Favicon

Documentation Index

Fetch the complete documentation index at: https://docs.go-mizu.dev/llms.txt

Use this file to discover all available pages before exploring further.

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Overview

• Serve favicon from memory
• Prevent favicon 404 logs
• Custom favicon handling

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Installation

import "github.com/go-mizu/mizu/middlewares/favicon"

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Quick Start

app := mizu.New()

// Serve favicon from file
app.Use(favicon.New("./static/favicon.ico"))

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Configuration

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Options

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Examples

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From File

app.Use(favicon.New("./static/favicon.ico"))

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From Embedded Data

//go:embed favicon.ico
var faviconData []byte

app.Use(favicon.FromData(faviconData))

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Custom Cache Control

app.Use(favicon.WithOptions(favicon.Options{
    File:         "./static/favicon.ico",
    CacheControl: "public, max-age=86400", // 1 day
}))

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Disable Favicon

// Return empty response for favicon requests
app.Use(favicon.Disabled())

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API Reference

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Functions

// New creates favicon middleware from file
func New(file string) mizu.Middleware

// FromData creates middleware from byte data
func FromData(data []byte) mizu.Middleware

// WithOptions creates middleware with configuration
func WithOptions(opts Options) mizu.Middleware

// Disabled returns empty response for favicon requests
func Disabled() mizu.Middleware

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Behavior

• Caches favicon in memory after first read
• Sets proper Content-Type (image/x-icon)
• Handles both GET and HEAD requests
• Only matches exact /favicon.ico path

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Technical Details

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Implementation

1. Memory Caching: Favicon data is loaded once during middleware initialization and cached in memory for the lifetime of the application.
2. Content Type Detection: Uses http.DetectContentType() to automatically detect the content type from the favicon data. Falls back to image/x-icon if detection returns application/octet-stream or text/plain.
3. File System Support: Supports three data sources:
   • Direct file path using os.ReadFile
   • Embedded data using []byte
   • File system interface (fs.FS) for advanced use cases
4. Request Handling:
   • Only processes requests matching the configured URL path (default: /favicon.ico)
   • Only handles GET and HEAD methods, passes other methods to next handler
   • Sets appropriate headers: Content-Type, Content-Length, and Cache-Control
   • HEAD requests return headers without body
5. Special Behaviors:
   • Empty configuration (no data) returns HTTP 204 No Content
   • SVG middleware supports both /favicon.ico and /favicon.svg paths
   • Redirect middleware returns HTTP 301 Moved Permanently

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Performance Considerations

• Favicon is loaded once at startup (panic on file errors)
• No disk I/O during request handling
• Minimal memory allocation per request
• Early path matching prevents unnecessary processing

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Best Practices

• Use embedded data for portable deployments
• Set long cache duration for production
• Place before other middleware to avoid unnecessary processing

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Testing

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Related Middlewares

• static - Static file serving
• spa - Single Page Application
• cache - Cache headers