add an example of SetContextErrorHandler

_examples/response-writer/write-rest/main.go

@@ -4,6 +4,7 @@ import (
 	"encoding/xml"
 
 	"github.com/kataras/iris/v12"
+	"github.com/kataras/iris/v12/x/errors"
 )
 
 // User example struct for json and msgpack.
@@ -29,15 +30,16 @@ type ExampleYAML struct {
 
 func main() {
 	app := iris.New()
-
+	// Optionally, set a custom handler for JSON, JSONP, Protobuf, MsgPack, YAML, Markdown...
+	// write errors.
+	app.SetContextErrorHandler(new(errorHandler))
 	// Read
 	app.Post("/decode", func(ctx iris.Context) {
 		// Read https://github.com/kataras/iris/blob/master/_examples/request-body/read-json/main.go as well.
 		var user User
 		err := ctx.ReadJSON(&user)
 		if err != nil {
-			ctx.StatusCode(iris.StatusBadRequest)
-			ctx.Writef("unable to read body: %s\nbody is empty: %v", err.Error(), iris.IsErrEmptyJSON(err))
+			errors.InvalidArgument.Details(ctx, "unable to parse body", err.Error())
 			return
 		}
 
@@ -165,3 +167,9 @@ func main() {
 	// if passed to the `Run` then it will not print its passed error as an actual server error.
 	app.Listen(":8080", iris.WithOptimizations)
 }
+
+type errorHandler struct{}
+
+func (h *errorHandler) HandleContextError(ctx iris.Context, err error) {
+	errors.Internal.Err(ctx, err)
+}

context/context.go

@@ -3966,9 +3966,9 @@ func WriteJSON(ctx stdContext.Context, writer io.Writer, v interface{}, options
 }
 
 // See https://golang.org/src/strings/builder.go#L45
-func bytesToString(b []byte) string {
-	return *(*string)(unsafe.Pointer(&b))
-}
+// func bytesToString(b []byte) string {
+// 	return *(*string)(unsafe.Pointer(&b))
+// }
 
 func stringToBytes(s string) []byte {
 	return *(*[]byte)(unsafe.Pointer(&s))