☕ add a dependency-injection examples folder for the next release and some improvements

Former-commit-id: 040168afb7caf808618f7da5e68ae8eb01cb7170

hero/func_result.go

@@ -225,7 +225,7 @@ func dispatchFuncResult(ctx context.Context, values []reflect.Value) error {
 				continue
 			}
 
-			if statusCode < 400 {
+			if statusCode < 400 && value != ErrStopExecution {
 				statusCode = DefaultErrStatusCode
 			}
 
@@ -286,7 +286,11 @@ func dispatchCommon(ctx context.Context,
 	if contentType == "" {
 		// to respect any ctx.ContentType(...) call
 		// especially if v is not nil.
-		contentType = ctx.GetContentType()
+		if contentType = ctx.GetContentType(); contentType == "" {
+			// if it's still empty set to JSON. (useful for dynamic middlewares that returns an int status code and the next handler dispatches the JSON,
+			// see dependency-injection/basic/middleware example)
+			contentType = context.ContentJSONHeaderValue
+		}
 	}
 
 	if v != nil {
@@ -302,10 +306,13 @@ func dispatchCommon(ctx context.Context,
 		if strings.HasPrefix(contentType, context.ContentJavascriptHeaderValue) {
 			_, err = ctx.JSONP(v)
 		} else if strings.HasPrefix(contentType, context.ContentXMLHeaderValue) {
-			_, err = ctx.XML(v, context.XML{Indent: " "})
+			_, err = ctx.XML(v)
+			// no need: context.XML{Indent: "  "}), after v12.2,
+			// if not iris.WithOptimizations passed and indent is empty then it sets it to two spaces for JSON, JSONP and XML,
+			// otherwise given indentation.
 		} else {
 			// defaults to json if content type is missing or its application/json.
-			_, err = ctx.JSON(v, context.JSON{Indent: " "})
+			_, err = ctx.JSON(v)
 		}
 
 		return err

hero/handler.go

@@ -18,23 +18,6 @@ func (fn ErrorHandlerFunc) HandleError(ctx context.Context, err error) {
 	fn(ctx, err)
 }
 
-var (
-	// DefaultErrStatusCode is the default error status code (400)
-	// when the response contains a non-nil error or a request-scoped binding error occur.
-	DefaultErrStatusCode = 400
-
-	// DefaultErrorHandler is the default error handler which is fired
-	// when a function returns a non-nil error or a request-scoped dependency failed to binded.
-	DefaultErrorHandler = ErrorHandlerFunc(func(ctx context.Context, err error) {
-		if status := ctx.GetStatusCode(); status == 0 || !context.StatusCodeNotSuccessful(status) {
-			ctx.StatusCode(DefaultErrStatusCode)
-		}
-
-		ctx.WriteString(err.Error())
-		ctx.StopExecution()
-	})
-)
-
 var (
 	// ErrSeeOther may be returned from a dependency handler to skip a specific dependency
 	// based on custom logic.
@@ -45,6 +28,26 @@ var (
 	ErrStopExecution = fmt.Errorf("stop execution")
 )
 
+var (
+	// DefaultErrStatusCode is the default error status code (400)
+	// when the response contains a non-nil error or a request-scoped binding error occur.
+	DefaultErrStatusCode = 400
+
+	// DefaultErrorHandler is the default error handler which is fired
+	// when a function returns a non-nil error or a request-scoped dependency failed to binded.
+	DefaultErrorHandler = ErrorHandlerFunc(func(ctx context.Context, err error) {
+		if err != ErrStopExecution {
+			if status := ctx.GetStatusCode(); status == 0 || !context.StatusCodeNotSuccessful(status) {
+				ctx.StatusCode(DefaultErrStatusCode)
+			}
+
+			ctx.WriteString(err.Error())
+		}
+
+		ctx.StopExecution()
+	})
+)
+
 func makeHandler(fn interface{}, c *Container) context.Handler {
 	if fn == nil {
 		panic("makeHandler: function is nil")
@@ -77,10 +80,12 @@ func makeHandler(fn interface{}, c *Container) context.Handler {
 			if err != nil {
 				if err == ErrSeeOther {
 					continue
-				} else if err == ErrStopExecution {
-					ctx.StopExecution()
-					return // return without error.
 				}
+				// handled inside ErrorHandler.
+				// else if err == ErrStopExecution {
+				// 	ctx.StopExecution()
+				// 	return // return without error.
+				// }
 
 				c.GetErrorHandler(ctx).HandleError(ctx, err)
 				return

hero/handler_test.go

@@ -156,7 +156,7 @@ before begin the implementation of it.
 	b.Register("user_dep", func(db myDB) User{...}).DependsOn("db")
 	b.Handler(func(user User) error{...})
 	b.Handler(func(ctx iris.Context, reuseDB myDB) {...})
-Why linked over automatically? Because more thna one dependency can implement the same input and
+Why linked over automatically? Because more than one dependency can implement the same input and
 end-user does not care about ordering the registered ones.
 Link with `DependsOn` SHOULD be optional, if exists then limit the available dependencies,
 `DependsOn` SHOULD accept comma-separated values, e.g. "db, otherdep" and SHOULD also work
@@ -170,6 +170,8 @@ so, in theory, end-developers could achieve same results by hand-code(inside the
 
 26 Feb 2020. Gerasimos Maropoulos
 ______________________________________________
+
+29 Feb 2020. It's done.
 */
 
 type testMessage struct {