3 files changed, 121 insertions, 46 deletions

diff --git a/server/lib/cache/abstract-video-static-file-cache.ts b/server/lib/cache/abstract-video-static-file-cache.ts
new file mode 100644
index 000000000..7eeeb6b3a
--- /dev/null
+++ b/server/lib/cache/abstract-video-static-file-cache.ts
@@ -0,0 +1,54 @@
+import * as AsyncLRU from 'async-lru'
+import { createWriteStream } from 'fs'
+import { join } from 'path'
+import { unlinkPromise } from '../../helpers/core-utils'
+import { logger } from '../../helpers/logger'
+import { CACHE, CONFIG } from '../../initializers'
+import { VideoModel } from '../../models/video/video'
+import { fetchRemoteVideoStaticFile } from '../activitypub'
+import { VideoCaptionModel } from '../../models/video/video-caption'
+
+export abstract class AbstractVideoStaticFileCache <T> {
+
+  protected lru
+
+  abstract getFilePath (params: T): Promise<string>
+
+  // Load and save the remote file, then return the local path from filesystem
+  protected abstract loadRemoteFile (key: string): Promise<string>
+
+  init (max: number) {
+    this.lru = new AsyncLRU({
+      max,
+      load: (key, cb) => {
+        this.loadRemoteFile(key)
+          .then(res => cb(null, res))
+          .catch(err => cb(err))
+      }
+    })
+
+    this.lru.on('evict', (obj: { key: string, value: string }) => {
+      unlinkPromise(obj.value).then(() => logger.debug('%s evicted from %s', obj.value, this.constructor.name))
+    })
+  }
+
+  protected loadFromLRU (key: string) {
+    return new Promise<string>((res, rej) => {
+      this.lru.get(key, (err, value) => {
+        err ? rej(err) : res(value)
+      })
+    })
+  }
+
+  protected saveRemoteVideoFileAndReturnPath (video: VideoModel, remoteStaticPath: string, destPath: string) {
+    return new Promise<string>((res, rej) => {
+      const req = fetchRemoteVideoStaticFile(video, remoteStaticPath, rej)
+
+      const stream = createWriteStream(destPath)
+
+      req.pipe(stream)
+         .on('error', (err) => rej(err))
+         .on('finish', () => res(destPath))
+    })
+  }
+}
diff --git a/server/lib/cache/videos-caption-cache.ts b/server/lib/cache/videos-caption-cache.ts
new file mode 100644
index 000000000..1336610b2
--- /dev/null
+++ b/server/lib/cache/videos-caption-cache.ts
@@ -0,0 +1,53 @@
+import { join } from 'path'
+import { CACHE, CONFIG } from '../../initializers'
+import { VideoModel } from '../../models/video/video'
+import { VideoCaptionModel } from '../../models/video/video-caption'
+import { AbstractVideoStaticFileCache } from './abstract-video-static-file-cache'
+
+type GetPathParam = { videoId: string, language: string }
+
+class VideosCaptionCache extends AbstractVideoStaticFileCache <GetPathParam> {
+
+  private static readonly KEY_DELIMITER = '%'
+  private static instance: VideosCaptionCache
+
+  private constructor () {
+    super()
+  }
+
+  static get Instance () {
+    return this.instance || (this.instance = new this())
+  }
+
+  async getFilePath (params: GetPathParam) {
+    const videoCaption = await VideoCaptionModel.loadByVideoIdAndLanguage(params.videoId, params.language)
+    if (!videoCaption) return undefined
+
+    if (videoCaption.isOwned()) return join(CONFIG.STORAGE.CAPTIONS_DIR, videoCaption.getCaptionName())
+
+    const key = params.videoId + VideosCaptionCache.KEY_DELIMITER + params.language
+    return this.loadFromLRU(key)
+  }
+
+  protected async loadRemoteFile (key: string) {
+    const [ videoId, language ] = key.split(VideosCaptionCache.KEY_DELIMITER)
+
+    const videoCaption = await VideoCaptionModel.loadByVideoIdAndLanguage(videoId, language)
+    if (!videoCaption) return undefined
+
+    if (videoCaption.isOwned()) throw new Error('Cannot load remote caption of owned video.')
+
+    // Used to fetch the path
+    const video = await VideoModel.loadByUUIDAndPopulateAccountAndServerAndTags(videoId)
+    if (!video) return undefined
+
+    const remoteStaticPath = videoCaption.getCaptionStaticPath()
+    const destPath = join(CACHE.DIRECTORIES.VIDEO_CAPTIONS, videoCaption.getCaptionName())
+
+    return this.saveRemoteVideoFileAndReturnPath(video, remoteStaticPath, destPath)
+  }
+}
+
+export {
+  VideosCaptionCache
+}
diff --git a/server/lib/cache/videos-preview-cache.ts b/server/lib/cache/videos-preview-cache.ts
index d09d55e11..1c0e7ed9d 100644
--- a/server/lib/cache/videos-preview-cache.ts
+++ b/server/lib/cache/videos-preview-cache.ts
@@ -1,71 +1,39 @@
-import * as asyncLRU from 'async-lru'
-import { createWriteStream } from 'fs'
 import { join } from 'path'
-import { unlinkPromise } from '../../helpers/core-utils'
-import { logger } from '../../helpers/logger'
-import { CACHE, CONFIG } from '../../initializers'
+import { CACHE, CONFIG, STATIC_PATHS } from '../../initializers'
 import { VideoModel } from '../../models/video/video'
-import { fetchRemoteVideoPreview } from '../activitypub'
+import { AbstractVideoStaticFileCache } from './abstract-video-static-file-cache'
 
-class VideosPreviewCache {
+class VideosPreviewCache extends AbstractVideoStaticFileCache <string> {
 
   private static instance: VideosPreviewCache
 
-  private lru
-
-  private constructor () { }
+  private constructor () {
+    super()
+  }
 
   static get Instance () {
     return this.instance || (this.instance = new this())
   }
 
-  init (max: number) {
-    this.lru = new asyncLRU({
-      max,
-      load: (key, cb) => {
-        this.loadPreviews(key)
-          .then(res => cb(null, res))
-          .catch(err => cb(err))
-      }
-    })
-
-    this.lru.on('evict', (obj: { key: string, value: string }) => {
-      unlinkPromise(obj.value).then(() => logger.debug('%s evicted from VideosPreviewCache', obj.value))
-    })
-  }
-
-  async getPreviewPath (key: string) {
-    const video = await VideoModel.loadByUUID(key)
+  async getFilePath (videoUUID: string) {
+    const video = await VideoModel.loadByUUID(videoUUID)
     if (!video) return undefined
 
     if (video.isOwned()) return join(CONFIG.STORAGE.PREVIEWS_DIR, video.getPreviewName())
 
-    return new Promise<string>((res, rej) => {
-      this.lru.get(key, (err, value) => {
-        err ? rej(err) : res(value)
-      })
-    })
+    return this.loadFromLRU(videoUUID)
   }
 
-  private async loadPreviews (key: string) {
+  protected async loadRemoteFile (key: string) {
     const video = await VideoModel.loadByUUIDAndPopulateAccountAndServerAndTags(key)
     if (!video) return undefined
 
-    if (video.isOwned()) throw new Error('Cannot load preview of owned video.')
-
-    return this.saveRemotePreviewAndReturnPath(video)
-  }
+    if (video.isOwned()) throw new Error('Cannot load remote preview of owned video.')
 
-  private saveRemotePreviewAndReturnPath (video: VideoModel) {
-    return new Promise<string>((res, rej) => {
-      const req = fetchRemoteVideoPreview(video, rej)
-      const path = join(CACHE.DIRECTORIES.PREVIEWS, video.getPreviewName())
-      const stream = createWriteStream(path)
+    const remoteStaticPath = join(STATIC_PATHS.PREVIEWS, video.getPreviewName())
+    const destPath = join(CACHE.DIRECTORIES.PREVIEWS, video.getPreviewName())
 
-      req.pipe(stream)
-        .on('error', (err) => rej(err))
-        .on('finish', () => res(path))
-    })
+    return this.saveRemoteVideoFileAndReturnPath(video, remoteStaticPath, destPath)
   }
 }