[browser] Load appsettings to VFS

src/mono/wasm/runtime/loader/blazor/BootConfig.ts

@@ -5,7 +5,7 @@ import type { BootJsonData } from "../../types/blazor";
 import type { WebAssemblyBootResourceType } from "../../types";
 import { loaderHelpers } from "../globals";
 
-type LoadBootResourceCallback = (type: WebAssemblyBootResourceType, name: string, defaultUri: string, integrity: string) => string | Promise<Response> | null | undefined;
+export type LoadBootResourceCallback = (type: WebAssemblyBootResourceType, name: string, defaultUri: string, integrity: string) => string | Promise<Response> | null | undefined;
 
 export class BootConfigResult {
     private constructor(public bootConfig: BootJsonData, public applicationEnvironment: string) {

src/mono/wasm/runtime/loader/blazor/_Integration.ts

@@ -6,7 +6,7 @@ import type { AssetBehaviours, AssetEntry, LoadingResource, WebAssemblyBootResou
 import type { BootJsonData } from "../../types/blazor";
 
 import { INTERNAL, loaderHelpers } from "../globals";
-import { BootConfigResult } from "./BootConfig";
+import { BootConfigResult, LoadBootResourceCallback } from "./BootConfig";
 import { WebAssemblyResourceLoader } from "./WebAssemblyResourceLoader";
 import { hasDebuggingEnabled } from "./_Polyfill";
 import { ICUDataMode } from "../../types/blazor";
@@ -19,7 +19,7 @@ export async function loadBootConfig(config: MonoConfigInternal, module: DotnetM
     const bootConfigPromise = BootConfigResult.initAsync(candidateOptions.loadBootResource, environment);
     const bootConfigResult: BootConfigResult = await bootConfigPromise;
     INTERNAL.resourceLoader = resourceLoader = await WebAssemblyResourceLoader.initAsync(bootConfigResult.bootConfig, candidateOptions || {});
-    mapBootConfigToMonoConfig(loaderHelpers.config, bootConfigResult.applicationEnvironment);
+    mapBootConfigToMonoConfig(loaderHelpers.config, bootConfigResult.applicationEnvironment, candidateOptions.loadBootResource);
     setupModuleForBlazor(module);
 }
 
@@ -73,7 +73,7 @@ export function setupModuleForBlazor(module: DotnetModuleInternal) {
     module.disableDotnet6Compatibility = false;
 }
 
-export function mapBootConfigToMonoConfig(moduleConfig: MonoConfigInternal, applicationEnvironment: string) {
+export function mapBootConfigToMonoConfig(moduleConfig: MonoConfigInternal, applicationEnvironment: string, customLoadBootResource?: LoadBootResourceCallback) {
     const resources = resourceLoader.bootConfig.resources;
 
     const assets: AssetEntry[] = [];
@@ -157,6 +157,43 @@ export function mapBootConfigToMonoConfig(moduleConfig: MonoConfigInternal, appl
         };
         assets.push(asset);
     }
+    for (let i = 0; i < resourceLoader.bootConfig.config.length; i++) {
+        let config = resourceLoader.bootConfig.config[i];
+        if (config === "appsettings.json" || config === `appsettings.${applicationEnvironment}.json`) {
+            const asset: AssetEntry = {
+                name: config,
+                resolvedUrl: `_framework/${name}`,
+                behavior: "vfs",
+            };
+
+            let response: Promise<Response> | null = null;
+            if (customLoadBootResource) {
+                const customLoadResult = customLoadBootResource("configuration", config, config, "");
+                if (customLoadResult instanceof Promise<Response>) {
+                    // They are supplying an entire custom response, so just use that
+                    response = customLoadResult;
+                } else if (typeof customLoadResult === "string") {
+                    // They are supplying a custom URL, so use that with the default fetch behavior
+                    config = customLoadResult;
+                }
+            }
+
+            if (!response) {
+                response = fetch(config, {
+                    method: "GET",
+                    credentials: "include",
+                    cache: "no-cache",
+                });
+            }
+
+            asset.pendingDownload = {
+                name: config,
+                url: config,
+                response
+            };
+            assets.push(asset);
+        }
+    }
 
     if (!hasIcuData) {
         moduleConfig.globalizationMode = "invariant";

src/mono/wasm/runtime/types/blazor.ts

@@ -45,4 +45,4 @@ export enum ICUDataMode {
     All = 1,
     Invariant = 2,
     Custom = 3
-}
+}