authelia/internal/middlewares/strip_path.go

package middlewares

import (
	"strings"

	"github.com/valyala/fasthttp"
)

// StripPath strips the first level of a path.
func StripPath(path string, next fasthttp.RequestHandler) fasthttp.RequestHandler {
	return func(ctx *fasthttp.RequestCtx) {
		uri := ctx.RequestURI()

		if strings.HasPrefix(string(uri), path) {
			ctx.SetUserValueBytes(UserValueKeyBaseURL, path)

			newURI := strings.TrimPrefix(string(uri), path)
			ctx.Request.SetRequestURI(newURI)
		}

		next(ctx)
	}
}