如何在PHP中实现OAuth认证

<?php
//定义SP的OAuth认证终结点
$oauthEndpoint = "https://example.com/oauth/authorize";
//定义Client应用程序的回调URL
$callbackUrl = "https://example.com/callback";

//定义授权请求参数
$params = array(
    'client_id' => '12345', //Client ID
    'redirect_uri' => $callbackUrl, //回调URL
    'response_type' => 'code', //需要的授权类型
);

//生成授权请求URL
$requestUrl = $oauthEndpoint . '?' . http_build_query($params);

//重定向到授权请求URL
header('Location: ' . $requestUrl);
exit;
?>

<?php
//定义OAuth认证信息
$clientId = '12345'; //Client ID
$clientSecret = 'abcdefgh'; //Client Secret
$redirectUri = 'https://example.com/callback'; //回调URL

//获取回调参数
$code = $_GET['code'];
$state = $_GET['state'];

//点对点访问令牌终结点
$accessTokenUrl = 'https://example.com/oauth/access_token';

//定义请求参数
$requestHeaders = array(
    'Content-type: application/x-www-form-urlencoded',
    'Authorization: Basic ' . base64_encode($clientId . ':' . $clientSecret),
);

$accessTokenParams = array(
  'grant_type' => 'authorization_code',
  'code' => $code,
  'redirect_uri' => $redirectUri,
);

$requestOptions = array(
  'http' => array(
    'header' => implode("
", $requestHeaders),
    'method' => 'POST',
    'content' => http_build_query($accessTokenParams),
  ),
);

$context = stream_context_create($requestOptions);

//向SP发送请求以获取访问令牌
$accessTokenResult = file_get_contents($accessTokenUrl, false, $context);
$accessTokenData = json_decode($accessTokenResult, true);

$accessToken = $accessTokenData['access_token'];

//使用令牌请求服务提供商的受保护资源
$resourceUrl = 'https://example.com/resource';

$requestHeaders = array(
  'Authorization: Bearer ' . $accessToken,
);

$requestOptions = array(
  'http' => array(
    'header' => implode("
", $requestHeaders),
    'method' => 'GET',
  ),
);

$context = stream_context_create($requestOptions);

//向SP发送请求以获取资源
$resourceResult = file_get_contents($resourceUrl, false, $context);
?>