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

server/utils/torrent.ts

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+import { mkdir, rm } from 'node:fs/promises'
+import { tmpdir } from 'node:os'
+import { join } from 'node:path'
+import parseTorrent, { toMagnetURI } from 'parse-torrent'
+import type { TorrentFileEntry } from './types'
+
+export interface TorrentInfo {
+  infoHash: string
+  name: string
+  size: number
+  files: TorrentFileEntry[] | null
+  fileCount: number | null
+  trackers: string[]
+  magnet: string
+  comment: string | null
+  creationDate: Date | null
+  pieceLength: number | null
+  isPrivate: boolean
+}
+
+export const DEFAULT_TRACKERS = [
+  'udp://tracker.opentrackr.org:1337/announce',
+  'udp://open.tracker.cl:1337/announce',
+  'udp://open.demonii.com:1337/announce',
+  'udp://tracker.openbittorrent.com:6969/announce',
+  'udp://exodus.desync.com:6969/announce',
+  'udp://tracker.torrent.eu.org:451/announce'
+]
+
+export function buildMagnet(infoHash: string, name?: string | null, trackers: string[] = DEFAULT_TRACKERS): string {
+  const params = [`xt=urn:btih:${infoHash}`]
+  if (name) params.push(`dn=${encodeURIComponent(name)}`)
+  for (const tr of trackers) params.push(`tr=${encodeURIComponent(tr)}`)
+  return `magnet:?${params.join('&')}`
+}
+
+/** 从磁力链里取出已有的 tracker */
+function trackersInMagnet(magnet: string): string[] {
+  const out = new Set<string>()
+  for (const m of magnet.matchAll(/[?&]tr=([^&]+)/g)) {
+    try {
+      out.add(decodeURIComponent(m[1]))
+    } catch {
+      /* 编码坏了就跳过 */
+    }
+  }
+  return [...out]
+}
+
+/**
+ * 给没有 tracker 的磁力链补上 tracker。
+ * 社区里流传的裸磁力链（只有 xt + dn）常常一个 tracker 都没有，
+ * 纯靠 DHT 在家庭网络/被墙环境里几乎拉不到元数据，补公共 tracker 能显著提高成功率。
+ */
+export function withDefaultTrackers(magnet: string, extra: string[] = []): string {
+  if (!magnet || /[?&]tr=/.test(magnet)) return magnet
+  const list = extra.length ? extra : DEFAULT_TRACKERS
+  return magnet + list.map((t) => `&tr=${encodeURIComponent(t)}`).join('')
+}
+
+function toInfoHash(value: unknown): string {
+  if (!value) return ''
+  if (typeof value === 'string') return value.toLowerCase()
+  if (value instanceof Uint8Array || Buffer.isBuffer(value)) return Buffer.from(value as Uint8Array).toString('hex')
+  return String(value).toLowerCase()
+}
+
+function pickTrackers(parsed: Record<string, unknown>): string[] {
+  const out = new Set<string>()
+  const announce = parsed.announce
+  if (typeof announce === 'string') out.add(announce)
+  else if (Array.isArray(announce)) for (const a of announce) if (typeof a === 'string') out.add(a)
+  const list = parsed.announceList
+  if (Array.isArray(list)) {
+    for (const tier of list) {
+      if (Array.isArray(tier)) for (const a of tier) if (typeof a === 'string') out.add(a)
+    }
+  }
+  return [...out]
+}
+
+function normalize(parsed: Record<string, any>, magnetFallback?: string): TorrentInfo {
+  const infoHash = toInfoHash(parsed.infoHash)
+  let files: TorrentFileEntry[] | null = null
+  if (Array.isArray(parsed.files) && parsed.files.length) {
+    files = parsed.files.map((f: any) => ({
+      // parse-torrent 用 path.sep 拼接，Windows 下是反斜杠，统一成正斜杠便于展示
+      path: String(f.path ?? f.name ?? '').replace(/\\/g, '/'),
+      length: Number(f.length) || 0
+    }))
+  } else if (typeof parsed.length === 'number') {
+    // 单文件种子：parse-torrent 只给出 length + name
+    files = [{ path: String(parsed.name || 'unknown'), length: Number(parsed.length) || 0 }]
+  }
+
+  const size = files ? files.reduce((sum, f) => sum + (f.length || 0), 0) : Number(parsed.length) || 0
+  let trackers = pickTrackers(parsed)
+
+  let magnet = magnetFallback || ''
+  if (!magnet) {
+    try {
+      magnet = toMagnetURI(parsed as never)
+    } catch {
+      magnet = infoHash ? buildMagnet(infoHash, parsed.name, trackers.length ? trackers : DEFAULT_TRACKERS) : ''
+    }
+  }
+  magnet = withDefaultTrackers(magnet, trackers)
+  // 补过 tracker 的磁力链，trackers 以最终磁力链为准，避免 UI 显示“无 tracker”
+  if (!trackers.length) trackers = trackersInMagnet(magnet)
+
+  return {
+    infoHash,
+    name: String(parsed.name || ''),
+    size,
+    files,
+    fileCount: files ? files.length : null,
+    trackers,
+    magnet,
+    comment: typeof parsed.comment === 'string' ? parsed.comment : null,
+    creationDate: parsed.created instanceof Date
+      ? parsed.created
+      : parsed.creationDate instanceof Date
+        ? parsed.creationDate
+        : null,
+    pieceLength: typeof parsed.pieceLength === 'number' ? parsed.pieceLength : null,
+    isPrivate: parsed.private === true
+  }
+}
+
+/** 解析 .torrent 文件内容（parse-torrent v11 起为异步 API） */
+export async function parseTorrentBuffer(buf: Buffer): Promise<TorrentInfo> {
+  let parsed: any
+  try {
+    parsed = await parseTorrent(buf)
+  } catch {
+    throw new Error('种子文件解析失败，可能不是合法的 .torrent 文件')
+  }
+  const info = normalize(parsed)
+  if (!info.infoHash) throw new Error('种子文件中缺少 info 字段，无法计算 infoHash')
+  return info
+}
+
+/** 解析磁力链（不含文件清单，需要通过 fetchMetadataFromMagnet 才能拿到） */
+export async function parseMagnet(uri: string): Promise<TorrentInfo> {
+  const raw = uri.trim()
+  if (!/^magnet:\?/i.test(raw)) throw new Error('不是合法的磁力链接，应以 magnet:? 开头')
+  if (!/xt=urn:btih:[a-z0-9]+/i.test(raw)) throw new Error('磁力链接中缺少 xt=urn:btih: 参数')
+  let parsed: any
+  try {
+    parsed = await parseTorrent(raw)
+  } catch {
+    throw new Error('磁力链接解析失败')
+  }
+  const info = normalize(parsed, raw)
+  if (!info.infoHash) throw new Error('无法从磁力链接中提取 infoHash')
+  return info
+}
+
+/** 判断字符串是否为磁力链 */
+export function isMagnet(input: string): boolean {
+  return /^magnet:\?/i.test(input.trim())
+}
+
+let webTorrentMod: unknown = null
+
+export async function loadWebTorrent(): Promise<any> {
+  if (webTorrentMod) return webTorrentMod
+  try {
+    const mod: any = await import('webtorrent')
+    webTorrentMod = mod?.default || mod
+    return webTorrentMod
+  } catch {
+    throw new Error('未安装 webtorrent 依赖，无法通过磁力链在线获取文件清单（仅能显示 infoHash）')
+  }
+}
+
+export function hasWebTorrent(): boolean {
+  return webTorrentMod !== null
+}
+
+/** 探测 webtorrent 依赖是否可用（用于健康检查与 UI 提示） */
+export async function checkWebTorrent(): Promise<boolean> {
+  try {
+    await loadWebTorrent()
+    return true
+  } catch {
+    return false
+  }
+}
+
+/**
+ * 通过磁力链从 DHT / tracker 拉取种子元数据，从而得到文件清单。
+ * 只取元数据，取到后立刻销毁客户端并清理临时目录。
+ */
+export async function fetchMetadataFromMagnet(
+  magnetUri: string,
+  timeoutMs = 30000
+): Promise<{ name: string; files: TorrentFileEntry[]; size: number }> {
+  const WebTorrent = await loadWebTorrent()
+  const dir = join(tmpdir(), `dsl-meta-${Date.now().toString(36)}-${Math.random().toString(36).slice(2, 8)}`)
+  await mkdir(dir, { recursive: true })
+
+  const client = new WebTorrent({ dht: true, lsd: false, utp: false })
+  try {
+    // 纯 DHT 很可能找不到节点，没 tracker 的磁力链先补上公共 tracker
+    const torrent = client.add(withDefaultTrackers(magnetUri), { path: dir })
+    torrent.on('warning', () => {})
+
+    await new Promise<void>((resolve, reject) => {
+      const timer = setTimeout(() => {
+        reject(new Error(`获取种子元数据超时（${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.on('metadata', () => done(resolve))
+      torrent.on('error', (err: Error) => done(() => reject(err)))
+      client.on('error', (err: Error) => done(() => reject(err)))
+    })
+
+    const files: TorrentFileEntry[] = (torrent.files || []).map((f: any) => ({
+      // Windows 下 webtorrent 用反斜杠拼路径，统一成正斜杠便于展示
+      path: String(f.path || f.name || '').replace(/\\/g, '/'),
+      length: Number(f.length) || 0
+    }))
+    return {
+      name: String(torrent.name || ''),
+      files,
+      size: files.reduce((sum, f) => sum + f.length, 0)
+    }
+  } finally {
+    try {
+      // webtorrent v3 的 destroy 是回调式 API
+      await new Promise<void>((resolve) => client.destroy(() => resolve()))
+    } catch {
+      /* ignore */
+    }
+    rm(dir, { recursive: true, force: true }).catch(() => {})
+  }
+}