Added as simple callback with the filter object so it can be dynamically changed

ipfilter.go

@@ -24,6 +24,11 @@ type Config struct {
 
 	// Block by default.
 	BlockByDefault bool
+
+	// called with the newly created filter object to allow for
+	// controlling the filter during runtime.
+	// The underlying filter implementation is thankfully threadsafe
+	CreatedFilter func(*ipfilter.IPFilter)
 }
 
 // DefaultConfig is the default IPFilter middleware config
@@ -55,7 +60,9 @@ func MiddlewareWithConfig(config Config) echo.MiddlewareFunc {
 		BlockByDefault: config.BlockByDefault,
 		Logger:         nil,
 	})
-
+	if config.CreatedFilter != nil {
+		config.CreatedFilter(filter)
+	}
 	return func(next echo.HandlerFunc) echo.HandlerFunc {
 		return func(c echo.Context) error {
 			if config.Skipper(c) {

ipfilter_test.go

@@ -7,6 +7,7 @@ import (
 	"testing"
 
 	ipfilter "github.com/crazy-max/echo-ipfilter"
+	jpillorafilter "github.com/jpillora/ipfilter"
 	"github.com/labstack/echo/v4"
 )
 
@@ -94,6 +95,36 @@ func TestMiddlewareWithConfig(t *testing.T) {
 			ip:  "10.1.4.1:80",
 			err: nil,
 		},
+		{
+			name: "dynamically allowed by whitelist",
+			config: ipfilter.Config{
+				WhiteList: []string{
+					"10.1.2.0/24",
+					// this will be dynamically added "10.1.4.0/24",
+				},
+				BlockByDefault: true,
+				CreatedFilter: func(filter *jpillorafilter.IPFilter) {
+					filter.AllowIP("10.1.4.0/24")
+				},
+			},
+			ip:  "10.1.4.1:80",
+			err: nil,
+		},
+		{
+			name: "dynamically allowed by whitelist",
+			config: ipfilter.Config{
+				WhiteList: []string{
+					"10.1.2.0/24", // will be dynamicaly blocked
+					"10.1.4.0/24",
+				},
+				BlockByDefault: true,
+				CreatedFilter: func(filter *jpillorafilter.IPFilter) {
+					filter.BlockIP("10.1.2.0/24")
+				},
+			},
+			ip:  "10.1.2.7:80",
+			err: echo.NewHTTPError(http.StatusForbidden, fmt.Sprintf("IP address %s not allowed", "10.1.2.7")),
+		},
 	}
 
 	for _, tt := range cases {