feat: media proxy for anonymous loads

package.json

@@ -16,6 +16,7 @@
     "axios": "^0.27.2",
     "cheerio": "1.0.0-rc.12",
     "next": "12.2.5",
+    "node-fetch": "^3.2.10",
     "react": "18.2.0",
     "react-dom": "18.2.0",
     "sharp": "^0.31.0"

src/pages/api/media_proxy.ts

@@ -0,0 +1,83 @@
+import { NextApiRequest, NextApiResponse } from 'next'
+import fetch from 'node-fetch'
+
+const acceptableExtensions = ['.jpg', '.png', '.gif', '.webp']
+
+export default async function handler(
+  req: NextApiRequest,
+  res: NextApiResponse
+) {
+  // get query param
+  const mediaUrl = (req.query as { url: string }).url
+
+  if (!mediaUrl) {
+    res.status(400)
+    res.send(null)
+    return
+  }
+
+  let mediaUrlParsed: URL
+
+  try {
+    mediaUrlParsed = new URL(mediaUrl)
+  } catch {
+    res.status(400)
+    res.send(null)
+    return
+  }
+
+  // get media domain
+  const mediaDomain = mediaUrlParsed.hostname
+
+  if (!mediaDomain.endsWith('media-amazon.com')) {
+    res.status(400)
+    res.send(null)
+    return
+  }
+
+  if (mediaUrlParsed.protocol !== 'https:') {
+    res.status(400)
+    res.send(null)
+    return
+  }
+
+  let validExtension = false
+
+  for (const acceptableExtension of acceptableExtensions) {
+    if (mediaUrlParsed.pathname.endsWith(acceptableExtension)) {
+      validExtension = true
+      break
+    }
+  }
+
+  if (!validExtension) {
+    res.status(400)
+    res.send(null)
+    return
+  }
+
+  // download media
+  const mediaRes = await fetch(mediaUrl)
+
+  if (!mediaRes.ok) {
+    res.status(mediaRes.status)
+    return
+  }
+
+  // get media type
+  const mediaType = mediaRes.headers.get('content-type')
+
+  if (!mediaType) {
+    res.status(500)
+    res.send(null)
+    return
+  }
+
+  // set media type
+  res.setHeader('content-type', mediaType)
+
+  const mediaBuffer = await mediaRes.arrayBuffer()
+
+  // send media
+  res.send(Buffer.from(mediaBuffer))
+}