event/reflect.go

// Package event ...
//
// Description : event ...
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 2023-02-01 14:30
package event

import (
	"reflect"
	"strings"
	"sync"
)

var (
	// ReflectTypeInstance 反射实例
	ReflectTypeInstance *ReflectType
)

func init() {
	ReflectTypeInstance = &ReflectType{
		lock:       &sync.RWMutex{},
		cacheTable: make(map[string]*StructInfo),
	}
}

// ReflectType 反射数据类型
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 14:31 2023/2/1
type ReflectType struct {
	// 数据锁
	lock *sync.RWMutex
	// 反射结果缓存
	cacheTable map[string]*StructInfo
}

// Do 反射获取数据类型
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 14:34 2023/2/1
//
// 为特定结构体生成全局唯一的标识, 并进行缓存, 加速反射结果获取
func (rt *ReflectType) Do(dataFlag string, data interface{}) *StructInfo {
	rt.lock.Lock()
	defer rt.lock.Unlock()
	if cacheResult, exist := rt.cacheTable[dataFlag]; exist {
		// 缓存存在, 直接是有缓存结果
		return cacheResult
	}

	// 缓存不存在, 解析
	res := &StructInfo{
		Flag:            dataFlag,
		IsStruct:        false,
		StructFieldList: make([]*StructField, 0),
	}
	reflectType := reflect.TypeOf(data)
	if reflectType.Kind() == reflect.Ptr {
		reflectType = reflectType.Elem()
	}
	if reflectType.Kind() != reflect.Struct {
		// 非结构体，无需反射
		return res
	}
	res.IsStruct = true
	for idx := 0; idx < reflectType.NumField(); idx++ {
		field := &StructField{
			Idx:             idx,
			Name:            reflectType.Field(idx).Name,
			Type:            reflectType.Field(idx).Type.Kind(),
			JsonTag:         reflectType.Field(idx).Tag.Get(JsonTag),
			EventTag:        reflectType.Field(idx).Tag.Get(OutEventTag),
			MappingRuleList: make([]MappingRuleItem, 0),
		}
		rt.fillMappingRule(field, reflectType.Field(idx).Tag.Get(MappingTag))
		res.StructFieldList = append(res.StructFieldList, field)
	}
	rt.cacheTable[dataFlag] = res
	return res
}

// fillTagInfo 填充标签信息
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 17:11 2023/2/1
func (rt *ReflectType) fillTagInfo(field *StructField) {
	if len(field.JsonTag) == 0 {
		field.JsonTag = field.Name
	}

	// jsonTag 去掉 omitempty
	jsonTagValArr := strings.Split(field.JsonTag, ",")
	for _, item := range jsonTagValArr {
		if len(item) > 0 && item != OmitemptyTag {
			field.JsonTag = item
			break
		}
	}

	// 没有设置event tag,则和 json tag保持一致
	if len(field.EventTag) == 0 {
		field.EventTag = field.JsonTag
	}
}

// fillMappingRule 解析参数映射规则
//
// Author : go_developer@163.com<白茶清欢>
//
// Date : 17:14 2023/2/1
//
// mapping:"user_id:param#user_id|header#id"
func (rt *ReflectType) fillMappingRule(field *StructField, inputMappingVal string) {

	if len(inputMappingVal) == 0 {
		// 没有指定规则, 有默认规则
		for _, location := range mappingLocationList {
			field.MappingRuleList = append(field.MappingRuleList, MappingRuleItem{
				Location: location,
				Field:    field.JsonTag,
			})
		}
		return
	}
	mappingArr := strings.Split(inputMappingVal, ",")
	for _, item := range mappingArr {
		item = strings.TrimSpace(item)
		// 要赋值的字段名
		itemArr := strings.Split(item, ":")
		if len(itemArr) != 2 {
			// 配置格式错误, 跳过
			continue
		}
		mapRuleArr := strings.Split(strings.TrimSpace(itemArr[1]), "|")
		for _, itemMapRule := range mapRuleArr {
			itemMapRule = strings.TrimLeft(itemMapRule, "#")
			itemMapRuleArr := strings.Split(itemMapRule, "#")
			// 注意 : # 为特殊分隔符, 如配置成 mapping:"project_id:#source_project_id#xxx_project_id" 实际等价于 mapping:"project_id:#source_project_id" 多余配置自动跳过
			if len(itemMapRuleArr[0]) < 2 {
				// 没有指定位置，默认all, 即配置格式: mapping:"project_id:#source_project_id"
				itemMapRuleArr[0] = MappingLocationAll
				itemMapRuleArr = []string{MappingLocationAll, itemMapRuleArr[0]}
			}

			switch itemMapRuleArr[0] {
			// 从header读取
			case MappingLocationHeader:
				field.MappingRuleList = append(field.MappingRuleList, MappingRuleItem{
					Location: MappingLocationHeader,
					Field:    itemMapRuleArr[1],
				})
			// 从请求参数读取
			case MappingLocationParam:
				field.MappingRuleList = append(field.MappingRuleList, MappingRuleItem{
					Location: MappingLocationParam,
					Field:    itemMapRuleArr[1],
				})
			// 从响应数据读取
			case MappingLocationResponse:
				field.MappingRuleList = append(field.MappingRuleList, MappingRuleItem{
					Location: MappingLocationResponse,
					Field:    itemMapRuleArr[1],
				})
			// 从扩展数据读取
			case MappingLocationExtension:
				field.MappingRuleList = append(field.MappingRuleList, MappingRuleItem{
					Location: MappingLocationExtension,
					Field:    itemMapRuleArr[1],
				})
				// 全部读取一遍
			case MappingLocationAll:
				fallthrough
			default:
				for _, itemLocation := range mappingLocationList {
					field.MappingRuleList = append(field.MappingRuleList, MappingRuleItem{
						Location: itemLocation,
						Field:    itemMapRuleArr[1],
					})
				}
			}
		}
	}
}