Resolving Linked Content in GraphQL

While you are sourcing and querying content in Gatsby, you are likely to come across a scenario where you need to retrieve a content item and its related content. In Agility CMS, Linked Content fields are used to related content to one another in various ways.

When querying a Post, for example, you may want to also retrieve the details for the Category. On your Post GraphQL node, you may notice a category property, however, it will only contain a contentID reference, not the entire node representing the Category.

You'll need to resolve this Linked Content when you need it.

How to Resolve Linked Content

In the Gatsby Blog Starter, we resolve Linked Content by using Gatsby Resolvers.

Resolvers are added to your gatsby-node.js in your site, and they allow you to add a new field to your content node which will handle resolving your Linked Content reference.

This means you are telling GraphQL, when you query a specific property on a node, it will actually run a function to go and get your Linked Content and return it.

An example of this can be found here in our starter site:

const agility = require("./src/agility/utils")

//gatsy-node.js
//CREATE RESOLVERS *******************************************************************************************
exports.createResolvers = args => {
  const {
    createResolvers,
    getNode,
    createNodeId,
    createNode,
    createContentDigest,
    configOptions,
  } = args

  // here we use resolvers to resolve the data we need for linked content
  const resolvers = {
    // on the 'agilityPost' node type
    agilityPost: {
      // get the sitemap node that represents this item ( i.e. /blog/my-blog-post )
      sitemapNode: agility.getDynamicPageItemSitemapNode(),

      // get the category
      linkedContent_agilityCategory: agility.getLinkedContentItem({
        type: "agilityCategory",
        linkedContentFieldName: "category",
      }),
    },
  }
  createResolvers(resolvers)
}