Théotime Lévêque 1cddc56f13
Cache middleware: Store e2e headers. (#1807)
*  Cache middleware: Store e2e headers.

As defined in RFC2616 - section-13.5.1, shared caches MUST
store end-to-end headers from backend response and MUST be
transmitted in any response formed from a cache entry.

This commit ensures a stronger consistency between responses
served from the handlers & from the cache middleware.

*  Cache middleware: Add flag for e2e headers.

Set flag to prevent e2e headers caching to
be the default behavior of the cache middleware.
This would otherwise change quite a lot the
experience for cache middleware current users.

*  Cache middleware: Add Benchmark for additionalHeaders feature.

*  Cache middleware: Rename E2Eheaders into StoreResponseHeaders.

E2E is an acronym commonly associated with test.
While in the present case it refers to end-to-end
HTTP headers (by opposition to hop-by-hop), this
still remains confusing. This commits renames it
to a more generic name.

*  Cache middleware: Update README

*  Cache middleware: Move map instanciation.

This will prevent an extra memory allocation for users
not interested in this feature.

*  Cache middleware: Prevent memory allocation when StoreResponseHeaders is disabled.

*  Cache middleware: Store e2e headers. #1807
- use set instead of add for the headers
- copy value from the headers -> prevent problems with mutable values

Co-authored-by: wernerr <rene@gofiber.io>
2022-03-08 10:18:04 +01:00
..

Cache Middleware

Cache middleware for Fiber designed to intercept responses and cache them. This middleware will cache the Body, Content-Type and StatusCode using the c.Path() (or a string returned by the Key function) as unique identifier. Special thanks to @codemicro for creating this middleware for Fiber core!

Table of Contents

Signatures

func New(config ...Config) fiber.Handler

Examples

First import the middleware from Fiber,

import (
  "github.com/gofiber/fiber/v2"
  "github.com/gofiber/fiber/v2/middleware/cache"
)

Then create a Fiber app with app := fiber.New().

Default Config

app.Use(cache.New())

Custom Config

app.Use(cache.New(cache.Config{
	Next: func(c *fiber.Ctx) bool {
		return c.Query("refresh") == "true"
	},
	Expiration: 30 * time.Minute,
	CacheControl: true,
}))

Custom Cache Key Or Expiration

app.Use(New(Config{
	ExpirationGenerator: func(c *fiber.Ctx, cfg *Config) time.Duration {
		newCacheTime, _ := strconv.Atoi(c.GetRespHeader("Cache-Time", "600"))
		return time.Second * time.Duration(newCacheTime)
	},
	KeyGenerator: func(c *fiber.Ctx) string {
		return utils.CopyString(c.Path())
	}
}))

app.Get("/", func(c *fiber.Ctx) error {
	c.Response().Header.Add("Cache-Time", "6000")
	return c.SendString("hi")
})

Config

// Config defines the config for middleware.
type Config struct {
	// Next defines a function to skip this middleware when returned true.
	//
	// Optional. Default: nil
	Next func(c *fiber.Ctx) bool

	// Expiration is the time that an cached response will live
	//
	// Optional. Default: 1 * time.Minute
	Expiration time.Duration

	// CacheHeader header on response header, indicate cache status, with the following possible return value
	//
	// hit, miss, unreachable
	//
	// Optional. Default: X-Cache
	CacheHeader string

	// CacheControl enables client side caching if set to true
	//
	// Optional. Default: false
	CacheControl bool

	// Key allows you to generate custom keys, by default c.Path() is used
	//
	// Default: func(c *fiber.Ctx) string {
	//   return utils.CopyString(c.Path())
	// }
	KeyGenerator func(*fiber.Ctx) string

	// allows you to generate custom Expiration Key By Key, default is Expiration (Optional)
	//
	// Default: nil
	ExpirationGenerator func(*fiber.Ctx, *Config) time.Duration

	// Store is used to store the state of the middleware
	//
	// Default: an in memory store for this process only
	Storage fiber.Storage

	// allows you to store additional headers generated by next middlewares & handler
	//
	// Default: false
	StoreResponseHeaders bool
}

Default Config

// ConfigDefault is the default config
var ConfigDefault = Config{
	Next:         nil,
	Expiration:   1 * time.Minute,
	CacheHeader:  "X-Cache",
	CacheControl: false,
	KeyGenerator: func(c *fiber.Ctx) string {
		return utils.CopyString(c.Path())
	},
	ExpirationGenerator : nil,
	StoreResponseHeaders: false,
	Storage:      nil,
}