Score:4

What is the nginx Variable for a custom Header?

cn flag

A client is sending a custom HTTP Header X-ABC-LOGIN-NAME to my Nginx reverse proxy. To be sure that it is actually arriving, a PHP server (fastcgi) was installed and this header is really showing up (with a value) in phpinfo(), section 'PHP Variables'.

I operate a Django backend with a gunicorn server and in the Django code, I print all headers to the console. When I assign a static value to the X-ABC-LOGIN-NAME in /etc/nginx/sites-enabled/default, the value arrives at the backend. In the nginx default file this looks as:

server {
    listen      443 ssl http2 default_server;
    listen [::]:443 ssl http2 default_server;

    ssl_certificate /etc/nginx/ssl/nginx.crt;
    ssl_certificate_key /etc/nginx/ssl/nginx.key;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;

    # include snippets/self-signed.conf;
    # include snippets/ssl-params.conf;
    # server_name   localhost;
    server_name dev_server;

    underscores_in_headers on;

    location / {
    
        proxy_pass http://localhost:8000;
        proxy_pass_request_headers on;
    
        proxy_http_version 1.1;
    
        proxy_set_header Upgrade $http_upgrade;
    
        proxy_set_header X-ABC-LOGIN-NAME "static_name"; # <-- "static_name" arrives in the python print statement
        proxy_set_header X-ABC-LOGIN-NAME $http_x_abc_login_name;  # <-- This value is empty
    
        proxy_set_header   Connection keep-alive;
        proxy_set_header   Host $host;
        proxy_cache_bypass $http_upgrade;
        proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header   X-Forwarded-Proto $scheme;
    
    }

...
}

I exhaustively searched the internet and cannot tell how to find the name of the variable that contains the value, or where it gets lost.


Edit: Adding picture to clarify problem: enter image description here

Inbetween a Browser (Client) and a Server sits a proxy (called ABC). This proxy inserts a Header (X-ABC-LOGIN-NAME) in every request from the client to the server. After inserting the header, the request by the client is forwarded to the Nginx reverse proxy server. From there I am unable to forward the inserted X-ABC-LOGIN-NAME to the gunicorn application server.


Edit 2: nginx -T

ubuntu@xyz-ubuntu:~$ sudo nginx -T
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful
# configuration file /etc/nginx/nginx.conf:
user www-data;
worker_processes auto;
pid /run/nginx.pid;
include /etc/nginx/modules-enabled/*.conf;

events {
        worker_connections 768;
        # multi_accept on;
}

http {

        underscores_in_headers on;

        ##
        # Basic Settings
        ##

        sendfile on;
        tcp_nopush on;
        tcp_nodelay on;
        keepalive_timeout 65;
        types_hash_max_size 2048;
        # server_tokens off;

        server_names_hash_bucket_size 64;
        # server_name_in_redirect off;

        include /etc/nginx/mime.types;
        default_type application/octet-stream;

        ##
        # SSL Settings
        ##

        ssl_protocols TLSv1 TLSv1.1 TLSv1.2 TLSv1.3; # Dropping SSLv3, ref: POODLE
        ssl_prefer_server_ciphers on;

        ##
        # Logging Settings
        ##

        access_log /var/log/nginx/access.log;
        error_log /var/log/nginx/error.log;


        ##
        # Gzip Settings
        ##

        gzip on;

        # gzip_vary on;
        # gzip_proxied any;
        # gzip_comp_level 6;
        # gzip_buffers 16 8k;
        # gzip_http_version 1.1;
        # gzip_types text/plain text/css application/json application/javascript text/xml application/xml application/xml+rss text/javascript;

        ##
        # Virtual Host Configs
        ##

        include /etc/nginx/conf.d/*.conf;
        include /etc/nginx/sites-enabled/*;
}


#mail {
#       # See sample authentication script at:
#       # http://wiki.nginx.org/ImapAuthenticateWithApachePhpScript
#
#       # auth_http localhost/auth.php;
#       # pop3_capabilities "TOP" "USER";
#       # imap_capabilities "IMAP4rev1" "UIDPLUS";
#
#       server {
#               listen     localhost:110;
#               protocol   pop3;
#               proxy      on;
#       }
#
#       server {
#               listen     localhost:143;
#               protocol   imap;
#               proxy      on;
#       }
#}

# configuration file /etc/nginx/modules-enabled/50-mod-http-image-filter.conf:
load_module modules/ngx_http_image_filter_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-http-xslt-filter.conf:
load_module modules/ngx_http_xslt_filter_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-mail.conf:
load_module modules/ngx_mail_module.so;

# configuration file /etc/nginx/modules-enabled/50-mod-stream.conf:
load_module modules/ngx_stream_module.so;

# configuration file /etc/nginx/mime.types:

types {
    text/html                             html htm shtml;
    text/css                              css;
    text/xml                              xml;
    image/gif                             gif;
    image/jpeg                            jpeg jpg;
    application/javascript                js;
    application/atom+xml                  atom;
    application/rss+xml                   rss;

    text/mathml                           mml;
    text/plain                            txt;
    text/vnd.sun.j2me.app-descriptor      jad;
    text/vnd.wap.wml                      wml;
    text/x-component                      htc;

    image/png                             png;
    image/tiff                            tif tiff;
    image/vnd.wap.wbmp                    wbmp;
    image/x-icon                          ico;
    image/x-jng                           jng;
    image/x-ms-bmp                        bmp;
    image/svg+xml                         svg svgz;
    image/webp                            webp;

    application/font-woff                 woff;
    application/java-archive              jar war ear;
    application/json                      json;
    application/mac-binhex40              hqx;
    application/msword                    doc;
    application/pdf                       pdf;
    application/postscript                ps eps ai;
    application/rtf                       rtf;
    application/vnd.apple.mpegurl         m3u8;
    application/vnd.ms-excel              xls;
    application/vnd.ms-fontobject         eot;
    application/vnd.ms-powerpoint         ppt;
    application/vnd.wap.wmlc              wmlc;
    application/vnd.google-earth.kml+xml  kml;
    application/vnd.google-earth.kmz      kmz;
    application/x-7z-compressed           7z;
    application/x-cocoa                   cco;
    application/x-java-archive-diff       jardiff;
    application/x-java-jnlp-file          jnlp;
    application/x-makeself                run;
    application/x-perl                    pl pm;
    application/x-pilot                   prc pdb;
    application/x-rar-compressed          rar;
    application/x-redhat-package-manager  rpm;
    application/x-sea                     sea;
    application/x-shockwave-flash         swf;
    application/x-stuffit                 sit;
    application/x-tcl                     tcl tk;
    application/x-x509-ca-cert            der pem crt;
    application/x-xpinstall               xpi;
    application/xhtml+xml                 xhtml;
    application/xspf+xml                  xspf;
    application/zip                       zip;

    application/octet-stream              bin exe dll;
    application/octet-stream              deb;
    application/octet-stream              dmg;
    application/octet-stream              iso img;
    application/octet-stream              msi msp msm;

    application/vnd.openxmlformats-officedocument.wordprocessingml.document    docx;
    application/vnd.openxmlformats-officedocument.spreadsheetml.sheet          xlsx;
    application/vnd.openxmlformats-officedocument.presentationml.presentation  pptx;

    audio/midi                            mid midi kar;
    audio/mpeg                            mp3;
    audio/ogg                             ogg;
    audio/x-m4a                           m4a;
    audio/x-realaudio                     ra;

    video/3gpp                            3gpp 3gp;
    video/mp2t                            ts;
    video/mp4                             mp4;
    video/mpeg                            mpeg mpg;
    video/quicktime                       mov;
    video/webm                            webm;
    video/x-flv                           flv;
    video/x-m4v                           m4v;
    video/x-mng                           mng;
    video/x-ms-asf                        asx asf;
    video/x-ms-wmv                        wmv;
    video/x-msvideo                       avi;
}

# configuration file /etc/nginx/sites-enabled/default:


#
#
# Default server configuration
#
server {
    listen        443 ssl http2 default_server;
    listen [::]:443 ssl http2 default_server;

    ssl_certificate /etc/nginx/ssl/nginx.crt;
    ssl_certificate_key /etc/nginx/ssl/nginx.key;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;

    # include snippets/self-signed.conf;
    # include snippets/ssl-params.conf;
    # server_name   localhost;
    server_name xyz_server;

    underscores_in_headers on;

    # REST API Backend
    location ^~ /api  {

        proxy_pass_request_headers on;
    
        proxy_http_version 1.1;
        proxy_set_header   Upgrade $http_upgrade;

        add_header X-Abc-Login-Name $http_x_abc_login_name;

        proxy_set_header   Connection keep-alive;
        proxy_set_header   Host $host;
        proxy_cache_bypass $http_upgrade;
        proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header   X-Forwarded-Proto $scheme;

        proxy_pass         http://localhost:8000;
    }

    # Frontend
    location / {

        proxy_pass_request_headers on;

        proxy_http_version 1.1;
        proxy_set_header   Upgrade $http_upgrade;
 
        add_header X-Abc-Login-Name $http_x_abc_login_name;  

        proxy_set_header   Connection keep-alive;
        proxy_set_header   Host $host;
        proxy_cache_bypass $http_upgrade;
        proxy_set_header   X-Forwarded-For $proxy_add_x_forwarded_for;
        proxy_set_header   X-Forwarded-Proto $scheme;

        proxy_pass         http://localhost:3000;

    }

    root /var/www/html;
    index index.php;
    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/run/php/php7.4-fpm.sock;
    }

}

server {

    listen   80; # default_server;

    root /var/www/html;

    index index.php
    server_name php_server;

    location ~ \.php$ {
        include snippets/fastcgi-php.conf;
        fastcgi_pass unix:/run/php/php7.4-fpm.sock;
    }
}

# configuration file /etc/nginx/snippets/fastcgi-php.conf:
# regex to split $uri to $fastcgi_script_name and $fastcgi_path
fastcgi_split_path_info ^(.+?\.php)(/.*)$;

# Check that the PHP script exists before passing it
try_files $fastcgi_script_name =404;

# Bypass the fact that try_files resets $fastcgi_path_info
# see: http://trac.nginx.org/nginx/ticket/321
set $path_info $fastcgi_path_info;
fastcgi_param PATH_INFO $path_info;

fastcgi_index index.php;
include fastcgi.conf;

# configuration file /etc/nginx/fastcgi.conf:

fastcgi_param  SCRIPT_FILENAME    $document_root$fastcgi_script_name;
fastcgi_param  QUERY_STRING       $query_string;
fastcgi_param  REQUEST_METHOD     $request_method;
fastcgi_param  CONTENT_TYPE       $content_type;
fastcgi_param  CONTENT_LENGTH     $content_length;

fastcgi_param  SCRIPT_NAME        $fastcgi_script_name;
fastcgi_param  REQUEST_URI        $request_uri;
fastcgi_param  DOCUMENT_URI       $document_uri;
fastcgi_param  DOCUMENT_ROOT      $document_root;
fastcgi_param  SERVER_PROTOCOL    $server_protocol;
fastcgi_param  REQUEST_SCHEME     $scheme;
fastcgi_param  HTTPS              $https if_not_empty;

fastcgi_param  GATEWAY_INTERFACE  CGI/1.1;
fastcgi_param  SERVER_SOFTWARE    nginx/$nginx_version;

fastcgi_param  REMOTE_ADDR        $remote_addr;
fastcgi_param  REMOTE_PORT        $remote_port;
fastcgi_param  SERVER_ADDR        $server_addr;
fastcgi_param  SERVER_PORT        $server_port;
fastcgi_param  SERVER_NAME        $server_name;

# PHP only, required if PHP was built with --enable-force-cgi-redirect
fastcgi_param  REDIRECT_STATUS    200;

Edit 3:

Left: Application log, Right: Nginx as running:

enter image description here

djdomi avatar
za flag
Does this answer your question? [Forward Custom Header from Nginx Reverse Proxy](https://serverfault.com/questions/391554/forward-custom-header-from-nginx-reverse-proxy)
cn flag
I wish.. I found that question and tried to do it as described. However (as I wrote in my question), the value is lost when using `$http_x_abc_login_name` and I am out of ideas why that might be (given that the phpinfo() running behind the same reverse proxy receives the value).
djdomi avatar
za flag
did you see `underscores_in_headers on;` and applied it?
cn flag
Absolutely. It is set in the `server { underscores_in_headers on; ...}` section. Added that section to the nginx defaults file in my original question post.
Michael Hampton avatar
cz flag
What you have posted should have worked fine from the beginning. It's time to look a bit farther out. Please post the output of `nginx -T`
cn flag
@MichaelHampton I added the output. It is the state of the configuration after the latest suggestion by djdomi (using `add_header`).
Michael Hampton avatar
cz flag
Well that won't work. `add_header` adds a response header. Change it back to `proxy_set_header` in both locations.
cn flag
I reverted back to `proxy_set_header`. As shown to the left, the application can receive and print the statit "TEST" header. Not so however with the `http_x_hin_login_name`. But I know that it is there because phpinfo() sees it in PHP Variables.
Michael Hampton avatar
cz flag
Hmm, so why do you try to pass this header explicitly? They all should be sent to your app anyway if you do nothing, just like all the others are.
cn flag
I can write an `if` Statement that returns a 412 like this `if ($http_x_hin_login_name) { return 412; }` and I get the 412 status code. But I dont receive this header in my app.
mangohost

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