How to make a GraphQL Query (or Mutation!) in PHP with Guzzle

1: Define a Query

First, we're going to start off with creating a query. This will be a simple query that will ask for the "name" field for our site.

$query = 'query { site { name } }';

Now, this works, but it gets awkward and inconvenient to have to keep our whole query on one line. To fix this, we can use a Heredoc which will allow us to break our query into multiple lines.

$query = <<<GQL
  query {
    site {
      name
    }
  }
GQL;

Note: Make sure the ending GQL; statement is not indented at all as that breaks Heredoc syntax.

2: Make the HTTP request

$graphqlEndpoint = 'https://example.com/graphql-api';
$client = new \GuzzleHttp\Client();

$response = $client->request('POST', $graphqlEndpoint, [
  'headers' => [
    // include any auth tokens here
  ],
  'json' => [
    'query' => $query
  ]
]);

This is a pretty standard request, but there are two notable things:

1. We're making a POST request. All (properly configured) GraphQL endpoints will only accept a POST request.
2. We're using json not body.
3. We're not doing any authentication, but you probably will. This will often either be a token you can add as a header, or it will be basic HTTP authentication that you can pass as a top-level option to Guzzle (see docs).

3: Retrieve the response

$json = $response->getBody()->getContents();
$body = json_decode($json);
$data = $body->data;

4: Put it all together

$query = <<<GQL
  query {
    site {
      name
    }
  }
GQL;
$graphqlEndpoint = 'https://example.com/graphql-api';
$client = new \GuzzleHttp\Client();

$response = $client->request('POST', $graphqlEndpoint, [
  'headers' => [
    'Content-Type' => 'application/json',
    // include any auth tokens here
  ],
  'json' => [
    'query' => $query
  ]
]);

$json = $response->getBody()->getContents();
$body = json_decode($json);
$data = $body->data;