New Context.SetLogoutFunc/Logout and SetFunc/CallFunc methods

Read HISTORY.md

_examples/routing/writing-a-middleware/share-funcs/main.go

@@ -0,0 +1,109 @@
+// Package main shows how you can share a
+// function between handlers of the same chain.
+// Note that, this case is very rarely used and it exists,
+// mostly, for 3rd-party middleware creators.
+//
+// The middleware creator registers a dynamic function by Context.SetFunc and
+// the route handler just needs to call Context.CallFunc(funcName, arguments),
+// without knowning what is the specific middleware's implementation or who was the creator
+// of that function, it may be a basicauth middleware's logout or session's logout.
+//
+// See Context.SetLogoutFunc and Context.Logout methods too (these are not covered here).
+package main
+
+import (
+	"fmt"
+
+	"github.com/kataras/iris/v12"
+)
+
+func main() {
+	app := newApp()
+
+	// GET: http://localhost:8080
+	app.Listen(":8080")
+}
+
+func newApp() *iris.Application {
+	app := iris.New()
+	app.Use(middleware)
+	// OR app.UseRouter(middleware)
+	// to register it everywhere,
+	// including the HTTP errors.
+
+	app.Get("/", handler)
+	app.Get("/2", middleware2, handler2)
+	app.Get("/3", middleware3, handler3)
+
+	return app
+}
+
+// Assume: this is a middleware which does not export
+// the 'hello' function for several reasons
+// but we offer a 'greeting' optional feature to the route handler.
+func middleware(ctx iris.Context) {
+	ctx.SetFunc("greet", hello)
+	ctx.Next()
+}
+
+// Assume: this is a handler which needs to "greet" the client but
+// the function for that job is not predictable,
+// it may change - dynamically (SetFunc) - depending on
+// the middlewares registered before this route handler.
+// E.g. it may be a "Hello $name" or "Greetings $Name".
+func handler(ctx iris.Context) {
+	outputs, err := ctx.CallFunc("greet", "Gophers")
+	if err != nil {
+		ctx.StopWithError(iris.StatusInternalServerError, err)
+		return
+	}
+
+	response := outputs[0].Interface().(string)
+	ctx.WriteString(response)
+}
+
+func middleware2(ctx iris.Context) {
+	ctx.SetFunc("greet", sayHello)
+	ctx.Next()
+}
+
+func handler2(ctx iris.Context) {
+	_, err := ctx.CallFunc("greet", "Gophers [2]")
+	if err != nil {
+		ctx.StopWithError(iris.StatusInternalServerError, err)
+		return
+	}
+}
+
+func middleware3(ctx iris.Context) {
+	ctx.SetFunc("job", function3)
+	ctx.Next()
+}
+
+func handler3(ctx iris.Context) {
+	_, err := ctx.CallFunc("job")
+	if err != nil {
+		ctx.StopWithError(iris.StatusInternalServerError, err)
+		return
+	}
+
+	ctx.WriteString("OK, job was executed.\nSee the command prompt.")
+}
+
+/*
+| ------------------------ |
+| function implementations |
+| ------------------------ |
+*/
+
+func hello(name string) string {
+	return fmt.Sprintf("Hello, %s!", name)
+}
+
+func sayHello(ctx iris.Context, name string) {
+	ctx.WriteString(hello(name))
+}
+
+func function3() {
+	fmt.Printf("function3 called\n")
+}