feat: Theme temporals supports time zone (#2297)

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#### What type of PR is this?
/kind feature
/area core
/milestone 2.0
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#### What this PR does / why we need it:
主题可以通过 temporals 表达式方言来格式化日期，格式化时会根据时区显示，例如：`${#temporals.format(instants, 'yyyy-MM-dd HH:mm:ss')}`
访问主题时通过携带 cookie 如 cookie:time_zone=Africa/Accra 来切换时区

支持的时区列表参考：https://jenkov.com/tutorials/java-date-time/java-util-timezone.html
表达式更多用法参考：https://github.com/thymeleaf/thymeleaf-extras-java8time
#### Which issue(s) this PR fixes:

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Fixes #2293

#### Special notes for your reviewer:
/cc @halo-dev/sig-halo 
#### Does this PR introduce a user-facing change?

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src/main/java/run/halo/app/theme/ThemeConfiguration.java

@@ -11,8 +11,10 @@ import org.springframework.http.MediaType;
 import org.springframework.web.reactive.function.server.RouterFunction;
 import org.springframework.web.reactive.function.server.RouterFunctions;
 import org.springframework.web.reactive.function.server.ServerResponse;
+import org.thymeleaf.extras.java8time.dialect.Java8TimeDialect;
 import run.halo.app.infra.properties.HaloProperties;
 import run.halo.app.infra.utils.FilePathUtils;
+import run.halo.app.theme.dialect.ThemeJava8TimeDialect;
 
 /**
  * @author guqing
@@ -59,4 +61,9 @@ public class ThemeConfiguration {
         return FilePathUtils.combinePath(haloProperties.getWorkDir().toString(),
             "themes", themeName, "templates", "assets", resource);
     }
+
+    @Bean
+    Java8TimeDialect java8TimeDialect() {
+        return new ThemeJava8TimeDialect();
+    }
 }

src/main/java/run/halo/app/theme/dialect/DefaultJava8TimeExpressionFactory.java

@@ -0,0 +1,28 @@
+package run.halo.app.theme.dialect;
+
+import static run.halo.app.theme.ThemeLocaleContextResolver.TIME_ZONE_REQUEST_ATTRIBUTE_NAME;
+
+import java.util.TimeZone;
+import org.thymeleaf.context.IExpressionContext;
+import org.thymeleaf.extras.java8time.dialect.Java8TimeExpressionFactory;
+import org.thymeleaf.extras.java8time.expression.Temporals;
+
+/**
+ * @author guqing
+ * @since 2.0.0
+ */
+public class DefaultJava8TimeExpressionFactory extends Java8TimeExpressionFactory {
+    private static final String TEMPORAL_EVALUATION_VARIABLE_NAME = "temporals";
+
+    @Override
+    public Object buildObject(IExpressionContext context, String expressionObjectName) {
+        TimeZone timeZone = (TimeZone) context.getVariable(TIME_ZONE_REQUEST_ATTRIBUTE_NAME);
+        if (timeZone == null) {
+            timeZone = TimeZone.getDefault();
+        }
+        if (TEMPORAL_EVALUATION_VARIABLE_NAME.equals(expressionObjectName)) {
+            return new Temporals(context.getLocale(), timeZone.toZoneId());
+        }
+        return null;
+    }
+}

src/main/java/run/halo/app/theme/dialect/ThemeJava8TimeDialect.java

@@ -0,0 +1,18 @@
+package run.halo.app.theme.dialect;
+
+import org.thymeleaf.expression.IExpressionObjectFactory;
+import org.thymeleaf.extras.java8time.dialect.Java8TimeDialect;
+
+/**
+ * @author guqing
+ * @since 2.0.0
+ */
+public class ThemeJava8TimeDialect extends Java8TimeDialect {
+    private final IExpressionObjectFactory expressionObjectFactory =
+        new DefaultJava8TimeExpressionFactory();
+
+    @Override
+    public IExpressionObjectFactory getExpressionObjectFactory() {
+        return expressionObjectFactory;
+    }
+}

src/test/java/run/halo/app/theme/dialect/ThemeJava8TimeDialectIntegrationTest.java

@@ -0,0 +1,147 @@
+package run.halo.app.theme.dialect;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static run.halo.app.theme.ThemeLocaleContextResolver.TIME_ZONE_COOKIE_NAME;
+
+import java.io.FileNotFoundException;
+import java.net.URL;
+import java.nio.file.Paths;
+import java.time.Instant;
+import java.time.ZoneId;
+import java.util.Locale;
+import java.util.Map;
+import java.util.TimeZone;
+import java.util.function.Function;
+import org.junit.jupiter.api.AfterEach;
+import org.junit.jupiter.api.BeforeEach;
+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.boot.test.context.TestConfiguration;
+import org.springframework.context.annotation.Bean;
+import org.springframework.http.MediaType;
+import org.springframework.http.server.reactive.ServerHttpRequest;
+import org.springframework.test.web.reactive.server.WebTestClient;
+import org.springframework.util.ResourceUtils;
+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.ServerResponse;
+import org.thymeleaf.extras.java8time.expression.Temporals;
+import run.halo.app.theme.ThemeContext;
+import run.halo.app.theme.ThemeResolver;
+
+/**
+ * Tests for {@link ThemeJava8TimeDialect}.
+ *
+ * @author guqing
+ * @since 2.0.0
+ */
+@SpringBootTest
+@AutoConfigureWebTestClient
+class ThemeJava8TimeDialectIntegrationTest {
+    private static final Instant INSTANT = Instant.now();
+
+    @Autowired
+    private ThemeResolver themeResolver;
+
+    private URL defaultThemeUrl;
+
+    Function<ServerHttpRequest, ThemeContext> themeContextFunction;
+
+    @Autowired
+    private WebTestClient webTestClient;
+
+    private TimeZone defaultTimeZone;
+
+    @BeforeEach
+    void setUp() throws FileNotFoundException {
+        themeContextFunction = themeResolver.getThemeContextFunction();
+        themeResolver.setThemeContextFunction(request -> createDefaultContext());
+
+        defaultThemeUrl = ResourceUtils.getURL("classpath:themes/default");
+        defaultTimeZone = TimeZone.getDefault();
+    }
+
+    @AfterEach
+    void tearDown() {
+        TimeZone.setDefault(defaultTimeZone);
+        this.themeResolver.setThemeContextFunction(themeContextFunction);
+    }
+
+    @Test
+    void temporalsInAmerica() {
+        TimeZone timeZone = TimeZone.getTimeZone("America/Los_Angeles");
+        TimeZone.setDefault(timeZone);
+
+        assertTemporals(timeZone);
+    }
+
+    @Test
+    void temporalsInChina() {
+        TimeZone timeZone = TimeZone.getTimeZone("Asia/Shanghai");
+        TimeZone.setDefault(timeZone);
+
+        assertTemporals(timeZone);
+    }
+
+
+    @Test
+    void timeZoneFromCookie() {
+        TimeZone timeZone = TimeZone.getTimeZone("Africa/Accra");
+        String formatTime = timeZoneTemporalFormat(timeZone.toZoneId());
+
+        webTestClient.get()
+            .uri("/timezone?language=zh")
+            .cookie(TIME_ZONE_COOKIE_NAME, timeZone.toZoneId().toString())
+            .exchange()
+            .expectStatus()
+            .isOk()
+            .expectBody(String.class)
+            .isEqualTo(String.format("<p>%s</p>\n", formatTime));
+    }
+
+    @Test
+    void invalidTimeZone() {
+        TimeZone timeZone = TimeZone.getTimeZone("invalid/timezone");
+        //the GMT zone if the given ID cannot be understood.
+        assertThat(timeZone.toZoneId().toString()).isEqualTo("GMT");
+    }
+
+    private void assertTemporals(TimeZone timeZone) {
+        String formatTime = timeZoneTemporalFormat(timeZone.toZoneId());
+        webTestClient.get()
+            .uri("/timezone?language=zh")
+            .exchange()
+            .expectStatus()
+            .isOk()
+            .expectBody(String.class)
+            .isEqualTo(String.format("<p>%s</p>\n", formatTime));
+    }
+
+    private String timeZoneTemporalFormat(ZoneId zoneId) {
+        Temporals temporals = new Temporals(Locale.CHINESE, zoneId);
+        return temporals.format(INSTANT, "yyyy-MM-dd HH:mm:ss");
+    }
+
+    ThemeContext createDefaultContext() {
+        return ThemeContext.builder()
+            .name("default")
+            .path(Paths.get(defaultThemeUrl.getPath()))
+            .active(true)
+            .build();
+    }
+
+    @TestConfiguration
+    static class MessageResolverConfig {
+
+        @Bean
+        RouterFunction<ServerResponse> routeTestIndex() {
+            return RouterFunctions
+                .route(RequestPredicates.GET("/timezone")
+                        .and(RequestPredicates.accept(MediaType.TEXT_HTML)),
+                    request -> ServerResponse.ok().render("timezone", Map.of("instants", INSTANT)));
+        }
+    }
+}

src/test/java/run/halo/app/theme/message/ThemeMessageResolverIntegrationTest.java

@@ -3,15 +3,14 @@ package run.halo.app.theme.message;
 import java.io.FileNotFoundException;
 import java.net.URL;
 import java.nio.file.Paths;
-import java.time.Duration;
 import java.util.function.Function;
 import org.junit.jupiter.api.AfterEach;
 import org.junit.jupiter.api.BeforeEach;
 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.boot.test.context.TestConfiguration;
-import org.springframework.context.ApplicationContext;
 import org.springframework.context.annotation.Bean;
 import org.springframework.http.MediaType;
 import org.springframework.http.server.reactive.ServerHttpRequest;
@@ -30,27 +29,25 @@ import run.halo.app.theme.ThemeResolver;
  * @author guqing
  * @since 2.0.0
  */
-@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
+@SpringBootTest
+@AutoConfigureWebTestClient
 public class ThemeMessageResolverIntegrationTest {
-    @Autowired
+
-    private ApplicationContext applicationContext;
     @Autowired
     private ThemeResolver themeResolver;
+
     private URL defaultThemeUrl;
+
     private URL otherThemeUrl;
 
     Function<ServerHttpRequest, ThemeContext> themeContextFunction;
 
+    @Autowired
     private WebTestClient webTestClient;
 
     @BeforeEach
     void setUp() throws FileNotFoundException {
         themeContextFunction = themeResolver.getThemeContextFunction();
-        webTestClient = WebTestClient
-            .bindToApplicationContext(applicationContext)
-            .configureClient()
-            .responseTimeout(Duration.ofMinutes(1))
-            .build();
 
         defaultThemeUrl = ResourceUtils.getURL("classpath:themes/default");
         otherThemeUrl = ResourceUtils.getURL("classpath:themes/other");

src/test/resources/themes/default/templates/timezone.html

@@ -0,0 +1 @@
+<p th:text="${#temporals.format(instants, 'yyyy-MM-dd HH:mm:ss')}"></p>