perf(server): improvement of external mediaProxy (#9787)

* perf(server): improvement of external mediaProxy

* add a comment

* ✌️

* /filesでsharpの処理を行わずリダイレクトする

* fix

* thumbnail => static

* Fix #9788

* add avatar mode

* add url

* fix

* static.webp

* remove encodeURIComponent from media proxy path

* remove existance check

packages/backend/src/config.ts

@@ -87,6 +87,8 @@ export type Mixin = {
 	userAgent: string;
 	clientEntry: string;
 	clientManifestExists: boolean;
+	mediaProxy: string;
+	externalMediaProxyEnabled: boolean;
 };
 
 export type Config = Source & Mixin;
@@ -135,6 +137,13 @@ export function loadConfig() {
 	mixin.clientEntry = clientManifest['src/init.ts'];
 	mixin.clientManifestExists = clientManifestExists;
 
+	const externalMediaProxy = config.mediaProxy ?
+		config.mediaProxy.endsWith('/') ? config.mediaProxy.substring(0, config.mediaProxy.length - 1) : config.mediaProxy
+		: null;
+	const internalMediaProxy = `${mixin.scheme}://${mixin.host}/proxy`;
+	mixin.mediaProxy = externalMediaProxy ?? internalMediaProxy;
+	mixin.externalMediaProxyEnabled = externalMediaProxy !== null && externalMediaProxy !== internalMediaProxy;
+
 	if (!config.redis.prefix) config.redis.prefix = mixin.host;
 
 	return Object.assign(config, mixin);