

• Eric Dugre - the original author of the SDK

Would you like to become a hero too? Pick an issue and send us a pull request!