代理转发浏览器请求至stackoverflow.com时返回301状态码的处理咨询

Great question—your initial approach is on the right track, but there’s a bit more to it to make the flow work end-to-end. Let’s break this down clearly:

First, why you’re seeing that 301: Stack Overflow strictly enforces HTTPS, so any incoming HTTP request (like the one your browser sent to http://stackoverflow.com) gets redirected to the HTTPS version via a 301 "Moved Permanently" response. That’s expected behavior from the site.

Your idea to update the request line is correct, but you’ll need to adjust a couple more things to make the proxy successfully communicate with the HTTPS endpoint:

• Update the request line: As you suggested, change GET http://stackoverflow.com/ HTTP/1.1 to GET https://stackoverflow.com/ HTTP/1.1.
• Switch to TLS encryption: Since you’re now targeting an HTTPS URL, your proxy can’t use a plaintext HTTP connection to the server. You’ll need to establish an SSL/TLS connection to stackoverflow.com before sending the modified request.
• Verify the Host header: Ensure the Host header in your request is set to stackoverflow.com (it’s probably already correct, but aligning it with the HTTPS domain avoids any potential issues).

Once you make these adjustments, forward the modified HTTPS request to the target server. You should then receive a valid 200 response (or other non-redirect status) which you can relay back to the browser.

A few extra best practices to keep in mind:

• Don’t hardcode the protocol switch—always use the exact URL from the Location header, since redirects can sometimes point to entirely different domains or paths.
• Handle other redirect status codes (302, 307, 308) using the same pattern, though their intended behavior (temporary vs permanent) might affect whether you cache the redirect.
• Add a limit to how many redirects your proxy follows to avoid infinite loops.

内容的提问来源于stack exchange，提问作者kmeshavkin