Nginx proxy when $http_user_agent matches mobile - nginx

Question

I make two version of website, one for pc while the other for mobile.
The pc version runs through django which points to a reverse_proxy through http://127.0.0.1:8000/.
While the mobile version only serves the static path in /path/for/mobile.
I tried many ways, for example, but cannot get it work.
location / {
if ($http_user_agent ~ Mobile) {
root /path/for/mobile;
}
else {
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Scheme $scheme;
proxy_pass http://127.0.0.1:8000;
}
}

Answer 1

After some attempt, it turns out using extra server with fixed port number works good.
The if statement only affects a number variable, which affects the port proxy to different version of any content.
server {
# static server
listen 11112;
root /path/to/static/html;
}
server {
# dynamic server
listen 11111;
client_max_body_size 300m;
location / {
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Scheme $scheme;
proxy_pass http://django_devaluation:8000/;
}
}
server {
listen 80;
server_name www.example.com;
index index.html;
// here do the condition separation
set $proxy_port 11111;
if ($http_user_agent ~* mobile) {
set $proxy_port 11112;
}
location / {
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Scheme $scheme;
proxy_pass http://127.0.0.1:$proxy_port;
}
}

Answer 2

Try this - If is mobile, use the default root, otherwise proxy_pass.
location / {
set $mobile 0;
root /path/for/mobile;
if ($http_user_agent ~ Mobile) {
set $mobile 1;
}
if ($mobile = 0) {
proxy_set_header Host $http_host;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Scheme $scheme;
proxy_pass http://127.0.0.1:8000;
break;
}
}

Answer 3

The only safe operations on nginx if blocks are rewrite and return.
Try something like:
if ($mobile = 0) {
add_header Content-Type text/plain;
return 200 "Desktop Version";
break;
}
to verify that your $mobile variable is set correctly, then:
if ($mobile = 0) {
rewrite ^ /desktopProxy/$request_uri;
}
location ~* ^/desktopProxy/(.*)$ {
...
proxy_pass http://127.0.0.1:8000/$1$is_args$args;
break;
}
I didn't test the "$1$is_args$args" condition, verify that before using on prod.