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Intro

go-rule-engine是用Golang实现的小型规则引擎,可以使用json串构造子规则,以及逻辑表达式表征子规则间逻辑运算关系。也可以通过直接构造子规则对象传入,这样方便子规则的持久化和复用。

Usage

    // build rules
	jsonRules := []byte(`[
	{"op": "=", "key": "Grade", "val": 3, "id": 1, "msg": "Grade not match"},
	{"op": "=", "key": "Sex", "val": "male", "id": 2, "msg": "not male"},
	{"op": ">=", "key": "Score.Math", "val": 90, "id": 3, "msg": "Math not so well"},
	{"op": ">=", "key": "Score.Physic", "val": 90, "id": 4, "msg": "Physic not so well"}
	]`)
	logic := "1 and not 2 and (3 or 4)"
	ruleToFit, err := NewRulesWithJSONAndLogic(jsonRules, logic)
	if err != nil {
		t.Error(err)
	}

	// prepare obj
	type Exams struct {
		Math int
		Physic int
	}
	type Student struct {
		Name string
		Grade int
		Sex string
		Score *Exams
	}
	Chris := &Student{
		Name: "Chris",
		Grade: 3,
		Sex: "female",
		Score: &Exams{Math: 88, Physic: 91},
	}

	// fit
	fit, msg := ruleToFit.Fit(Chris)
	t.Log(fit)
	t.Log(msg)
	// result
	true    // fit
	map[1:Grade not match 2:not male 4:Physic not so well]   // 注意:当fit=true,msg是命中的ruleIds
	Helen := &Student{
		Name: "Helen",
		Grade: 4,
		Sex: "female",
		Score: &Exams{Math: 96, Physic: 93},
	}
	// result
	false   				// fit
	map[1:Grade not match]   // msg

概念

子规则Rule
// key支持链式表达
{"op": ">=", "key": "Score.Physic", "val": 90, "id": 4, "msg": "Physic not so well"}

// Rule 最小单元,子规则
type Rule struct {
	Op  string      `json:"op"`  // 预算符
	Key string      `json:"key"` // 目标变量键名
	Val interface{} `json:"val"` // 目标变量子规则存值
	ID  int         `json:"id"`  // 子规则ID
	Msg string      `json:"msg"` // 该规则抛出的负提示
}
逻辑表达式logic
// 数字是rule的ID,当需要所有rule都为true,可以缺省写法:logic=""
"1 and not 2 and (3 or 4)"
规则Rules
// 即创建的ruleToFit对象
ruleToFit, err := NewRulesWithJSONAndLogic(jsonRules, logic)

// Rules 规则,拥有逻辑表达式
type Rules struct {
	Rules []*Rule // 子规则集合
	Logic string  // 逻辑表达式,使用子规则ID运算表达
	Name  string  // 规则名称
	Msg   string  // 规则抛出的负提示
}
匹配结果Fit
fit, msg := ruleToFit.Fit(Chris)
t.Log(fit)

false
原因msg
fit, msg := ruleToFit.Fit(Chris)
t.Log(fit)
t.Log(msg)

false
// fit=false, 键1是导致fit为false的那个rule的ID,值是那个rule的msg字段,用于提示
map[1:Grade not match]
// 注意:若fit=true, msg则是参与导致fit为true的那些rule的IDs,这是为了表达反向逻辑的规则中的原因

API

// NewRulesWithJSONAndLogic 用json串构造Rules的标准方法,logic表达式如果没有则传空字符串
func NewRulesWithJSONAndLogic(jsonStr []byte, logic string) (*Rules, error)

// NewRulesWithArrayAndLogic 用rule数组构造Rules的标准方法,logic表达式如果没有则传空字符串
func NewRulesWithArrayAndLogic(rules []*Rule, logic string) (*Rules, error) 

// Fit Rules匹配传入结构体
func (rs *Rules) Fit(o interface{}) (bool, map[int]string) 

// FitWithMap Rules匹配map
func (rs *Rules) FitWithMap(o map[string]interface{}) (bool, map[int]string) 

// FitAskVal Rules匹配结构体,同时返回所有子规则key对应实际值
func (rs *Rules) FitAskVal(o interface{}) (bool, map[int]string, map[int]interface{}) 

// FitWithMapAskVal Rules匹配map,同时返回所有子规则key对应实际值
func (rs *Rules) FitWithMapAskVal(o map[string]interface{}) (bool, map[int]string, map[int]interface{}) 

// GetRuleIDsByLogicExpression 根据逻辑表达式得到规则id列表
func GetRuleIDsByLogicExpression(logic string) ([]int, error) 

支持的算符

// 等于
case "=", "eq":

// 大于
case ">", "gt":

// 小于		
case "<", "lt":

// 大于或等于	
case ">=", "gte":

// 小于或等于		
case "<=", "lte":

// 不等于		
case "!=", "neq":

// 取值在...之中(val用逗号,分隔取值)		
case "@", "in":

// 取值不能在...之中		
case "!@", "nin":

// 正则表达式
case "^$", "regex":

// 为空不存在
case "0", "empty":

// 不为空
case "1", "nempty":

// 区间(只支持数字比较)
// 支持开闭区间格式,val="[,12.1]", "(1, 3]", "(8, )" etc.
case "<<", "between":

支持的逻辑

// 与
and

// 或
or

// 非
not

// 括号,可嵌套
()

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