Fix the problem of crashing requests when slug names of single page contains special chars (#4013)

#### What type of PR is this?

/kind bug
/area core
/milestone 2.6.x

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

This PR refactors request predicate of path when building router functions for single page. I only compare the exact slug name instead of treating it as a URI template.

See <https://github.com/halo-dev/halo/issues/3931> for more.

#### Which issue(s) this PR fixes:

Fixes <https://github.com/halo-dev/halo/issues/3931>

#### Special notes for your reviewer:

1. Try to create a single page with slug name like `{}[]{[]}[{}]`.
2. Publish the single page.
3. Try to request the page.
4. See the result.

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

```release-note
修复页面别名包含特殊字符导致无法访问的问题
```

application/src/main/java/run/halo/app/theme/router/SinglePageRoute.java

@@ -1,24 +1,29 @@
 package run.halo.app.theme.router;
 
-import static org.springframework.web.reactive.function.server.RequestPredicates.GET;
+import static org.springframework.web.reactive.function.server.RequestPredicates.methods;
 
+import java.nio.charset.StandardCharsets;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;
 import lombok.RequiredArgsConstructor;
 import org.apache.commons.lang3.BooleanUtils;
 import org.apache.commons.lang3.StringUtils;
 import org.springframework.beans.factory.DisposableBean;
+import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
 import org.springframework.lang.NonNull;
 import org.springframework.stereotype.Component;
 import org.springframework.web.reactive.function.server.HandlerFunction;
+import org.springframework.web.reactive.function.server.RequestPredicate;
 import org.springframework.web.reactive.function.server.RequestPredicates;
 import org.springframework.web.reactive.function.server.RouterFunction;
 import org.springframework.web.reactive.function.server.RouterFunctions;
 import org.springframework.web.reactive.function.server.ServerRequest;
 import org.springframework.web.reactive.function.server.ServerResponse;
+import org.springframework.web.util.UriUtils;
 import reactor.core.publisher.Flux;
 import reactor.core.publisher.Mono;
 import run.halo.app.core.extension.content.SinglePage;
@@ -41,7 +46,7 @@ import run.halo.app.theme.finders.SinglePageFinder;
 @RequiredArgsConstructor
 public class SinglePageRoute
     implements RouterFunction<ServerResponse>, Reconciler<Reconciler.Request>, DisposableBean {
-    private final Map<NameSlugPair, HandlerFunction<ServerResponse>> quickRouteMap =
+    private Map<NameSlugPair, HandlerFunction<ServerResponse>> quickRouteMap =
         new ConcurrentHashMap<>();
 
     private final ExtensionClient client;
@@ -58,6 +63,15 @@ public class SinglePageRoute
             .next();
     }
 
+    /**
+     * Set quickRouteMap. This method is only for testing.
+     *
+     * @param quickRouteMap fresh quickRouteMap.
+     */
+    void setQuickRouteMap(Map<NameSlugPair, HandlerFunction<ServerResponse>> quickRouteMap) {
+        this.quickRouteMap = quickRouteMap;
+    }
+
     @Override
     public void accept(@NonNull RouterFunctions.Visitor visitor) {
         routerFunctions().forEach(routerFunction -> routerFunction.accept(visitor));
@@ -66,14 +80,23 @@ public class SinglePageRoute
     private List<RouterFunction<ServerResponse>> routerFunctions() {
         return quickRouteMap.keySet().stream()
             .map(nameSlugPair -> {
-                String routePath = singlePageRoute(nameSlugPair.slug());
-                return RouterFunctions.route(GET(routePath)
+                var routePath = singlePageRoute(nameSlugPair.slug());
+                return RouterFunctions.route(methods(HttpMethod.GET)
+                        .and(exactPath(routePath))
                         .and(RequestPredicates.accept(MediaType.TEXT_HTML)),
                     handlerFunction(nameSlugPair.name()));
             })
             .collect(Collectors.toList());
     }
 
+    private RequestPredicate exactPath(String path) {
+        return request -> {
+            var encodedRoutePath = UriUtils.encodePath(path, StandardCharsets.UTF_8);
+            var requestPath = request.requestPath().pathWithinApplication().value();
+            return Objects.equals(requestPath, encodedRoutePath);
+        };
+    }
+
     @Override
     public Result reconcile(Request request) {
         client.fetch(SinglePage.class, request.name())

application/src/test/java/run/halo/app/theme/router/SinglePageRouteTest.java

@@ -1,17 +1,24 @@
 package run.halo.app.theme.router;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.when;
 
+import java.net.URI;
 import java.util.Map;
 import org.junit.jupiter.api.Test;
 import org.junit.jupiter.api.extension.ExtendWith;
 import org.mockito.InjectMocks;
 import org.mockito.Mock;
 import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
 import org.springframework.http.MediaType;
+import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
+import org.springframework.mock.web.reactive.function.server.MockServerRequest;
+import org.springframework.mock.web.server.MockServerWebExchange;
 import org.springframework.test.web.reactive.server.WebTestClient;
 import org.springframework.web.reactive.function.server.HandlerFunction;
 import org.springframework.web.reactive.function.server.HandlerStrategies;
@@ -20,13 +27,16 @@ import org.springframework.web.reactive.function.server.RouterFunctions;
 import org.springframework.web.reactive.function.server.ServerResponse;
 import org.springframework.web.reactive.result.view.ViewResolver;
 import org.springframework.web.server.ServerWebExchange;
+import org.springframework.web.util.UriUtils;
 import reactor.core.publisher.Mono;
+import reactor.test.StepVerifier;
 import run.halo.app.core.extension.content.SinglePage;
 import run.halo.app.extension.GroupVersionKind;
 import run.halo.app.extension.Metadata;
 import run.halo.app.theme.DefaultTemplateEnum;
 import run.halo.app.theme.finders.SinglePageFinder;
 import run.halo.app.theme.finders.vo.SinglePageVo;
+import run.halo.app.theme.router.SinglePageRoute.NameSlugPair;
 
 /**
  * Tests for {@link SinglePageRoute}.
@@ -97,4 +107,27 @@ class SinglePageRouteTest {
             .exchange()
             .expectStatus().isOk();
     }
+
+    @Test
+    void shouldNotThrowErrorIfSlugNameContainsSpecialChars() {
+        var specialChars = "/with-special-chars-{}-[]-{{}}-{[]}-[{}]";
+        var specialCharsUri =
+            URI.create(UriUtils.encodePath(specialChars, UTF_8));
+        var mockHttpRequest = MockServerHttpRequest.get(specialCharsUri.toString())
+            .accept(MediaType.TEXT_HTML)
+            .build();
+        var mockExchange = MockServerWebExchange.from(mockHttpRequest);
+        var request = MockServerRequest.builder()
+            .exchange(mockExchange)
+            .uri(specialCharsUri)
+            .method(HttpMethod.GET)
+            .header(HttpHeaders.ACCEPT, MediaType.TEXT_HTML_VALUE)
+            .build();
+        var nameSlugPair = new NameSlugPair("fake-single-page", specialChars);
+        singlePageRoute.setQuickRouteMap(Map.of(nameSlugPair, r -> ServerResponse.ok().build()));
+        StepVerifier.create(singlePageRoute.route(request))
+            .expectNextCount(1)
+            .verifyComplete();
+    }
+
 }