PHP webhook未在Google上的操作中出现

履行响应在Dialogflow环境的诊断信息中可见。但当我在谷歌上测试它时，它并没有出现。有人知道如何让它工作吗？以下是我的webhook代码：

<?php

$method = $_SERVER['REQUEST_METHOD'];

if($method == 'POST'){
        $requestBody = file_get_contents('php://input');
        $json = json_decode($requestBody);

        $text = $json->queryResult->queryText;

        $date = (!empty($json->queryResult->parameters->date)) ? $json->queryResult->parameters->date : '';
        $environment  = (!empty($json->queryResult->parameters->environment)) ? $json->queryResult->parameters->environment : '';
        $intent   = (!empty($json->queryResult->intent->displayName)) ? $json->queryResult->intent->displayName : '';

        $responseText = prepareResponse($intent, $text, $date, $environment);

        $response = new \stdClass();
        $response->speech = $responseText;
        $response->displayText = $responseText;
        $response->source = "webhook";
        header("Content-type:application/json");
        echo json_encode($response);
}
else
{
        echo "Method not allowed";
}

function prepareResponse($intent, $text, $date, $environment)
    {
    return "You said: " . $text . " | I found Intent: " . $intent . " | with parameters: date=" . $date . " environment=" . $environment;    
    }
?>

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对Google上的操作的响应应位于

有效负载

属性下的对象中，该属性包含一个带有

我还没有测试过它，这可能不是构建它的最佳方式，但类似于以下的东西应该可以工作：

$response->payload = array(
  "google" => array(
    "expectUserResponse" => TRUE,
    "richResponse" => array(
      "items" => array(
        array(
          "simpleResponse" => array(
            "textToSpeech" => $responseText
          )
        )
      )
    )
  )
);

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伟大的如果答案有帮助，接受和/或投票总是很感激的。