Swiftpack.co - Package - contentful-labs/rich-text-renderer.swift

Render Contentful Rich Text fields to native strings and views

When integrated into an iOS project, this library renders Contentful RichText to NSAttributedString with native UIView embedded in the text. This is made possible because this library is built on top of TextKit, and provides a powerful plugin system to render Contentful entries and assets that are embedded in RichText.

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.

Getting started

Installation

CocoaPods installation
platform :ios, '11.0'
use_frameworks!
pod 'ContentfulRichTextRenderer'
Carthage installation

You can also use Carthage for integration by adding the following to your Cartfile:

github "contentful/rich-text-renderer-swift"

Integrating the renderer into your

The main entry point for the library is the RichTextViewController. You can either use it standalone, or subclass it. The view instance for RichTextViewController has a UITextView subview that uses a custom NSLayoutManager and NSTextContainer to lay out text, enabling text to wrap around nested views for embedded assets and entries, and also enabling blockquote styling analogous to that seen on websites.

  import Contentful
  import RichTextRenderer
  import UIKit

  class ViewController: RichTextViewController {
      private let client = ContentfulService() /// Your service fetching data from Contentful.

      init() {
          /// Default configuration of the renderer.
          let configuration = DefaultRendererConfiguration()

          let renderer = RichTextDocumentRenderer(configuration: configuration)
          
          super.init(renderer: renderer)
      }

      required init?(coder aDecoder: NSCoder) {
          fatalError("init(coder:) has not been implemented")
      }

      override func viewDidLoad() {
          super.viewDidLoad()

          fetchContent()
      }

      private func fetchContent() {
          client.fetchArticle { [weak self] result in
              switch result {
              case .success(let article):
                  self?.richTextDocument = article.content

              case .failure(let error):
                  break
              }
          }
      }
  }

You can configure how the renderer renders content by modifying DefaultRendererConfiguration instance or by creating new one conforming to RendererConfiguration protocol.

Initializing instance of DefaultRendererConfiguration provides a configuration with sane defaults. Simply create an instance, then mutate it to further customize the rendering.

Rendering view for ResourceLinkBlock node.

You can render custom views for ResourceLinkBlock nodes by passing a view provider to the configuration object.

  var configuration = DefaultRendererConfiguration()
  configuration.resourceLinkBlockViewProvider = ExampleBlockViewProvider()

Below is the example implementation on the view provider that is cappable of rendering Car model and the Asset.

  struct ExampleViewProvider: ResourceLinkBlockViewProviding {
      func view(for resource: Link, context: [CodingUserInfoKey: Any]) -> ResourceLinkBlockViewRepresentable? {
          switch resource {
          case .entryDecodable(let entryDecodable):
              if let car = entryDecodable as? Car {
                  return CarView(car: car)
              }

              return nil

          case .entry:
              return nil

          case .asset(let asset):
              guard asset.file?.details?.imageInfo != nil else { return nil }

              let imageView = ResourceLinkBlockImageView(asset: asset)

              imageView.backgroundColor = .gray
              imageView.setImageToNaturalHeight()
              return imageView

          default:
              return nil
          }
      }
  }

  final class CarView: UIView, ResourceLinkBlockViewRepresentable {
      private let car: Car

      var surroundingTextShouldWrap: Bool = false
      var context: [CodingUserInfoKey : Any] = [:]

      public init(car: Car) {
          self.car = car
          super.init(frame: .zero)

          let title = UILabel(frame: .zero)
          title.text = "🚗 " + car.model + " 🚗"
          title.translatesAutoresizingMaskIntoConstraints = false
          addSubview(title)

          title.topAnchor.constraint(equalTo: topAnchor).isActive = true
          title.trailingAnchor.constraint(equalTo: trailingAnchor).isActive = true
          title.bottomAnchor.constraint(equalTo: bottomAnchor).isActive = true
          title.leadingAnchor.constraint(equalTo: leadingAnchor).isActive = true
          title.sizeToFit()

          frame = title.bounds
          backgroundColor = .lightGray
      }

      required init?(coder: NSCoder) {
          fatalError("init(coder:) has not been implemented")
      }

      func layout(with width: CGFloat) {}
  }

Rendering ResourceLinkInline node.

Inline elements in the RichTextDocument can be rendered as NSMutableAttributedString object.

  var configuration = DefaultRendererConfiguration()
  configuration.resourceLinkInlineStringProvider = ExampleInlineStringProvider()

Below is the implementation of the inline string provider that renders Cat type.

  import Contentful
  import RichTextRenderer
  import UIKit

  final class ExampleInlineStringProvider: ResourceLinkInlineStringProviding {
      func string(
          for resource: Link,
          context: [CodingUserInfoKey : Any]
      ) -> NSMutableAttributedString {
          switch resource {
          case .entryDecodable(let entryDecodable):
              if let cat = entryDecodable as? Cat {
                  return CatInlineProvider.string(for: cat)
              }

          default:
              break
          }

          return NSMutableAttributedString(string: "")
      }
  }

  private final class CatInlineProvider {
      static func string(for cat: Cat) -> NSMutableAttributedString {
          return NSMutableAttributedString(
              string: "🐈 \(cat.name) ❤️",
              attributes: [
                  .foregroundColor: UIColor.rtrLabel
              ]
          )
      }
  }

Custom renderers

The library has been implemented the way that you can provide custom renderers for specific node types.

Simply create a class that inherits from one of the default renderers and write your own. Then attach to a DefaultRenderersProvider and that's it.

final class ExampleParagraphRenderer: ParagraphRenderer {
  typealias NodeType = Paragraph

  override func render(
      node: Paragraph,
      rootRenderer: RichTextDocumentRendering,
      context: [CodingUserInfoKey : Any]
  ) -> [NSMutableAttributedString] {
      /// Your code for rendering paragraphs.
  }
}
  let configuration = DefaultRendererConfiguration()

  var renderersProvider = DefaultRenderersProvider()
  renderersProvider.paragraph = ExampleParagraphRenderer()

  let renderer = RichTextDocumentRenderer(
      configuration: configuration,
      nodeRenderers: renderersProvider
  )

  super.init(renderer: renderer)

Example Usage

The best way to get acquainted with using this library in an iOS app is to check out the example that is a part of this repository. In particular, pay attention to the view provider and inline provider in order to learn how to render entries and assets that are embedded in the rich text.

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

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.

Github

link
Stars: 13

Used By

Total: 0

Releases

Swift Package Manager Support - 2020-09-03 16:51:18

  • Added Swift Package Manager Support.

Improved codebase and fixes - 2020-08-26 06:48:18

Breaking Changes

  • The public interface is redesigned. Please read example code in README to get familiar with the most important changes.

Fixes

  • Fixed presentation of H6 element,
  • Fixed rendering underline text that wasn't rendered correctly in some cases,
  • Fixed rendering lines and image assets – several images are now rendered correctly when one is under another,
  • Fixed rendering text when placed under image asset.

Added

  • Dark mode support,
  • When heading element is on a list, the bullet/number is rendered in the style of the heading,
  • Code safety,
  • Bumped Swift version,
  • Updated documentation comments.