Support bypassing the proxy for some Lemmy instances (#338)

* Support bypassing the proxy for some Lemmy instances

Since LemmyNet/lemmy#3421 was merged, Lemmy instances on 0.18.1
and newer allow cross-origin requests.

* Fix image uploading not being possible cross origin (yet)

---------

Co-authored-by: Alexander Harding <2166114+aeharding@users.noreply.github.com>

src/services/lemmy.ts

@@ -1,11 +1,27 @@
 import { LemmyHttp } from "lemmy-js-client";
 import { reduceFileSize } from "../helpers/imageCompress";
 
+const UNPROXIED_LEMMY_SERVERS = [
+  "lemmy.ml",
+  "beehaw.org",
+  "sh.itjust.works",
+  "lemm.ee",
+  "feddit.de",
+  "midwest.social",
+  "lemmynsfw.com",
+  "lemmy.ca",
+  "lemmy.sdf.org",
+];
+
 function buildBaseUrl(url: string): string {
-  // if (url === "lemmy.world") {
-  //   return `https://lemmy.world`;
-  // }
+  if (UNPROXIED_LEMMY_SERVERS.includes(url)) {
+    return `https://${url}`;
+  }
+
+  return buildProxiedBaseUrl(url);
+}
 
+function buildProxiedBaseUrl(url: string): string {
   return `${location.origin}/api/${url}`;
 }
 
@@ -37,8 +53,10 @@ export async function uploadImage(url: string, auth: string, image: File) {
 
   formData.append("images[]", compressedImageIfNeeded);
 
+  // All requests for image upload must be proxied due to Lemmy not accepting
+  // parameterized JWT for this request (see: https://github.com/LemmyNet/lemmy/issues/3567)
   const response = await fetch(
-    `${buildBaseUrl(url)}${PICTRS_URL}?${new URLSearchParams({ auth })}`,
+    `${buildProxiedBaseUrl(url)}${PICTRS_URL}?${new URLSearchParams({ auth })}`,
     {
       method: "POST",
       body: formData,