程序员老张
6/27/2025
Here's my rewrite:
Hey Flask friends! 👋 I'm stuck on something weird with response headers and could really use some help. 😅
I've got a Flask app running behind nginx with uWSGI, and I'm seeing some magic happening to my Location header that I can't explain. Here's what's up:
@app.after_request def add_header(response): # Just trying to see what headers are being set print(response.headers) # Shows simple Location: / return response
In my uWSGI logs, I see the basic Location: / that I'd expect. But when I check the actual traffic between uWSGI and nginx (with a packet capture), suddenly the Location header has a full URL! 🤯
The hex dump shows it's getting transformed from just / to something like http://<full-url>/m/. Where is this sorcery happening?? 🔮
Things I've tried:
This is driving me nuts because I need to understand where URLs are being constructed for some auth work. Anyone run into this before? Is this some hidden uWSGI or nginx feature I don't know about?
PS: Deployments are the worst sometimes, amirite? 😂 Appreciate any pointers! 🙏
#flask #python #deploymentwoes
程序员Alex
6/27/2025
Hey there! 👋 Oh man, I feel your pain with this header transformation mystery - I had a similar head-scratcher a while back with Location headers magically changing on me! Deployment quirks like this can be so frustrating, especially when you're just trying to get auth working right. 😅
Here's the scoop - this is actually nginx being "helpful" (read: overly opinionated) with its absolute_redirect directive! By default, nginx will rewrite relative Location headers to absolute URLs. It's one of those "features" that's great until it's not.
In your nginx config, you'll want to add:
server { # ... your existing config ... absolute_redirect off; # This stops the magic URL rewriting }
Or if you need absolute URLs but want control over the domain:
server { # ... your existing config ... server_name_in_redirect off; # Gives you more control }
From my experience, this behavior bites people because:
If you're debugging headers, I've found this nginx log format super helpful:
log_format headers '$remote_addr - $remote_user [$time_local] ' '"$request" $status $body_bytes_sent ' '"$http_referer" "$http_user_agent" ' 'Req Headers: "$req_headers" ' 'Resp Headers: "$resp_headers"'; server { # ... your config ... set $resp_headers ""; add_header X-Debug-Resp-Headers $resp_headers; access_log /path/to/access.log headers; }
nginx -t test and nginx -s reload after changesYou got this! The fact you're digging into packet captures shows you're on the right track. 🕵️♂️ If you hit any snags implementing this or need help with the auth flow, just shout - happy to help debug!
#nginx #flask #deploymenttips #webdev
PS: And yes, deployments ARE the worst sometimes! 😂 But hey, at least we get these fun debugging stories to tell, right?