feat: expose rss feed endpoint

backend/src/main/java/com/openisle/config/SecurityConfig.java

@@ -119,6 +119,7 @@ public class SecurityConfig {
                     .requestMatchers(HttpMethod.GET, "/api/reaction-types").permitAll()
                     .requestMatchers(HttpMethod.GET, "/api/activities/**").permitAll()
                     .requestMatchers(HttpMethod.GET, "/api/sitemap.xml").permitAll()
+                    .requestMatchers(HttpMethod.GET, "/api/rss").permitAll()
                     .requestMatchers(HttpMethod.GET, "/api/point-goods").permitAll()
                     .requestMatchers(HttpMethod.POST, "/api/point-goods").permitAll()
                     .requestMatchers(HttpMethod.POST, "/api/categories/**").hasAuthority("ADMIN")
@@ -154,7 +155,8 @@ public class SecurityConfig {
                          uri.startsWith("/api/reaction-types") || uri.startsWith("/api/config") ||
                          uri.startsWith("/api/activities") || uri.startsWith("/api/push/public-key") ||
                                 uri.startsWith("/api/point-goods") ||
-                         uri.startsWith("/api/sitemap.xml") || uri.startsWith("/api/medals"));
+                         uri.startsWith("/api/sitemap.xml") || uri.startsWith("/api/medals") ||
+                         uri.startsWith("/api/rss"));
 
                 if (authHeader != null && authHeader.startsWith("Bearer ")) {
                     String token = authHeader.substring(7);

backend/src/main/java/com/openisle/controller/AdminPostController.java

@@ -45,4 +45,14 @@ public class AdminPostController {
     public PostSummaryDto unpin(@PathVariable Long id) {
         return postMapper.toSummaryDto(postService.unpinPost(id));
     }
+
+    @PostMapping("/{id}/rss-exclude")
+    public PostSummaryDto excludeFromRss(@PathVariable Long id) {
+        return postMapper.toSummaryDto(postService.excludeFromRss(id));
+    }
+
+    @PostMapping("/{id}/rss-include")
+    public PostSummaryDto includeInRss(@PathVariable Long id) {
+        return postMapper.toSummaryDto(postService.includeInRss(id));
+    }
 }

backend/src/main/java/com/openisle/controller/RssController.java

@@ -0,0 +1,78 @@
+package com.openisle.controller;
+
+import com.openisle.model.Post;
+import com.openisle.service.PostService;
+import lombok.RequiredArgsConstructor;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.time.ZoneId;
+import java.time.format.DateTimeFormatter;
+import java.util.List;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+
+@RestController
+@RequiredArgsConstructor
+public class RssController {
+    private final PostService postService;
+
+    @Value("${app.website-url:https://www.open-isle.com}")
+    private String websiteUrl;
+
+    private static final Pattern MD_IMAGE = Pattern.compile("!\\[[^\\]]*\\]\\(([^)]+)\\)");
+    private static final Pattern HTML_IMAGE = Pattern.compile("<img[^>]+src=[\"']?([^\"'>]+)[\"']?[^>]*>");
+
+    @GetMapping(value = "/api/rss", produces = "application/rss+xml;charset=UTF-8")
+    public String feed() {
+        List<Post> posts = postService.listLatestRssPosts(10);
+        StringBuilder sb = new StringBuilder();
+        sb.append("<?xml version=\"1.0\" encoding=\"UTF-8\"?>");
+        sb.append("<rss version=\"2.0\">");
+        sb.append("<channel>");
+        sb.append("<title>OpenIsle RSS</title>");
+        sb.append("<link>").append(websiteUrl).append("</link>");
+        sb.append("<description>Latest posts</description>");
+        DateTimeFormatter fmt = DateTimeFormatter.RFC_1123_DATE_TIME;
+        for (Post p : posts) {
+            String link = websiteUrl + "/posts/" + p.getId();
+            sb.append("<item>");
+            sb.append("<title><![CDATA[").append(p.getTitle()).append("]]></title>");
+            sb.append("<link>").append(link).append("</link>");
+            sb.append("<guid isPermaLink=\"true\">").append(link).append("</guid>");
+            sb.append("<pubDate>")
+                    .append(p.getCreatedAt().atZone(ZoneId.systemDefault()).format(fmt))
+                    .append("</pubDate>");
+            String desc = p.getContent() + "\n<p>更多细节请访问原文：" + link + "</p>";
+            sb.append("<description><![CDATA[").append(desc).append("]]></description>");
+            String img = firstImage(p.getContent());
+            if (img != null) {
+                sb.append("<enclosure url=\"").append(img).append("\" type=\"")
+                        .append(getMimeType(img)).append("\" />");
+            }
+            sb.append("</item>");
+        }
+        sb.append("</channel></rss>");
+        return sb.toString();
+    }
+
+    private String firstImage(String content) {
+        Matcher m = MD_IMAGE.matcher(content);
+        if (m.find()) {
+            return m.group(1);
+        }
+        m = HTML_IMAGE.matcher(content);
+        if (m.find()) {
+            return m.group(1);
+        }
+        return null;
+    }
+
+    private String getMimeType(String url) {
+        String lower = url.toLowerCase();
+        if (lower.endsWith(".png")) return "image/png";
+        if (lower.endsWith(".gif")) return "image/gif";
+        return "image/jpeg";
+    }
+}

backend/src/main/java/com/openisle/dto/PostSummaryDto.java

@@ -31,5 +31,6 @@ public class PostSummaryDto {
     private int pointReward;
     private PostType type;
     private LotteryDto lottery;
+    private boolean rssExcluded;
 }
 

backend/src/main/java/com/openisle/mapper/PostMapper.java

@@ -63,6 +63,7 @@ public class PostMapper {
         dto.setCommentCount(commentService.countComments(post.getId()));
         dto.setStatus(post.getStatus());
         dto.setPinnedAt(post.getPinnedAt());
+        dto.setRssExcluded(post.isRssExcluded());
 
         List<ReactionDto> reactions = reactionService.getReactionsForPost(post.getId())
                 .stream()

backend/src/main/java/com/openisle/model/Post.java

@@ -67,4 +67,7 @@ public class Post {
     @Column
     private LocalDateTime pinnedAt;
 
+    @Column(nullable = false)
+    private boolean rssExcluded = false;
+
 }

backend/src/main/java/com/openisle/repository/PostRepository.java

@@ -106,4 +106,6 @@ public interface PostRepository extends JpaRepository<Post, Long> {
            "WHERE p.createdAt >= :start AND p.createdAt < :end GROUP BY d ORDER BY d")
     java.util.List<Object[]> countDailyRange(@Param("start") LocalDateTime start,
                                              @Param("end") LocalDateTime end);
+
+    List<Post> findByStatusAndRssExcludedFalseOrderByCreatedAtDesc(PostStatus status, Pageable pageable);
 }

backend/src/main/java/com/openisle/service/PostService.java

@@ -132,6 +132,23 @@ public class PostService {
         this.publishMode = publishMode;
     }
 
+    public List<Post> listLatestRssPosts(int limit) {
+        Pageable pageable = PageRequest.of(0, limit, Sort.by(Sort.Direction.DESC, "createdAt"));
+        return postRepository.findByStatusAndRssExcludedFalseOrderByCreatedAtDesc(PostStatus.PUBLISHED, pageable);
+    }
+
+    public Post excludeFromRss(Long id) {
+        Post post = postRepository.findById(id).orElseThrow(() -> new com.openisle.exception.NotFoundException("Post not found"));
+        post.setRssExcluded(true);
+        return postRepository.save(post);
+    }
+
+    public Post includeInRss(Long id) {
+        Post post = postRepository.findById(id).orElseThrow(() -> new com.openisle.exception.NotFoundException("Post not found"));
+        post.setRssExcluded(false);
+        return postRepository.save(post);
+    }
+
     public Post createPost(String username,
                            Long categoryId,
                            String title,