Favicon Caching Strategy Guide

# Apache .htaccess or httpd.conf

# Enable expires module
<IfModule mod_expires.c>
    ExpiresActive On
    
    # Favicon files - 1 year
    ExpiresByType image/x-icon "access plus 1 year"
    ExpiresByType image/png "access plus 1 year"
    ExpiresByType image/svg+xml "access plus 1 year"
    ExpiresByType application/manifest+json "access plus 1 year"
</IfModule>

# Cache-Control headers
<IfModule mod_headers.c>
    <FilesMatch "\.(ico|png|svg|webmanifest)$">
        Header set Cache-Control "public, max-age=31536000, immutable"
    </FilesMatch>
</IfModule>

# Optional: Disable ETag to save bandwidth
FileETag None

<!-- IIS web.config -->
<configuration>
  <system.webServer>
    <staticContent>
      <clientCache cacheControlMode="UseMaxAge" 
                   cacheControlMaxAge="365.00:00:00" />
    </staticContent>
    
    <outboundRules>
      <rule name="Add immutable">
        <match serverVariable="RESPONSE_Cache-Control" 
               pattern=".*" />
        <conditions>
          <add input="{REQUEST_FILENAME}" 
               pattern="\.(ico|png|svg)$" />
        </conditions>
        <action type="Rewrite" value="public, max-age=31536000, immutable" />
      </rule>
    </outboundRules>
  </system.webServer>
</configuration>

// Express.js favicon caching
const express = require('express');
const app = express();

// Static files with caching
app.use(express.static('public', {
  maxAge: '1y', // 1 year
  immutable: true,
  setHeaders: (res, path) => {
    if (path.match(/\.(ico|png|svg|webmanifest)$/)) {
      res.setHeader('Cache-Control', 'public, max-age=31536000, immutable');
    }
  }
}));

// Or specific route
app.get('/favicon.ico', (req, res) => {
  res.set('Cache-Control', 'public, max-age=31536000, immutable');
  res.sendFile(__dirname + '/public/favicon.ico');
});