Nginx Content disposion - Trim file name - nginx

Question

I will briefly tell my problem, I need to trim the first 14 characters (0-9 and -), when downloading a file, it is just about header Content-Disposition, how to achieve something like that?
I want the file to look like this:
1235467890123-FileName.txt
for such
FileName.txt
Config file:
upstream oxide_io {
ip_hash;
server 127.0.0.1:xxx;
server 127.0.0.1:xxx;
server 127.0.0.1:xxx;
}
server {
listen 443 ssl http2;
listen [::]:443 ssl http2;
server_name oxidepolska.pl;
error_log /var/log/nginx/forum-error.log error;
ssl ***
proxy_hide_header X-Powered-By;
proxy_set_header X-Real-IP $remote_addr;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Forwarded-Proto $scheme;
proxy_set_header Host $http_host;
proxy_set_header X-NginX-Proxy true;
proxy_redirect off;
proxy_http_version 1.1;
proxy_set_header Upgrade $http_upgrade;
proxy_set_header Connection "upgrade";
gzip ***
location #oxide {
proxy_pass http://oxide_io;
}
location ~ ^/assets/(.*) {
root /var/www/forum/;
try_files /build/public/$1 /public/$1 #oxide;
}
location /plugins/ {
root /var/www/forum/build/public/;
try_files $uri #oxide;
}
location ~ ^/public/uploads/files/(.*)$ {
root /var/www/forum/public/uploads/files/;
add_header Content-Disposition 'inline; filename="$1"';
}
location / {
proxy_pass http://oxide_io;
}
error_page 502 503 /503.html;
location = /503.html {
root /var/www/forum/public/;
}
}
server {
if ($host = oxidepolska.pl) {
return 301 https://$host$request_uri;
} # managed by Certbot
listen 80;
listen [::]:80;
server_name oxidepolska.pl;
}

Answer 1

As I finally understand, you are trying to get rid of timestamp prefix added to files uploaded on some forum? Here is the another config, manually adding Content-Disposition header:
map $uri $content_disposition {
'~/\d{13}-([^/]+)$' 'attachment; filename="$1"';
}
server {
...
location <uploaded_files_location> {
add_header Content-Disposition $content_disposition;
}
...
}
When requested file is not matching the pattern \d{13}- (13 digits and "-" sign before the rest of filename), $content_disposition variable evaluated as empty string, so Content-Disposition header is not added to response.

Answer 2

➜ ~ curl -I https://ddl.oxidepolska.pl/1544820059040-lootconfig.zip
HTTP/2 200
server: nginx
date: Fri, 14 Dec 2018 21:54:56 GMT
content-type: application/zip
content-length: 7138
last-modified: Fri, 14 Dec 2018 20:40:59 GMT
etag: "5c14155b-1be2"
accept-ranges: bytes

Answer 3

Disclaimer: This answer is about modifying existing Content-Disposition header, which is not what required by OP.
map $upstream_http_content_disposition $content_disposition {
default $upstream_http_content_disposition;
'~^(.*filename="?)[-\d]{14}(.+?)("?$)' $1$2$3;
}
server {
...
location #oxide {
proxy_pass http://oxide_io;
proxy_hide_header Content-Disposition;
add_header Content-Disposition $content_disposition;
}
...
location / {
proxy_pass http://oxide_io;
proxy_hide_header Content-Disposition;
add_header Content-Disposition $content_disposition;
}
...
}
(assuming first 14 characters can be only 0-9 and '-')