From 2961513d2201a63c1338216b0a571b1bc381c8be Mon Sep 17 00:00:00 2001
From: John Livingston <git@john-livingston.fr>
Date: Wed, 24 May 2023 16:26:57 +0200
Subject: [PATCH] Refresh remote server infos when outdated.

---
 server/lib/debug.ts                  |  3 +++
 server/lib/federation/fetch-infos.ts |  8 ++++--
 server/lib/federation/storage.ts     | 38 ++++++++++++++++++++++++++--
 3 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/server/lib/debug.ts b/server/lib/debug.ts
index 84083eba..c032ede5 100644
--- a/server/lib/debug.ts
+++ b/server/lib/debug.ts
@@ -13,6 +13,7 @@ interface DebugContent {
   renewSelfSignedCertInterval?: number
   logRotateCheckInterval?: number
   logRotateEvery?: number
+  remoteServerInfosMaxAge?: number
   prosodyDebuggerOptions?: ProsodyDebuggerOptions
 }
 
@@ -20,6 +21,7 @@ type DebugNumericValue = 'renewCertCheckInterval'
 | 'renewSelfSignedCertInterval'
 | 'logRotateEvery'
 | 'logRotateCheckInterval'
+| 'remoteServerInfosMaxAge'
 
 let debugContent: DebugContent | null | false = null
 function _readDebugFile (options: RegisterServerOptions): DebugContent | false {
@@ -52,6 +54,7 @@ function _readDebugFile (options: RegisterServerOptions): DebugContent | false {
     debugContent.logRotateEvery = _getNumericOptions(options, json, 'log_rotate_every')
     debugContent.renewCertCheckInterval = _getNumericOptions(options, json, 'renew_cert_check_interval')
     debugContent.renewSelfSignedCertInterval = _getNumericOptions(options, json, 'renew_self_signed_cert_interval')
+    debugContent.remoteServerInfosMaxAge = _getNumericOptions(options, json, 'remote_server_infos_max_age')
   } catch (err) {
     logger.error('Failed to read the debug_mode file content:', err)
   }
diff --git a/server/lib/federation/fetch-infos.ts b/server/lib/federation/fetch-infos.ts
index 9b5f75f8..2c405e11 100644
--- a/server/lib/federation/fetch-infos.ts
+++ b/server/lib/federation/fetch-infos.ts
@@ -3,6 +3,7 @@ import { hasRemoteServerInfos, storeRemoteServerInfos } from './storage'
 import { getBaseRouterRoute } from '../helpers'
 import { canonicalizePluginUri } from '../uri/canonicalize'
 import { sanitizePeertubeLiveChatServerInfos } from './sanitize'
+import { debugNumericParameter } from '../debug'
 import { URL } from 'url'
 const got = require('got')
 
@@ -42,8 +43,11 @@ async function fetchMissingRemoteServerInfos (
   const logger = options.peertubeHelpers.logger
   logger.debug(`remoteServerInfos: checking if we have remote server infos for host ${remoteInstanceUrl}.`)
 
-  // FIXME: add a max age.
-  if (await hasRemoteServerInfos(options, remoteInstanceUrl)) {
+  // maxAge: max allowed aged for stored remote server infos (in milliseconds).
+  // In production: 24 hours
+  // In debug mode: 1hour
+  const maxAge = debugNumericParameter(options, 'remoteServerInfosMaxAge', 3600000, 3600 * 1000 * 24)
+  if (await hasRemoteServerInfos(options, remoteInstanceUrl, maxAge)) {
     return
   }
 
diff --git a/server/lib/federation/storage.ts b/server/lib/federation/storage.ts
index 3c24ec75..92f81a27 100644
--- a/server/lib/federation/storage.ts
+++ b/server/lib/federation/storage.ts
@@ -171,8 +171,13 @@ async function storeRemoteServerInfos (
  * Indicate if we have the remote hosts informations.
  * @param options server options
  * @param host host domain
+ * @param maxAge if given, the max age (in milliseconds) allowed for remote server informations
  */
-async function hasRemoteServerInfos (options: RegisterServerOptions, hostParam: any): Promise<boolean> {
+async function hasRemoteServerInfos (
+  options: RegisterServerOptions,
+  hostParam: any,
+  maxAge?: number
+): Promise<boolean> {
   const host = sanitizeXMPPHostFromInstanceUrl(options, hostParam)
   if (!host) {
     return false
@@ -187,7 +192,36 @@ async function hasRemoteServerInfos (options: RegisterServerOptions, hostParam:
     host,
     'last-update'
   )
-  return fs.existsSync(filePath)
+  if (!fs.existsSync(filePath)) {
+    return false
+  }
+  if (maxAge === undefined) {
+    return true
+  }
+
+  // We must check the 'last-update' to be newer than maxAge
+  try {
+    const content = await fs.promises.readFile(filePath, {
+      encoding: 'utf-8'
+    })
+    const json = JSON.parse(content)
+    if (!json) { return false }
+    if (typeof json !== 'object') { return false }
+    if (!json.timestamp) { return false }
+    if ((typeof json.timestamp) !== 'number') { return false }
+    const now = (new Date()).getTime()
+    if (now - (json.timestamp as number) > maxAge) {
+      options.peertubeHelpers.logger.info(
+        `Remote informations for server ${host} are outdated.`
+      )
+      return false
+    }
+  } catch (err) {
+    options.peertubeHelpers.logger.error('Failed reading the last-update file:', err)
+    return false
+  }
+
+  return true
 }
 
 async function _getFilePath (