Read public/CNAME for domain name in --externel-assets mode

README.md

@@ -295,7 +295,7 @@ If you are specifically building a theme to integrate with an app or a website t
 to first browse unauthenticated before logging in, you will get a significant
 performance boost if you jump through those hoops:
 
--   Provide the url of your app in the `homepage` field of package.json. [ex](https://github.com/garronej/keycloakify-demo-app/blob/7847cc70ef374ab26a6cc7953461cf25603e9a6d/package.json#L2)
+-   Provide the url of your app in the `homepage` field of package.json. [ex](https://github.com/garronej/keycloakify-demo-app/blob/7847cc70ef374ab26a6cc7953461cf25603e9a6d/package.json#L2) or in a `public/CNAME` file. [ex](https://github.com/garronej/keycloakify-demo-app/blob/main/public/CNAME).
 -   Build the theme using `npx build-keycloak-theme --external-assets` [ex](https://github.com/garronej/keycloakify-demo-app/blob/7847cc70ef374ab26a6cc7953461cf25603e9a6d/.github/workflows/ci.yaml#L21)
 -   Enable [long-term assets caching](https://create-react-app.dev/docs/production-build/#static-file-caching) on the server hosting your app.
 -   Make sure not to build your app and the keycloak theme separately

src/bin/build-keycloak-theme/build-keycloak-theme.ts

@@ -4,6 +4,7 @@ import { join as pathJoin, relative as pathRelative, basename as pathBasename }
 import * as child_process from "child_process";
 import { generateDebugFiles, containerLaunchScriptBasename } from "./generateDebugFiles";
 import { URL } from "url";
+import * as fs from "fs";
 
 type ParsedPackageJson = {
     name: string;
@@ -41,7 +42,17 @@ export function main() {
             const url = (() => {
                 const { homepage } = parsedPackageJson;
 
-                return homepage === undefined ? undefined : new URL(homepage);
+                if (homepage !== undefined) {
+                    return new URL(homepage);
+                }
+
+                const cnameFilePath = pathJoin(reactProjectDirPath, "public", "CNAME");
+
+                if (fs.existsSync(cnameFilePath)) {
+                    return new URL(fs.readFileSync(cnameFilePath).toString("utf8").replace(/\s+$/, ""));
+                }
+
+                return undefined;
             })();
 
             return {