Cookies: Ability to set custom cookie encoders to encode the cookie's…

… value before sent by `ctx.SetCookie` and `ctx.SetCookieKV` and cookie decoders to decode the cookie's value when retrieving from `ctx.GetCookie`. That was the second and final part relative to a community's question at: #1018

_examples/README.md

@@ -398,6 +398,7 @@ iris cache library lives on its own [package](https://github.com/kataras/iris/tr
 ### Cookies
 
 - [Basic](cookies/basic/main.go)
+- [Encode/Decode (securecookie)](cookies/securecookie/main.go)
 
 ### Sessions
 

_examples/README_ZH.md

@@ -397,6 +397,7 @@ Iris 独立缓存包 [package](https://github.com/kataras/iris/tree/master/cache
 ### Cookies
 
 - [Basic](cookies/basic/main.go)
+- [Encode/Decode (securecookie)](cookies/securecookie/main.go)
 
 ### Sessions
 

_examples/cookies/securecookie/main.go

@@ -0,0 +1,59 @@
+package main
+
+// developers can use any library to add a custom cookie encoder/decoder.
+// At this example we use the gorilla's securecookie package:
+// $ go get github.com/gorilla/securecookie
+// $ go run main.go
+
+import (
+	"github.com/kataras/iris"
+
+	"github.com/gorilla/securecookie"
+)
+
+var (
+	// AES only supports key sizes of 16, 24 or 32 bytes.
+	// You either need to provide exactly that amount or you derive the key from what you type in.
+	hashKey  = []byte("the-big-and-secret-fash-key-here")
+	blockKey = []byte("lot-secret-of-characters-big-too")
+	sc       = securecookie.New(hashKey, blockKey)
+)
+
+func newApp() *iris.Application {
+	app := iris.New()
+
+	// Set A Cookie.
+	app.Get("/cookies/{name}/{value}", func(ctx iris.Context) {
+		name := ctx.Params().Get("name")
+		value := ctx.Params().Get("value")
+
+		ctx.SetCookieKV(name, value, iris.CookieEncode(sc.Encode)) // <--
+
+		ctx.Writef("cookie added: %s = %s", name, value)
+	})
+
+	// Retrieve A Cookie.
+	app.Get("/cookies/{name}", func(ctx iris.Context) {
+		name := ctx.Params().Get("name")
+
+		value := ctx.GetCookie(name, iris.CookieDecode(sc.Decode)) // <--
+
+		ctx.WriteString(value)
+	})
+
+	// Delete A Cookie.
+	app.Delete("/cookies/{name}", func(ctx iris.Context) {
+		name := ctx.Params().Get("name")
+
+		ctx.RemoveCookie(name) // <--
+
+		ctx.Writef("cookie %s removed", name)
+	})
+
+	return app
+}
+
+func main() {
+	app := newApp()
+	app.Run(iris.Addr(":8080"))
+}

_examples/cookies/securecookie/main_test.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/kataras/iris/httptest"
+)
+
+func TestCookiesBasic(t *testing.T) {
+	app := newApp()
+	e := httptest.New(t, app, httptest.URL("http://example.com"))
+
+	cookieName, cookieValue := "my_cookie_name", "my_cookie_value"
+
+	// Test Set A Cookie.
+	t1 := e.GET(fmt.Sprintf("/cookies/%s/%s", cookieName, cookieValue)).Expect().Status(httptest.StatusOK)
+	// note that this will not work because it doesn't always returns the same value:
+	// cookieValueEncoded, _ := sc.Encode(cookieName, cookieValue)
+	t1.Cookie(cookieName).Value().NotEqual(cookieValue) // validate cookie's existence and value is not on its raw form.
+	t1.Body().Contains(cookieValue)
+
+	// Test Retrieve A Cookie.
+	t2 := e.GET(fmt.Sprintf("/cookies/%s", cookieName)).Expect().Status(httptest.StatusOK)
+	t2.Body().Equal(cookieValue)
+
+	// Test Remove A Cookie.
+	t3 := e.DELETE(fmt.Sprintf("/cookies/%s", cookieName)).Expect().Status(httptest.StatusOK)
+	t3.Body().Contains(cookieName)
+
+	t4 := e.GET(fmt.Sprintf("/cookies/%s", cookieName)).Expect().Status(httptest.StatusOK)
+	t4.Cookies().Empty()
+	t4.Body().Empty()
+}