add function gutil.Try/g.Try;improve error string for gconv.Struct

.example/net/ghttp/server/hello.go

@@ -3,15 +3,21 @@ package main
 import (
 	"github.com/gogf/gf/frame/g"
 	"github.com/gogf/gf/net/ghttp"
-	"github.com/gogf/gf/os/glog"
 )
 
+type GetById struct {
+	Id *g.Var `p:"id" v:"required|integer#id不能为空|id必须为整数"`
+}
+
 func main() {
 	s := g.Server()
 	s.SetIndexFolder(true)
 	s.BindHandler("/", func(r *ghttp.Request) {
-		glog.Println(r.Header)
-		r.Response.Write("hello world")
+		var idInfo *GetById
+		if err := r.Parse(&idInfo); err != nil {
+			r.Response.Write(err)
+		}
+		r.Response.Write("ok")
 	})
 	s.SetPort(8999)
 	s.Run()

.example/util/gutil/try_catch.go

@@ -11,7 +11,7 @@ func main() {
 		fmt.Println(1)
 		gutil.Throw("error")
 		fmt.Println(2)
-	}, func(err interface{}) {
+	}, func(err error) {
 		fmt.Println(err)
 	})
 }

frame/g/g_func.go

@@ -39,8 +39,15 @@ func Throw(exception interface{}) {
 	gutil.Throw(exception)
 }
 
-// TryCatch does the try...catch... mechanism.
-func TryCatch(try func(), catch ...func(exception interface{})) {
+// Try implements try... logistics using internal panic...recover.
+// It returns error if any exception occurs, or else it returns nil.
+func Try(try func()) (err error) {
+	return gutil.Try(try)
+}
+
+// TryCatch implements try...catch... logistics using internal panic...recover.
+// It automatically calls function <catch> if any exception occurs ans passes the exception as an error.
+func TryCatch(try func(), catch ...func(exception error)) {
 	gutil.TryCatch(try, catch...)
 }
 

net/ghttp/ghttp_request_middleware.go

@@ -120,7 +120,7 @@ func (m *Middleware) Next() {
 				// There should be a "Next" function to be called in the middleware in order to manage the workflow.
 				loop = false
 			}
-		}, func(exception interface{}) {
+		}, func(exception error) {
 			if e, ok := exception.(gerror.ApiStack); ok {
 				// It's already an error that has stack info.
 				m.request.error = e.(error)

util/gconv/gconv_struct.go

@@ -259,8 +259,11 @@ func bindVarToStructAttr(elem reflect.Value, name string, value interface{}, rec
 		return nil
 	}
 	defer func() {
-		if recover() != nil {
+		if e := recover(); e != nil {
 			err = bindVarToReflectValue(structFieldValue, value, recursive, mapping...)
+			if err != nil {
+				err = gerror.Wrapf(err, `error binding value to attribute "%s"`, name)
+			}
 		}
 	}()
 	if empty.IsNil(value) {
@@ -283,8 +286,7 @@ func bindVarToReflectValue(structFieldValue reflect.Value, value interface{}, re
 				v.Set(value)
 				return nil
 			} else if v, ok := structFieldValue.Interface().(apiUnmarshalValue); ok {
-				err = v.UnmarshalValue(value)
-				if err == nil {
+				if err = v.UnmarshalValue(value); err == nil {
 					return err
 				}
 			}

util/gutil/gutil.go

@@ -8,6 +8,7 @@
 package gutil
 
 import (
+	"fmt"
 	"github.com/gogf/gf/internal/empty"
 )
 
@@ -16,11 +17,24 @@ func Throw(exception interface{}) {
 	panic(exception)
 }
 
+// Try implements try... logistics using internal panic...recover.
+// It returns error if any exception occurs, or else it returns nil.
+func Try(try func()) (err error) {
+	defer func() {
+		if e := recover(); e != nil {
+			err = fmt.Errorf(`%v`, e)
+		}
+	}()
+	try()
+	return
+}
+
 // TryCatch implements try...catch... logistics using internal panic...recover.
-func TryCatch(try func(), catch ...func(exception interface{})) {
+// It automatically calls function <catch> if any exception occurs ans passes the exception as an error.
+func TryCatch(try func(), catch ...func(exception error)) {
 	defer func() {
 		if e := recover(); e != nil && len(catch) > 0 {
-			catch[0](e)
+			catch[0](fmt.Errorf(`%v`, e))
 		}
 	}()
 	try()

util/gutil/gutil_z_bench_test.go

@@ -25,7 +25,7 @@ func Benchmark_TryCatch(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		TryCatch(func() {
 
-		}, func(err interface{}) {
+		}, func(err error) {
 
 		})
 	}

util/gutil/gutil_z_unit_test.go

@@ -21,6 +21,15 @@ func Test_Dump(t *testing.T) {
 	})
 }
 
+func Test_Try(t *testing.T) {
+	gtest.C(t, func(t *gtest.T) {
+		s := `gutil Try test`
+		t.Assert(gutil.Try(func() {
+			panic(s)
+		}), s)
+	})
+}
+
 func Test_TryCatch(t *testing.T) {
 	gtest.C(t, func(t *gtest.T) {
 		gutil.TryCatch(func() {
@@ -32,21 +41,19 @@ func Test_TryCatch(t *testing.T) {
 		gutil.TryCatch(func() {
 			panic("gutil TryCatch test")
 
-		}, func(err interface{}) {
+		}, func(err error) {
 			t.Assert(err, "gutil TryCatch test")
 		})
 	})
 }
 
 func Test_IsEmpty(t *testing.T) {
-
 	gtest.C(t, func(t *gtest.T) {
 		t.Assert(gutil.IsEmpty(1), false)
 	})
 }
 
 func Test_Throw(t *testing.T) {
-
 	gtest.C(t, func(t *gtest.T) {
 		defer func() {
 			t.Assert(recover(), "gutil Throw test")