Support impersonating other users for super admin (#7351)

#### What type of PR is this?

/kind feature
/area core
/milestone 2.20.x

#### What this PR does / why we need it:

This PR adds support for impersonating other users for super admin.

1. Login as super admin
2. Request `POST /login/impersonate?username=xxx` and the current user should be xxx
3. Request `POST /logout/impersonate` and the current user should be super admin

#### Does this PR introduce a user-facing change?

```release-note
None
```

application/src/main/java/run/halo/app/infra/config/WebServerSecurityConfig.java

@@ -25,7 +25,6 @@ import org.springframework.session.MapSession;
 import org.springframework.session.config.annotation.web.server.EnableSpringWebSession;
 import run.halo.app.core.user.service.RoleService;
 import run.halo.app.core.user.service.UserService;
-import run.halo.app.extension.ReactiveExtensionClient;
 import run.halo.app.infra.AnonymousUserConst;
 import run.halo.app.infra.properties.HaloProperties;
 import run.halo.app.security.DefaultUserDetailService;
@@ -51,11 +50,8 @@ public class WebServerSecurityConfig {
 
     @Bean
     SecurityWebFilterChain filterChain(ServerHttpSecurity http,
-        RoleService roleService,
         ObjectProvider<SecurityConfigurer> securityConfigurers,
         ServerSecurityContextRepository securityContextRepository,
-        ReactiveExtensionClient client,
-        CryptoService cryptoService,
         HaloProperties haloProperties,
         ServerRequestCache serverRequestCache) {
 

application/src/main/java/run/halo/app/security/HaloRedirectAuthenticationSuccessHandler.java

@@ -0,0 +1,54 @@
+package run.halo.app.security;
+
+import static run.halo.app.security.HaloServerRequestCache.uriInApplication;
+
+import java.net.URI;
+import lombok.extern.slf4j.Slf4j;
+import org.springframework.security.core.Authentication;
+import org.springframework.security.web.server.DefaultServerRedirectStrategy;
+import org.springframework.security.web.server.ServerRedirectStrategy;
+import org.springframework.security.web.server.WebFilterExchange;
+import org.springframework.security.web.server.authentication.ServerAuthenticationSuccessHandler;
+import reactor.core.publisher.Mono;
+
+/**
+ * This class is responsible for handling the redirection after a successful authentication.
+ * It checks if a valid 'redirect_uri' query parameter is present in the request. If it is,
+ * the user is redirected to the specified URI. Otherwise, the user is redirected to a default
+ * location.
+ *
+ * @author johnniang
+ */
+@Slf4j
+public class HaloRedirectAuthenticationSuccessHandler
+    implements ServerAuthenticationSuccessHandler {
+
+    private final ServerRedirectStrategy redirectStrategy = new DefaultServerRedirectStrategy();
+
+    private final URI location;
+
+    public HaloRedirectAuthenticationSuccessHandler(String location) {
+        this.location = URI.create(location);
+    }
+
+    @Override
+    public Mono<Void> onAuthenticationSuccess(WebFilterExchange webFilterExchange,
+        Authentication authentication) {
+        var request = webFilterExchange.getExchange().getRequest();
+        var redirectUriQuery = request.getQueryParams()
+            .getFirst("redirect_uri");
+        if (redirectUriQuery == null || redirectUriQuery.isBlank()) {
+            return redirectStrategy.sendRedirect(webFilterExchange.getExchange(), location);
+        }
+        var redirectUri = uriInApplication(request, URI.create(redirectUriQuery));
+        if (log.isDebugEnabled()) {
+            log.debug(
+                "Redirecting to: {} after switching to {}",
+                redirectUri, authentication.getName()
+            );
+        }
+        return redirectStrategy.sendRedirect(
+            webFilterExchange.getExchange(), URI.create(redirectUri)
+        );
+    }
+}

application/src/main/java/run/halo/app/security/HaloServerRequestCache.java

@@ -87,11 +87,11 @@ public class HaloServerRequestCache extends WebSessionServerRequestCache {
             .then();
     }
 
-    private static String uriInApplication(ServerHttpRequest request, URI uri) {
+    public static String uriInApplication(ServerHttpRequest request, URI uri) {
         return uriInApplication(request, uri, true);
     }
 
-    private static String uriInApplication(
+    public static String uriInApplication(
         ServerHttpRequest request, URI uri, boolean appendFragment
     ) {
         var path = RequestPath.parse(uri, request.getPath().contextPath().value());

application/src/main/java/run/halo/app/security/authorization/AuthorizationExchangeConfigurers.java

@@ -9,6 +9,7 @@ import org.springframework.security.authentication.AuthenticationTrustResolver;
 import org.springframework.security.authentication.AuthenticationTrustResolverImpl;
 import org.springframework.security.authorization.AuthorizationDecision;
 import org.springframework.security.core.Authentication;
+import org.springframework.security.web.server.authentication.SwitchUserWebFilter;
 import org.springframework.security.web.server.util.matcher.AndServerWebExchangeMatcher;
 import org.springframework.security.web.server.util.matcher.MediaTypeServerWebExchangeMatcher;
 import org.springframework.security.web.server.util.matcher.NegatedServerWebExchangeMatcher;
@@ -55,12 +56,18 @@ class AuthorizationExchangeConfigurers {
     @Bean
     @Order(200)
     SecurityConfigurer preAuthenticationAuthorizationConfigurer() {
-        return http -> http.authorizeExchange(spec -> spec.pathMatchers(
+        return http -> http.authorizeExchange(spec -> spec
+            .pathMatchers("/login/impersonate")
+            .hasRole(AuthorityUtils.SUPER_ROLE_NAME)
+            .pathMatchers("/logout/impersonate")
+            .hasAuthority(SwitchUserWebFilter.ROLE_PREVIOUS_ADMINISTRATOR)
+            .pathMatchers(
                 "/login/**",
                 "/challenges/**",
                 "/password-reset/**",
                 "/signup"
-        ).permitAll());
+            )
+            .permitAll());
     }
 
     @Bean

application/src/main/java/run/halo/app/security/switchuser/SwitchUserConfigurer.java

@@ -0,0 +1,35 @@
+package run.halo.app.security.switchuser;
+
+import org.springframework.security.config.web.server.SecurityWebFiltersOrder;
+import org.springframework.security.config.web.server.ServerHttpSecurity;
+import org.springframework.security.core.userdetails.ReactiveUserDetailsService;
+import org.springframework.security.web.server.authentication.RedirectServerAuthenticationFailureHandler;
+import org.springframework.security.web.server.authentication.SwitchUserWebFilter;
+import org.springframework.stereotype.Component;
+import run.halo.app.security.HaloRedirectAuthenticationSuccessHandler;
+import run.halo.app.security.authentication.SecurityConfigurer;
+
+/**
+ * Switch user configurer.
+ *
+ * @author johnniang
+ */
+@Component
+class SwitchUserConfigurer implements SecurityConfigurer {
+
+    private final ReactiveUserDetailsService userDetailsService;
+
+    SwitchUserConfigurer(ReactiveUserDetailsService userDetailsService) {
+        this.userDetailsService = userDetailsService;
+    }
+
+    @Override
+    public void configure(ServerHttpSecurity http) {
+        var successHandler = new HaloRedirectAuthenticationSuccessHandler("/console");
+        var failureHandler =
+            new RedirectServerAuthenticationFailureHandler("/login?error=impersonate");
+        var filter = new SwitchUserWebFilter(userDetailsService, successHandler, failureHandler);
+        http.addFilterAfter(filter, SecurityWebFiltersOrder.AUTHORIZATION);
+    }
+
+}

application/src/test/java/run/halo/app/security/switchuser/SwitchUserConfigurerTest.java

@@ -0,0 +1,72 @@
+package run.halo.app.security.switchuser;
+
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.mockito.Mockito.when;
+import static org.springframework.security.test.web.reactive.server.SecurityMockServerConfigurers.csrf;
+import static org.springframework.security.test.web.reactive.server.SecurityMockServerConfigurers.mockUser;
+
+import org.junit.jupiter.api.Test;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.reactive.AutoConfigureWebTestClient;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.security.core.userdetails.ReactiveUserDetailsService;
+import org.springframework.security.core.userdetails.User;
+import org.springframework.security.test.context.support.WithMockUser;
+import org.springframework.test.context.bean.override.mockito.MockitoSpyBean;
+import org.springframework.test.web.reactive.server.WebTestClient;
+import reactor.core.publisher.Mono;
+import run.halo.app.security.authorization.AuthorityUtils;
+
+
+@SpringBootTest
+@AutoConfigureWebTestClient
+class SwitchUserConfigurerTest {
+
+    @Autowired
+    WebTestClient webClient;
+
+    @MockitoSpyBean
+    ReactiveUserDetailsService userDetailsService;
+
+    @Test
+    void shouldSwitchWithSuperRole() {
+        when(userDetailsService.findByUsername("faker"))
+            .thenReturn(Mono.fromSupplier(() -> User.withUsername("faker")
+                .password("password")
+                .roles("user")
+                .build()));
+        var result = webClient.mutateWith(csrf())
+            .mutateWith(mockUser("admin").roles(AuthorityUtils.SUPER_ROLE_NAME))
+            .post()
+            .uri("/login/impersonate?username={username}&redirect_uri={redirect_uri}",
+                "faker", "/fake-success"
+            )
+            .exchange()
+            .expectStatus().isFound()
+            .expectHeader().location("/fake-success")
+            .expectCookie().exists("SESSION")
+            .expectBody().returnResult();
+        var session = result.getResponseCookies().getFirst("SESSION");
+        assertNotNull(session);
+
+        webClient.mutateWith(csrf())
+            .post().uri("/logout/impersonate?redirect_uri={redirect_uri}", "/fake-logout-success")
+            .cookie(session.getName(), session.getValue())
+            .exchange()
+            .expectStatus().isFound()
+            .expectHeader().location("/fake-logout-success");
+    }
+
+    @Test
+    @WithMockUser(username = "admin", roles = "non-super-role")
+    void shouldNotSwitchWithoutSuperRole() {
+        webClient.mutateWith(csrf())
+            .post()
+            .uri("/login/impersonate?username={username}&redirect_uri={redirect_uri}",
+                "faker", "/fake-success"
+            )
+            .exchange()
+            .expectStatus().isForbidden();
+    }
+
+}