Static Files

Static files are files that are sent as-is to the client, without backend processing.

Examples: HTML (.html), CSS (.css), JavaScript (.js), Images (.png, .jpg), Downloads (.zip, .pdf)

NGINX is extremely efficient at serving static content due to:

• Event-driven architecture
• Zero-copy (sendfile)
• Kernel-level optimizations

Basic Request Flow for Static Files

Client → NGINX → File System → Client

No application server is involved.

Core Directives Used for Static Files

Directive	Purpose
root	Defines base directory
alias	Maps URI to different path
index	Default file
try_files	File existence check
autoindex	Directory listing
sendfile	Efficient file transfer
expires	Client-side caching
gzip	Compression

Simple Static File Server Example

server {
    listen 80;
    server_name example.com;

        root /var/www/html;
        index index.html;

    }

• Request: http://example.com/about.html
• NGINX looks for: /var/www/html/about.html
• If found → served directly
• If not → 404

root Directive (Most Common)

Syntax

root path;

How Path Is Built

Full path = root + URI

location /images/ {
root /var/www;
}

Request:

/images/logo.png

File served:

/var/www/images/logo.png

alias Directive (Important Difference)

Syntax

alias path;

Example

location /images/ {
alias /data/pictures/;
}

Request:

/images/logo.png

File served:

/data/pictures/logo.png

Key Difference

root	alias
Appends URI	Replaces URI
More common	Needs care

Default Files with index

index index.html index.htm;

Example

Request: http://example.com/

NGINX tries:

• /var/www/html/index.html
• /var/www/html/index.htm

File Existence Control with try_files

location / {
   try_files $uri $uri/ =404;
}

• Checks if file exists
• Prevents unwanted proxying
• Improves security

Serving Assets from a Separate Directory

location /assets/ {
   root /var/www;
   expires 30d;
}

Request:

/assets/style.css

File:

/var/www/assets/style.css

Adds caching:

Cache-Control: max-age=2592000

Auto Directory Listing (autoindex)

location /downloads/ {
    root /var/www;
    autoindex on;
}

• Lists files if no index file exists
• Use carefully (security risk)

MIME Types & Content-Type

http {
    include mime.types;
    default_type application/octet-stream;
}

• Correct Content-Type headers
• Browser renders files properly

Performance Optimizations

• sendfile: sendfile on;
  • Uses zero-copy file transfer.
• TCP Optimizations

tcp_nopush on;
tcp_nodelay on;

• Gzip Compression

gzip on;
gzip_types text/css application/javascript;

Static Files + Reverse Proxy (Hybrid Setup)

server {
    listen 80;

        location / {
            root /var/www/html;
            try_files $uri $uri/ @backend;
        }

        location @backend {
            proxy_pass http://app_backend;
        }

    }

• Static files served directly
• Dynamic requests proxied
• Best performance pattern

Security Best Practices

Disable access to hidden files:

location ~ /\. {
deny all;
}

Prevent directory traversal:

disable_symlinks on;

Restrict file types:

location ~ \.(php|sh)$ {
deny all;
}

Real-World Production Example

server {
    listen 80;
    server_name example.com;

        root /var/www/app/public;
        index index.html;

        location / {
            try_files $uri $uri/ =404;
        }

        location /static/ {
            expires 7d;
            access_log off;
        }

    }

Common Mistakes

• Mixing root and alias incorrectly
• Forgetting trailing slash with alias
• Leaving autoindex enabled
• Not setting cache headers