单点登录(Single Sign-On,简称SSO)是一种用户身份验证技术，允许用户只需一次登录即可访问多个相互信任的系统和服务。在PHP中实现单点登录，可以使用OAuth2.0协议。以下是一个简单的PHP单点登录示例：

安装依赖库：

        bash复制代码composer require league/oauth2-servercomposer require league/oauth2-client    

        php复制代码<?phpreturn [    'server' => [        'token_ttl' => 86400, // 令牌有效期(秒)        'access_lifetime' => 3600, // 访问令牌有效期(秒)        'refresh_token_ttl' => 86400, // 刷新令牌有效期(秒)        'verify_ssl' => false, // 是否验证SSL证书(布尔值)    ],    'database' => [        'connections' => [            'default' => [                'table' => 'oauth_server_db', // 数据库表名                'driver' => 'mysqli', // 数据库驱动                'host' => 'localhost', // 数据库主机地址                'port' => 3306, // 数据库端口号                'user' => 'root', // 数据库用户名                'password' => 'your_password', // 数据库密码                'charset' => 'utf8mb4', // 数据库字符集            ],        ],    ],];    

        php复制代码<?phprequire_once 'vendor/autoload.php';require_once 'config.php';require_once 'lib/League/OAuth2/Server.php';require_once 'lib/League/OAuth2/Storage/Database.php';require_once 'lib/League/OAuth2/Server/GrantType/RefreshToken.php';require_once 'lib/League/OAuth2/Server/Exception\AccessDeniedException.php';require_once 'lib/League/OAuth2/Server/Exception\InvalidRequestException.php';require_once 'lib/League/OAuth2/Server/Exception\InvalidScopeException.php';require_once 'lib/League/OAuth2/Server/Exception\ResourceOwnerNotFoundException.php';require_once 'lib/League/OAuth2/Server/Exception\ServerErrorException.php';require_once 'lib/League/OAuth2/Server/Exception\UnsupportedGrantTypeException.php';require_once 'lib/League/OAuth2/Server/GrantTypeInterface.php';require_once 'lib/League/OAuth2/ServerBundle.php';use League\OAuth2\Server\GrantType\RefreshToken as GrantType;use League\OAuth2\Server\Repository\RefreshTokenRepository;use League\OAuth2\Server\Repositories\ClientRepository;use League\OAuth2\Server\Repositories\ScopeRepository;use League\OAuth2\Server\Repositories\UserRepository;use League\OAuth2\Server\RequestHandlerInterface;use League\OAuth2\Server\ResponseTypes\BearerTokenResponse;use League\OAuth2\Server\ResponseTypes\CodeResponse;use League\OAuth2\Server\ResponseTypes\JsonWebKeySetResponse;use League\OAuth2\Server\ResponseTypes\LocationResponse;use League\OAuth2\Server\ResponseTypes\RedirectResponse;use League\OAuth2\Server\ResponseTypes\ScopeResponse;use League\OAuth2\Server\ResponseTypes\SessionResponse;use League\OAuth2\Server\ResponseTypes\TemporaryUrlResponse;use League\OAuth2\Server\ResponseTypes\TokenResponse;use League\OAuth2\Server\ResponseTypes\UriResponse;use League\OAuth2\ServerBundle\Entity\{AccessToken, Client, RefreshToken};use League\OAuth2\ServerBundle\Managers\{AccessTokenManager, ClientManager, UserManager};use Psr\\Http\\Message\\ResponseInterface;use Psr\\Http\\Message\\StreamInterface;use Psr\\Http\\Message\\UriInterface;use Psr\\Log\\LoggerInterface;use Psr\\Log\\NullLogger;use function GuzzleHttp\Psr7\{create_stream, stream_for};use function GuzzleHttp\{post};use function GuzzleHttp\{get};use function GuzzleHttp\{parse_query, json_decode};$app = new \LeagueWrapPhpSdk();// 引入LeagueWrapPhpSdk库并实例化一个对象app作为中间件容器使用。//注意：需要先安装leaguewrap-php-sdk包。//{% endraw %}" class="language-php">{% raw %}";// 定义一个处理POST请求的路由。如果请求的URL是授权服务器的授权端点//(例如：),则返回一个授权页面。//如果请求的URL是授权服务器的令牌端点(例如：),//则根据请求类型返回相应的响应。{% endraw %}" class="language-php">{% raw %}";// 定义一个处理GET请求的路文