go-macaron#49 custom 500 handler

README.md

@@ -5,7 +5,7 @@ Macaron [![Build Status](https://drone.io/github.com/Unknwon/macaron/status.png)
 
 Package macaron is a high productive and modular design web framework in Go.
 
-##### Current version: 0.6.5
+##### Current version: 0.6.6
 
 ## Getting Started
 

macaron.go

@@ -29,7 +29,7 @@ import (
 	"github.com/Unknwon/macaron/inject"
 )
 
-const _VERSION = "0.6.5.0720"
+const _VERSION = "0.6.6.0728"
 
 func Version() string {
 	return _VERSION
@@ -83,11 +83,19 @@ func NewWithLogger(out io.Writer) *Macaron {
 	m.Router.m = m
 	m.Map(m.logger)
 	m.Map(defaultReturnHandler())
-	m.notFound = func(resp http.ResponseWriter, req *http.Request) {
-		c := m.createContext(resp, req)
+	m.notFound = func(ShouldStartWith http.ResponseWriter, req *http.Request) {
+		c := m.createContext(ShouldStartWith, req)
 		c.handlers = append(c.handlers, http.NotFound)
 		c.run()
 	}
+	m.internalServerError = func(rw http.ResponseWriter, req *http.Request, err error) {
+		c := m.createContext(rw, req)
+		c.handlers = append(c.handlers, func(rw http.ResponseWriter, req *http.Request, err error) {
+			http.Error(rw, err.Error(), 500)
+		})
+		c.Map(err)
+		c.run()
+	}
 	return m
 }
 

return_handler.go

@@ -32,28 +32,37 @@ func canDeref(val reflect.Value) bool {
 	return val.Kind() == reflect.Interface || val.Kind() == reflect.Ptr
 }
 
+func isError(val reflect.Value) bool {
+	_, ok := val.Interface().(error)
+	return ok
+}
+
 func isByteSlice(val reflect.Value) bool {
 	return val.Kind() == reflect.Slice && val.Type().Elem().Kind() == reflect.Uint8
 }
 
 func defaultReturnHandler() ReturnHandler {
 	return func(ctx *Context, vals []reflect.Value) {
 		rv := ctx.GetVal(inject.InterfaceOf((*http.ResponseWriter)(nil)))
-		res := rv.Interface().(http.ResponseWriter)
+		resp := rv.Interface().(http.ResponseWriter)
 		var respVal reflect.Value
 		if len(vals) > 1 && vals[0].Kind() == reflect.Int {
-			res.WriteHeader(int(vals[0].Int()))
+			resp.WriteHeader(int(vals[0].Int()))
 			respVal = vals[1]
 		} else if len(vals) > 0 {
 			respVal = vals[0]
+			if isError(respVal) {
+				ctx.internalServerError(ctx.Resp, ctx.Req.Request, respVal.Interface().(error))
+				return
+			}
 		}
 		if canDeref(respVal) {
 			respVal = respVal.Elem()
 		}
 		if isByteSlice(respVal) {
-			res.Write(respVal.Bytes())
+			resp.Write(respVal.Bytes())
 		} else {
-			res.Write([]byte(respVal.String()))
+			resp.Write([]byte(respVal.String()))
 		}
 	}
 }

return_handler_test.go

@@ -15,6 +15,7 @@
 package macaron
 
 import (
+	"errors"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -24,7 +25,7 @@ import (
 
 func Test_Return_Handler(t *testing.T) {
 	Convey("Return with status and body", t, func() {
-		m := Classic()
+		m := New()
 		m.Get("/", func() (int, string) {
 			return 418, "i'm a teapot"
 		})
@@ -38,8 +39,23 @@ func Test_Return_Handler(t *testing.T) {
 		So(resp.Body.String(), ShouldEqual, "i'm a teapot")
 	})
 
+	Convey("Return with error", t, func() {
+		m := New()
+		m.Get("/", func() error {
+			return errors.New("what the hell!!!")
+		})
+
+		resp := httptest.NewRecorder()
+		req, err := http.NewRequest("GET", "/", nil)
+		So(err, ShouldBeNil)
+		m.ServeHTTP(resp, req)
+
+		So(resp.Code, ShouldEqual, http.StatusInternalServerError)
+		So(resp.Body.String(), ShouldEqual, "what the hell!!!\n")
+	})
+
 	Convey("Return with pointer", t, func() {
-		m := Classic()
+		m := New()
 		m.Get("/", func() *string {
 			str := "hello world"
 			return &str
@@ -54,7 +70,7 @@ func Test_Return_Handler(t *testing.T) {
 	})
 
 	Convey("Return with byte slice", t, func() {
-		m := Classic()
+		m := New()
 		m.Get("/", func() []byte {
 			return []byte("hello world")
 		})

router.go

@@ -79,8 +79,9 @@ type Router struct {
 	*routeMap
 	namedRoutes map[string]*Leaf
 
-	groups   []group
-	notFound http.HandlerFunc
+	groups              []group
+	notFound            http.HandlerFunc
+	internalServerError func(http.ResponseWriter, *http.Request, error)
 }
 
 func NewRouter() *Router {
@@ -261,6 +262,18 @@ func (r *Router) NotFound(handlers ...Handler) {
 	}
 }
 
+// Configurable handler which is called when route handler returns
+// error. If it is not set, default handler is used.
+// Be sure to set 500 response code in your handler.
+func (r *Router) InternalServerError(handlers ...Handler) {
+	r.internalServerError = func(rw http.ResponseWriter, req *http.Request, err error) {
+		c := r.m.createContext(rw, req)
+		c.handlers = append(r.m.handlers, handlers...)
+		c.Map(err)
+		c.run()
+	}
+}
+
 func (r *Router) ServeHTTP(rw http.ResponseWriter, req *http.Request) {
 	if t, ok := r.routers[req.Method]; ok {
 		h, p, ok := t.Match(req.URL.Path)

router_test.go

@@ -15,6 +15,7 @@
 package macaron
 
 import (
+	"errors"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -24,7 +25,7 @@ import (
 
 func Test_Router_Handle(t *testing.T) {
 	Convey("Register all HTTP methods routes", t, func() {
-		m := Classic()
+		m := New()
 		m.Get("/get", func() string {
 			return "GET"
 		})
@@ -135,7 +136,7 @@ func Test_Router_Handle(t *testing.T) {
 	})
 
 	Convey("Register all HTTP methods routes with combo", t, func() {
-		m := Classic()
+		m := New()
 		m.SetURLPrefix("/prefix")
 		m.Use(Renderer())
 		m.Combo("/", func(ctx *Context) {
@@ -243,7 +244,7 @@ func Test_Router_URLFor(t *testing.T) {
 
 func Test_Router_Group(t *testing.T) {
 	Convey("Register route group", t, func() {
-		m := Classic()
+		m := New()
 		m.Group("/api", func() {
 			m.Group("/v1", func() {
 				m.Get("/list", func() string {
@@ -261,7 +262,7 @@ func Test_Router_Group(t *testing.T) {
 
 func Test_Router_NotFound(t *testing.T) {
 	Convey("Custom not found handler", t, func() {
-		m := Classic()
+		m := New()
 		m.Get("/", func() {})
 		m.NotFound(func() string {
 			return "Custom not found"
@@ -274,9 +275,28 @@ func Test_Router_NotFound(t *testing.T) {
 	})
 }
 
+func Test_Router_InternalServerError(t *testing.T) {
+	Convey("Custom internal server error handler", t, func() {
+		m := New()
+		m.Get("/", func() error {
+			return errors.New("Custom internal server error")
+		})
+		m.InternalServerError(func(rw http.ResponseWriter, err error) {
+			rw.WriteHeader(500)
+			rw.Write([]byte(err.Error()))
+		})
+		resp := httptest.NewRecorder()
+		req, err := http.NewRequest("GET", "/", nil)
+		So(err, ShouldBeNil)
+		m.ServeHTTP(resp, req)
+		So(resp.Code, ShouldEqual, 500)
+		So(resp.Body.String(), ShouldEqual, "Custom internal server error")
+	})
+}
+
 func Test_Router_splat(t *testing.T) {
 	Convey("Register router with glob", t, func() {
-		m := Classic()
+		m := New()
 		m.Get("/*", func(ctx *Context) string {
 			return ctx.Params("*")
 		})