fix: add an option to disable dynamic OG image generation (#476)

* fix: add an option to disable dynamic OG image generation

Add new `dynamicOgImage` option in the `SITE` object inside 
`src/config.ts` file to disable auto og-image generation during build.

Resolves #428

* docs: update guides for `SITE.dynamicOgImage` option

src/pages/posts/[slug]/index.png.ts

@@ -2,8 +2,13 @@ import type { APIRoute } from "astro";
 import { getCollection, type CollectionEntry } from "astro:content";
 import { generateOgImageForPost } from "@/utils/generateOgImages";
 import { slugifyStr } from "@/utils/slugify";
+import { SITE } from "@/config";
 
 export async function getStaticPaths() {
+  if (!SITE.dynamicOgImage) {
+    return [];
+  }
+
   const posts = await getCollection("blog").then(p =>
     p.filter(({ data }) => !data.draft && !data.ogImage)
   );
@@ -14,7 +19,18 @@ export async function getStaticPaths() {
   }));
 }
 
-export const GET: APIRoute = async ({ props }) =>
-  new Response(await generateOgImageForPost(props as CollectionEntry<"blog">), {
-    headers: { "Content-Type": "image/png" },
-  });
+export const GET: APIRoute = async ({ props }) => {
+  if (!SITE.dynamicOgImage) {
+    return new Response(null, {
+      status: 404,
+      statusText: "Not found",
+    });
+  }
+
+  return new Response(
+    await generateOgImageForPost(props as CollectionEntry<"blog">),
+    {
+      headers: { "Content-Type": "image/png" },
+    }
+  );
+};