diff --git a/routes/api/file/random.ts b/routes/api/file/random.ts
index ebfd9de..38869cb 100644
--- a/routes/api/file/random.ts
+++ b/routes/api/file/random.ts
@@ -1,6 +1,7 @@
 import { Handlers } from "$fresh/server.ts";
 import { get_task_manager } from "../../../server.ts";
 import { parse_bool } from "../../../server/parse_form.ts";
+import { get_host } from "../../../server/utils.ts";
 
 export const handler: Handlers = {
     async GET(req, _ctx) {
@@ -12,6 +13,6 @@ export const handler: Handlers = {
         const f = m.db.get_random_file(is_nsfw, is_ad);
         if (!f) return new Response("File not found.", { status: 404 });
         const t = thumb ? "thumbnail" : "file";
-        return Response.redirect(`${u.origin}/api/${t}/${f.id}`);
+        return Response.redirect(`${get_host(req)}/api/${t}/${f.id}`);
     },
 };
diff --git a/routes/api/thumbnail/[id].ts b/routes/api/thumbnail/[id].ts
index d62dcb6..90531a6 100644
--- a/routes/api/thumbnail/[id].ts
+++ b/routes/api/thumbnail/[id].ts
@@ -10,6 +10,7 @@ import {
     get_file_response,
     GetFileResponseOptions,
 } from "../../../server/get_file_response.ts";
+import { get_host } from "../../../server/utils.ts";
 
 export const handler: Handlers = {
     async GET(req, ctx) {
@@ -52,7 +53,7 @@ export const handler: Handlers = {
         }
         if (!force) {
             if (cfg.width > f.width || cfg.height > f.height) {
-                return Response.redirect(`${u.origin}/api/file/${f.id}`);
+                return Response.redirect(`${get_host(req)}/api/file/${f.id}`);
             }
         }
         const output = generate_filename(b, f, cfg);
diff --git a/server/i18ns.ts b/server/i18ns.ts
index 37e942d..edec77b 100644
--- a/server/i18ns.ts
+++ b/server/i18ns.ts
@@ -3,6 +3,7 @@ import { parse } from "std/jsonc/mod.ts";
 import { join } from "std/path/mod.ts";
 import { I18NMap } from "./i18n.ts";
 import { pick } from "accept-language-parser/";
+import { get_host } from "./utils.ts";
 
 const whole_maps = new Map<string, I18NMap>();
 const LANGUAGES = ["zh-cn"];
@@ -67,6 +68,6 @@ export function i18n_handle_request(req: Request) {
                 params.append(p[0], p[1]);
             }
         }
-        return Response.redirect(`${u.origin}${u.pathname}?${params}`);
+        return Response.redirect(`${get_host(req)}${u.pathname}?${params}`);
     }
 }
diff --git a/server/utils.ts b/server/utils.ts
index e028c99..4c7a9f3 100644
--- a/server/utils.ts
+++ b/server/utils.ts
@@ -40,3 +40,9 @@ export function return_json<T = unknown>(data: T, status = 200) {
         headers: { "Content-Type": "application/json" },
     });
 }
+
+export function get_host(req: Request) {
+    const u = new URL(req.url);
+    const proto = req.headers.get("X-Forwarded-Proto");
+    return proto ? `${proto}://${u.host}` : u.origin;
+}