Request headers

Some Graph endpoints only work when you send a particular header. Advanced queries on directory objects are the usual case: they need ConsistencyLevel: eventual alongside $count=true, and without it Graph answers with an error about an unsupported query.

Both getGraphData() and sendGraphData() take an array of headers as their last argument.

Reading

public function getGraphData(
  string $endpoint,
  string $type = 'GET',
  bool $raw = FALSE,
  bool|string $version = FALSE,
  bool|string $returnType = FALSE,
  array $headers = [],
): mixed

A call that walks the manager chain of a user, which needs both the beta endpoint and the consistency header:

$headers = [
  'ConsistencyLevel' => 'eventual',
];

$data = $this->graphService->getGraphData(
  '/users/' . $user_id . '?$expand=manager($levels=50;$select=id,displayName)&$count=true',
  'GET',
  FALSE,
  'beta',
  FALSE,
  $headers
);

Note the two FALSE values before $headers. They are $raw and $returnType, and they have to be there because PHP has no way to skip a positional argument. Named arguments are tidier if you are on PHP 8 anyway:

$data = $this->graphService->getGraphData(
  '/users/' . $user_id . '?$expand=manager($levels=50;$select=id,displayName)&$count=true',
  version: 'beta',
  headers: ['ConsistencyLevel' => 'eventual'],
);

Writing

sendGraphData() has the payload in second position and the headers at the end again:

public function sendGraphData(
  string $endpoint,
  mixed $data = [],
  string $type = 'POST',
  bool $raw = FALSE,
  bool|string $version = FALSE,
  bool|string $returnType = FALSE,
  array $headers = [],
): mixed

Older examples

If you are copying code from a 5.x site or from an older version of this page, check the argument count. The signature used to carry an extra parameter between $version and $returnType, so a call written as

$this->o365Graph->getGraphData($endpoint, 'GET', FALSE, 'beta', [], FALSE, $headers);

now passes seven arguments to a method that takes six, and the empty array lands on $returnType:

TypeError: Drupal\o365\GraphService::getGraphData(): Argument #5 ($returnType)
must be of type string|bool, array given

Drop the [] and you are back to the current signature.