Ruby client for the Contentful Content Delivery API
Latest commit a2134b2 Sep 12, 2018

README.md

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contentful.rb - Contentful Ruby Delivery SDK

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Ruby SDK for the Contentful Content Delivery API and Content Preview API. It helps you to easily access your Content stored in Contentful with your Ruby applications.

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What is Contentful?

Contentful provides content infrastructure for digital teams to power websites, apps, and devices. Unlike a CMS, Contentful was built to integrate with the modern software stack. It offers a central hub for structured content, powerful management and delivery APIs, and a customizable web app that enable developers and content creators to ship their products faster.

Table of contents

Core Features

Getting started

In order to get started with the Contentful Ruby SDK you'll need not only to install it, but also to get credentials which will allow you to have access to your content in Contentful.

Installation

Add to your Gemfile and bundle:

gem 'contentful'

Or install it directly from your console:

gem i contentful

Your first request

The following code snippet is the most basic one you can use to get some content from Contentful with this SDK:

require 'contentful'

client = Contentful::Client.new(
  space: 'cfexampleapi',  # This is the space ID. A space is like a project folder in Contentful terms
  access_token: 'b4c0n73n7fu1'  # This is the access token for this space. Normally you get both ID and the token in the Contentful web app
)

# This API call will request an entry with the specified ID from the space defined at the top, using a space-specific access token.
entry = client.entry('nyancat')

Using this SDK with the Preview API

This SDK can also be used with the Preview API. In order to do so, you need to use the Preview API Access token, available on the same page where you get the Delivery API token, and specify the host of the preview API, such as:

require 'contentful'

client = Contentful::Client.new(
  space: 'cfexampleapi',
  access_token: 'b4c0n73n7fu1',
  api_url: 'preview.contentful.com'
)

You can query for entries, assets, etc. very similar as described in the Delivery API Documentation. Please note, that all methods of the Ruby client library are snake_cased, instead of JavaScript's camelCase:

Authentication

To get your own content from Contentful, an app should authenticate with an OAuth bearer token.

You can create API keys using the Contentful web interface. Go to the app, open the space that you want to access (top left corner lists all the spaces), and navigate to the APIs area. Open the API Keys section and create your first token. Done.

Don't forget to also get your Space ID.

For more information, check the Contentful REST API reference on Authentication.

Documentation & References

To help you get the most out of this SDK, we've prepared all available client configuration options, reference documentation, tutorials and other examples that will help you learn and understand how to use this library.

Configuration

The client constructor supports several options you may set to achieve the expected behavior:

client = Contentful::Client.new(
  # ... your options here ...
)
Name Default Description
access_token Required. Your access token.
space Required. Your space ID.
environment 'master' Your environment ID.
api_url 'cdn.contentful.com' Set the host used to build the request URIs.
default_locale 'en-US' Defines default locale for the client.
secure true Defines whether to use HTTPS or HTTP. By default we use HTTPS.
authentication_mechanism :header Sets the authentication mechanisms, valid options are :header or :query_string
raise_errors true Determines whether errors are raised or returned.
dynamic_entries :manual Determines if content type caching is enabled automatically or not, allowing for accessing of fields even when they are not present on the response. Valid options are :auto and :manual.
raw_mode false If enabled, API responses are not parsed and the raw response object is returned instead.
resource_mapping {} Allows for overriding default resource classes with custom ones.
entry_mapping {} Allows for overriding of specific entry classes by content type.
gzip_encoded true Enables gzip response content encoding.
max_rate_limit_retries 1 To increase or decrease the retry attempts after a 429 Rate Limit error. Default value is 1. Using 0 will disable retry behaviour. Each retry will be attempted after the value (in seconds) of the X-Contentful-RateLimit-Reset header, which contains the amount of seconds until the next non rate limited request is available, has passed. This is blocking per execution thread.
max_rate_limit_wait 60 Maximum time to wait for next available request (in seconds). Default value is 60 seconds. Keep in mind that if you hit the hourly rate limit maximum, you can have up to 60 minutes of blocked requests. It is set to a default of 60 seconds in order to avoid blocking processes for too long, as rate limit retry behaviour is blocking per execution thread.
max_include_resolution_depth 20 Maximum amount of levels to resolve includes for SDK entities (this is independent of API-level includes - it represents the maximum depth the include resolution tree is allowed to resolved before falling back to Link objects). This include resolution strategy is in place in order to avoid having infinite circular recursion on resources with circular dependencies. Note: If you're using something like Rails::cache it's advisable to considerably lower this value (around 5 has proven to be a good compromise - but keep it higher or equal than your maximum API-level include parameter if you need the entire tree resolution). Note that when reuse_entries is enabled, the max include resolution depth only affects deep chains of unique objects (ie, not simple circular references).
reuse_entries false When enabled, reuse hydrated Entry and Asset objects within the same request when possible. Can result in a large speed increase and better handles cyclical object graphs. This can be a good alternative to max_include_resolution_depth if your content model contains (or can contain) circular references. Caching may break if this option is enabled, as it may generate stack errors. When caching, deactivate this option and opt for a conservative max_include_resolution_depth value.
use_camel_case false When doing the v2 upgrade, all keys and accessors were changed to always use snake_case. This option introduces the ability to use camelCase for keys and method accessors. This is very useful for isomorphic applications.
proxy_host nil To be able to perform a request behind a proxy, this needs to be set. It can be a domain or IP address of the proxy server.
proxy_port nil Specify the port number that is used by the proxy server for client connections.
proxy_username nil Username for proxy authentication.
proxy_password nil Password for proxy authentication.
logger nil To enable logging pass a logger instance compatible with ::Logger.
log_level ::Logger::INFO The default severity is set to INFO and logs only the request attributes (headers, parameters and url). Setting it to DEBUG will also log the raw JSON response.

Reference documentation

Basic queries

content_types = client.content_types
cat_content_type = client.content_type 'cat'
nyancat = client.entry 'nyancat'
entries = client.entries
assets = client.assets
nyancat_asset = client.asset 'nyancat'

Filtering options

You can pass the usual filter options to the query:

client.entries(content_type: 'cat') # query for a content-type by its ID (not name)
client.entries('sys.id[ne]' => 'nyancat') # query for all entries except 'nyancat'
client.entries(include: 1) # include one level of linked resources
client.entries(content_type: 'cat', include: 1) # you can also combine multiple parameters

To read more about filtering options you can check our search parameters documentation.

The results are returned as Contentful::BaseResource objects. Multiple results will be returned as Contentful::Array. The properties of a resource can be accessed through Ruby methods.

Accessing fields and sys properties

content_type = client.content_type 'cat'
content_type.description # "Meow."

System Properties behave the same and can be accessed via the #sys method.

content_type.id # => 'cat'
entry.type # => 'Entry'
asset.sys # { id: '...', type: '...' }

Entry fields also have direct accessors and will be coerced to the type defined in it's content type. However, if using dynamic_entries: :manual, coercion will not be done.

entry = client.entry 'nyancat'
entry.fields[:color] # 'rainbow'
entry.color # 'rainbow'
entry.birthday # #<DateTime: 2011-04-04T22:00:00+00:00 ((2455656j,79200s,0n),+0s,2299161j)>

Dynamic entries

However, you can (and should) set :dynamic_entries to :auto in your client configuration. When using this option, the client will cache all available content types and use them to hydrate entries when fields are missing in the response and coerce fields to their proper types.

client = Contentful::Client.new(
  access_token: 'b4c0n73n7fu1',
  space: 'cfexampleapi',
  dynamic_entries: :auto
)

entry = client.entry 'nyancat' # => #<Contentful::Entry[cat]: ...>
entry.color # => 'rainbow'
entry.birthday # #<DateTime: 2011-04-04T22:00:00+00:00 ((2455656j,79200s,0n),+0s,2299161j)>

Dynamic entries will have getter classes for the fields and do type conversions properly.

The :auto mode will fetch all content types on initialization. If you want to do it by hand later, you will need to set the option to :manual and call client.update_dynamic_entry_cache! to initialize the cache.

Using different locales

Entries can have multiple locales, by default, the client only fetches the entry with only its default locale. If you want to fetch a different locale you can do the following:

entries = client.entries(locale: 'de-DE')

Then all the fields will be fetched for the requested locale.

Contentful Delivery API also allows to fetch all locales, you can do so by doing:

entries = client.entries(content_type: 'cat', locale: '*')

# assuming the entry has a field called name
my_spanish_name = entries.first.fields('es-AR')[:name]

When requesting multiple locales, the object accessor shortcuts only work for the default locale.

Arrays

Contentful::Array has an #each method that delegates to its items. It also includes Ruby's Enumerable module, providing methods like #min or #first. See the Ruby core documentation for further details.

Arrays also have a #next_page URL, which will rerun the request with a increased skip parameter, as described in the documentation.

Links

You can easily request a resource that is represented by a link by calling #resolve:

happycat = client.entry 'happycat'
happycat.image
# => #<Contentful::Link: @sys={:type=>"Link", :linkType=>"Asset", :id=>"happycat"}>
happycat.image.resolve(client) # => #<Contentful::Asset: @fields={ ...

Assets

There is a helpful method to add image resize options for an asset image:

client.asset('happycat').url
# => "//images.contentful.com/cfexampleapi/3MZPnjZTIskAIIkuuosCss/
#     382a48dfa2cb16c47aa2c72f7b23bf09/happycatw.jpg"

client.asset('happycat').url(width: 300, height: 200, format: 'jpg', quality: 100)
# => "//images.contentful.com/cfexampleapi/3MZPnjZTIskAIIkuuosCss/
#     382a48dfa2cb16c47aa2c72f7b23bf09/happycatw.jpg?w=300&h=200&fm=jpg&q=100"

Resource options

Resources, that have been requested directly (i.e. no child resources), can be fetched from the server again by calling #reload:

entries = client.entries
entries.reload # Fetches the array of entries again

Field type Object

While for known field types, the field data is accessible using methods or the #fields hash with symbol keys, it behaves differently for nested data of the type "Object". The client will treat them as arbitrary hashes and will not parse the data inside.

Advanced concepts

Proxy example

client = Contentful::Client.new(
  access_token: 'b4c0n73n7fu1',
  space: 'cfexampleapi',
  proxy_host: '127.0.0.1',
  proxy_port: 8080,
  proxy_username: 'username',
  proxy_password: 'secret_password',
)

Custom resource classes

You can define your own classes that will be returned instead of the predefined ones. Consider, you want to build a better Asset class. One way to do this is:

class MyBetterAsset < Contentful::Asset
  def https_image_url
    image_url.sub %r<\A//>, 'https://'
  end
end

You can register your custom class on client initialization:

client = Contentful::Client.new(
  space: 'cfexampleapi',
  access_token: 'b4c0n73n7fu1',
  resource_mapping: {
    'Asset' => MyBetterAsset
  }
)

More information on :resource_mapping can be found in examples/resource_mapping.rb and more on custom classes in examples/custom_classes.rb.

You can also register custom entry classes to be used based on the entry's content_type using the :entry_mapping configuration:

class Cat < Contentful::Entry
  # define methods based on :fields, etc
end

client = Contentful::Client.new(
  space: 'cfexampleapi',
  access_token: 'b4c0n73n7fu1',
  entry_mapping: {
    'cat' => Cat
  }
)

client.entry('nyancat') # is instance of Cat

Synchronization

The client also includes a wrapper for the synchronization endpoint. You can initialize it with the options described in the Delivery API Documentation or an URL you received from a previous sync:

client = Contentful::Client.new(
  access_token: 'b4c0n73n7fu1',
  space: 'cfexampleapi',
  default_locale: 'en-US'
)

sync = client.sync(initial: true, type: 'Deletion') # Only returns deleted entries and assets
sync = client.sync("https://cdn.contentful.com/spaces/cfexampleapi/sync?sync_token=w5ZGw6JFwqZmVcKsE8Kow4gr...sGPg") # Continues a sync

You can access the results either wrapped in Contentful::SyncPage objects:

sync.each_page do |page|
  # Find resources at: page.items
end

# More explicit version:
page = sync.first_page
until sync.completed?
  page = sync.next_page
end

Or directly iterative over all resources:

sync.each_item do |resource|
  # ...
end

When a sync is completed, the next sync url can be read from the Sync or SyncPage object:

sync.next_sync_url

Please note that synchronization entries come in all locales, so make sure, you supply a :default_locale property to the client configuration, when using the sync feature. This locale will be returned by default, when you call Entry#fields. The other localized data will also be saved and can be accessed by calling the fields method with a locale parameter:

first_entry = client.sync(initial: true, type: 'Entry').first_page.items.first
first_entry.fields('de-DE') # Returns German localizations

Migrating to 2.x

If you're a 0.x or a 1.x user of this gem, and are planning to migrate to the current 2.x branch. There are a few breaking changes you have to take into account:

  • Contentful::Link#resolve and Contentful::Array#next_page now require a Contentful::Client instance as a parameter.
  • Contentful::CustomResource does no longer exist, custom entry classes can now inherit from Contentful::Entry and have proper marshalling working.
  • Contentful::Resource does no longer exist, all resource classes now inherit from Contentful::BaseResource. Contentful::Entry and Contentful::Asset inherit from Contentful::FieldsResource which is a subclass of Contentful::BaseResource.
  • Contentful::DynamicEntry does no longer exist, if code checked against that base class, it should now check against Contentful::Entry instead.
  • Contentful::Client#dynamic_entry_cache (private) has been extracted to it's own class, and can be now manually cleared by using Contentful::ContentTypeCache::clear.
  • Contentful::BaseResource#sys and Contentful::FieldsResource#fields internal representation for keys are now snake cased to match the instance accessors. E.g. entry.fields[:myField] previously had the accessor entry.my_field, now it is entry.fields[:my_field]. The value in both cases would correspond to the same field, only change is to unify the style. If code accessed the values through the #sys or #fields methods, keys now need to be snake cased.
  • Circular references are handled as individual objects to simplify marshalling and reduce stack errors, this introduces a performance hit on extremely interconnected content. Therefore, to limit the impact of circular references, an additional configuration flag max_include_resolution_depth has been added. It is set to 20 by default (which corresponds to the maximum include level value * 2). This allows for non-circular but highly connected content to resolve properly. In very interconnected content, it also allows to reduce this number to improve performance. For a more in depth look into this you can read this issue.
  • #inspect now offers a clearer and better output for all resources. If your code had assertions based on the string representation of the resources, update to the new format <Contentful::#{RESOURCE_CLASS}#{additional_info} id="#{RESOURCE_ID}">.

For more information on the internal changes present in the 2.x release, please read the CHANGELOG

Tutorials & other resources

  • This library is a wrapper around our Contentful Delivery REST API. Some more specific details such as search parameters and pagination are better explained on the REST API reference, and you can also get a better understanding of how the requests look under the hood.
  • Check the Contentful for Ruby page for Tutorials, Demo Apps, and more information on other ways of using Ruby with Contentful

Reach out to us

You have questions about how to use this library?

  • Reach out to our community forum: Contentful Community Forum
  • Jump into our community slack channel: Contentful Community Slack

You found a bug or want to propose a feature?

  • File an issue here on GitHub: File an issue. Make sure to remove any credential from your code before sharing it.

You need to share confidential information or have other questions?

  • File a support ticket at our Contentful Customer Support: File support ticket

Get involved

PRs Welcome

We appreciate any help on our repositories. For more details about how to contribute see our CONTRIBUTING.md document.

License

This repository is published under the MIT license.

Code of Conduct

We want to provide a safe, inclusive, welcoming, and harassment-free space and experience for all participants, regardless of gender identity and expression, sexual orientation, disability, physical appearance, socioeconomic status, body size, ethnicity, nationality, level of experience, age, religion (or lack thereof), or other identity markers.

Read our full Code of Conduct.