Cache

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Overview

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Installation

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

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Quick Start

app := mizu.New()

// Cache for 1 hour
app.Use(cache.New(time.Hour))

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Configuration

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Examples

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Basic Caching

// Cache for 1 hour
app.Use(cache.New(time.Hour))

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Public Cache (CDN)

// Allow CDN caching
app.Get("/static/*", staticHandler, cache.Public(24*time.Hour))

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Private Cache (Browser Only)

// User-specific data, browser only
app.Get("/profile", profileHandler, cache.Private(time.Hour))

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Immutable Assets

// Never changes (versioned assets)
app.Get("/assets/*", assetHandler, cache.Immutable(365*24*time.Hour))

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Stale-While-Revalidate

// Serve stale for 1 hour while revalidating
app.Get("/api/feed", feedHandler, cache.SWR(time.Minute, time.Hour))

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Full Configuration

app.Use(cache.WithOptions(cache.Options{
    MaxAge:               time.Hour,
    SMaxAge:              24 * time.Hour,
    Public:               true,
    MustRevalidate:       true,
    StaleWhileRevalidate: 10 * time.Minute,
}))

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Different Cache Strategies

// API: Short cache with revalidation
api := app.Group("/api")
api.Use(cache.SWR(time.Minute, 5*time.Minute))

// Static: Long cache, immutable
static := app.Group("/static")
static.Use(cache.Immutable(365*24*time.Hour))

// Private data: Browser only
private := app.Group("/user")
private.Use(cache.Private(5*time.Minute))

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API Reference

func New(maxAge time.Duration) mizu.Middleware
func WithOptions(opts Options) mizu.Middleware
func Public(maxAge time.Duration) mizu.Middleware
func Private(maxAge time.Duration) mizu.Middleware
func Immutable(maxAge time.Duration) mizu.Middleware
func Static(maxAge time.Duration) mizu.Middleware
func SWR(maxAge, stale time.Duration) mizu.Middleware

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Common Patterns

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Technical Details

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Implementation

1. Header Construction: Uses the buildCacheControl function to build the Cache-Control header string from the Options struct
2. Non-Overriding Behavior: Only sets the Cache-Control header if it hasn’t been set by the handler or previous middleware
3. Default Fallback: Returns no-cache when no options are specified
4. Time Conversion: Converts Go time.Duration values to seconds for cache directives (max-age, s-maxage, etc.)

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Cache-Control Directives

• public: Response may be cached by any cache (browsers, CDNs, proxies)
• private: Response is intended for a single user and should only be cached by the browser
• no-cache: Cache must revalidate with the origin server before using cached content
• no-store: Response must not be stored in any cache
• no-transform: Intermediaries must not transform the response (e.g., image compression)
• must-revalidate: Cache must verify the status of stale resources and expired ones should not be used
• proxy-revalidate: Same as must-revalidate but only for shared caches
• max-age=N: Maximum time (in seconds) a resource is considered fresh
• s-maxage=N: Overrides max-age for shared caches (CDNs, proxies)
• immutable: Resource will never change during its freshness lifetime
• stale-while-revalidate=N: Cache may serve stale content while revalidating in the background
• stale-if-error=N: Cache may serve stale content if an error occurs during revalidation

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Helper Functions

• New(maxAge): Basic caching with max-age
• Public(maxAge): Public caching with max-age
• Private(maxAge): Private caching with max-age
• Immutable(maxAge): Immutable public content with max-age
• Static(maxAge): Alias for Immutable, suitable for static assets
• SWR(maxAge, stale): Stale-while-revalidate pattern for improved perceived performance

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Best Practices

1. Use appropriate cache strategies for different content types
2. Leverage stale-while-revalidate for improved user experience
3. Set immutable for versioned static assets
4. Use private for user-specific data
5. Combine with CDN using s-maxage for better edge caching

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Testing

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Security Considerations

• Sensitive data: Always use private or no-store for sensitive information
• User-specific content: Never use public for personalized data
• Authentication: Consider using no-cache or no-store for authenticated routes

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Related Middlewares

• nocache - Prevent caching