Comment the image generator

packages/website/src/routes/blog/image/+server.ts

@@ -9,41 +9,36 @@ import { format } from "@tusbar/cache-control";
 const cache = new TTLCache({ max: 10000, ttl: 1000 * 60 * 60 })
 import fnv from "fnv-plus"
 
-// import type { Endpoints } from "@octokit/types";
-
-// let repoRegex = new RegExp("https?://github\.com/(?<repo>[a-zA-Z0-9]+/[a-zA-Z0-9]+)/?")
-
 const fontFile = await fetch('https://og-playground.vercel.app/inter-latin-ext-700-normal.woff');
 const fontData: ArrayBuffer = await fontFile.arrayBuffer();
 
-// const height = 630;
-// const width = 1200;
 const defaultWidth = 800;
 const defaultRatio = 0.5
-// const defaultWidth = 800;
 
+// JSX stub
 const h = (type: any, props: any) => { return { type, props } }
+
 type a = RequestHandler;
 /** @type {RequestHandler} */
 export async function GET({ url, request }) {
+    // First, get the information about the post
+    // We have the slug and date of the post, which we can use to look up the post
     const slug = url.searchParams.get('slug')
     let dateParts = url.searchParams.get('date')?.split(/[\/-]/)?.map((p: string) => parseInt(p, 10))
     if (dateParts && dateParts.length > 3) {
         throw error(404, 'Post not found (bad date)')
     }
+    // Next, get the width and ratio of the image
+    // to determine the size of the image
     const width = Number(url.searchParams.get('width'))
     const ratio = Number(url.searchParams.get('ratio'))
+    // If the width or ratio is too big, don't render the image to prevent DoS attacks
     if (width > 10000 || ratio > 50) {
         throw error(400, 'Image too big')
     }
     let image;
 
-    // let start = new Date(dateParts[0] || 1, dateParts[1] || 0, dateParts[2] || 0);
-    // // @ts-ignore
-    // let end = new Date(...dateParts);
-    // console.log(dateParts)
-
-    // get post with metadata
+    // Look up the post in the database
     const page = pages
         .filter((post) => slug === post.slug)
         .filter((post) => {
@@ -61,16 +56,21 @@ export async function GET({ url, request }) {
         throw error(404, 'Post not found')
     }
 
+    // Generate a cache key based on the post's canonical URL, reading time, width, and ratio
+    // Caching the image based on this key ensures that the image is not regenerated every time
+    // The cache key is also used for browser caching
     let cache_key = fnv.hash(page.canonical + "\x00" + page.readingTime.text + "\x00" + width + "\x00" + ratio).str()
 
-    let recieved_etag = request.headers.get("if-none-match");
-
-    if (recieved_etag == cache_key) {
-        console.log("304")
+    let received_etag = request.headers.get("if-none-match");
+    // If the client has a cached version of the image, return a 304 Not Modified response, indicating that the image has not changed
+    // This means we don't even have to have the image cached in memory
+    if (received_etag == cache_key) {
         return new Response(null, { status: 304 })
     }
 
+    // If the image is not cached, generate the image and cache it
     if (!cache.has(cache_key)) {
+        // First, render the HTML / JSX-based template
         let template = h("div", {
             style: {
                 display: 'flex',
@@ -114,6 +114,7 @@ export async function GET({ url, request }) {
                 children: `Published on ${new Date(page.date).toLocaleDateString()} by Jade Ellis · ${page.readingTime.text}`
             })]
         });
+        // Then, convert the vdom to SVG using satori
         const svg = await satori(template, {
             fonts: [
                 {
@@ -126,6 +127,7 @@ export async function GET({ url, request }) {
             width: defaultWidth,
         });
 
+        // Then, convert the SVG to a PNG image using resvg
         const resvg = new Resvg(svg, {
             fitTo: {
                 mode: 'width',
@@ -134,20 +136,25 @@ export async function GET({ url, request }) {
         });
 
         image = resvg.render().asPng();
+        // Finally, save the image to the cache
         cache.set(cache_key, image);
     } else {
+        // If the image is cached, return it
         image = cache.get(cache_key) as Buffer
     }
-
+    // Finally, return the image as a response
     return new Response(image, {
         headers: {
             'Content-Type': 'image/png',
+            // Cache the image for 24 hours
             'Cache-Control': format({
                 public: true,
                 // immutable: true
                 maxAge: 60 * 60 * 24
             }),
+            // Set the cache key as the ETag
             'ETag': cache_key,
+            // Allow cross-origin requests to serve the image
             'Cross-Origin-Resource-Policy': 'cross-origin'
         }
     });