Why nginx works with error 301 HTTP1.1/Moved permanently? - nginx

Question

I'm trying to configure Location directive on my nginx web-server (Ubuntu).
I can have access to:
http://127.0.0.1/app1/
BUT when I'm trying to get access whitout slash in the end like:
http://127.0.0.1/app1
I get an error 301 HTTP1.1/Moved permanently
I have following nginx config:
user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;
events {
worker_connections 768;
}
http {
sendfile on;
tcp_nopush on;
tcp_nodelay on;
keepalive_timeout 65;
types_hash_max_size 2048;
include /etc/nginx/mime.types;
default_type application/octet-stream;
ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_prefer_server_ciphers on;
access_log /var/log/nginx/access.log;
error_log /var/log/nginx/error.log;
gzip on;
include /etc/nginx/conf.d/*.conf;
include /etc/nginx/sites-enabled/*;
}
Looks like everything is OK.
And following default.conf:
server {
listen 80 default_server;
root /var/www/html;
index index.html index.htm index.nginx-debian.html;
server_name _;
location / {
# First attempt to serve request as file, then
# as directory, then fall back to displaying a 404.
try_files $uri $uri/ =404;
}
location /app1/ {
root /var/www/html/;
index index.html;
try_files $uri $uri/ /app1/index.html;
}
}
Curl output
http://127.0.0.1/app1/
root#ubuntu-test:/etc/nginx/sites-available# curl 127.0.0.1/app1/ -Iv
* Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 80 (#0)
> HEAD /app1/ HTTP/1.1
> Host: 127.0.0.1
> User-Agent: curl/7.58.0
> Accept: */*
>
< HTTP/1.1 200 OK
HTTP/1.1 200 OK
< Server: nginx/1.14.0 (Ubuntu)
Server: nginx/1.14.0 (Ubuntu)
< Date: Thu, 20 Feb 2020 09:14:12 GMT
Date: Thu, 20 Feb 2020 09:14:12 GMT
< Content-Type: text/html
Content-Type: text/html
< Content-Length: 5
Content-Length: 5
< Last-Modified: Tue, 18 Feb 2020 10:49:53 GMT
Last-Modified: Tue, 18 Feb 2020 10:49:53 GMT
< Connection: keep-alive
Connection: keep-alive
< ETag: "5e4bc151-5"
ETag: "5e4bc151-5"
< Accept-Ranges: bytes
Accept-Ranges: bytes
<
* Connection #0 to host 127.0.0.1 left intact
http://127.0.0.1/app1
root#ubuntu-test:/etc/nginx/sites-available# curl 127.0.0.1/app1 -Iv
* Trying 127.0.0.1...
* TCP_NODELAY set
* Connected to 127.0.0.1 (127.0.0.1) port 80 (#0)
> HEAD /app1 HTTP/1.1
> Host: 127.0.0.1
> User-Agent: curl/7.58.0
> Accept: */*
>
< HTTP/1.1 301 Moved Permanently
HTTP/1.1 301 Moved Permanently
< Server: nginx/1.14.0 (Ubuntu)
Server: nginx/1.14.0 (Ubuntu)
< Date: Thu, 20 Feb 2020 09:19:31 GMT
Date: Thu, 20 Feb 2020 09:19:31 GMT
< Content-Type: text/html
Content-Type: text/html
< Content-Length: 194
Content-Length: 194
< Location: http://127.0.0.1/app1/
Location: http://127.0.0.1/app1/
< Connection: keep-alive
Connection: keep-alive
Why does it happen?

Answer 1

Nginx selects the location / block to process the URI /app1 as no other locations are a better match. See how Nginx processes a request.
The $uri/ term of the try_files statement informs Nginx to append a / to any URI that matches a directory. The directory /var/www/html/app1 matches this requirement, so a 301 redirection is generated to append a / to the URI. See this document for details.
In addition, the default behaviour for a URI which ends with a / and points to a directory is to search that directory for a file that matches the index directive. See this document for details.
It is possible to deviate from this default behaviour, but you will need to make a number of changes to your configuration. The location /app1/ needs to lose the trailing / if you want it to match /app1. Your try_files directives need to lose the $uri/ term, if you want to avoid the 301 redirect. You will also lose default index processing, so the index directive will be useless.