🐛 [Bug]: Static server in sub app does not work

[lephattan]

Question Description

I am trying to set app a static server in a sub app, but it does not seem to work.
The problem can be reproduced with the snippet below.

Project struture:

tree .
#.
#├── go.mod
#├── go.sum
#├── main.go
#└── public
#    └── test.txt

Tests:

cat public/test.txt
# test

curl http://127.0.0.1:3000/
# Hello, world!%

curl http://127.0.0.1:3000/public/test.txt
# test

curl http://127.0.0.1:3000/subApp
# Hello from subApp%

curl http://127.0.0.1:3000/subApp/public/test.txt
# Cannot GET /subApp/public/test.txt%

Code Snippet (optional)

package main

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

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

	app.Static("/public", "./public")

	app.Get("/", func(c *fiber.Ctx) error {
		return c.SendString("Hello, world!")
	})

	subApp := fiber.New()
	subApp.Use(logger)

	subApp.Static("/public", "./public")

	subApp.Get("/", func(c *fiber.Ctx) error {
		return c.SendString("Hello from subApp")
	})

	app.Mount("/subApp", subApp)
	app.Listen(":3000")
}

Checklist:

• I agree to follow Fiber's Code of Conduct.
• I have checked for existing issues that describe my questions prior to opening this one.
• I understand that improperly formatted questions may be closed without explanation.

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[ReneWerner87]

thx for sharing, which version do you use?

[lephattan]

@ReneWerner87 I am using fiber v2.52.5 with go 1.23.0

thx for sharing, which version do you use?

[Skyenought]

fiber/router.go

Line 404 in 6e74114

fileHandler(c.fasthttp)

@ReneWerner87
I found that when using mount, although the expected path of fs.root is correct, the result of fasthttp ctx.Path is '/' and '/public', which causes the access path to change from public to public/public, which is the reason for this bug.

fs := &fasthttp.FS{
	Root:                 root,

https://github.com/valyala/fasthttp/blob/c3050516d957b5bf75b353683c50302e4f955c6b/fs.go#L1074

// expect: ctx.Path ="/" filepath = "E:\projects_go\server\public"
// fact: ctx.Path = "/public" filepath = "E:\projects_go\server\public\public" 
ff, err = h.openFSFile(filePath, mustCompress, fileEncoding)

[yinheli]

Same issue for me. So I submit a PR.