Setting request body for Guzzle 6 put() - put

Question

I am setting the request body incorrectly for these Guzzle put() calls. I am making get() calls to same API using same token without issue.
The API has a test environment and here is what a successful put call looks like in cURL:
curl -X PUT --header 'Content-Type: application/json' --header 'Accept: application/json' --header 'Authorization: Basic tokenishere=' -d '{ \
"OrganizationCode": "10", \
"EventID": 5524, \
"FunctionID": 321, \
"Description": "Test" \
}' 'https://example.com/api/v1/Functions/10/5524/321'
My Guzzle code is
use GuzzleHttp\Psr7;
use GuzzleHttp\Exception\RequestException;
$client = new \GuzzleHttp\Client(array("base_uri" => "https://example.com"));
$response = $client->put("/api/v1/Functions/10/".$_SESSION['eventID'].'/'.$functionID,
array(
'headers' => array(
'token' => $token,
'debug' => true,
),
'body' => $data
)
I have also tried
$request = $client->put("/api/v1/Functions/10/$_SESSION[eventID]/$functionID", array('headers' => array('token' => $token)));
$request->setBody($data);
$response = $request->send();
And I have tried using param name json instead of body.
I have verified the JSON string in $data.
https://guzzle3.readthedocs.io/http-client/request.html shows an example where the body is 3rd arg:
$request = $client->put('http://httpbin.org/put', array(), 'this is the body');
So I also tried this below but same issue...
$request = $client->put("/api/v1/Functions/10/".$_SESSION['eventID'].'/'.$functionID, array(
'headers' => array(
'token' => $token,
'debug' => true,
)), $data);
Debug output is
PUT /api/v1/Functions/10/5524/321 HTTP/1.1
User-Agent: GuzzleHttp/6.3.3 curl/7.52.1 PHP/7.3.6-1+0~20190531112735.39+stretch~1.gbp6131b7
Host: example.com
token: tokenisreallyhere==
debug: 1
{"OrganizationCode":10,"EventID":"5524","FunctionID":"321","Description":"Test"}PUT /api/v1/Functions/10/5524/321 HTTP/1.1
User-Agent: GuzzleHttp/6.3.3 curl/7.52.1 PHP/7.3.6-1+0~20190531112735.39+stretch~1.gbp6131b7
Host: example.com
token: tokenisreallyhere==
debug: 1
{"OrganizationCode":10,"EventID":"5524","FunctionID":"321","Description":"Test"}HTTP/1.1 400 Missing model object in request body. Check body And header content type.
Cache-Control: no-cache
Pragma: no-cache
Expires: -1
ETag: ""
X-Frame-Options: SAMEORIGIN
Date: Thu, 05 Sep 2019 21:57:06 GMT
Content-Length: 0
Where do I set the body?

Answer 1

Use form_params body is deprecated
$response = $client->put("/api/v1/Functions/10/".$_SESSION['eventID'].'/'.$functionID,
array(
'headers' => array(
'token' => $token,
'debug' => true,
),
'form_params' => $data
)

Answer 2

Of course the part I think is irrelevant is the answer: I did not show that I was using json_encode() on $data before passing it. The array, not a json object string, was expected so with $data as an array this works correctly.
$response = $client->put("/api/v1/Functions/10/".$_SESSION['eventID'].'/'.$functionID,
array(
'headers' => array(
'token' => $token,
'debug' => true
),
'json' => $data
)
);