fix csrf_token and GuildSelect

src/lib/backend.ts

@@ -44,6 +44,32 @@ export type ServerHealth = {
 };
 
 
+// caches an oath (CSRF token)
+class OathKeeper {
+    lastOath : number;
+    csrfToken: string | null;
+
+    constructor () {
+        this.lastOath = 0;
+        this.csrfToken = null;
+    }
+
+    set (tok: string) {
+        this.lastOath = +new Date;
+        this.csrfToken = tok;
+    }
+
+    get () {
+        if (this.lastOath === 0 || +new Date() - this.lastOath > 1800000) {
+            // 30 minutes decay
+            return null;
+        }
+        return this.csrfToken;
+    }
+}
+
+const oathKeeper = new OathKeeper();
+
 export class Backend {
     static ENDPOINT_BASE = '/v1';
 
@@ -60,33 +86,42 @@ export class Backend {
 }
 
 class EventBackend extends Backend {
-    event: any;
+    event: any | null;
 
-    constructor (event: any) {
+    constructor (event: any | null) {
         super();
         this.event = event;
     }
 
     async oath (): Promise<CsrfEventBackend> {
-        const resp = await this.fetch("oath");
-        if (resp.status !== 200) {
-            throw new Error();
+        let csrfToken = oathKeeper.get();
+        if (!csrfToken) {
+            const resp = await this.fetch("oath");
+            if (resp.status !== 200) {
+                throw new Error();
+            }
+            const respJ = await resp.json();
+            csrfToken = respJ.csrf_token;
+        }
+        if (!csrfToken) {
+            console.warn("csrf_token is null");
+        }
+        else {
+            oathKeeper.set(csrfToken);
         }
-        const respJ = await resp.json();
-        const { csrfToken } = respJ;
         return new CsrfEventBackend(this.event, csrfToken);
     }
 
     async fetch(url: string, options?: RequestInit): Promise<Response> {
         console.debug(`fetch ${Backend.ENDPOINT_BASE}/${url.replace(/^\/+/, '')}`);
-        return await this.event.fetch(`${Backend.ENDPOINT_BASE}/${url.replace(/^\/+/, '')}`, options);
+        return await (this.event?.fetch||fetch)(`${Backend.ENDPOINT_BASE}/${url.replace(/^\/+/, '')}`, options);
     }
 }
 
 class CsrfEventBackend extends EventBackend {
-    csrfToken: string;
+    csrfToken: string | null;
 
-    constructor(event:EventBackend, csrfToken: string) {
+    constructor(event: EventBackend | null, csrfToken: string | null) {
         super(event);
         this.csrfToken = csrfToken;
     }
@@ -97,7 +132,7 @@ class CsrfEventBackend extends EventBackend {
             body: JSON.stringify(data),
             headers: {
                 'content-type': 'application/json',
-                'x-csrftoken': this.csrfToken
+                'x-csrftoken': this.csrfToken || ""
             }
         });
     }