🐛 Can't get added header by proxy

[jney]

Fiber version

v2.1.0

Issue description

Can't get the added header by proxy in targeted server.
Look at the following code, I can't get "test" header.

Code snippet

	app := fiber.New()

	app.Use(compress.New())
	app.Use(cors.New(cors.Config{AllowCredentials: true}))

	app.Use(proxy.Balancer(proxy.Config{
		Servers: []string{"http://localhost:9090"},
		ModifyRequest: func(c *fiber.Ctx) error {
			c.Set("test", "ok")
			return nil
		},
	}))

	app.Listen(":8888")

in targeted server

c.Get("test") // returns ""

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[Fenny]

Quick question, are you testing this with CORS requests specifically?

[jney]

Hi @Fenny , I tested without it too, same result. I should have removed it from example to avoid confusion.

You can try it with this very minimal code:

proxy:

package main

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

func main() {
	app := fiber.New()

	app.Use(proxy.Balancer(proxy.Config{
		Servers: []string{
			"http://localhost:8001",
		},
		ModifyRequest: func(c *fiber.Ctx) error {
			c.Set("hello", "world")
			return nil
		},
	}))

	app.Listen(":8000")
}

server:

package main

import "github.com/gofiber/fiber/v2"

func main() {
	app := fiber.New()

	app.All("/*", func(c *fiber.Ctx) error {
		return c.SendString("hello "+c.Get("hello"))
	})

	app.Listen(":8001")
}

run both, then curl 'http://0.0.0.0:8000/': still empty header

[jney]

I figured out. It looks like I have to use c.Request().Header.Add instead of c.Set.
Maybe is it me, or the README is confusing?

[Fenny]

I will update the example 👍