Allow browser fetch option overrides (#3096).

packages/web/src.ts/browser-geturl.ts

@@ -23,6 +23,15 @@ export async function getUrl(href: string, options?: Options): Promise<GetUrlRes
         request.referrer = "client";                     // no-referrer, *client
     };
 
+    if (options.fetchOptions != null) {
+        const opts = options.fetchOptions;
+        if (opts.mode) { request.mode = <RequestMode>(opts.mode); }
+        if (opts.cache) { request.cache = <RequestCache>(opts.cache); }
+        if (opts.credentials) { request.credentials = <RequestCredentials>(opts.credentials); }
+        if (opts.redirect) { request.redirect = <RequestRedirect>(opts.redirect); }
+        if (opts.referrer) { request.referrer = opts.referrer; }
+    }
+
     const response = await fetch(href, request);
     const body = await response.arrayBuffer();
 

packages/web/src.ts/index.ts

@@ -50,6 +50,7 @@ export type ConnectionInfo = {
     throttleCallback?: (attempt: number, url: string) => Promise<boolean>,
 
     skipFetchSetup?: boolean;
+    fetchOptions?: Record<string, string>;
     errorPassThrough?: boolean;
 
     timeout?: number,
@@ -158,7 +159,12 @@ export function _fetchData<T = Uint8Array>(connection: string | ConnectionInfo,
         if (connection.skipFetchSetup != null) {
             options.skipFetchSetup = !!connection.skipFetchSetup;
         }
+
+        if (connection.fetchOptions != null) {
+            options.fetchOptions = shallowCopy(connection.fetchOptions);
+        }
     }
+
     const reData = new RegExp("^data:([a-z0-9-]+/[a-z0-9-]+);base64,(.*)$", "i");
     const dataMatch = ((url) ? url.match(reData): null);
     if (dataMatch) {

packages/web/src.ts/types.ts

@@ -13,5 +13,6 @@ export type Options = {
     body?: Uint8Array;
     headers?: { [ key: string] : string };
     skipFetchSetup?: boolean;
+    fetchOptions?: Record<string, string>;
 };