Augment data from an external API | Gato GraphQL for WordPress

If we need to fetch data from an external API, but we need to somehow modify the results (such as providing a default value when some field is empty), we can then use Gato GraphQL to implement an API gateway that transforms the entries as needed.

For instance, when invoking the REST API endpoint /users from some WordPress site, we can add a default value when the url field is empty, and an additional link property with the HTML code:

query FilterDataFromWordPressAPI(
  # eg: https://somesite.com/wp-json/wp/v2/users/?_fields=id,name,url
  $endpointURL: URL!
) {
  usersWithLinkAndDefaultURL: _sendJSONObjectCollectionHTTPRequest(
    input: {
      url: $endpointURL
    }
  )
    # Set a default URL for users without any
    @underEachArrayItem
      @underJSONObjectProperty(
        by: {
          key: "url"
        }
      )
        @default(
          value: "https://mysite.com"
          condition: IS_EMPTY
        )
 
    # Add a new "link" entry on the JSON object
    @underEachArrayItem(
      affectDirectivesUnderPos: [1, 2, 3, 4],
      passValueOnwardsAs: "userListItem"
    )
      @applyField(
        name: "_objectProperty",
        arguments: {
          object: $userListItem,
          by: {
            key: "name"
          }
        },
        passOnwardsAs: "userName"
      )
      @applyField(
        name: "_objectProperty",
        arguments: {
          object: $userListItem,
          by: {
            key: "url"
          }
        },
        passOnwardsAs: "userURL"
      )
      @applyField(
        name: "_sprintf",
        arguments: {
          string: "<a href=\"%s\">%s</a>",
          values: [$userURL, $userName]
        },
        passOnwardsAs: "userLink"
      )
      @applyField(
        name: "_objectAddEntry",
        arguments: {
          object: $userListItem,
          key: "link",
          value: $userLink
        },
        setResultInResponse: true
      )
}