iris/_examples/beginner/routing/basic/main.go

package main

import (
	"github.com/kataras/iris"
	"github.com/kataras/iris/context"
)

func main() {
	app := iris.New()

	// registers a custom handler for 404 not found http (error) status code,
	// fires when route not found or manually by ctx.StatusCode(iris.StatusNotFound).
	app.OnErrorCode(iris.StatusNotFound, notFoundHandler)

	// GET -> HTTP Method
	// / -> Path
	// func(ctx context.Context) -> The route's handler.
	//
	// Third receiver should contains the route's handler(s), they are executed by order.
	app.Handle("GET", "/", func(ctx context.Context) {
		// navigate to the middle of $GOPATH/src/github.com/kataras/iris/context/context.go
		// to overview all context's method (there a lot of them, read that and you will learn how iris works too)
		ctx.HTML("Hello from " + ctx.Path()) // Hello from /
	})

	app.Get("/home", func(ctx context.Context) {
		ctx.Writef(`Same as app.Handle("GET", "/", [...])`)
	})

	app.Get("/donate", donateHandler, donateFinishHandler)

	// Pssst, don't forget dynamic-path example for more "magic"!
	app.Get("/api/users/{userid:int min(1)}", func(ctx context.Context) {
		userID, err := ctx.Params().GetInt("userid")

		if err != nil {
			ctx.Writef("error while trying to parse userid parameter," +
				"this will never happen if :int is being used because if it's not integer it will fire Not Found automatically.")
			ctx.StatusCode(iris.StatusBadRequest)
			return
		}

		ctx.JSON(map[string]interface{}{
			// you can pass any custom structured go value of course.
			"user_id": userID,
		})
	})
	// app.Post("/", func(ctx context.Context){}) -> for POST http method.
	// app.Put("/", func(ctx context.Context){})-> for "PUT" http method.
	// app.Delete("/", func(ctx context.Context){})-> for "DELETE" http method.
	// app.Options("/", func(ctx context.Context){})-> for "OPTIONS" http method.
	// app.Trace("/", func(ctx context.Context){})-> for "TRACE" http method.
	// app.Head("/", func(ctx context.Context){})-> for "HEAD" http method.
	// app.Connect("/", func(ctx context.Context){})-> for "CONNECT" http method.
	// app.Patch("/", func(ctx context.Context){})-> for "PATCH" http method.
	// app.Any("/", func(ctx context.Context){}) for all http methods.

	// More than one route can contain the same path with a different http mapped method.
	// You can catch any route creation errors with:
	// route, err := app.Get(...)
	// set a name to a route: route.Name = "myroute"

	// You can also group routes by path prefix, sharing middleware(s) and done handlers.

	adminRoutes := app.Party("/admin", adminMiddleware)

	adminRoutes.Done(func(ctx context.Context) { // executes always last if ctx.Next()
		ctx.Application().Log("response sent to " + ctx.Path())
	})
	// adminRoutes.Layout("/views/layouts/admin.html") // set a view layout for these routes, see more at intermediate/view examples.

	// GET: http://localhost:8080/admin
	adminRoutes.Get("/", func(ctx context.Context) {
		// [...]
		ctx.StatusCode(iris.StatusOK) // default is 200 == iris.StatusOK
		ctx.HTML("<h1>Hello from admin/</h1>")

		ctx.Next() // in order to execute the party's "Done" Handler(s)
	})

	// GET: http://localhost:8080/admin/login
	adminRoutes.Get("/login", func(ctx context.Context) {
		// [...]
	})
	// POST: http://localhost:8080/admin/login
	adminRoutes.Post("/login", func(ctx context.Context) {
		// [...]
	})

	// subdomains, easier than ever, should add localhost or 127.0.0.1 into your hosts file,
	// etc/hosts on unix or C:/windows/system32/drivers/etc/hosts on windows.
	v1 := app.Party("v1.")
	{ // braces are optional, it's just type of style, to group the routes visually.

		// http://v1.localhost:8080
		v1.Get("/", func(ctx context.Context) {
			ctx.HTML("Version 1 API. go to <a href='" + ctx.Path() + "/api" + "'>/api/users</a>")
		})

		usersAPI := v1.Party("/api/users")
		{
			// http://v1.localhost:8080/api/users
			usersAPI.Get("/", func(ctx context.Context) {
				ctx.Writef("All users")
			})
			// http://v1.localhost:8080/api/users/42
			usersAPI.Get("/{userid:int}", func(ctx context.Context) {
				ctx.Writef("user with id: %s", ctx.Params().Get("userid"))
			})
		}
	}

	// wildcard subdomains.
	wildcardSubdomain := app.Party("*.")
	{
		wildcardSubdomain.Get("/", func(ctx context.Context) {
			ctx.Writef("Subdomain can be anything, now you're here from: %s", ctx.Subdomain())
		})
	}

	// http://localhost:8080
	// http://localhost:8080/home
	// http://localhost:8080/donate
	// http://localhost:8080/api/users/42
	// http://localhost:8080/admin
	// http://localhost:8080/admin/login
	//
	// http://localhost:8080/api/users/0
	// http://localhost:8080/api/users/blabla
	// http://localhost:8080/wontfound
	//
	// if hosts edited:
	//  http://v1.localhost:8080
	//  http://v1.localhost:8080/api/users
	//  http://v1.localhost:8080/api/users/42
	//  http://anything.localhost:8080
	app.Run(iris.Addr(":8080"))
}

func adminMiddleware(ctx context.Context) {
	// [...]
	ctx.Next() // to move to the next handler, or don't that if you have any auth logic.
}

func donateHandler(ctx context.Context) {
	ctx.Writef("Just like an inline handler, but it can be " +
		"used by other package, anywhere in your project.")

	// let's pass a value to the next handler
	// Values is the way handlers(or middleware) are communicating between each other.
	ctx.Values().Set("donate_url", "https://github.com/kataras/iris#buy-me-a-cup-of-coffee")
	ctx.Next() // in order to execute the next handler in the chain, look donate route.
}

func donateFinishHandler(ctx context.Context) {
	// values can be any type of object so we could cast the value to a string
	// but Iris provides an easy to do that, if donate_url is not defined, then it returns an empty string instead.
	donateURL := ctx.Values().GetString("donate_url")
	ctx.Application().Log("donate_url value was: " + donateURL)
	ctx.Writef("\n\nDonate sent(?).")
}

func notFoundHandler(ctx context.Context) {
	ctx.HTML("Custom route for 404 not found http code, here you can render a view, html, json <b>any valid response</b>.")
}

// Notes:
// A path parameter name should contain only alphabetical letters, symbols, containing '_' and numbers are NOT allowed.
// If route failed to be registered, the app will panic without any warnings
// if you didn't catch the second return value(error) on .Handle/.Get....