Googlebot无法抓取我的JavaScript文件问题排查求助

First, let's recap your situation for clarity:

My JavaScript file at https://api-staging-weld.freetls.fastly.net/scripts/customdomain_weld.19f3e9ec.js is showing a "Temporarily unreachable" error in Google Search Console with no extra details. I think there's an HTTP Header issue but can't figure out which one. Here's the partial HTTP Headers I have:

accept-ranges: bytes
access-control-allow-origin: *
age: 4905
cache-control: public, max-age=31536000
content-encoding: gzip
content-length: 29990
content-type: application/javascript; charset=UTF-8
date: Fri, 20 Apr 2018 12:46:37...

Let's Start with the Headers You Provided #

Looking at the partial headers, most things seem in order, but let's check a few potential red flags:

• Cache Control & Age: Your cache-control sets a 1-year max-age, and the age shows the file's been cached for ~1.3 hours — that's well within the allowed window, so this shouldn't be the immediate problem. Still, double-check Fastly's caching rules to make sure there's no unexpected stale content behavior that could trip up crawlers.
• Content Encoding: The file uses gzip compression, which is fine, but confirm the compressed content is valid. You can test this by fetching the file without accepting gzip (run curl -H "Accept-Encoding: identity" https://api-staging-weld.freetls.fastly.net/scripts/customdomain_weld.19f3e9ec.js) to see if it serves uncompressed content correctly. If the uncompressed version is broken, that could cause issues.
• Missing Headers to Check: The partial list doesn't include headers like X-Robots-Tag (if set to noindex, that'd block crawlers, though you'd get a different error), server, or Fastly's x-cache status. Make sure there's no header that explicitly restricts crawler access, and confirm the HTTP status code is 200 OK (you didn't mention this, but it's critical — a hidden 4xx/5xx could trigger the "unreachable" error).

Beyond Headers: Other Likely Culprits #

Since the header clues aren't screaming "problem," let's look at other angles:

• Use Google's URL Inspection Tool: The live test feature in Search Console will simulate Googlebot accessing your file and give you a detailed breakdown of the request/response cycle — this is way more helpful than the generic "temporarily unreachable" message. It'll show you exactly if the request failed, what status code was returned, and any blocking factors.
• Check Fastly's Configuration: Fastly might have WAF rules, access controls, or geo-restrictions that are blocking Googlebot's IP ranges. Check Fastly's logs or access control lists to see if crawler requests are being blocked or throttled.
• Verify Connectivity & DNS: Ensure your domain resolves correctly (use dig or nslookup to check) and that there are no intermittent network issues between Google's crawlers and your Fastly endpoint. A traceroute can help spot routing problems.
• Rate Limiting: If your Fastly setup has rate limits, Googlebot might be hitting them. Check Fastly's request logs to see if crawler requests are being throttled.

Quick Hands-On Tests to Run #

1. Mimic Googlebot's Request: Run this curl command to see exactly what headers and status code Googlebot would get:

   curl -A "Mozilla/5.0 (compatible; Googlebot/2.1; +http://www.google.com/bot.html)" -I https://api-staging-weld.freetls.fastly.net/scripts/customdomain_weld.19f3e9ec.js
   

   Compare the full header output and status code to what you expect.
2. Fetch as Google: Use the "Fetch as Google" tool in Search Console to get a step-by-step report of how Googlebot interacts with your file.

内容的提问来源于stack exchange，提问作者Henric Malmberg