feat: add /reproduce-cloudflare-error route to access-api (#380)

Motivation:
* cloudflare support asked for a URL to reproduce the undelrying cause
of #363
* this adds a route just for that. once they use it to reproduce and
diagnose, we remove it

packages/access-api/src/index.js

@@ -18,6 +18,7 @@ r.add('get', '/validate-email', validateEmail)
 r.add('get', '/validate-ws', validateWS)
 r.add('post', '/', postRoot)
 r.add('post', '/raw', postRaw)
+r.add('get', '/reproduce-cloudflare-error', reproduceCloudflareError)
 
 /** @type {import('./bindings.js').ModuleWorker} */
 const worker = {
@@ -39,3 +40,30 @@ const worker = {
 }
 
 export default worker
+
+/**
+ * @param {import('@web3-storage/worker-utils/router').ParsedRequest} request
+ * @returns
+ */
+async function reproduceCloudflareError(request) {
+  const fetchUrl = request.query.url || 'https://up.web3.storage'
+  let fetchedResponse
+  try {
+    fetchedResponse = await fetch(fetchUrl)
+  } catch (error) {
+    const message = `/reproduce-cloudflare-error fetch ${fetchUrl} threw unexpected error: ${error}`
+    // eslint-disable-next-line no-console
+    console.error(message, error)
+    return new Response(JSON.stringify({ message }, undefined, 2), {
+      status: 500,
+    })
+  }
+  const response = {
+    message: `got response from fetching ${fetchUrl}`,
+    response: {
+      status: fetchedResponse.status,
+      statusText: fetchedResponse.statusText,
+    },
+  }
+  return new Response(JSON.stringify(response, undefined, 2), { status: 200 })
+}