JWT refresh (#636)

## Description:

Implement refresh for JWTs.

Related to https://github.com/openfrontio/infra/pull/26

## Please complete the following:

- [x] I have added screenshots for all UI updates
- [x] I confirm I have thoroughly tested these changes and take full
responsibility for any bugs introduced
- [x] I understand that submitting code with bugs that could have been
caught through manual testing blocks releases and new features for all
contributors

---------

Co-authored-by: Scott Anderson <662325+scottanderson@users.noreply.github.com>

src/client/ApiSchemas.ts

@@ -1,6 +1,11 @@
 import { z } from "zod";
 import { base64urlToUuid } from "./Base64";
 
+export const RefreshResponseSchema = z.object({
+  token: z.string(),
+});
+export type RefreshResponse = z.infer<typeof RefreshResponseSchema>;
+
 export const TokenPayloadSchema = z.object({
   jti: z.string(),
   sub: z

src/client/jwt.ts

@@ -1,5 +1,6 @@
 import { decodeJwt } from "jose";
 import {
+  RefreshResponseSchema,
   TokenPayload,
   TokenPayloadSchema,
   UserMeResponse,
@@ -97,10 +98,17 @@ export function _isLoggedIn(): TokenPayload | false {
       localStorage.removeItem("token");
       return false;
     }
-    // const maxAge: number | undefined = undefined;
-    // if (iat !== undefined && maxAge !== undefined && now >= iat + maxAge) {
-    //   // TODO: Refresh token...
-    // }
+    const refreshAge: number = 6 * 3600; // 6 hours
+    if (iat !== undefined && now >= iat + refreshAge) {
+      console.log("Refreshing access token...");
+      postRefresh().then((success) => {
+        if (success) {
+          console.log("Refreshed access token successfully.");
+        } else {
+          console.error("Failed to refresh access token.");
+        }
+      });
+    }
 
     const result = TokenPayloadSchema.safeParse(payload);
     if (!result.success) {
@@ -120,6 +128,36 @@ export function _isLoggedIn(): TokenPayload | false {
   }
 }
 
+export async function postRefresh(): Promise<boolean> {
+  try {
+    const token = getToken();
+    if (!token) return false;
+
+    // Refresh the JWT
+    const response = await fetch(getApiBase() + "/refresh", {
+      method: "POST",
+      headers: {
+        authorization: `Bearer ${token}`,
+      },
+    });
+    if (response.status !== 200) return false;
+    const body = await response.json();
+    const result = RefreshResponseSchema.safeParse(body);
+    if (!result.success) {
+      console.error(
+        "Invalid response",
+        JSON.stringify(body),
+        JSON.stringify(result.error),
+      );
+      return false;
+    }
+    localStorage.setItem("token", result.data.token);
+    return true;
+  } catch (e) {
+    return false;
+  }
+}
+
 export async function getUserMe(): Promise<UserMeResponse | false> {
   try {
     const token = getToken();