Dialogflow ES PHP Client Library 500 (Internal Server Error) - php

Question

Dialogflow and PHP newbie here.
I have created and implemented a mini button-based chatbot using Dialogflow ES PHP client library in one of my client's WordPress site.
Everything worked as expected in my local environment, but when I pushed my codes to the staging site, I got a 500 (Internal Server Error) in my DevTool. The Dialogflow console still got my initial intent from staging and responded accordingly with logs without any error, however.
This is the error shown in my server error.log
PHP Fatal error:
Uncaught Google\ApiCore\ApiException: {
"message": "Input text not set.",
"code": 3,
"status": "INVALID_ARGUMENT",
"details": []
}
thrown in /var/www/my-staging-domain.com/public/vendor/google/gax/src/ApiException.php on line 267, referer: https://my-staging-domain.com/
AJAX call frontend JS file
async function sendDataToDialogflow(text, sessionID) {
let result;
try {
result = await $.ajax({
url: /dialogflow.php,
type: "POST",
data: {
query: text,
lang: "en",
sessionId: sessionID,
},
success: function(res, status, xhr) {
setDialogflowResponse(res);
},
error: function(error) {
console.warn(error);
}
});
return result;
} catch (error) {
console.log(error);
}
}
My backend dialogflow.php file setting
<?php
namespace Google\Cloud\Samples\Dialogflow;
namespace Google\Protobuf;
use Google\Cloud\Dialogflow\V2\SessionsClient;
use Google\Cloud\Dialogflow\V2\TextInput;
use Google\Cloud\Dialogflow\V2\QueryInput;
use Google\Cloud\Dialogflow\V2\Context;
require $_SERVER['DOCUMENT_ROOT']. '/vendor/autoload.php';
if (isset($_POST) && isset($_POST["query"])) {
$query = $_POST["query"];
$lang = $_POST["lang"];
$sessionId = $_POST["sessionId"];
if (isset($_POST['query'])) {
detect_intent_texts($projectId,$query,$sessionId);
}
}
function detect_intent_texts($projectId, $text, $sessionId, $context = '', $parameters = '', $languageCode = 'en-US')
{
// -------------- new session --------------
$credential = array('credentials' => $_SERVER['DOCUMENT_ROOT'].'/client-secret.json');
$sessionsClient = new SessionsClient($credential);
$session = $sessionsClient->sessionName($projectId, $sessionId ?: uniqid());
//printf('Session path: %s' . PHP_EOL, $session);
// -------------- create text input --------------
$textInput = new TextInput();
$textInput->setText($text);
$textInput->setLanguageCode($languageCode);
if($context !== '') {
// -------------- create context struct --------------
$contextStruct = new Struct();
$contextStruct->setFields($context['parameters']);
// -------------- create context input --------------
$contextInput = new Context();
$contextInput->setLifespanCount($context['lifespan']);
$contextInput->setName($context['name']);
$contextInput->setParameters($contextStruct);
}
if($parameters !== '') {
$paramStruct = new Struct();
$paramStruct->setFields($parameters['parameters']);
}
// -------------- create query input --------------
$queryInput = new QueryInput();
$queryInput->setText($textInput);
// -------------- get response and relevant info --------------
$response = ($parameters ? $sessionsClient->detectIntent($session, $queryInput) : $sessionsClient->detectIntent($session, $queryInput));
$responseId = $response->getResponseId();
$queryResult = $response->getQueryResult();
$fields = $queryResult->getParameters()->getFields();
$jsonString = $queryResult->serializeToJsonString();
$queryText = $queryResult->getQueryText();
$intent = $queryResult->getIntent();
$displayName = $intent->getDisplayName();
$confidence = $queryResult->getIntentDetectionConfidence();
$fulfillmentText = $queryResult->getFulfillmentText();
$fulfillmentMessages = json_decode($queryResult->getFulfillmentMessages()[0]->serializeToJsonString(), true);
function get_field_value($field)
{
$kind = $field->getKind();
if ($kind == "string_value")
return $field->getStringValue();
else if ($kind == "number_value")
return $field->getNumberValue();
else if ($kind == "bool_value")
return $field->getBoolValue();
else if ($kind == "null_value")
return $field->getNullValue();
else if ($kind == "list_value") {
$list_values = $field->getListValue()->getValues();
$values = [];
foreach($list_values as $list_value)
$values[] = get_field_value($list_value);
return $values;
}
else if ($kind == "struct_value")
return $field->getStructValue();
}
$parameters = [];
foreach($fields as $key => $field) {
$parameters[$key] = get_field_value($field);
}
$returnResponse = array(
'responseId' => $responseId,
'fulfillmentText' => $fulfillmentText,
'fulfillmentMessages' => $fulfillmentMessages,
'queryText' => $queryText,
'parameters' => json_decode($jsonString)->parameters
);
echo json_encode($returnResponse);
$sessionsClient->close();
}
composer.json
{
"require": {
"google/cloud-dialogflow": "^0.29.0",
"google/protobuf": "^3.21",
"protobuf-php/protobuf": "^0.1.3",
"ext-bcmath": "*"
}
}
Any insights on this issue would be much appreciated!
I've updated staging from http to https, but this didn't fix the issue.
I've read through all the documents/questions on stackoverflow I could find, but in vain.