fiber/middleware/proxy

Proxy

Proxy middleware for Fiber that allows you to proxy requests to multiple servers.

Table of Contents

• Signatures
• Examples
• Config
• Default Config

Signatures

// Balancer create a load balancer among multiple upstrem servers.
func Balancer(config Config) fiber.Handler
// Forward performs the given http request and fills the given http response.
func Forward(addr string, clients ...*fasthttp.Client) fiber.Handler
// Do performs the given http request and fills the given http response.
func Do(c *iber.Ctx, addr string, clients ...*fasthttp.Client) error
// DomainForward the given http request based on the given domain and fills the given http response
func DomainForward(hostname string, addr string, clients ...*fasthttp.Client) fiber.Handler
// BalancerForward performs the given http request based round robin balancer and fills the given http response
func BalancerForward(servers []string, clients ...*fasthttp.Client) fiber.Handler

Examples

Import the middleware package that is part of the Fiber web framework

import (
 "github.com/gofiber/fiber/v3"
 "github.com/gofiber/fiber/v3/middleware/proxy"
)

After you initiate your Fiber app, you can use the following possibilities:

// if target https site uses a self-signed certificate, you should
// call WithTlsConfig before Do and Forward
proxy.WithTlsConfig(&tls.Config{
    InsecureSkipVerify: true,
})

// if you need to use global self-custom client, you should use proxy.WithClient.
proxy.WithClient(&fasthttp.Client{
 NoDefaultUserAgentHeader: true, 
 DisablePathNormalizing:   true,
})

// Forward to url
app.Get("/gif", proxy.Forward("https://i.imgur.com/IWaBepg.gif"))

// If you want to forward with a specific domain. You have to use proxy.DomainForward.
app.Get("/payments", proxy.DomainForward("docs.gofiber.io", "http://localhost:8000"))

// Forward to url with local custom client
app.Get("/gif", proxy.Forward("https://i.imgur.com/IWaBepg.gif", &fasthttp.Client{
 NoDefaultUserAgentHeader: true, 
 DisablePathNormalizing:   true,
}))

// Make request within handler
app.Get("/:id", func(c fiber.Ctx) error {
 url := "https://i.imgur.com/"+c.Params("id")+".gif"
 if err := proxy.Do(c, url); err != nil {
  return err
 }
 // Remove Server header from response
 c.Response().Header.Del(fiber.HeaderServer)
 return nil
})

// Minimal round robin balancer
app.Use(proxy.Balancer(proxy.Config{
 Servers: []string{
  "http://localhost:3001",
  "http://localhost:3002",
  "http://localhost:3003",
 },
}))

// Or extend your balancer for customization
app.Use(proxy.Balancer(proxy.Config{
 Servers: []string{
  "http://localhost:3001",
  "http://localhost:3002",
  "http://localhost:3003",
 },
 ModifyRequest: func(c fiber.Ctx) error {
  c.Request().Header.Add("X-Real-IP", c.IP())
  return nil
 },
 ModifyResponse: func(c fiber.Ctx) error {
  c.Response().Header.Del(fiber.HeaderServer)
  return nil
 },
}))

// Or this way if the balancer is using https and the destination server is only using http.
app.Use(proxy.BalancerForward([]string{
  "http://localhost:3001",
  "http://localhost:3002",
  "http://localhost:3003",
}))

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

 // Servers defines a list of <scheme>://<host> HTTP servers,
 //
 // which are used in a round-robin manner.
 // i.e.: "https://foobar.com, http://www.foobar.com"
 //
 // Required
 Servers []string

 // ModifyRequest allows you to alter the request
 //
 // Optional. Default: nil
 ModifyRequest fiber.Handler

 // ModifyResponse allows you to alter the response
 //
 // Optional. Default: nil
 ModifyResponse fiber.Handler
 
 // Timeout is the request timeout used when calling the proxy client
 //
 // Optional. Default: 1 second
 Timeout time.Duration

 // Per-connection buffer size for requests' reading.
 // This also limits the maximum header size.
 // Increase this buffer if your clients send multi-KB RequestURIs
 // and/or multi-KB headers (for example, BIG cookies).
 ReadBufferSize int
    
 // Per-connection buffer size for responses' writing.
 WriteBufferSize int

 // tls config for the http client.
 TlsConfig *tls.Config 
 
 // Client is custom client when client config is complex. 
 // Note that Servers, Timeout, WriteBufferSize, ReadBufferSize and TlsConfig 
 // will not be used if the client are set.
 Client *fasthttp.LBClient
}

Default Config

// ConfigDefault is the default config
var ConfigDefault = Config{
    Next:           nil,
    ModifyRequest:  nil,
    ModifyResponse: nil,
    Timeout:        fasthttp.DefaultLBClientTimeout,
}