Improve error message for image resizing (#2898)

Author: SamyPesse

packages/gitbook-v2/src/lib/images/createImageResizer.ts

@@ -66,6 +66,7 @@ export function createImageResizer({
                     linker.toAbsoluteURL(linker.toPathInContent('/~gitbook/image'))
                 );
                 url.searchParams.set('url', getImageAPIUrl(urlInput));
+                url.searchParams.set('host', host);
 
                 if (options.width) {
                     url.searchParams.set('width', options.width.toString());

packages/gitbook/src/routes/image.ts

@@ -45,7 +45,10 @@ export async function serveResizedImage(request: Request) {
         { signature, version: signatureVersion }
     );
     if (!verified) {
-        return new Response(`Invalid signature "${signature ?? ''}" for "${url}"`, { status: 400 });
+        return new Response(
+            `Invalid signature "${signature ?? ''}" (version ${signatureVersion}) for "${url}" on "${requestURL.host}"`,
+            { status: 400 }
+        );
     }
 
     if (signatureVersion !== CURRENT_SIGNATURE_VERSION) {