Guzzle and Unable to parse response into JSON - php

Question

I have a little php api client with this method:
private function send($endpoint)
{
$headers = array();
$body = $this->xmlSerialiser->convertToXML($this->getQueue());
try {
$response = json_decode(
$this->guzzleClient->post(
$endpoint,
$headers, $body
)
->send()
->json()
);
} catch (\Guzzle\Http\Exception\BadResponseException $e) {
$response = array('Error' => $e->getMessage());
}
return $response;
}
I'm always receiving
Unable to parse response body into JSON: 4 (500 Internal Server Error)
I already tried to know an example of server response and seems to be fine:
echo (string) $this->guzzleClient->post(
$endpoint,
$headers, $body
)
->send()->getBody();
and this is the result:
<Messages xmlns="http://www.example.com/xxx/3.0">
<GetAccountResponse RequestType="GetAccount">
<AccountId>xxxx-xxx-xxx-xxxx-xxxx</AccountId>
<Token>xxxxxxxxxxxxxx/t3VkEJXC7f6b6G4yPJSZ5QfT2hdSQXUmi0e8cndSYLK4N7mswRHifzwGHLUJYHM17iGL8s=</Token>
</GetAccountResponse>

Answer 1

I answered myself
the Guzzle documentation says: json method -> Parse the JSON response body and return an array
so in my case I need to switch the json mehod to xml (cos the response is an xml).
Finally this is the result:
private function send($endpoint)
{
$headers = array();
$body = $this->xmlSerialiser->convertToXML($this->getQueue());
try {
$response = (array)(
$this->guzzleClient->post(
$endpoint,
$headers, $body
)
->send()
->xml()
);
} catch (\Guzzle\Http\Exception\BadResponseException $e) {
$response = array('Error' => $e->getMessage());
}
return $response;
}

Answer 2

Use following code.
$response->getBody()->getContents()