Support video views/viewers stats in server

 * Add "currentTime" and "event" body params to view endpoint
 * Merge watching and view endpoints
 * Introduce WatchAction AP activity
 * Add tables to store viewer information of local videos
 * Add endpoints to fetch video views/viewers stats of local videos
 * Refactor views/viewers handlers
 * Support "views" and "viewers" counters for both VOD and live videos

6 files changed, 180 insertions, 46 deletions

diff --git a/server/middlewares/validators/express.ts b/server/middlewares/validators/express.ts
new file mode 100644
index 000000000..718aec55b
--- /dev/null
+++ b/server/middlewares/validators/express.ts
@@ -0,0 +1,15 @@
+import * as express from 'express'
+
+const methodsValidator = (methods: string[]) => {
+  return (req: express.Request, res: express.Response, next: express.NextFunction) => {
+    if (methods.includes(req.method) !== true) {
+      return res.sendStatus(405)
+    }
+
+    return next()
+  }
+}
+
+export {
+  methodsValidator
+}
diff --git a/server/middlewares/validators/index.ts b/server/middlewares/validators/index.ts
index 94a3c2dea..b0ad04819 100644
--- a/server/middlewares/validators/index.ts
+++ b/server/middlewares/validators/index.ts
@@ -1,17 +1,26 @@
+export * from './activitypub'
+export * from './videos'
 export * from './abuse'
 export * from './account'
 export * from './actor-image'
 export * from './blocklist'
+export * from './bulk'
+export * from './config'
+export * from './express'
+export * from './feeds'
+export * from './follows'
+export * from './jobs'
+export * from './logs'
 export * from './oembed'
-export * from './activitypub'
 export * from './pagination'
-export * from './follows'
-export * from './feeds'
-export * from './sort'
-export * from './users'
-export * from './user-subscriptions'
-export * from './videos'
+export * from './plugins'
+export * from './redundancy'
 export * from './search'
 export * from './server'
+export * from './sort'
+export * from './themes'
 export * from './user-history'
+export * from './user-notifications'
+export * from './user-subscriptions'
+export * from './users'
 export * from './webfinger'
diff --git a/server/middlewares/validators/videos/index.ts b/server/middlewares/validators/videos/index.ts
index c7dea4b3d..bd2590bc5 100644
--- a/server/middlewares/validators/videos/index.ts
+++ b/server/middlewares/validators/videos/index.ts
@@ -6,9 +6,10 @@ export * from './video-files'
 export * from './video-imports'
 export * from './video-live'
 export * from './video-ownership-changes'
-export * from './video-watch'
+export * from './video-view'
 export * from './video-rates'
 export * from './video-shares'
+export * from './video-stats'
 export * from './video-studio'
 export * from './video-transcoding'
 export * from './videos'
diff --git a/server/middlewares/validators/videos/video-stats.ts b/server/middlewares/validators/videos/video-stats.ts
new file mode 100644
index 000000000..358b6b473
--- /dev/null
+++ b/server/middlewares/validators/videos/video-stats.ts
@@ -0,0 +1,73 @@
+import express from 'express'
+import { param } from 'express-validator'
+import { isValidStatTimeserieMetric } from '@server/helpers/custom-validators/video-stats'
+import { HttpStatusCode, UserRight } from '@shared/models'
+import { logger } from '../../../helpers/logger'
+import { areValidationErrors, checkUserCanManageVideo, doesVideoExist, isValidVideoIdParam } from '../shared'
+
+const videoOverallStatsValidator = [
+  isValidVideoIdParam('videoId'),
+
+  async (req: express.Request, res: express.Response, next: express.NextFunction) => {
+    logger.debug('Checking videoOverallStatsValidator parameters', { parameters: req.body })
+
+    if (areValidationErrors(req, res)) return
+    if (!await commonStatsCheck(req, res)) return
+
+    return next()
+  }
+]
+
+const videoRetentionStatsValidator = [
+  isValidVideoIdParam('videoId'),
+
+  async (req: express.Request, res: express.Response, next: express.NextFunction) => {
+    logger.debug('Checking videoRetentionStatsValidator parameters', { parameters: req.body })
+
+    if (areValidationErrors(req, res)) return
+    if (!await commonStatsCheck(req, res)) return
+
+    if (res.locals.videoAll.isLive) {
+      return res.fail({
+        status: HttpStatusCode.BAD_REQUEST_400,
+        message: 'Cannot get retention stats of live video'
+      })
+    }
+
+    return next()
+  }
+]
+
+const videoTimeserieStatsValidator = [
+  isValidVideoIdParam('videoId'),
+
+  param('metric')
+    .custom(isValidStatTimeserieMetric)
+    .withMessage('Should have a valid timeserie metric'),
+
+  async (req: express.Request, res: express.Response, next: express.NextFunction) => {
+    logger.debug('Checking videoTimeserieStatsValidator parameters', { parameters: req.body })
+
+    if (areValidationErrors(req, res)) return
+    if (!await commonStatsCheck(req, res)) return
+
+    return next()
+  }
+]
+
+// ---------------------------------------------------------------------------
+
+export {
+  videoOverallStatsValidator,
+  videoTimeserieStatsValidator,
+  videoRetentionStatsValidator
+}
+
+// ---------------------------------------------------------------------------
+
+async function commonStatsCheck (req: express.Request, res: express.Response) {
+  if (!await doesVideoExist(req.params.videoId, res, 'all')) return false
+  if (!checkUserCanManageVideo(res.locals.oauth.token.User, res.locals.videoAll, UserRight.SEE_ALL_VIDEOS, res)) return false
+
+  return true
+}
diff --git a/server/middlewares/validators/videos/video-view.ts b/server/middlewares/validators/videos/video-view.ts
new file mode 100644
index 000000000..7a4994e8a
--- /dev/null
+++ b/server/middlewares/validators/videos/video-view.ts
@@ -0,0 +1,74 @@
+import express from 'express'
+import { body, param } from 'express-validator'
+import { isVideoTimeValid } from '@server/helpers/custom-validators/video-view'
+import { LocalVideoViewerModel } from '@server/models/view/local-video-viewer'
+import { HttpStatusCode } from '../../../../shared/models/http/http-error-codes'
+import { exists, isIdValid, isIntOrNull, toIntOrNull } from '../../../helpers/custom-validators/misc'
+import { logger } from '../../../helpers/logger'
+import { areValidationErrors, doesVideoExist, isValidVideoIdParam } from '../shared'
+
+const getVideoLocalViewerValidator = [
+  param('localViewerId')
+    .custom(isIdValid).withMessage('Should have a valid local viewer id'),
+
+  async (req: express.Request, res: express.Response, next: express.NextFunction) => {
+    logger.debug('Checking getVideoLocalViewerValidator parameters', { parameters: req.params })
+
+    if (areValidationErrors(req, res)) return
+
+    const localViewer = await LocalVideoViewerModel.loadFullById(+req.params.localViewerId)
+    if (!localViewer) {
+      return res.fail({
+        status: HttpStatusCode.NOT_FOUND_404,
+        message: 'Local viewer not found'
+      })
+    }
+
+    res.locals.localViewerFull = localViewer
+
+    return next()
+  }
+]
+
+const videoViewValidator = [
+  isValidVideoIdParam('videoId'),
+
+  body('currentTime')
+    .optional() // TODO: remove optional in a few versions, introduced in 4.2
+    .customSanitizer(toIntOrNull)
+    .custom(isIntOrNull).withMessage('Should have correct current time'),
+
+  async (req: express.Request, res: express.Response, next: express.NextFunction) => {
+    logger.debug('Checking videoView parameters', { parameters: req.body })
+
+    if (areValidationErrors(req, res)) return
+    if (!await doesVideoExist(req.params.videoId, res, 'only-video')) return
+
+    const video = res.locals.onlyVideo
+    const videoDuration = video.isLive
+      ? undefined
+      : video.duration
+
+    if (!exists(req.body.currentTime)) { // TODO: remove in a few versions, introduced in 4.2
+      req.body.currentTime = Math.min(videoDuration ?? 0, 30)
+    }
+
+    const currentTime: number = req.body.currentTime
+
+    if (!isVideoTimeValid(currentTime, videoDuration)) {
+      return res.fail({
+        status: HttpStatusCode.BAD_REQUEST_400,
+        message: 'Current time is invalid'
+      })
+    }
+
+    return next()
+  }
+]
+
+// ---------------------------------------------------------------------------
+
+export {
+  videoViewValidator,
+  getVideoLocalViewerValidator
+}
diff --git a/server/middlewares/validators/videos/video-watch.ts b/server/middlewares/validators/videos/video-watch.ts
deleted file mode 100644
index d83710a64..000000000
--- a/server/middlewares/validators/videos/video-watch.ts
+++ /dev/null
@@ -1,38 +0,0 @@
-import express from 'express'
-import { body } from 'express-validator'
-import { HttpStatusCode } from '../../../../shared/models/http/http-error-codes'
-import { toIntOrNull } from '../../../helpers/custom-validators/misc'
-import { logger } from '../../../helpers/logger'
-import { areValidationErrors, doesVideoExist, isValidVideoIdParam } from '../shared'
-
-const videoWatchingValidator = [
-  isValidVideoIdParam('videoId'),
-
-  body('currentTime')
-    .customSanitizer(toIntOrNull)
-    .isInt().withMessage('Should have correct current time'),
-
-  async (req: express.Request, res: express.Response, next: express.NextFunction) => {
-    logger.debug('Checking videoWatching parameters', { parameters: req.body })
-
-    if (areValidationErrors(req, res)) return
-    if (!await doesVideoExist(req.params.videoId, res, 'id')) return
-
-    const user = res.locals.oauth.token.User
-    if (user.videosHistoryEnabled === false) {
-      logger.warn('Cannot set videos to watch by user %d: videos history is disabled.', user.id)
-      return res.fail({
-        status: HttpStatusCode.CONFLICT_409,
-        message: 'Video history is disabled'
-      })
-    }
-
-    return next()
-  }
-]
-
-// ---------------------------------------------------------------------------
-
-export {
-  videoWatchingValidator
-}