morrisxyang / xreflect

A simple and user-friendly reflection utility library.

xreflect

A simple and user-friendly reflection utility library.

The xreflect package aims to provide developers with high-level abstractions over the Go standard reflect library. This library's API is often considered low-level and unintuitive, making simple tasks like setting structure field values more complex than necessary.

The main features supported are:

• Setting the values of structure fields, supporting nested structure field values by using paths such as A.B.C.

• Getting the values, types, tags, etc., of structure fields.

• Traversing all fields of a structure, supporting both select mode and range mode. If a deep traversal method like FieldsDeep is used, it will traverse all nested structures.

• Function calls and method calls, supporting variadic parameters.

• Creating new instances, checking interface implementations, and more.

Installation and Docs

Install using go get github.com/morrisxyang/xreflect.

Full documentation is available at https://pkg.go.dev/github.com/morrisxyang/xreflect

Quick Start

Set nested struct field value

person := &Person{
	Name: "John",
	Age:  20,
	Country: Country{
		ID:   0,
		Name: "Perk",
	},
}

_ = SetEmbedField(person, "Country.ID", 1)

// Perk's ID: 1 
fmt.Printf("Perk's ID: %d \n", person.Country.ID)

Find json tag

type Person struct {
	Name string `json:"name" xml:"_name"`
}
p := &Person{}
// json:"name" xml:"_name"
fmt.Println(StructFieldTag(p, "Name"))
// name <nil>
fmt.Println(StructFieldTagValue(p, "Name", "json"))
// _name <nil>
fmt.Println(StructFieldTagValue(p, "Name", "xml"))

Filter instance fields (deep traversal)

type Person struct {
	id   string
	Age  int    `json:"int"`
	Name string `json:"name"`
	Home struct {
		Address string `json:"address"`
	}
}

p := &Person{}
fields, _ := SelectFieldsDeep(p, func(s string, field reflect.StructField, value reflect.Value) bool {
	return field.Tag.Get("json") != ""
})
// key: Age type: int
// key: Name type: string
// key: Home.Address type: string
for k, v := range fields {
	fmt.Printf("key: %s type: %v\n", k, v.Type())
}

Call a function

var addFunc = func(nums ...int) int {
		var sum int
		for _, num := range nums {
			sum += num
		}
		return sum
}

res, _ := CallFunc(addFunc, 1, 2, 3)

// 6
fmt.Println(res[0].Interface())

Core Methods

FieldX

• func Field(obj interface{}, fieldName string) (reflect.Value, error)
• func FieldValue(obj interface{}, fieldName string) (interface{}, error)
• func EmbedField(obj interface{}, fieldPath string) (reflect.Value, error)
• func EmbedFieldValue(obj interface{}, fieldPath string) (interface{}, error)
• func Fields(obj interface{}) (map[string]reflect.Value, error)
• func FieldsDeep(obj interface{}) (map[string]reflect.Value, error)
• func RangeFields(obj interface{}, f func(string, reflect.StructField, reflect.Value) bool) error
• func SelectFields(obj interface{}, f func(string, reflect.StructField, reflect.Value) bool) (map[string]reflect.Value, error)
• etc.

SetX

• func SetEmbedField(obj interface{}, fieldPath string, fieldValue interface{}) error

• func SetField(obj interface{}, fieldName string, fieldValue interface{}) error

• func SetPrivateField(obj interface{}, fieldName string, fieldValue interface{}) error

• etc.

StrcutFieldX

• func StructField(obj interface{}, fieldName string) (reflect.StructField, error)

• func StructFieldTagValue(obj interface{}, fieldName, tagKey string) (string, error)

• func EmbedStructField(obj interface{}, fieldPath string) (reflect.StructField, error)

• func StructFields(obj interface{}) ([]reflect.StructField, error)

• func StructFieldsFlatten(obj interface{}) ([]reflect.StructField, error)

• func SelectStructFields(obj interface{}, f func(int, reflect.StructField) bool) ([]reflect.StructField, error)

• func RangeStructFields(obj interface{}, f func(int, reflect.StructField) bool) error

• etc.

FuncX

• func CallFunc(fn interface{}, args ...interface{}) ([]reflect.Value, error)

• func CallMethod(obj interface{}, method string, params ...interface{}) ([]reflect.Value, error)

• etc.

Others

• func NewInstance(obj interface{}) interface{}
• func Type(obj interface{}) reflect.Type
• func TypePenetrateElem(obj interface{}) reflect.Type
• func Value(obj interface{}) reflect.Value
• func ValuePenetrateElem(obj interface{}) reflect.Value
• etc.

FAQ

What is the difference between Field and StructField?

Field returns reflect.Value, while StructField returns reflect.StructField.