fix: api permacache validate content length header

packages/api/src/perma-cache/post.js

@@ -50,14 +50,33 @@ export async function permaCachePost(request, env, ctx) {
 
   if (!r2Object) {
     // Fetch Response from provided URL
-    const response = await getResponse(request, env, ctx, normalizedUrl)
+    let response = await getResponse(request, env, ctx, normalizedUrl)
     if (!response.ok) {
       throw new HTTPError(
         'Failed to get response from provided URL',
         response.status
       )
     }
 
+    // Content length is mandatory given R2 needs a known size of the readable stream
+    // TODO: We need public gateways to set content-length for JSON content
+    const contentLengthMb = response.headers.get('content-length')
+    if (
+      !contentLengthMb &&
+      response.headers.get('content-type') === 'application/json'
+    ) {
+      const headers = response.headers
+      const content = await response.json()
+      response = new Response(content, {
+        headers: headers,
+      })
+    } else {
+      throw new HTTPError(
+        'Failed to get response with content length header',
+        400
+      )
+    }
+
     // TODO: Validate headers per https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Cache-Control
     // Store in R2 and add to Database if not existent
     r2Object = await env.SUPERHOT.put(r2Key, response.body, {