MVC how to use multiple Handler?

[NextGringo]

Hi, I can't finde any info about how to use multiple handler for a function in a controller.

I would like to use for some routes(funcs) a pre handler func, that checks if a user is loggedIn and load then the needed Informations, else it should Skip the next handler and use the next after it.

Is there a possibility for that? Or need I code that all now in one handle?

[krokite]

Yes, It is possible with Iris.

You need to Create and Use "Middleware" for that.

[NextGringo]

Is there no direct or simpler method? Because I think the middelware is inappropriate for my purposes, but it wouldn't be nice to have to go back to the non-MVC-style for some paths.

[praeto]

You can override BeginRequest for your mvc controller and add some handlers to the context.
Same for mvc route, if you need to execute a handler before your main code you can wrap it into a handler and use AddHandler.

[NextGringo]

@praeto are you abel to show me a example, because i get with my try only a panic

[NextGringo]

// BeginRequest saves login state to the context, the user id.
func (c *MyController) BeginRequest(ctx iris.Context) {
	c.Ctx.AddHandler(func(ctx2 iris.Context) { // LINE 21
		userID, err := ctx2.Params().GetInt64("user")
		if err != nil {
			logR.Println(err.Error())
		}
		if userID > 0 {
			logR.Println(userID, "Erfolgreich")
		}
	})
}

./server
[WARN] 2017/09/19 10:11 Recovered from a route's Handler('MyProject/vendor/github.com/kataras/iris/mvc/activator.TController.HandlerOf.func1')
At Request: 200 /_external/payment/information/via/paypal GET 127.0.0.1
Trace: runtime error: invalid memory address or nil pointer dereference

/Go/src/runtime/asm_amd64.s:509
/Go/src/runtime/panic.go:491
/Go/src/runtime/panic.go:63
/Go/src/runtime/signal_unix.go:367
/GoProjects/src/MyProject/routes/MyController.go:21
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/mvc/activator/activator.go:136
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/context/context.go:824
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/context/context.go:1036
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/middleware/logger/logger.go:50
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/middleware/logger/logger.go:31
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/context/context.go:824
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/context/context.go:1036
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/middleware/recover/recover.go:56
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/context/context.go:837
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/context/context.go:979
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/core/router/handler.go:216
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/core/router/router.go:70
/GoProjects/src/MyProject/vendor/github.com/kataras/iris/core/router/router.go:147
/Go/src/net/http/server.go:2619
/Go/src/net/http/server.go:1801
/Go/src/runtime/asm_amd64.s:2337

[praeto]

@NextGringo, you should first call default BeginRequest
for example:

// BeginRequest saves login state to the context, the user id.
func (c *MyController) BeginRequest(ctx iris.Context) {
        c.Controller.BeginRequest(ctx)
	c.Ctx.AddHandler(func(ctx2 iris.Context) { // LINE 21
		userID, err := ctx2.Params().GetInt64("user")
		if err != nil {
			logR.Println(err.Error())
		}
		if userID > 0 {
			logR.Println(userID, "Erfolgreich")
		}
	})
}

[praeto]

@NextGringo, sorry, I forgot to mention that after adding handlers you should call them

func (c *MyController) BeginRequest(ctx iris.Context) {
        c.Controller.BeginRequest(ctx) // <- call default BeginRequest
	c.Ctx.AddHandler(...)
	c.Ctx.Next() // <- call first handler
} 

[NextGringo]

ok, now it works.
Thanks.

[kataras]

BeginRequest is a good abstraction but you can use an easier way, which is documented as well; You could just pass the handlers you want with app.Controller("/path", new(Controller), handler1, handler2, handler3) those three handlers will be executed before "/path" controller.