feat: DSL 磁力聚合 — 搜索/解析/预览/投递 + cilisousuo 源 + 中英双语 + Docker 部署

2026-10-16 18:53:45 +08:00
commit d6999104bf
64 changed files with 16524 additions and 0 deletions
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+import { mkdir, rm } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import { loadWebTorrent, withDefaultTrackers } from './torrent'
+
+/** 会话空闲多久后释放（毫秒） */
+const IDLE_MS = 120_000
+
+interface SwarmSession {
+  client: any
+  torrent: any
+  dir: string
+  ready: Promise<any>
+  timer: NodeJS.Timeout | null
+}
+
+const sessions = new Map<string, SwarmSession>()
+
+/**
+ * 复用一个常驻的 webtorrent 会话来取文件内容。
+ * 每张图片都重建一次客户端就得重新找一遍节点（快则 1 秒，慢则十几秒），
+ * 所以同一个 infoHash 的连续预览共用一条会话，空闲 2 分钟自动释放。
+ */
+export async function withSwarm<T>(
+  infoHash: string,
+  magnet: string,
+  timeoutMs: number,
+  fn: (torrent: any) => Promise<T>
+): Promise<T> {
+  const key = infoHash.toLowerCase()
+  let session = sessions.get(key)
+  if (!session) {
+    session = await createSession(key, magnet, timeoutMs)
+    sessions.set(key, session)
+  }
+  touchSession(key, session)
+  const torrent = await session.ready
+  return fn(torrent)
+}
+
+function touchSession(key: string, session: SwarmSession) {
+  if (session.timer) clearTimeout(session.timer)
+  session.timer = setTimeout(() => releaseSession(key), IDLE_MS)
+  session.timer.unref?.()
+}
+
+async function createSession(infoHash: string, magnet: string, timeoutMs: number): Promise<SwarmSession> {
+  const WebTorrent = await loadWebTorrent()
+  const dir = join(tmpdir(), `dsl-swarm-${infoHash.slice(0, 8)}-${Date.now().toString(36)}`)
+  await mkdir(dir, { recursive: true })
+
+  const client = new WebTorrent({ dht: true, lsd: false, utp: false })
+  client.on('error', () => {})
+
+  const torrent = client.add(withDefaultTrackers(magnet), { path: dir })
+  torrent.on('warning', () => {})
+
+  const ready = new Promise<any>((resolve, reject) => {
+    const timer = setTimeout(() => {
+      reject(new Error(`获取种子元数据超时（${Math.round(timeoutMs / 1000)}s），可能没有可用节点或 tracker 被墙`))
+    }, timeoutMs)
+    const done = (fn: () => void) => {
+      clearTimeout(timer)
+      fn()
+    }
+    if (torrent.metadata) return done(() => resolve(torrent))
+    torrent.on('metadata', () => done(() => resolve(torrent)))
+    torrent.on('error', (err: Error) => done(() => reject(err)))
+    client.on('error', (err: Error) => done(() => reject(err)))
+  })
+
+  const session: SwarmSession = { client, torrent, dir, ready, timer: null }
+  touchSession(infoHash, session)
+  // 元数据都拿不到就别留着占资源
+  ready.catch(() => releaseSession(infoHash))
+  return session
+}
+
+function releaseSession(infoHash: string) {
+  const session = sessions.get(infoHash)
+  if (!session) return
+  sessions.delete(infoHash)
+  if (session.timer) clearTimeout(session.timer)
+  try {
+    session.client.destroy(() => {})
+  } catch {
+    /* ignore */
+  }
+  rm(session.dir, { recursive: true, force: true }).catch(() => {})
+}