Dynamic struct

Author: CodeHariK

secretary/docs/secretary.excalidraw.svg

@@ -0,0 +1,77 @@
+package dynamicstruct
+
+import (
+	"encoding/json"
+	"fmt"
+	"reflect"
+	"strings"
+)
+
+type FieldInfo struct {
+	Type string `json:"type"`
+	Enc  int    `json:"enc,omitempty"`
+	Size int    `json:"size,omitempty"`
+}
+
+func Parse(jsonData string) {
+	// Parse the JSON metadata
+	var metadata map[string]FieldInfo
+	err := json.Unmarshal([]byte(jsonData), &metadata)
+	if err != nil {
+		panic(err)
+	}
+
+	// Create a dynamic struct based on metadata
+	fields := []reflect.StructField{}
+	for name, info := range metadata {
+		var fieldType reflect.Type
+		switch info.Type {
+		case "int":
+			fieldType = reflect.TypeOf(0)
+		case "string":
+			fieldType = reflect.TypeOf("")
+		default:
+			continue
+		}
+
+		// Capitalize field name
+		fieldName := strings.ToUpper(name[:1]) + name[1:]
+
+		fields = append(fields, reflect.StructField{
+			Name: fieldName,
+			Type: fieldType,
+			Tag:  reflect.StructTag(fmt.Sprintf(`custom:"enc=%d,size=%d"`, info.Enc, info.Size)),
+		})
+	}
+
+	// Create a struct type dynamically
+	dynamicType := reflect.StructOf(fields)
+	instance := reflect.New(dynamicType).Elem()
+
+	fmt.Println(dynamicType)
+	fmt.Println(instance)
+
+	// Assign values dynamically
+	if len(fields) > 0 && fields[0].Type.Kind() == reflect.Int {
+		instance.Field(0).SetInt(42) // Set int value
+	}
+	if len(fields) > 1 && fields[1].Type.Kind() == reflect.String {
+		instance.Field(1).SetString("abc") // Set string value
+	}
+
+	// Print dynamic struct values
+	fmt.Println("Dynamically Created Struct:")
+	for i := 0; i < dynamicType.NumField(); i++ {
+		field := dynamicType.Field(i)
+		fmt.Printf("%s: %v\n", field.Name, instance.Field(i).Interface())
+	}
+
+	// Access struct tags
+	fmt.Println("\nStruct Field Tags:")
+	for i := 0; i < dynamicType.NumField(); i++ {
+		field := dynamicType.Field(i)
+		fmt.Printf("%s tag: %s\n", field.Name, field.Tag)
+	}
+
+	fmt.Println(instance)
+}

secretary/dynamic_serialization.md

@@ -0,0 +1,12 @@
+package dynamicstruct
+
+import "testing"
+
+func TestParse(t *testing.T) {
+	jsonData := `{
+		"a": { "type": "int", "enc": 3 },
+		"s": { "type": "string", "size": 3 }
+	}`
+
+	Parse(jsonData)
+}