new apps/switch (beta)

.gitignore

@@ -1,5 +1,6 @@
 .vscode
 .directory
+coverage.out
 package-lock.json
 go.sum
 node_modules

.travis.yml

@@ -5,6 +5,8 @@ os:
   - linux
   - osx
 go:
+# We support the latest two major Go versions:
+# https://golang.org/doc/devel/release.html
   - 1.14.x
   - 1.15.x
 # - master
@@ -12,6 +14,15 @@ go_import_path: github.com/kataras/iris/v12
 env:
  global:
    - GO111MODULE=on
+addons:
+  hosts:
+    - mydomain.com
+    - www.mydomain.com
+    - myotherdomain.com
+    - mymy.com
+    - testdomain.com
+    - testdomain1.com
+    - testdomain2.com
 install:
   - go get ./...
 script:

apps/apps.go

@@ -0,0 +1,4 @@
+// Package apps is responsible to control many Iris Applications.
+// This package directly imports the iris root package and cannot be used
+// inside Iris' codebase itself. Only external packages/programs can make use of it.
+package apps

apps/switch.go

@@ -0,0 +1,127 @@
+package apps
+
+import (
+	"github.com/kataras/iris/v12"
+)
+
+// Switch returns a new Application
+// with the sole purpose of routing the
+// matched Applications through the provided "cases".
+//
+// The cases are filtered in order of register.
+//
+// Example:
+//  switcher := Switch(Hosts{
+//      "mydomain.com": app,
+//      "test.mydomain.com": testSubdomainApp,
+//      "otherdomain.com": "appName",
+//  })
+//  switcher.Listen(":80")
+//
+// Note that this is NOT a load balancer. The filters
+// are executed by registration order and matched Application
+// handles the request.
+//
+// The returned Switch Application can register routes that will run
+// if no application is matched against the given filters.
+// The returned Switch Application can also register custom error code handlers,
+// e.g. to inject the 404 on not application found.
+// It can also be wrapped with its `WrapRouter` method,
+// which is really useful for logging and statistics.
+func Switch(providers ...SwitchProvider) *iris.Application {
+	if len(providers) == 0 {
+		panic("iris: switch: empty providers")
+	}
+
+	var cases []SwitchCase
+	for _, p := range providers {
+		for _, c := range p.GetSwitchCases() {
+			cases = append(cases, c)
+		}
+	}
+
+	if len(cases) == 0 {
+		panic("iris: switch: empty cases")
+	}
+
+	app := iris.New()
+	// Try to build the cases apps on app.Build/Listen/Run so
+	// end-developers don't worry about it.
+	app.OnBuild = func() error {
+		for _, c := range cases {
+			if err := c.App.Build(); err != nil {
+				return err
+			}
+		}
+		return nil
+	}
+	// If we have a request to support
+	// middlewares in that switcher app then
+	// we can use app.Get("{p:path}"...) instead.
+	app.UseRouter(func(ctx iris.Context) {
+		for _, c := range cases {
+			if c.Filter(ctx) {
+				c.App.ServeHTTP(ctx.ResponseWriter().Naive(), ctx.Request())
+
+				// if c.App.Downgraded() {
+				// 	c.App.ServeHTTP(ctx.ResponseWriter(), ctx.Request())
+				// } else {
+				// Note(@kataras): don't ever try something like that;
+				// the context pool is the switcher's one.
+				// 	ctx.SetApplication(c.App)
+				// 	c.App.ServeHTTPC(ctx)
+				// 	ctx.SetApplication(app)
+				// }
+				return
+			}
+		}
+
+		// let the "switch app" handle it or fire a custom 404 error page,
+		// next is the switch app's router.
+		ctx.Next()
+	})
+
+	return app
+}
+
+type (
+	// SwitchCase contains the filter
+	// and the matched Application instance.
+	SwitchCase struct {
+		Filter iris.Filter
+		App    *iris.Application
+	}
+
+	// A SwitchProvider should return the switch cases.
+	// It's an interface instead of a direct slice because
+	// we want to make available different type of structures
+	// without wrapping.
+	SwitchProvider interface {
+		GetSwitchCases() []SwitchCase
+	}
+
+	// Join returns a new slice which joins different type of switch cases.
+	Join []SwitchProvider
+)
+
+var _ SwitchProvider = SwitchCase{}
+
+// GetSwitchCases completes the SwitchProvider, it returns itself.
+func (sc SwitchCase) GetSwitchCases() []SwitchCase {
+	return []SwitchCase{sc}
+}
+
+var _ SwitchProvider = Join{}
+
+// GetSwitchCases completes the switch provider.
+func (j Join) GetSwitchCases() (cases []SwitchCase) {
+	for _, p := range j {
+		if p == nil {
+			continue
+		}
+
+		cases = append(cases, p.GetSwitchCases()...)
+	}
+
+	return
+}

apps/switch_go_test.go

@@ -0,0 +1,37 @@
+package apps
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/kataras/iris/v12"
+)
+
+func TestSwitchJoin(t *testing.T) {
+	myapp := iris.New()
+	customFilter := func(ctx iris.Context) bool {
+		pass, _ := ctx.URLParamBool("filter")
+		return pass
+	}
+
+	joinedCases := Join{
+		SwitchCase{
+			Filter: customFilter,
+			App:    myapp,
+		},
+		Hosts{{Pattern: "^test.*$", Target: myapp}},
+	}
+
+	cases := []SwitchCase{
+		{
+			Filter: customFilter,
+			App:    myapp,
+		},
+		{Filter: hostFilter("^test.*$"), App: myapp},
+	}
+
+	if expected, got := fmt.Sprintf("%#+v", cases), fmt.Sprintf("%#+v", joinedCases.GetSwitchCases()); expected != got {
+		t.Fatalf("join does not match with the expected slice of cases, expected:\n%s\nbut got:\n%s", expected, got)
+	}
+
+}

apps/switch_hosts.go

@@ -0,0 +1,120 @@
+package apps
+
+import (
+	"fmt"
+	"net/http"
+	"net/url"
+	"regexp"
+
+	"github.com/kataras/iris/v12"
+	"github.com/kataras/iris/v12/context"
+)
+
+type (
+	// Host holds the pattern for the SwitchCase filter
+	// and the Target host or application.
+	Host struct {
+		// Pattern is the incoming host matcher regexp or a literal.
+		Pattern string
+		// Target is the target Host that incoming requests will be redirected on pattern match
+		// or an Application's Name that will handle the incoming request matched the Pattern.
+		Target interface{} // It was a string in my initial design but let's do that interface{}, we may support more types here in the future, until generics are in, keep it interface{}.
+	}
+	// Hosts is a switch provider.
+	// It can be used as input argument to the `Switch` function
+	// to map host to existing Iris Application instances, e.g.
+	// { "www.mydomain.com": "mydomainApp" } .
+	// It can accept regexp as a host too, e.g.
+	// { "^my.*$": "mydomainApp" } .
+	Hosts []Host
+
+	// Good by we need order and map can't provide it for us
+	//  (e.g. "fallback" regexp }
+	// Hosts map[string]*iris.Application
+)
+
+var _ SwitchProvider = Hosts{}
+
+// GetSwitchCases completes the SwitchProvider.
+// It returns a slice of SwitchCase which
+// if passed on `Switch` function, they act
+// as a router between matched domains and subdomains
+// between existing Iris Applications.
+func (hosts Hosts) GetSwitchCases() []SwitchCase {
+	cases := make([]SwitchCase, 0, len(hosts))
+
+	for _, host := range hosts {
+		cases = append(cases, SwitchCase{
+			Filter: hostFilter(host.Pattern),
+			App:    hostApp(host),
+		})
+	}
+
+	return cases
+}
+
+func hostApp(host Host) *iris.Application {
+	if host.Target == nil {
+		return nil
+	}
+
+	switch target := host.Target.(type) {
+	case context.Application:
+		return target.(*iris.Application)
+	case string:
+		// Check if the given target is an application name, if so
+		// we must not redirect (loop) we must serve the request
+		// using that app.
+		if targetApp, ok := context.GetApplication(target); ok {
+			// It's always iris.Application so we are totally safe here.
+			return targetApp.(*iris.Application)
+		}
+		// If it's a real host, warn the user of invalid input.
+		u, err := url.Parse(target)
+		if err == nil && u.IsAbs() {
+			// remember, we redirect hosts, not full URLs here.
+			panic(fmt.Sprintf(`iris: switch: hosts: invalid target host: "%s"`, target))
+		}
+
+		if regex := regexp.MustCompile(host.Pattern); regex.MatchString(target) {
+			panic(fmt.Sprintf(`iris: switch: hosts: loop detected between expression: "%s" and target host: "%s"`, host.Pattern, host.Target))
+		}
+
+		return newHostRedirectApp(target, HostsRedirectCode)
+	default:
+		panic(fmt.Sprintf("iris: switch: hosts: invalid target type: %T", target))
+	}
+}
+
+func hostFilter(expr string) iris.Filter {
+	regex := regexp.MustCompile(expr)
+	return func(ctx iris.Context) bool {
+		return regex.MatchString(ctx.Host())
+	}
+}
+
+// HostsRedirectCode is the default status code is used
+// to redirect a matching host to a url.
+var HostsRedirectCode = iris.StatusMovedPermanently
+
+func newHostRedirectApp(targetHost string, code int) *iris.Application {
+	app := iris.New()
+	app.Downgrade(func(w http.ResponseWriter, r *http.Request) {
+		if targetHost == context.GetHost(r) {
+			// Note(@kataras):
+			// this should never happen as the HostsRedirect
+			// carefully checks if the expression already matched the "redirectTo"
+			// to avoid the redirect loops at all.
+			// iris: switch: hosts redirect: loop detected between expression: "^my.*$" and target host: "mydomain.com"
+			http.Error(w, http.StatusText(iris.StatusLoopDetected), iris.StatusLoopDetected)
+			return
+		}
+
+		r.Host = targetHost
+		r.URL.Host = targetHost
+
+		// r.URL.User = nil
+		http.Redirect(w, r, r.URL.String(), code)
+	})
+	return app
+}

apps/switch_hosts_test.go

@@ -0,0 +1,211 @@
+package apps
+
+import (
+	"fmt"
+	"net/url"
+	"testing"
+
+	"github.com/kataras/iris/v12"
+	"github.com/kataras/iris/v12/context"
+	"github.com/kataras/iris/v12/httptest"
+)
+
+type testRequests map[string]map[string]int // url -> path -> status code
+
+func TestSwitchHosts(t *testing.T) {
+	var (
+		expected = func(app context.Application, host string) string {
+			return fmt.Sprintf("App Name: %s\nHost: %s", app, host)
+		}
+		index = func(ctx iris.Context) {
+			ctx.WriteString(expected(ctx.Application(), ctx.Host()))
+		}
+	)
+
+	testdomain1 := iris.New().SetName("test 1 domain")
+	testdomain1.Get("/", index) // should match host matching with "testdomain1.com".
+
+	testdomain2 := iris.New().SetName("test 2 domain")
+	testdomain2.Get("/", index) // should match host matching with "testdomain2.com".
+
+	mydomain := iris.New().SetName("my domain")
+	mydomain.OnErrorCode(iris.StatusNotFound, func(ctx iris.Context) {
+		ctx.WriteString(ctx.Host() + " custom not found")
+	})
+	mydomain.Get("/", index) // should match ALL hosts starting with "my".
+
+	tests := []struct {
+		Pattern  string
+		Target   *iris.Application
+		Requests testRequests
+	}{
+		{
+			"testdomain1.com",
+			testdomain1,
+			testRequests{
+				"http://testdomain1.com": {
+					"/": iris.StatusOK,
+				},
+			},
+		},
+		{
+			"testdomain2.com",
+			testdomain2,
+			testRequests{
+				"http://testdomain2.com": {
+					"/": iris.StatusOK,
+				},
+			},
+		},
+		{
+			"^my.*$",
+			mydomain,
+			testRequests{
+				"http://mydomain.com": {
+					"/":   iris.StatusOK,
+					"/nf": iris.StatusNotFound,
+				},
+				"http://myotherdomain.com": {
+					"/": iris.StatusOK,
+				},
+				"http://mymy.com": {
+					"/": iris.StatusOK,
+				},
+				"http://nmy.com": {
+					"/": iris.StatusBadGateway, /* 404 hijacked by switch.OnErrorCode */
+				},
+			},
+		},
+	}
+
+	var hosts Hosts
+	for _, tt := range tests {
+		hosts = append(hosts, Host{tt.Pattern, tt.Target})
+	}
+	switcher := Switch(hosts)
+	switcher.OnErrorCode(iris.StatusNotFound, func(ctx iris.Context) {
+		// inject the 404 to 502.
+		// tests the ctx.Next inside the Hosts switch provider.
+		ctx.StatusCode(iris.StatusBadGateway)
+		ctx.WriteString("Switcher: Bad Gateway")
+	})
+
+	e := httptest.New(t, switcher)
+	for i, tt := range tests {
+		for URL, paths := range tt.Requests {
+			u, err := url.Parse(URL)
+			if err != nil {
+				t.Fatalf("[%d] %v", i, err)
+			}
+			targetHost := u.Host
+			for requestPath, statusCode := range paths {
+				// url := fmt.Sprintf("http://%s", requestHost)
+				body := expected(tt.Target, targetHost)
+				switch statusCode {
+				case 404:
+					body = targetHost + " custom not found"
+				case 502:
+					body = "Switcher: Bad Gateway"
+				}
+
+				e.GET(requestPath).WithURL(URL).Expect().Status(statusCode).Body().Equal(body)
+			}
+		}
+	}
+}
+
+func TestSwitchHostsRedirect(t *testing.T) {
+	var (
+		expected = func(appName, host, path string) string {
+			return fmt.Sprintf("App Name: %s\nHost: %s\nPath: %s", appName, host, path)
+		}
+		index = func(ctx iris.Context) {
+			ctx.WriteString(expected(ctx.Application().String(), ctx.Host(), ctx.Path()))
+		}
+	)
+
+	mydomain := iris.New().SetName("mydomain")
+	mydomain.OnAnyErrorCode(func(ctx iris.Context) {
+		ctx.WriteString("custom: " + iris.StatusText(ctx.GetStatusCode()))
+	})
+	mydomain.Get("/", index)
+	mydomain.Get("/f", index)
+
+	tests := []struct {
+		Pattern  string
+		Target   string
+		Requests testRequests
+	}{
+		{
+			"www.mydomain.com",
+			"mydomain",
+			testRequests{
+				"http://www.mydomain.com": {
+					"/":   iris.StatusOK,
+					"/f":  iris.StatusOK,
+					"/nf": iris.StatusNotFound,
+				},
+			},
+		},
+		{
+			"^test.*$",
+			"mydomain",
+			testRequests{
+				"http://testdomain.com": {
+					"/":   iris.StatusOK,
+					"/f":  iris.StatusOK,
+					"/nf": iris.StatusNotFound,
+				},
+			},
+		},
+		// Something like this will panic to protect users:
+		// {
+		// 	...,
+		// 	"^my.*$",
+		// 	"mydomain.com",
+		// ...
+		//
+		{
+			"^www.*$",
+			"google.com",
+			testRequests{
+				"http://www.mydomain.com": {
+					"/": iris.StatusOK,
+				},
+				"http://www.golang.org": {
+					"/": iris.StatusNotFound, // should give not found because this is not a switcher's web app.
+				},
+			},
+		},
+	}
+
+	var hostsRedirect Hosts
+	for _, tt := range tests {
+		hostsRedirect = append(hostsRedirect, Host{tt.Pattern, tt.Target})
+	}
+
+	switcher := Switch(hostsRedirect)
+	e := httptest.New(t, switcher)
+
+	for i, tt := range tests {
+		for requestURL, paths := range tt.Requests {
+			u, err := url.Parse(requestURL)
+			if err != nil {
+				t.Fatalf("[%d] %v", i, err)
+			}
+			targetHost := u.Host
+			for requestPath, statusCode := range paths {
+				body := expected(mydomain.String(), targetHost, requestPath)
+				if statusCode != 200 {
+					if tt.Target != mydomain.String() { // it's external.
+						body = "Not Found"
+					} else {
+						body = "custom: " + iris.StatusText(statusCode)
+					}
+				}
+
+				e.GET(requestPath).WithURL(requestURL).Expect().Status(statusCode).Body().Equal(body)
+			}
+		}
+	}
+}

apps/switch_scheme.go

@@ -0,0 +1 @@
+package apps

context/application.go

@@ -84,9 +84,30 @@ type Application interface {
 	//
 	// Order may change.
 	FindClosestPaths(subdomain, searchPath string, n int) []string
+
+	// String returns the Application's Name.
+	String() string
 }
 
+// Notes(@kataras):
+// Alternative places...
+// 1. in apps/store, but it would require an empty `import _ "....apps/store"
+//	  from end-developers, to avoid the import cycle and *iris.Application access.
+// 2. in root package level, that could be the best option, it has access to the *iris.Application
+// instead of the context.Application interface, but we try to keep the root package
+// as minimum as possible, however: if in the future, those Application instances
+// can be registered through network instead of same-process then we must think of that choice.
+// 3. this is the best possible place, as the root package and all subpackages
+// have access to this context package without import cycles and they already using it,
+// the only downside is that we don't have access to the *iris.Application instance
+// but this context.Application is designed that way that can execute all important methods
+// as the whole Iris code base is so well written.
+
 var (
+	// registerApps holds all the created iris Applications by this process.
+	// It's slice instead of map because if IRIS_APP_NAME env var exists,
+	// by-default all applications running on the same machine
+	// will have the same name unless `Application.SetName` is called.
 	registeredApps []Application
 	mu             sync.RWMutex
 )
@@ -107,8 +128,8 @@ func RegisterApplication(app Application) {
 // use `Context.Application()` instead.
 func LastApplication() Application {
 	mu.RLock()
-	if n := len(registeredApps); n > 0 {
-		if app := registeredApps[n-1]; app != nil {
+	for i := len(registeredApps) - 1; i >= 0; i-- {
+		if app := registeredApps[i]; app != nil {
 			mu.RUnlock()
 			return app
 		}
@@ -117,6 +138,34 @@ func LastApplication() Application {
 	return nil
 }
 
+// GetApplication returns a registered Application
+// based on its name. If the "appName" is not unique
+// across Applications, then it will return the newest one.
+func GetApplication(appName string) (Application, bool) {
+	mu.RLock()
+
+	for i := len(registeredApps) - 1; i >= 0; i-- {
+		if app := registeredApps[i]; app != nil && app.String() == appName {
+			mu.RUnlock()
+			return app, true
+		}
+	}
+
+	mu.RUnlock()
+	return nil, false
+}
+
+// MustGetApplication same as `GetApplication` but it
+// panics if "appName" is not a registered Application's name.
+func MustGetApplication(appName string) Application {
+	app, ok := GetApplication(appName)
+	if !ok || app == nil {
+		panic(appName + " is not a registered Application")
+	}
+
+	return app
+}
+
 // DefaultLogger returns a Logger instance for an Iris module.
 // If the program contains at least one registered Iris Application
 // before this call then it will return a child of that Application's Logger

context/context.go

@@ -135,6 +135,14 @@ func NewContext(app Application) *Context {
 	return &Context{app: app}
 }
 
+/* Not required, unless requested.
+// SetApplication sets an Iris Application on-fly.
+// Do NOT use it after ServeHTTPC is fired.
+func (ctx *Context) SetApplication(app Application) {
+	ctx.app = app
+}
+*/
+
 // Clone returns a copy of the context that
 // can be safely used outside the request's scope.
 // Note that if the request-response lifecycle terminated
@@ -898,8 +906,22 @@ func (ctx *Context) Domain() string {
 	return GetDomain(ctx.Host())
 }
 
-// SubdomainFull returnst he full subdomain level, e.g.
+// GetSubdomainFull returns the full subdomain level, e.g.
 // [test.user.]mydomain.com.
+func GetSubdomainFull(r *http.Request) string {
+	host := GetHost(r)            // host:port
+	rootDomain := GetDomain(host) // mydomain.com
+	rootDomainIdx := strings.Index(host, rootDomain)
+	if rootDomainIdx == -1 {
+		return ""
+	}
+
+	return host[0:rootDomainIdx]
+}
+
+// SubdomainFull returns the full subdomain level, e.g.
+// [test.user.]mydomain.com.
+// Note that HostProxyHeaders are being respected here.
 func (ctx *Context) SubdomainFull() string {
 	host := ctx.Host()            // host:port
 	rootDomain := GetDomain(host) // mydomain.com

context/handler.go

@@ -19,7 +19,7 @@ var (
 )
 
 var (
-	handlerNames   = make(map[*nameExpr]string)
+	handlerNames   = make(map[*NameExpr]string)
 	handlerNamesMu sync.RWMutex
 )
 
@@ -44,19 +44,22 @@ func SetHandlerName(original string, replacement string) {
 	// when a handler name is declared as it's and cause regex parsing expression error,
 	// e.g. `iris/cache/client.(*Handler).ServeHTTP-fm`
 	regex, _ := regexp.Compile(original)
-	handlerNames[&nameExpr{
+	handlerNames[&NameExpr{
 		literal: original,
 		regex:   regex,
 	}] = replacement
 	handlerNamesMu.Unlock()
 }
 
-type nameExpr struct {
+// NameExpr regex or literal comparison through `MatchString`.
+type NameExpr struct {
 	regex   *regexp.Regexp
 	literal string
 }
 
-func (expr *nameExpr) MatchString(s string) bool {
+// MatchString reports whether "s" is literal of "literal"
+// or it matches the regex expression at "regex".
+func (expr *NameExpr) MatchString(s string) bool {
 	if expr.literal == s { // if matches as string, as it's.
 		return true
 	}

core/host/supervisor.go

@@ -492,6 +492,9 @@ func (su *Supervisor) RegisterOnShutdown(cb func()) {
 // for them to close, if desired.
 func (su *Supervisor) Shutdown(ctx context.Context) error {
 	atomic.StoreUint32(&su.closedManually, 1) // future-use
+	if ctx == nil {
+		ctx = context.Background()
+	}
 	return su.Server.Shutdown(ctx)
 }
 

core/router/router_subdomain_redirect.go

@@ -169,27 +169,6 @@ func (s *subdomainRedirectWrapper) Wrapper(w http.ResponseWriter, r *http.Reques
 	router(w, r)
 }
 
-func redirectAbsolute(w http.ResponseWriter, r *http.Request, url string, code int) {
-	h := w.Header()
-
-	// RFC 7231 notes that a short HTML body is usually included in
-	// the response because older user agents may not understand 301/307.
-	// Do it only if the request didn't already have a Content-Type header.
-	_, hadCT := h[context.ContentTypeHeaderKey]
-
-	h.Set("Location", url)
-	if !hadCT && (r.Method == http.MethodGet || r.Method == http.MethodHead) {
-		h.Set(context.ContentTypeHeaderKey, "text/html; charset=utf-8")
-	}
-	w.WriteHeader(code)
-
-	// Shouldn't send the body for POST or HEAD; that leaves GET.
-	if !hadCT && r.Method == "GET" {
-		body := "<a href=\"" + template.HTMLEscapeString(url) + "\">" + http.StatusText(code) + "</a>.\n"
-		fmt.Fprintln(w, body)
-	}
-}
-
 // NewSubdomainPartyRedirectHandler returns a handler which can be registered
 // through `UseRouter` or `Use` to redirect from the current request's
 // subdomain to the one which the given `to` Party can handle.
@@ -210,9 +189,34 @@ func NewSubdomainRedirectHandler(toSubdomain string) context.Handler {
 		// en-us.test.mydomain.com
 		host := ctx.Host()
 		fullSubdomain := ctx.SubdomainFull()
-		newHost := strings.Replace(host, fullSubdomain, toSubdomain, 1)
-		resturi := ctx.Request().URL.RequestURI()
-		urlToRedirect := ctx.Scheme() + newHost + resturi
-		redirectAbsolute(ctx.ResponseWriter(), ctx.Request(), urlToRedirect, http.StatusMovedPermanently)
+		targetHost := strings.Replace(host, fullSubdomain, toSubdomain, 1)
+		// resturi := ctx.Request().URL.RequestURI()
+		// urlToRedirect := ctx.Scheme() + newHost + resturi
+		r := ctx.Request()
+		r.Host = targetHost
+		r.URL.Host = targetHost
+		urlToRedirect := r.URL.String()
+		redirectAbsolute(ctx.ResponseWriter(), r, urlToRedirect, http.StatusMovedPermanently)
+	}
+}
+
+func redirectAbsolute(w http.ResponseWriter, r *http.Request, url string, code int) {
+	h := w.Header()
+
+	// RFC 7231 notes that a short HTML body is usually included in
+	// the response because older user agents may not understand 301/307.
+	// Do it only if the request didn't already have a Content-Type header.
+	_, hadCT := h[context.ContentTypeHeaderKey]
+
+	h.Set("Location", url)
+	if !hadCT && (r.Method == http.MethodGet || r.Method == http.MethodHead) {
+		h.Set(context.ContentTypeHeaderKey, "text/html; charset=utf-8")
+	}
+	w.WriteHeader(code)
+
+	// Shouldn't send the body for POST or HEAD; that leaves GET.
+	if !hadCT && r.Method == "GET" {
+		body := "<a href=\"" + template.HTMLEscapeString(url) + "\">" + http.StatusText(code) + "</a>.\n"
+		fmt.Fprintln(w, body)
 	}
 }

iris.go

@@ -82,8 +82,20 @@ type Application struct {
 	// used for build
 	builded     bool
 	defaultMode bool
+	// OnBuild is a single function which
+	// is fired on the first `Build` method call.
+	// If reports an error then the execution
+	// is stopped and the error is logged.
+	// It's nil by default except when `Switch` instead of `New` or `Default`
+	// is used to initialize the Application.
+	// Users can wrap it to accept more events.
+	OnBuild func() error
 
 	mu sync.Mutex
+	// name is the application name and the log prefix for
+	// that Application instance's Logger. See `SetName` and `String`.
+	// Defaults to IRIS_APP_NAME envrinoment variable otherwise empty.
+	name string
 	// Hosts contains a list of all servers (Host Supervisors) that this app is running on.
 	//
 	// Hosts may be empty only if application ran(`app.Run`) with `iris.Raw` option runner,
@@ -131,6 +143,41 @@ func Default() *Application {
 	return app
 }
 
+func newLogger(app *Application) *golog.Logger {
+	logger := golog.Default.Child(app)
+	if name := os.Getenv("IRIS_APP_NAME"); name != "" {
+		app.name = name
+		logger.SetChildPrefix(name)
+	}
+
+	return logger
+}
+
+// SetName sets a unique name to this Iris Application.
+// It sets a child prefix for the current Application's Logger.
+// Look `String` method too.
+//
+// It returns this Application.
+func (app *Application) SetName(appName string) *Application {
+	app.mu.Lock()
+	defer app.mu.Unlock()
+
+	if app.name == "" {
+		app.logger.SetChildPrefix(appName)
+	}
+	app.name = appName
+
+	return app
+}
+
+// String completes the fmt.Stringer interface and it returns
+// the application's name.
+// If name was not set by `SetName` or `IRIS_APP_NAME` environment variable
+// then this will return an empty string.
+func (app *Application) String() string {
+	return app.name
+}
+
 // WWW creates and returns a "www." subdomain.
 // The difference from `app.Subdomain("www")` or `app.Party("www.")` is that the `app.WWW()` method
 // wraps the router so all http(s)://mydomain.com will be redirect to http(s)://www.mydomain.com.
@@ -187,22 +234,6 @@ func (app *Application) ConfigurationReadOnly() context.ConfigurationReadOnly {
 	return app.config
 }
 
-// Maybe, if it's requested:
-// func (app *Application) SetName(appName string) *iris.Application {
-// 	app.config.name = appName
-// 	app.logger.SetChildPrefix(appName)
-// 	return app
-// }
-
-func newLogger(app *Application) *golog.Logger {
-	logger := golog.Default.Child(app)
-	if prefix := os.Getenv("IRIS_APP_NAME"); prefix != "" {
-		logger.SetChildPrefix(prefix)
-	}
-
-	return logger
-}
-
 // Logger returns the golog logger instance(pointer) that is being used inside the "app".
 //
 // Available levels:
@@ -488,6 +519,12 @@ func (app *Application) Build() error {
 		return nil
 	}
 
+	if cb := app.OnBuild; cb != nil {
+		if err := cb(); err != nil {
+			return err
+		}
+	}
+
 	// start := time.Now()
 	app.builded = true // even if fails.