Handle .srt subtitles

server/helpers/captions-utils.ts

@@ -0,0 +1,47 @@
+import { renamePromise, unlinkPromise } from './core-utils'
+import { join } from 'path'
+import { CONFIG } from '../initializers'
+import { VideoCaptionModel } from '../models/video/video-caption'
+import * as srt2vtt from 'srt-to-vtt'
+import { createReadStream, createWriteStream } from 'fs'
+
+async function moveAndProcessCaptionFile (physicalFile: { filename: string, path: string }, videoCaption: VideoCaptionModel) {
+  const videoCaptionsDir = CONFIG.STORAGE.CAPTIONS_DIR
+  const destination = join(videoCaptionsDir, videoCaption.getCaptionName())
+
+  // Convert this srt file to vtt
+  if (physicalFile.path.endsWith('.srt')) {
+    await convertSrtToVtt(physicalFile.path, destination)
+    await unlinkPromise(physicalFile.path)
+  } else { // Just move the vtt file
+    await renamePromise(physicalFile.path, destination)
+  }
+
+  // This is important in case if there is another attempt in the retry process
+  physicalFile.filename = videoCaption.getCaptionName()
+  physicalFile.path = destination
+}
+
+// ---------------------------------------------------------------------------
+
+export {
+  moveAndProcessCaptionFile
+}
+
+// ---------------------------------------------------------------------------
+
+function convertSrtToVtt (source: string, destination: string) {
+  return new Promise((res, rej) => {
+    const file = createReadStream(source)
+    const converter = srt2vtt()
+    const writer = createWriteStream(destination)
+
+    for (const s of [ file, converter, writer ]) {
+      s.on('error', err => rej(err))
+    }
+
+    return file.pipe(converter)
+               .pipe(writer)
+               .on('finish', () => res())
+  })
+}