Add demo (#4)

dev/test-proxy-server.ts

@@ -0,0 +1,46 @@
+/*
+ * Demo on how to proxy requests to the renderer with a given space ID and a base path.
+ */
+
+const spaceId = Bun.argv[2];
+const basePath = Bun.argv[3] ?? '';
+const port = 5000;
+
+if (!spaceId) {
+    throw new Error('Please provide a space id as an argument');
+}
+
+console.log(`Proxying space ${spaceId} on http://localhost:${port}/${basePath}`);
+
+Bun.serve({
+    port,
+    fetch: async (req) => {
+        const url = new URL(req.url);
+        const upUrl = isNextUrl(url)
+            ? `http://localhost:3000${url.pathname}`
+            : `http://localhost:3000/${spaceId}${url.pathname}`;
+
+        const headers = new Headers(req.headers);
+
+        headers.set('x-gitbook-host', url.host);
+        headers.set('x-gitbook-basepath', basePath);
+
+        const response = await fetch(upUrl, {
+            method: req.method,
+            headers: headers,
+            verbose: true,
+        });
+        const body = await response.text();
+
+        return new Response(body, {
+            status: response.status,
+            headers: {
+                'content-type': response.headers.get('content-type') || 'text/html',
+            },
+        });
+    },
+});
+
+function isNextUrl(url: URL) {
+    return url.pathname.startsWith('/_next/');
+}

src/app/[spaceId]/[[...pathname]]/page.tsx

@@ -3,7 +3,7 @@ import { notFound, redirect } from 'next/navigation';
 
 import { SpaceContent } from '@/components/SpaceContent';
 import { getPageDocument } from '@/lib/api';
-import { PageHrefContext, absoluteHref, pageHref } from '@/lib/links';
+import { PageHrefContext, absoluteHref, baseUrl, pageHref } from '@/lib/links';
 
 import { PagePathParams, fetchPageData, getPagePath } from '../fetch';
 
@@ -51,6 +51,7 @@ export async function generateMetadata({ params }: { params: PagePathParams }):
         title: { default: page.title, template: `%s | ${space.title}` },
         description: page.description,
         generator: 'GitBook',
+        metadataBase: new URL(baseUrl()),
         icons: {
             icon: [
                 {

src/lib/links.ts

@@ -13,17 +13,44 @@ export interface PageHrefContext {
 
 /**
  * Return the base path for the current request.
+ * The value will start and finish with /
  */
 export function basePath(): string {
     const headersList = headers();
-    return headersList.get('x-gitbook-basepath') ?? '';
+    let path = headersList.get('x-gitbook-basepath') ?? '/';
+
+    if (!path.startsWith('/')) {
+        path = '/' + path;
+    }
+
+    if (!path.endsWith('/')) {
+        path = path + '/';
+    }
+
+    return path;
+}
+
+/**
+ * Return the current host for the current request.
+ */
+export function host(): string {
+    const headersList = headers();
+    return headersList.get('x-gitbook-host') ?? headersList.get('host') ?? '';
+}
+
+/**
+ * Return the base URL for the current request.
+ */
+export function baseUrl(): string {
+    return `https://${host()}${basePath()}`;
 }
 
 /**
  * Create an absolute href in the current content.
  */
 export function absoluteHref(href: string): string {
-    return `${basePath()}/${href.startsWith('/') ? href.slice(1) : href}`;
+    const base = basePath();
+    return `${base === '/' ? '' : base}/${href.startsWith('/') ? href.slice(1) : href}`;
 }
 
 /**