detect.php

<?php
$ocpApimSubscriptionKey = 'PASTE_YOUR_FACE_SUBSCRIPTION_KEY_HERE';
$uriBase = 'PASTE_YOUR_FACE_ENDPOINT_HERE' . '/face/v1.0/';

$imageUrl =
    'https://raw.githubusercontent.com/Azure-Samples/cognitive-services-sample-data-files/master/ComputerVision/Images/faces.jpg';

// This sample uses the PHP5 HTTP_Request2 package
// (https://pear.php.net/package/HTTP_Request2).
require_once 'HTTP/Request2.php';

$request = new Http_Request2($uriBase . '/detect');
$url = $request->getUrl();

$headers = array(
    // Request headers
    'Content-Type' => 'application/json',
    'Ocp-Apim-Subscription-Key' => $ocpApimSubscriptionKey
);
$request->setHeader($headers);

$parameters = array(
    // Request parameters
    'detectionModel' => 'detection_03',
    'returnFaceId' => 'true');
$url->setQueryVariables($parameters);

$request->setMethod(HTTP_Request2::METHOD_POST);

// Request body parameters
$body = json_encode(array('url' => $imageUrl));

// Request body
$request->setBody($body);

try
{
    $response = $request->send();
    echo "<pre>" .
        json_encode(json_decode($response->getBody()), JSON_PRETTY_PRINT) . "</pre>";
}
catch (HttpException $ex)
{
    echo "<pre>" . $ex . "</pre>";
}
?>