change order of headers to try to make mastodon happy, and handle

redirects.

src/activity.ts

@@ -210,6 +210,8 @@ export const sendAccept = async (user: User, followId: string, follower: string,
     console.log("response status:", result.status);
     const response = await streamToString(result.body as ReadableStream);
     console.log("Response body:", response);
+
+    if (result.status >= 400) throw "bad http status code";
 };
 
 export const sendAll = async (keyId: string, privateKey: string, activity: Record<string, any> | string, inboxes: string[]) => {

src/net.ts

@@ -18,10 +18,10 @@ export interface SignedInit {
 };
 
 // TODO: Handle redirects.
-export const signedFetch = async (url: string, init: RequestInit, signedInit: SignedInit) => {
+export const signedFetch = async (url: string, init: RequestInit, signedInit: SignedInit): Promise<globalThis.Response> => {
     const signedHeaders: HeadersInit = [
-        ["Date", new Date().toUTCString()],
         ["Host", new URL(url).host],
+        ["Date", new Date().toUTCString()]
     ];
 
     const headerNames = ["(request-target)", "host", "date"];
@@ -57,33 +57,39 @@ export const signedFetch = async (url: string, init: RequestInit, signedInit: Si
 
     const newHeaders = new Headers(
         [
+            ...signedHeaders,
             ["Signature", signature],
             ["Content-Type", `application/ld+json; profile="${CONTEXT}"`]
         ]
     );
 
-    if (Array.isArray(init.headers) || !init.headers) {
-        for (const header of (init.headers || [])) {
-            if (Array.isArray(header))
-                newHeaders.set(header[0], header[1]);
-            else throw "unsupported headers type"; // Lazy.
-        }
-
-        for (const [key, value] of signedHeaders) {
-            newHeaders.set(key, value);
-        }
-    }
-    else throw "unsupported headers type"; // Lazy.
+    if (Array.isArray(init.headers))
+        init.headers
+            .filter((header) => Array.isArray(header))
+            .forEach(([key, value]) => newHeaders.set(key, value));
 
     console.log("Headers:");
     for (const [key, value] of newHeaders) {
         console.log(`${key}: ${value}`);
     }
 
-    return fetch(url, {
+    const result = await fetch(url, {
         ...init,
         headers: newHeaders
     });
+
+    if (result.status >= 300 && result.status <= 399) {
+        const newUrl = result.headers.get("location");
+        if (newUrl) {
+            return await signedFetch(newUrl, init, {
+                // Omit premade digest since url changed, it is invalid.
+                privateKey: signedInit.privateKey,
+                keyId: signedInit.keyId
+            });
+        }
+        else throw "signed fetch redirect without location header";
+    }
+    else return result; 
 };
 
 export const getActor = async (actorUrl: string, signedInit: SignedInit): Promise<Actor | null> => {