howood/imagereductor

package custommiddleware

import (
    "net"
    "os"
    "strings"

    "github.com/labstack/echo/v4"
)

// IPRestriction permit access by IP address
func IPRestriction() echo.MiddlewareFunc {
    return func(next echo.HandlerFunc) echo.HandlerFunc {
        return func(c echo.Context) error {
            if os.Getenv("TOKENAPI_ALLOW_IPS") == "" {
                return next(c)
            }
            allowIPs := strings.Split(os.Getenv("TOKENAPI_ALLOW_IPS"), ",")
            requestIP := net.ParseIP(c.RealIP())
            for _, ip := range allowIPs {
                _, ipnet, err := net.ParseCIDR(ip)
                if err != nil {
                    return err
                }
                if ipnet.Contains(requestIP) {
                    return next(c)
                }
            }
            return echo.ErrUnauthorized
        }
    }
}