Uploading a file to Google Signed URL with PHP cURL

I am trying to upload a file to a Google Signed URL with cURL in PHP.

I have the file being posted from a form and can access it with the $_FILES var.

However the file that actually gets uploaded is not the right file and I think it is to do with how I am handling the tmp file.

$file_name = $_FILES['file']['name'];
$temp_name = $_FILES['file']['tmp_name'];

// $file = fopen($temp_name, 'r');
// $file = realpath($temp_name);

$request = curl_init($request_url);

curl_setopt($request, CURLOPT_RETURNTRANSFER, true);
curl_setopt($request, CURLOPT_POSTFIELDS, $file);
curl_setopt($request, CURLOPT_HTTPHEADER, array('Content-Type:text/plain','Authorization:'.$token));
curl_setopt($request, CURLOPT_CUSTOMREQUEST, 'PUT');

$response = curl_exec($request);
$errors = curl_error($request);
curl_close($request);

var_dump($response);
var_dump($errors);

The following works as expected with content-type text instead of audio even though its a wav file.

curl -v -X PUT --upload-file file.wav --header "Content-Type: text/plain" request_url

Edit

I have tried this:

$file = new CurlFile($temp_name,$mime_type,$file_name);

but this just crashes my page altogether.

I think it may be to do with how I am calling the request, so I wanted to create a cURL function that I can just pass the url and data to for all my requests like so:

$file = new CurlFile($temp_name,$mime_type,$file_name);
$result = curl_request($conn,$signed_url,$file,'text/plain','PUT');

Then my function is like this:

function curl_request($conn,$request_url,$request_data,$content_type,$request_type){
    $api_username = 'API username';
    $stmt = $conn->prepare("SELECT * FROM config WHERE setting=:setting");
    $stmt->bindParam(':setting', $api_username);
    $stmt->execute();
    $result = $stmt->setFetchMode(PDO::FETCH_ASSOC);
    foreach($stmt->fetchAll() as $key=>$row) {
        $username = $row['value'];
    }
    $api_key = 'API key';
    $stmt = $conn->prepare("SELECT * FROM config WHERE setting=:setting");
    $stmt->bindParam(':setting', $api_key);
    $stmt->execute();
    $result = $stmt->setFetchMode(PDO::FETCH_ASSOC);
    foreach($stmt->fetchAll() as $key=>$row) {
        $key = $row['value'];
    }
    
    $data = array(
        'username' => $username,
        'password' => $key
    );
    $payload = json_encode($data);

    $initial_request = curl_init('https://example.com/auth');
    curl_setopt($initial_request, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($initial_request, CURLOPT_POSTFIELDS, $payload);
    curl_setopt($initial_request, CURLOPT_HTTPHEADER, array('Content-Type:application/json'));

    $initial_response = curl_exec($initial_request);
    $initial_errors = curl_error($initial_request);

    curl_close($initial_request);
    
    $decoded_response = (array)json_decode($initial_response);
    $token = $decoded_response['token'];
    
    $request = curl_init($request_url);
    
    curl_setopt($request, CURLOPT_RETURNTRANSFER, true);
    curl_setopt($request, CURLOPT_POSTFIELDS, $request_data);
    curl_setopt($request, CURLOPT_HTTPHEADER, array('Content-Type:'.$content_type,'Authorization:'.$token));
    curl_setopt($request, CURLOPT_CUSTOMREQUEST, $request_type);
    
    $response = curl_exec($request);
    $errors = curl_error($request);
    curl_close($request);
    
    if(empty($errors)){
        return $response;
    }else{
        return $errors;
    }
}

This works when I had $file = fopen($temp_name, 'r'); but the file uploaded was a weird file.

Edit 2

This is what the file looks like when the person at the other end of this API tries to open it.