Add ability for plugins to add custom routes

11 files changed, 482 insertions, 232 deletions

diff --git a/server/controllers/plugins.ts b/server/controllers/plugins.ts
index 1caee9a29..1fc49b646 100644
--- a/server/controllers/plugins.ts
+++ b/server/controllers/plugins.ts
@@ -2,7 +2,7 @@ import * as express from 'express'
 import { PLUGIN_GLOBAL_CSS_PATH } from '../initializers/constants'
 import { join } from 'path'
 import { PluginManager, RegisteredPlugin } from '../lib/plugins/plugin-manager'
-import { servePluginStaticDirectoryValidator } from '../middlewares/validators/plugins'
+import { getPluginValidator, pluginStaticDirectoryValidator } from '../middlewares/validators/plugins'
 import { serveThemeCSSValidator } from '../middlewares/validators/themes'
 import { PluginType } from '../../shared/models/plugins/plugin.type'
 import { isTestInstance } from '../helpers/core-utils'
@@ -24,22 +24,36 @@ pluginsRouter.get('/plugins/translations/:locale.json',
 )
 
 pluginsRouter.get('/plugins/:pluginName/:pluginVersion/static/:staticEndpoint(*)',
-  servePluginStaticDirectoryValidator(PluginType.PLUGIN),
+  getPluginValidator(PluginType.PLUGIN),
+  pluginStaticDirectoryValidator,
   servePluginStaticDirectory
 )
 
 pluginsRouter.get('/plugins/:pluginName/:pluginVersion/client-scripts/:staticEndpoint(*)',
-  servePluginStaticDirectoryValidator(PluginType.PLUGIN),
+  getPluginValidator(PluginType.PLUGIN),
+  pluginStaticDirectoryValidator,
   servePluginClientScripts
 )
 
+pluginsRouter.use('/plugins/:pluginName/router',
+  getPluginValidator(PluginType.PLUGIN, false),
+  servePluginCustomRoutes
+)
+
+pluginsRouter.use('/plugins/:pluginName/:pluginVersion/router',
+  getPluginValidator(PluginType.PLUGIN),
+  servePluginCustomRoutes
+)
+
 pluginsRouter.get('/themes/:pluginName/:pluginVersion/static/:staticEndpoint(*)',
-  servePluginStaticDirectoryValidator(PluginType.THEME),
+  getPluginValidator(PluginType.THEME),
+  pluginStaticDirectoryValidator,
   servePluginStaticDirectory
 )
 
 pluginsRouter.get('/themes/:pluginName/:pluginVersion/client-scripts/:staticEndpoint(*)',
-  servePluginStaticDirectoryValidator(PluginType.THEME),
+  getPluginValidator(PluginType.THEME),
+  pluginStaticDirectoryValidator,
   servePluginClientScripts
 )
 
@@ -85,22 +99,27 @@ function servePluginStaticDirectory (req: express.Request, res: express.Response
   const [ directory, ...file ] = staticEndpoint.split('/')
 
   const staticPath = plugin.staticDirs[directory]
-  if (!staticPath) {
-    return res.sendStatus(404)
-  }
+  if (!staticPath) return res.sendStatus(404)
 
   const filepath = file.join('/')
   return res.sendFile(join(plugin.path, staticPath, filepath), sendFileOptions)
 }
 
+function servePluginCustomRoutes (req: express.Request, res: express.Response, next: express.NextFunction) {
+  const plugin: RegisteredPlugin = res.locals.registeredPlugin
+  const router = PluginManager.Instance.getRouter(plugin.npmName)
+
+  if (!router) return res.sendStatus(404)
+
+  return router(req, res, next)
+}
+
 function servePluginClientScripts (req: express.Request, res: express.Response) {
   const plugin: RegisteredPlugin = res.locals.registeredPlugin
   const staticEndpoint = req.params.staticEndpoint
 
   const file = plugin.clientScripts[staticEndpoint]
-  if (!file) {
-    return res.sendStatus(404)
-  }
+  if (!file) return res.sendStatus(404)
 
   return res.sendFile(join(plugin.path, staticEndpoint), sendFileOptions)
 }
diff --git a/server/lib/plugins/plugin-manager.ts b/server/lib/plugins/plugin-manager.ts
index 44530d203..37fb07716 100644
--- a/server/lib/plugins/plugin-manager.ts
+++ b/server/lib/plugins/plugin-manager.ts
@@ -13,15 +13,14 @@ import { PLUGIN_GLOBAL_CSS_PATH } from '../../initializers/constants'
 import { PluginType } from '../../../shared/models/plugins/plugin.type'
 import { installNpmPlugin, installNpmPluginFromDisk, removeNpmPlugin } from './yarn'
 import { outputFile, readJSON } from 'fs-extra'
-import { ServerHook, ServerHookName, serverHookObject } from '../../../shared/models/plugins/server-hook.model'
+import { ServerHook, ServerHookName } from '../../../shared/models/plugins/server-hook.model'
 import { getHookType, internalRunHook } from '../../../shared/core-utils/plugins/hooks'
 import { RegisterServerOptions } from '../../typings/plugins/register-server-option.model'
 import { PluginLibrary } from '../../typings/plugins'
 import { ClientHtml } from '../client-html'
-import { RegisterServerHookOptions } from '../../../shared/models/plugins/register-server-hook.model'
-import { RegisterServerSettingOptions } from '../../../shared/models/plugins/register-server-setting.model'
 import { PluginTranslation } from '../../../shared/models/plugins/plugin-translation.model'
-import { buildRegisterHelpers, reinitVideoConstants } from './register-helpers'
+import { RegisterHelpersStore } from './register-helpers-store'
+import { RegisterServerHookOptions } from '@shared/models/plugins/register-server-hook.model'
 
 export interface RegisteredPlugin {
   npmName: string
@@ -59,10 +58,11 @@ export class PluginManager implements ServerHook {
   private static instance: PluginManager
 
   private registeredPlugins: { [name: string]: RegisteredPlugin } = {}
-  private settings: { [name: string]: RegisterServerSettingOptions[] } = {}
   private hooks: { [name: string]: HookInformationValue[] } = {}
   private translations: PluginLocalesTranslations = {}
 
+  private registerHelpersStore: { [npmName: string]: RegisterHelpersStore } = {}
+
   private constructor () {
   }
 
@@ -103,7 +103,17 @@ export class PluginManager implements ServerHook {
   }
 
   getRegisteredSettings (npmName: string) {
-    return this.settings[npmName] || []
+    const store = this.registerHelpersStore[npmName]
+    if (store) return store.getSettings()
+
+    return []
+  }
+
+  getRouter (npmName: string) {
+    const store = this.registerHelpersStore[npmName]
+    if (!store) return null
+
+    return store.getRouter()
   }
 
   getTranslations (locale: string) {
@@ -164,7 +174,6 @@ export class PluginManager implements ServerHook {
     }
 
     delete this.registeredPlugins[plugin.npmName]
-    delete this.settings[plugin.npmName]
 
     this.deleteTranslations(plugin.npmName)
 
@@ -176,7 +185,10 @@ export class PluginManager implements ServerHook {
         this.hooks[key] = this.hooks[key].filter(h => h.npmName !== npmName)
       }
 
-      reinitVideoConstants(plugin.npmName)
+      const store = this.registerHelpersStore[plugin.npmName]
+      store.reinitVideoConstants(plugin.npmName)
+
+      delete this.registerHelpersStore[plugin.npmName]
 
       logger.info('Regenerating registered plugin CSS to global file.')
       await this.regeneratePluginGlobalCSS()
@@ -429,34 +441,21 @@ export class PluginManager implements ServerHook {
   // ###################### Generate register helpers ######################
 
   private getRegisterHelpers (npmName: string, plugin: PluginModel): RegisterServerOptions {
-    const registerHook = (options: RegisterServerHookOptions) => {
-      if (serverHookObject[options.target] !== true) {
-        logger.warn('Unknown hook %s of plugin %s. Skipping.', options.target, npmName)
-        return
-      }
-
+    const onHookAdded = (options: RegisterServerHookOptions) => {
       if (!this.hooks[options.target]) this.hooks[options.target] = []
 
       this.hooks[options.target].push({
-        npmName,
+        npmName: npmName,
         pluginName: plugin.name,
         handler: options.handler,
         priority: options.priority || 0
       })
     }
 
-    const registerSetting = (options: RegisterServerSettingOptions) => {
-      if (!this.settings[npmName]) this.settings[npmName] = []
-
-      this.settings[npmName].push(options)
-    }
-
-    const registerHelpers = buildRegisterHelpers(npmName, plugin)
+    const registerHelpersStore = new RegisterHelpersStore(npmName, plugin, onHookAdded.bind(this))
+    this.registerHelpersStore[npmName] = registerHelpersStore
 
-    return Object.assign(registerHelpers, {
-      registerHook,
-      registerSetting
-    })
+    return registerHelpersStore.buildRegisterHelpers()
   }
 
   private sanitizeAndCheckPackageJSONOrThrow (packageJSON: PluginPackageJson, pluginType: PluginType) {
diff --git a/server/lib/plugins/register-helpers-store.ts b/server/lib/plugins/register-helpers-store.ts
new file mode 100644
index 000000000..c76c0161a
--- /dev/null
+++ b/server/lib/plugins/register-helpers-store.ts
@@ -0,0 +1,235 @@
+import { PluginSettingsManager } from '@shared/models/plugins/plugin-settings-manager.model'
+import { PluginModel } from '@server/models/server/plugin'
+import { PluginStorageManager } from '@shared/models/plugins/plugin-storage-manager.model'
+import { PluginVideoLanguageManager } from '@shared/models/plugins/plugin-video-language-manager.model'
+import { VIDEO_CATEGORIES, VIDEO_LANGUAGES, VIDEO_LICENCES } from '@server/initializers/constants'
+import { PluginVideoLicenceManager } from '@shared/models/plugins/plugin-video-licence-manager.model'
+import { PluginVideoCategoryManager } from '@shared/models/plugins/plugin-video-category-manager.model'
+import { RegisterServerOptions } from '@server/typings/plugins'
+import { buildPluginHelpers } from './plugin-helpers'
+import { logger } from '@server/helpers/logger'
+import { RegisterServerHookOptions } from '@shared/models/plugins/register-server-hook.model'
+import { serverHookObject } from '@shared/models/plugins/server-hook.model'
+import { RegisterServerSettingOptions } from '@shared/models/plugins/register-server-setting.model'
+import * as express from 'express'
+
+type AlterableVideoConstant = 'language' | 'licence' | 'category'
+type VideoConstant = { [key in number | string]: string }
+
+type UpdatedVideoConstant = {
+  [name in AlterableVideoConstant]: {
+    added: { key: number | string, label: string }[]
+    deleted: { key: number | string, label: string }[]
+  }
+}
+
+export class RegisterHelpersStore {
+  private readonly updatedVideoConstants: UpdatedVideoConstant = {
+    language: { added: [], deleted: [] },
+    licence: { added: [], deleted: [] },
+    category: { added: [], deleted: [] }
+  }
+
+  private readonly settings: RegisterServerSettingOptions[] = []
+
+  private readonly router: express.Router
+
+  constructor (
+    private readonly npmName: string,
+    private readonly plugin: PluginModel,
+    private readonly onHookAdded: (options: RegisterServerHookOptions) => void
+  ) {
+    this.router = express.Router()
+  }
+
+  buildRegisterHelpers (): RegisterServerOptions {
+    const registerHook = this.buildRegisterHook()
+    const registerSetting = this.buildRegisterSetting()
+
+    const getRouter = this.buildGetRouter()
+
+    const settingsManager = this.buildSettingsManager()
+    const storageManager = this.buildStorageManager()
+
+    const videoLanguageManager = this.buildVideoLanguageManager()
+
+    const videoLicenceManager = this.buildVideoLicenceManager()
+    const videoCategoryManager = this.buildVideoCategoryManager()
+
+    const peertubeHelpers = buildPluginHelpers(this.npmName)
+
+    return {
+      registerHook,
+      registerSetting,
+
+      getRouter,
+
+      settingsManager,
+      storageManager,
+
+      videoLanguageManager,
+      videoCategoryManager,
+      videoLicenceManager,
+
+      peertubeHelpers
+    }
+  }
+
+  reinitVideoConstants (npmName: string) {
+    const hash = {
+      language: VIDEO_LANGUAGES,
+      licence: VIDEO_LICENCES,
+      category: VIDEO_CATEGORIES
+    }
+    const types: AlterableVideoConstant[] = [ 'language', 'licence', 'category' ]
+
+    for (const type of types) {
+      const updatedConstants = this.updatedVideoConstants[type][npmName]
+      if (!updatedConstants) continue
+
+      for (const added of updatedConstants.added) {
+        delete hash[type][added.key]
+      }
+
+      for (const deleted of updatedConstants.deleted) {
+        hash[type][deleted.key] = deleted.label
+      }
+
+      delete this.updatedVideoConstants[type][npmName]
+    }
+  }
+
+  getSettings () {
+    return this.settings
+  }
+
+  getRouter () {
+    return this.router
+  }
+
+  private buildGetRouter () {
+    return () => this.router
+  }
+
+  private buildRegisterSetting () {
+    return (options: RegisterServerSettingOptions) => {
+      this.settings.push(options)
+    }
+  }
+
+  private buildRegisterHook () {
+    return (options: RegisterServerHookOptions) => {
+      if (serverHookObject[options.target] !== true) {
+        logger.warn('Unknown hook %s of plugin %s. Skipping.', options.target, this.npmName)
+        return
+      }
+
+      return this.onHookAdded(options)
+    }
+  }
+
+  private buildSettingsManager (): PluginSettingsManager {
+    return {
+      getSetting: (name: string) => PluginModel.getSetting(this.plugin.name, this.plugin.type, name),
+
+      setSetting: (name: string, value: string) => PluginModel.setSetting(this.plugin.name, this.plugin.type, name, value)
+    }
+  }
+
+  private buildStorageManager (): PluginStorageManager {
+    return {
+      getData: (key: string) => PluginModel.getData(this.plugin.name, this.plugin.type, key),
+
+      storeData: (key: string, data: any) => PluginModel.storeData(this.plugin.name, this.plugin.type, key, data)
+    }
+  }
+
+  private buildVideoLanguageManager (): PluginVideoLanguageManager {
+    return {
+      addLanguage: (key: string, label: string) => {
+        return this.addConstant({ npmName: this.npmName, type: 'language', obj: VIDEO_LANGUAGES, key, label })
+      },
+
+      deleteLanguage: (key: string) => {
+        return this.deleteConstant({ npmName: this.npmName, type: 'language', obj: VIDEO_LANGUAGES, key })
+      }
+    }
+  }
+
+  private buildVideoCategoryManager (): PluginVideoCategoryManager {
+    return {
+      addCategory: (key: number, label: string) => {
+        return this.addConstant({ npmName: this.npmName, type: 'category', obj: VIDEO_CATEGORIES, key, label })
+      },
+
+      deleteCategory: (key: number) => {
+        return this.deleteConstant({ npmName: this.npmName, type: 'category', obj: VIDEO_CATEGORIES, key })
+      }
+    }
+  }
+
+  private buildVideoLicenceManager (): PluginVideoLicenceManager {
+    return {
+      addLicence: (key: number, label: string) => {
+        return this.addConstant({ npmName: this.npmName, type: 'licence', obj: VIDEO_LICENCES, key, label })
+      },
+
+      deleteLicence: (key: number) => {
+        return this.deleteConstant({ npmName: this.npmName, type: 'licence', obj: VIDEO_LICENCES, key })
+      }
+    }
+  }
+
+  private addConstant<T extends string | number> (parameters: {
+    npmName: string
+    type: AlterableVideoConstant
+    obj: VideoConstant
+    key: T
+    label: string
+  }) {
+    const { npmName, type, obj, key, label } = parameters
+
+    if (obj[key]) {
+      logger.warn('Cannot add %s %s by plugin %s: key already exists.', type, npmName, key)
+      return false
+    }
+
+    if (!this.updatedVideoConstants[type][npmName]) {
+      this.updatedVideoConstants[type][npmName] = {
+        added: [],
+        deleted: []
+      }
+    }
+
+    this.updatedVideoConstants[type][npmName].added.push({ key, label })
+    obj[key] = label
+
+    return true
+  }
+
+  private deleteConstant<T extends string | number> (parameters: {
+    npmName: string
+    type: AlterableVideoConstant
+    obj: VideoConstant
+    key: T
+  }) {
+    const { npmName, type, obj, key } = parameters
+
+    if (!obj[key]) {
+      logger.warn('Cannot delete %s %s by plugin %s: key does not exist.', type, npmName, key)
+      return false
+    }
+
+    if (!this.updatedVideoConstants[type][npmName]) {
+      this.updatedVideoConstants[type][npmName] = {
+        added: [],
+        deleted: []
+      }
+    }
+
+    this.updatedVideoConstants[type][npmName].deleted.push({ key, label: obj[key] })
+    delete obj[key]
+
+    return true
+  }
+}
diff --git a/server/lib/plugins/register-helpers.ts b/server/lib/plugins/register-helpers.ts
deleted file mode 100644
index 4c0935a05..000000000
--- a/server/lib/plugins/register-helpers.ts
+++ /dev/null
@@ -1,180 +0,0 @@
-import { PluginSettingsManager } from '@shared/models/plugins/plugin-settings-manager.model'
-import { PluginModel } from '@server/models/server/plugin'
-import { PluginStorageManager } from '@shared/models/plugins/plugin-storage-manager.model'
-import { PluginVideoLanguageManager } from '@shared/models/plugins/plugin-video-language-manager.model'
-import { VIDEO_CATEGORIES, VIDEO_LANGUAGES, VIDEO_LICENCES } from '@server/initializers/constants'
-import { PluginVideoLicenceManager } from '@shared/models/plugins/plugin-video-licence-manager.model'
-import { PluginVideoCategoryManager } from '@shared/models/plugins/plugin-video-category-manager.model'
-import { RegisterServerOptions } from '@server/typings/plugins'
-import { buildPluginHelpers } from './plugin-helpers'
-import { logger } from '@server/helpers/logger'
-
-type AlterableVideoConstant = 'language' | 'licence' | 'category'
-type VideoConstant = { [key in number | string]: string }
-type UpdatedVideoConstant = {
-  [name in AlterableVideoConstant]: {
-    [npmName: string]: {
-      added: { key: number | string, label: string }[]
-      deleted: { key: number | string, label: string }[]
-    }
-  }
-}
-
-const updatedVideoConstants: UpdatedVideoConstant = {
-  language: {},
-  licence: {},
-  category: {}
-}
-
-function buildRegisterHelpers (npmName: string, plugin: PluginModel): Omit<RegisterServerOptions, 'registerHook' | 'registerSetting'> {
-  const settingsManager = buildSettingsManager(plugin)
-  const storageManager = buildStorageManager(plugin)
-
-  const videoLanguageManager = buildVideoLanguageManager(npmName)
-
-  const videoCategoryManager = buildVideoCategoryManager(npmName)
-  const videoLicenceManager = buildVideoLicenceManager(npmName)
-
-  const peertubeHelpers = buildPluginHelpers(npmName)
-
-  return {
-    settingsManager,
-    storageManager,
-    videoLanguageManager,
-    videoCategoryManager,
-    videoLicenceManager,
-    peertubeHelpers
-  }
-}
-
-function reinitVideoConstants (npmName: string) {
-  const hash = {
-    language: VIDEO_LANGUAGES,
-    licence: VIDEO_LICENCES,
-    category: VIDEO_CATEGORIES
-  }
-  const types: AlterableVideoConstant[] = [ 'language', 'licence', 'category' ]
-
-  for (const type of types) {
-    const updatedConstants = updatedVideoConstants[type][npmName]
-    if (!updatedConstants) continue
-
-    for (const added of updatedConstants.added) {
-      delete hash[type][added.key]
-    }
-
-    for (const deleted of updatedConstants.deleted) {
-      hash[type][deleted.key] = deleted.label
-    }
-
-    delete updatedVideoConstants[type][npmName]
-  }
-}
-
-export {
-  buildRegisterHelpers,
-  reinitVideoConstants
-}
-
-// ---------------------------------------------------------------------------
-
-function buildSettingsManager (plugin: PluginModel): PluginSettingsManager {
-  return {
-    getSetting: (name: string) => PluginModel.getSetting(plugin.name, plugin.type, name),
-
-    setSetting: (name: string, value: string) => PluginModel.setSetting(plugin.name, plugin.type, name, value)
-  }
-}
-
-function buildStorageManager (plugin: PluginModel): PluginStorageManager {
-  return {
-    getData: (key: string) => PluginModel.getData(plugin.name, plugin.type, key),
-
-    storeData: (key: string, data: any) => PluginModel.storeData(plugin.name, plugin.type, key, data)
-  }
-}
-
-function buildVideoLanguageManager (npmName: string): PluginVideoLanguageManager {
-  return {
-    addLanguage: (key: string, label: string) => addConstant({ npmName, type: 'language', obj: VIDEO_LANGUAGES, key, label }),
-
-    deleteLanguage: (key: string) => deleteConstant({ npmName, type: 'language', obj: VIDEO_LANGUAGES, key })
-  }
-}
-
-function buildVideoCategoryManager (npmName: string): PluginVideoCategoryManager {
-  return {
-    addCategory: (key: number, label: string) => {
-      return addConstant({ npmName, type: 'category', obj: VIDEO_CATEGORIES, key, label })
-    },
-
-    deleteCategory: (key: number) => {
-      return deleteConstant({ npmName, type: 'category', obj: VIDEO_CATEGORIES, key })
-    }
-  }
-}
-
-function buildVideoLicenceManager (npmName: string): PluginVideoLicenceManager {
-  return {
-    addLicence: (key: number, label: string) => {
-      return addConstant({ npmName, type: 'licence', obj: VIDEO_LICENCES, key, label })
-    },
-
-    deleteLicence: (key: number) => {
-      return deleteConstant({ npmName, type: 'licence', obj: VIDEO_LICENCES, key })
-    }
-  }
-}
-
-function addConstant<T extends string | number> (parameters: {
-  npmName: string
-  type: AlterableVideoConstant
-  obj: VideoConstant
-  key: T
-  label: string
-}) {
-  const { npmName, type, obj, key, label } = parameters
-
-  if (obj[key]) {
-    logger.warn('Cannot add %s %s by plugin %s: key already exists.', type, npmName, key)
-    return false
-  }
-
-  if (!updatedVideoConstants[type][npmName]) {
-    updatedVideoConstants[type][npmName] = {
-      added: [],
-      deleted: []
-    }
-  }
-
-  updatedVideoConstants[type][npmName].added.push({ key, label })
-  obj[key] = label
-
-  return true
-}
-
-function deleteConstant<T extends string | number> (parameters: {
-  npmName: string
-  type: AlterableVideoConstant
-  obj: VideoConstant
-  key: T
-}) {
-  const { npmName, type, obj, key } = parameters
-
-  if (!obj[key]) {
-    logger.warn('Cannot delete %s %s by plugin %s: key does not exist.', type, npmName, key)
-    return false
-  }
-
-  if (!updatedVideoConstants[type][npmName]) {
-    updatedVideoConstants[type][npmName] = {
-      added: [],
-      deleted: []
-    }
-  }
-
-  updatedVideoConstants[type][npmName].deleted.push({ key, label: obj[key] })
-  delete obj[key]
-
-  return true
-}
diff --git a/server/middlewares/validators/plugins.ts b/server/middlewares/validators/plugins.ts
index 910d03c29..65765f473 100644
--- a/server/middlewares/validators/plugins.ts
+++ b/server/middlewares/validators/plugins.ts
@@ -1,5 +1,5 @@
 import * as express from 'express'
-import { body, param, query } from 'express-validator'
+import { body, param, query, ValidationChain } from 'express-validator'
 import { logger } from '../../helpers/logger'
 import { areValidationErrors } from './utils'
 import { isNpmPluginNameValid, isPluginNameValid, isPluginTypeValid, isPluginVersionValid } from '../../helpers/custom-validators/plugins'
@@ -10,24 +10,43 @@ import { InstallOrUpdatePlugin } from '../../../shared/models/plugins/install-pl
 import { PluginType } from '../../../shared/models/plugins/plugin.type'
 import { CONFIG } from '../../initializers/config'
 
-const servePluginStaticDirectoryValidator = (pluginType: PluginType) => [
-  param('pluginName').custom(isPluginNameValid).withMessage('Should have a valid plugin name'),
-  param('pluginVersion').custom(isPluginVersionValid).withMessage('Should have a valid plugin version'),
-  param('staticEndpoint').custom(isSafePath).withMessage('Should have a valid static endpoint'),
+const getPluginValidator = (pluginType: PluginType, withVersion = true) => {
+  const validators: (ValidationChain | express.Handler)[] = [
+    param('pluginName').custom(isPluginNameValid).withMessage('Should have a valid plugin name')
+  ]
 
-  (req: express.Request, res: express.Response, next: express.NextFunction) => {
-    logger.debug('Checking servePluginStaticDirectory parameters', { parameters: req.params })
+  if (withVersion) {
+    validators.push(
+      param('pluginVersion').custom(isPluginVersionValid).withMessage('Should have a valid plugin version')
+    )
+  }
 
-    if (areValidationErrors(req, res)) return
+  return validators.concat([
+    (req: express.Request, res: express.Response, next: express.NextFunction) => {
+      logger.debug('Checking getPluginValidator parameters', { parameters: req.params })
+
+      if (areValidationErrors(req, res)) return
+
+      const npmName = PluginModel.buildNpmName(req.params.pluginName, pluginType)
+      const plugin = PluginManager.Instance.getRegisteredPluginOrTheme(npmName)
+
+      if (!plugin) return res.sendStatus(404)
+      if (withVersion && plugin.version !== req.params.pluginVersion) return res.sendStatus(404)
 
-    const npmName = PluginModel.buildNpmName(req.params.pluginName, pluginType)
-    const plugin = PluginManager.Instance.getRegisteredPluginOrTheme(npmName)
+      res.locals.registeredPlugin = plugin
 
-    if (!plugin || plugin.version !== req.params.pluginVersion) {
-      return res.sendStatus(404)
+      return next()
     }
+  ])
+}
+
+const pluginStaticDirectoryValidator = [
+  param('staticEndpoint').custom(isSafePath).withMessage('Should have a valid static endpoint'),
 
-    res.locals.registeredPlugin = plugin
+  (req: express.Request, res: express.Response, next: express.NextFunction) => {
+    logger.debug('Checking pluginStaticDirectoryValidator parameters', { parameters: req.params })
+
+    if (areValidationErrors(req, res)) return
 
     return next()
   }
@@ -149,7 +168,8 @@ const listAvailablePluginsValidator = [
 // ---------------------------------------------------------------------------
 
 export {
-  servePluginStaticDirectoryValidator,
+  pluginStaticDirectoryValidator,
+  getPluginValidator,
   updatePluginSettingsValidator,
   uninstallPluginValidator,
   listAvailablePluginsValidator,
diff --git a/server/tests/fixtures/peertube-plugin-test-five/main.js b/server/tests/fixtures/peertube-plugin-test-five/main.js
new file mode 100644
index 000000000..c1435b928
--- /dev/null
+++ b/server/tests/fixtures/peertube-plugin-test-five/main.js
@@ -0,0 +1,21 @@
+async function register ({
+  getRouter
+}) {
+  const router = getRouter()
+  router.get('/ping', (req, res) => res.json({ message: 'pong' }))
+
+  router.post('/form/post/mirror', (req, res) => {
+    res.json(req.body)
+  })
+}
+
+async function unregister () {
+  return
+}
+
+module.exports = {
+  register,
+  unregister
+}
+
+// ###########################################################################
diff --git a/server/tests/fixtures/peertube-plugin-test-five/package.json b/server/tests/fixtures/peertube-plugin-test-five/package.json
new file mode 100644
index 000000000..1f5d65d9d
--- /dev/null
+++ b/server/tests/fixtures/peertube-plugin-test-five/package.json
@@ -0,0 +1,20 @@
+{
+  "name": "peertube-plugin-test-five",
+  "version": "0.0.1",
+  "description": "Plugin test 5",
+  "engine": {
+    "peertube": ">=1.3.0"
+  },
+  "keywords": [
+    "peertube",
+    "plugin"
+  ],
+  "homepage": "https://github.com/Chocobozzz/PeerTube",
+  "author": "Chocobozzz",
+  "bugs": "https://github.com/Chocobozzz/PeerTube/issues",
+  "library": "./main.js",
+  "staticDirs": {},
+  "css": [],
+  "clientScripts": [],
+  "translations": {}
+}
diff --git a/server/tests/plugins/index.ts b/server/tests/plugins/index.ts
index 9c9499a79..1414e7e58 100644
--- a/server/tests/plugins/index.ts
+++ b/server/tests/plugins/index.ts
@@ -3,3 +3,4 @@ import './filter-hooks'
 import './translations'
 import './video-constants'
 import './plugin-helpers'
+import './plugin-router'
diff --git a/server/tests/plugins/plugin-router.ts b/server/tests/plugins/plugin-router.ts
new file mode 100644
index 000000000..cf4130f4b
--- /dev/null
+++ b/server/tests/plugins/plugin-router.ts
@@ -0,0 +1,91 @@
+/* eslint-disable @typescript-eslint/no-unused-expressions,@typescript-eslint/require-await */
+
+import 'mocha'
+import { cleanupTests, flushAndRunServer, ServerInfo } from '../../../shared/extra-utils/server/servers'
+import {
+  getPluginTestPath,
+  installPlugin,
+  makeGetRequest,
+  makePostBodyRequest,
+  setAccessTokensToServers, uninstallPlugin
+} from '../../../shared/extra-utils'
+import { expect } from 'chai'
+
+describe('Test plugin helpers', function () {
+  let server: ServerInfo
+  const basePaths = [
+    '/plugins/test-five/router/',
+    '/plugins/test-five/0.0.1/router/'
+  ]
+
+  before(async function () {
+    this.timeout(30000)
+
+    server = await flushAndRunServer(1)
+    await setAccessTokensToServers([ server ])
+
+    await installPlugin({
+      url: server.url,
+      accessToken: server.accessToken,
+      path: getPluginTestPath('-five')
+    })
+  })
+
+  it('Should answer "pong"', async function () {
+    for (const path of basePaths) {
+      const res = await makeGetRequest({
+        url: server.url,
+        path: path + 'ping',
+        statusCodeExpected: 200
+      })
+
+      expect(res.body.message).to.equal('pong')
+    }
+  })
+
+  it('Should mirror post body', async function () {
+    const body = {
+      hello: 'world',
+      riri: 'fifi',
+      loulou: 'picsou'
+    }
+
+    for (const path of basePaths) {
+      const res = await makePostBodyRequest({
+        url: server.url,
+        path: path + 'form/post/mirror',
+        fields: body,
+        statusCodeExpected: 200
+      })
+
+      expect(res.body).to.deep.equal(body)
+    }
+  })
+
+  it('Should remove the plugin and remove the routes', async function () {
+    await uninstallPlugin({
+      url: server.url,
+      accessToken: server.accessToken,
+      npmName: 'peertube-plugin-test-five'
+    })
+
+    for (const path of basePaths) {
+      await makeGetRequest({
+        url: server.url,
+        path: path + 'ping',
+        statusCodeExpected: 404
+      })
+
+      await makePostBodyRequest({
+        url: server.url,
+        path: path + 'ping',
+        fields: {},
+        statusCodeExpected: 404
+      })
+    }
+  })
+
+  after(async function () {
+    await cleanupTests([ server ])
+  })
+})
diff --git a/server/typings/plugins/register-server-option.model.ts b/server/typings/plugins/register-server-option.model.ts
index fda9afb11..3d6217d1b 100644
--- a/server/typings/plugins/register-server-option.model.ts
+++ b/server/typings/plugins/register-server-option.model.ts
@@ -6,6 +6,7 @@ import { PluginVideoCategoryManager } from '../../../shared/models/plugins/plugi
 import { PluginVideoLanguageManager } from '../../../shared/models/plugins/plugin-video-language-manager.model'
 import { PluginVideoLicenceManager } from '../../../shared/models/plugins/plugin-video-licence-manager.model'
 import { Logger } from 'winston'
+import { Router } from 'express'
 
 export type PeerTubeHelpers = {
   logger: Logger
@@ -32,5 +33,11 @@ export type RegisterServerOptions = {
   videoLanguageManager: PluginVideoLanguageManager
   videoLicenceManager: PluginVideoLicenceManager
 
+  // Get plugin router to create custom routes
+  // Base routes of this router are
+  //  * /plugins/:pluginName/:pluginVersion/router/...
+  //  * /plugins/:pluginName/router/...
+  getRouter(): Router
+
   peertubeHelpers: PeerTubeHelpers
 }
diff --git a/support/doc/plugins/guide.md b/support/doc/plugins/guide.md
index 8e720e94b..bdc9d2ad8 100644
--- a/support/doc/plugins/guide.md
+++ b/support/doc/plugins/guide.md
@@ -12,6 +12,7 @@
     - [Settings](#settings)
     - [Storage](#storage)
     - [Update video constants](#update-video-constants)
+    - [Add custom routes](#add-custom-routes)
   - [Client helpers (themes & plugins)](#client-helpers-themes--plugins)
   - [Plugin static route](#plugin-static-route)
     - [Translate](#translate)
@@ -71,7 +72,9 @@ async function register ({
   storageManager,
   videoCategoryManager,
   videoLicenceManager,
-  videoLanguageManager
+  videoLanguageManager,
+  peertubeHelpers,
+  getRouter
 }) {
   registerHook({
     target: 'action:application.listening',
@@ -178,6 +181,20 @@ videoLicenceManager.addLicence(42, 'Best licence')
 videoLicenceManager.deleteLicence(7) // Public domain
 ```
 
+#### Add custom routes
+
+You can create custom routes using an [express Router](https://expressjs.com/en/4x/api.html#router) for your plugin:
+
+```js
+const router = getRouter()
+router.get('/ping', (req, res) => res.json({ message: 'pong' }))
+```
+
+The `ping` route can be accessed using:
+ * `/plugins/:pluginName/:pluginVersion/router/ping`
+ * Or `/plugins/:pluginName/router/ping`
+
+
 ### Client helpers (themes & plugins)
 
 ### Plugin static route