Lesson 26: Filtering data from an external API

If the external API does not allow filtering by a certain property that we need, we can use Gato GraphQL to iterate over the entries in the API response, and remove those ones that do not satisfy our condition.

Let's refer again to REST API endpoint newapi.getpop.org/wp-json/wp/v2/users/?_fields=id,name,url, where some users have property url empty:

[
  {
    "id": 1,
    "name": "leo",
    "url": "https://leoloso.com"
  },
  {
    "id": 7,
    "name": "Test",
    "url": ""
  },
  {
    "id": 2,
    "name": "Theme Demos",
    "url": ""
  }
]

The GraphQL query below filters out those users where the url property is empty, by:

Retrieving data from the external API
Iterating over the entries via @underEachArrayItem, and placing each entry under dynamic variable $userDataEntry
Extracting property url from each entry, and placing this value under dynamic variable $websiteURL
Checking if this value is empty, and assigning the result under dynamic variable $isWebsiteURLEmpty
Applying conditional directive @if which, if $isWebsiteURLEmpty is true, sets the value of that entry as null
Executing directive @arrayFilter to filter out all null entries

query {
  usersWithWebsiteURL: _sendJSONObjectCollectionHTTPRequest(
    input: {
      url: "https://newapi.getpop.org/wp-json/wp/v2/users/?_fields=id,name,url"
    }
  )
    # Remove users without a website URL
    @underEachArrayItem(
      passValueOnwardsAs: "userDataEntry"
      affectDirectivesUnderPos: [1, 2, 3]
    )
      @applyField(
        name: "_objectProperty"
        arguments: {
          object: $userDataEntry
          by: {
            key: "url"
          }
        }
        passOnwardsAs: "websiteURL"
      )
      @applyField(
        name: "_isEmpty"
        arguments: {
          value: $websiteURL
        }
        passOnwardsAs: "isWebsiteURLEmpty"
      )
      @if(
        condition: $isWebsiteURLEmpty
      )
        @setNull
    @arrayFilter
}

The response is:

{
  "data": {
    "usersWithWebsiteURL": [
      {
        "id": 1,
        "name": "leo",
        "url": "https://leoloso.com"
      }
    ]
  }
}