refactor: append new episodes to existing podcast.xml

services/podcast.ts

@@ -43,6 +43,58 @@ export async function updatePodcastRSS() {
     `;
   }
 
+  const outputPath = join(__dirname, "../public/podcast.xml");
+  
+  // 既存のRSSファイルの読み込み
+  let existingXml = "";
+  try {
+    existingXml = await fs.readFile(outputPath, "utf-8");
+  } catch (err) {
+    // ファイルが存在しない場合は新規作成
+    console.log("既存のpodcast.xmlが見つかりません。新規作成します。");
+  }
+
+  if (existingXml) {
+    // 既存のitem部分を抽出
+    const existingItemsMatch = existingXml.match(/<channel>([\s\S]*?)<\/channel>/);
+    if (existingItemsMatch) {
+      const existingItems = existingItemsMatch[1];
+      const newItemStartIndex = existingItems.lastIndexOf("<item>");
+      
+      // 新しいitemを追加
+      const updatedItems = existingItems + itemsXml;
+      
+      // lastBuildDateを更新
+      const updatedXml = existingXml.replace(
+        /<lastBuildDate>.*?<\/lastBuildDate>/,
+        `<lastBuildDate>${lastBuildDate}</lastBuildDate>`
+      );
+      
+      // items部分を置き換え
+      const finalXml = updatedXml.replace(
+        /<channel>[\s\S]*?<\/channel>/,
+        `<channel>${updatedItems}</channel>`
+      );
+      
+      // ファイルに書き込み
+      await fs.writeFile(outputPath, finalXml.trim());
+    } else {
+      // 不正なフォーマットの場合は新規作成
+      const rssXml = `<?xml version="1.0" encoding="UTF-8"?>
+      <rss version="2.0">
+        <channel>
+          <title>${channelTitle}</title>
+          <link>${channelLink}</link>
+          <description>${channelDescription}]]></description>
+          <lastBuildDate>${lastBuildDate}</lastBuildDate>
+          ${itemsXml}
+        </channel>
+      </rss>
+      `;
+      await fs.writeFile(outputPath, rssXml.trim());
+    }
+  } else {
+    // 新規作成
     const rssXml = `<?xml version="1.0" encoding="UTF-8"?>
     <rss version="2.0">
       <channel>
@@ -55,8 +107,8 @@ export async function updatePodcastRSS() {
     </rss>
     `;
     
-  const outputPath = join(__dirname, "../public/podcast.xml");
     // Ensure directory exists
     await fs.mkdir(dirname(outputPath), { recursive: true });
     await fs.writeFile(outputPath, rssXml.trim());
   }
+}