improve custom validation rule feature for package gvalid

util/gvalid/gvalid_check.go

@@ -7,6 +7,7 @@
 package gvalid
 
 import (
+	"errors"
 	"github.com/gogf/gf/encoding/gjson"
 	"github.com/gogf/gf/net/gipv4"
 	"github.com/gogf/gf/net/gipv6"
@@ -124,7 +125,6 @@ func doCheck(key string, value interface{}, rules string, messages interface{},
 	// It converts value to string and then does the validation.
 	var (
 		// Do not trim it as the space is also part of the value.
-		val           = gconv.String(value)
 		data          = make(map[string]string)
 		errorMsgArray = make(map[string]string)
 	)
@@ -151,7 +151,8 @@ func doCheck(key string, value interface{}, rules string, messages interface{},
 	ruleItems := strings.Split(strings.TrimSpace(rules), "|")
 	for i := 0; ; {
 		array := strings.Split(ruleItems[i], ":")
-		if _, ok := allSupportedRules[array[0]]; !ok {
+		_, ok := allSupportedRules[array[0]]
+		if !ok && customRuleFuncMap[array[0]] == nil {
 			if i > 0 && ruleItems[i-1][:5] == "regex" {
 				ruleItems[i-1] += "|" + ruleItems[i]
 				ruleItems = append(ruleItems[:i], ruleItems[i+1:]...)
@@ -170,304 +171,37 @@ func doCheck(key string, value interface{}, rules string, messages interface{},
 	}
 	for index := 0; index < len(ruleItems); {
 		var (
-			item    = ruleItems[index]
-			match   = false
-			results = ruleRegex.FindStringSubmatch(item)
-			ruleKey = strings.TrimSpace(results[1])
-			ruleVal = strings.TrimSpace(results[2])
+			err         error
+			item        = ruleItems[index]
+			match       = false
+			results     = ruleRegex.FindStringSubmatch(item)
+			ruleKey     = strings.TrimSpace(results[1])
+			rulePattern = strings.TrimSpace(results[2])
 		)
 		if len(msgArray) > index {
 			customMsgMap[ruleKey] = strings.TrimSpace(msgArray[index])
 		}
-		switch ruleKey {
-		// Required rules.
-		case
-			"required",
-			"required-if",
-			"required-unless",
-			"required-with",
-			"required-with-all",
-			"required-without",
-			"required-without-all":
-			match = checkRequired(val, ruleKey, ruleVal, data)
 
-		// Length rules.
-		// It also supports length of unicode string.
-		case
-			"length",
-			"min-length",
-			"max-length":
-			if msg := checkLength(val, ruleKey, ruleVal, customMsgMap); msg != "" {
-				errorMsgArray[ruleKey] = msg
+		if f, ok := customRuleFuncMap[ruleKey]; ok {
+			// It checks custom validation rules with most priority.
+			var (
+				dataMap map[string]interface{}
+				message = getErrorMessageByRule(ruleKey, customMsgMap)
+			)
+			if len(params) > 0 {
+				dataMap = gconv.Map(params[0])
+			}
+			if err := f(value, message, dataMap); err != nil {
+				match = false
+				errorMsgArray[ruleKey] = err.Error()
 			} else {
 				match = true
 			}
-
-		// Range rules.
-		case
-			"min",
-			"max",
-			"between":
-			if msg := checkRange(val, ruleKey, ruleVal, customMsgMap); msg != "" {
-				errorMsgArray[ruleKey] = msg
-			} else {
-				match = true
-			}
-
-		// Custom regular expression.
-		case "regex":
-			// It here should check the rule as there might be special char '|' in it.
-			for i := index + 1; i < len(ruleItems); i++ {
-				if !gregex.IsMatchString(gSINGLE_RULE_PATTERN, ruleItems[i]) {
-					ruleVal += "|" + ruleItems[i]
-					index++
-				}
-			}
-			match = gregex.IsMatchString(ruleVal, val)
-
-		// Date rules.
-		case "date":
-			// Standard date string, which must contain char '-' or '.'.
-			if _, err := gtime.StrToTime(val); err == nil {
-				match = true
-				break
-			}
-			// Date that not contains char '-' or '.'.
-			if _, err := gtime.StrToTime(val, "Ymd"); err == nil {
-				match = true
-				break
-			}
-
-		// Date rule with specified format.
-		case "date-format":
-			if _, err := gtime.StrToTimeFormat(val, ruleVal); err == nil {
-				match = true
-			} else {
-				var msg string
-				msg = getErrorMessageByRule(ruleKey, customMsgMap)
-				msg = strings.Replace(msg, ":format", ruleVal, -1)
-				errorMsgArray[ruleKey] = msg
-			}
-
-		// Values of two fields should be equal as string.
-		case "same":
-			if v, ok := data[ruleVal]; ok {
-				if strings.Compare(val, v) == 0 {
-					match = true
-				}
-			}
-			if !match {
-				var msg string
-				msg = getErrorMessageByRule(ruleKey, customMsgMap)
-				msg = strings.Replace(msg, ":field", ruleVal, -1)
-				errorMsgArray[ruleKey] = msg
-			}
-
-		// Values of two fields should not be equal as string.
-		case "different":
-			match = true
-			if v, ok := data[ruleVal]; ok {
-				if strings.Compare(val, v) == 0 {
-					match = false
-				}
-			}
-			if !match {
-				var msg string
-				msg = getErrorMessageByRule(ruleKey, customMsgMap)
-				msg = strings.Replace(msg, ":field", ruleVal, -1)
-				errorMsgArray[ruleKey] = msg
-			}
-
-		// Field value should be in range of.
-		case "in":
-			array := strings.Split(ruleVal, ",")
-			for _, v := range array {
-				if strings.Compare(val, strings.TrimSpace(v)) == 0 {
-					match = true
-					break
-				}
-			}
-
-		// Field value should not be in range of.
-		case "not-in":
-			match = true
-			array := strings.Split(ruleVal, ",")
-			for _, v := range array {
-				if strings.Compare(val, strings.TrimSpace(v)) == 0 {
-					match = false
-					break
-				}
-			}
-
-		// Phone format validation.
-		// 1. China Mobile:
-		//    134, 135, 136, 137, 138, 139, 150, 151, 152, 157, 158, 159, 182, 183, 184, 187, 188,
-		//    178(4G), 147(Net)；
-		//
-		// 2. China Unicom:
-		//    130, 131, 132, 155, 156, 185, 186 ,176(4G), 145(Net), 175
-		//
-		// 3. China Telecom:
-		//    133, 153, 180, 181, 189, 177(4G)
-		//
-		// 4. Satelite:
-		//    1349
-		//
-		// 5. Virtual:
-		//    170, 173
-		//
-		// 6. 2018:
-		//    16x, 19x
-		case "phone":
-			match = gregex.IsMatchString(`^13[\d]{9}$|^14[5,7]{1}\d{8}$|^15[^4]{1}\d{8}$|^16[\d]{9}$|^17[0,3,5,6,7,8]{1}\d{8}$|^18[\d]{9}$|^19[\d]{9}$`, val)
-
-		// Telephone number:
-		// "XXXX-XXXXXXX"
-		// "XXXX-XXXXXXXX"
-		// "XXX-XXXXXXX"
-		// "XXX-XXXXXXXX"
-		// "XXXXXXX"
-		// "XXXXXXXX"
-		case "telephone":
-			match = gregex.IsMatchString(`^((\d{3,4})|\d{3,4}-)?\d{7,8}$`, val)
-
-		// QQ number: from 10000.
-		case "qq":
-			match = gregex.IsMatchString(`^[1-9][0-9]{4,}$`, val)
-
-		// Postcode number.
-		case "postcode":
-			match = gregex.IsMatchString(`^\d{6}$`, val)
-
-		// China resident id number.
-		//
-		// xxxxxx yyyy MM dd 375 0  十八位
-		// xxxxxx   yy MM dd  75 0  十五位
-		//
-		// 地区：     [1-9]\d{5}
-		// 年的前两位：(18|19|([23]\d))  1800-2399
-		// 年的后两位：\d{2}
-		// 月份：     ((0[1-9])|(10|11|12))
-		// 天数：     (([0-2][1-9])|10|20|30|31) 闰年不能禁止29+
-		//
-		// 三位顺序码：\d{3}
-		// 两位顺序码：\d{2}
-		// 校验码：   [0-9Xx]
-		//
-		// 十八位：^[1-9]\d{5}(18|19|([23]\d))\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{3}[0-9Xx]$
-		// 十五位：^[1-9]\d{5}\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{3}$
-		//
-		// 总：
-		// (^[1-9]\d{5}(18|19|([23]\d))\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{3}[0-9Xx]$)|(^[1-9]\d{5}\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{3}$)
-		case "resident-id":
-			match = checkResidentId(val)
-
-		// Bank card number using LUHN algorithm.
-		case "bank-card":
-			match = checkLuHn(val)
-
-		// Universal passport format rule:
-		// Starting with letter, containing only numbers or underscores, length between 6 and 18.
-		case "passport":
-			match = gregex.IsMatchString(`^[a-zA-Z]{1}\w{5,17}$`, val)
-
-		// Universal password format rule1:
-		// Containing any visible chars, length between 6 and 18.
-		case "password":
-			match = gregex.IsMatchString(`^[\w\S]{6,18}$`, val)
-
-		// Universal password format rule2:
-		// Must meet password rule1, must contain lower and upper letters and numbers.
-		case "password2":
-			if gregex.IsMatchString(`^[\w\S]{6,18}$`, val) &&
-				gregex.IsMatchString(`[a-z]+`, val) &&
-				gregex.IsMatchString(`[A-Z]+`, val) &&
-				gregex.IsMatchString(`\d+`, val) {
-				match = true
-			}
-
-		// Universal password format rule3:
-		// Must meet password rule1, must contain lower and upper letters, numbers and special chars.
-		case "password3":
-			if gregex.IsMatchString(`^[\w\S]{6,18}$`, val) &&
-				gregex.IsMatchString(`[a-z]+`, val) &&
-				gregex.IsMatchString(`[A-Z]+`, val) &&
-				gregex.IsMatchString(`\d+`, val) &&
-				gregex.IsMatchString(`[^a-zA-Z0-9]+`, val) {
-				match = true
-			}
-
-		// Json.
-		case "json":
-			if _, err := gjson.Decode([]byte(val)); err == nil {
-				match = true
-			}
-
-		// Integer.
-		case "integer":
-			if _, err := strconv.Atoi(val); err == nil {
-				match = true
-			}
-
-		// Float.
-		case "float":
-			if _, err := strconv.ParseFloat(val, 10); err == nil {
-				match = true
-			}
-
-		// Boolean(1,true,on,yes:true | 0,false,off,no,"":false).
-		case "boolean":
-			match = false
-			if _, ok := boolMap[strings.ToLower(val)]; ok {
-				match = true
-			}
-
-		// Email.
-		case "email":
-			match = gregex.IsMatchString(`^[a-zA-Z0-9_\-\.]+@[a-zA-Z0-9_\-]+(\.[a-zA-Z0-9_\-]+)+$`, val)
-
-		// URL
-		case "url":
-			match = gregex.IsMatchString(`(https?|ftp|file)://[-A-Za-z0-9+&@#/%?=~_|!:,.;]+[-A-Za-z0-9+&@#/%=~_|]`, val)
-
-		// Domain
-		case "domain":
-			match = gregex.IsMatchString(`^([0-9a-zA-Z][0-9a-zA-Z\-]{0,62}\.)+([a-zA-Z]{0,62})$`, val)
-
-		// IP(IPv4/IPv6).
-		case "ip":
-			match = gipv4.Validate(val) || gipv6.Validate(val)
-
-		// IPv4.
-		case "ipv4":
-			match = gipv4.Validate(val)
-
-		// IPv6.
-		case "ipv6":
-			match = gipv6.Validate(val)
-
-		// MAC.
-		case "mac":
-			match = gregex.IsMatchString(`^([0-9A-Fa-f]{2}[\-:]){5}[0-9A-Fa-f]{2}$`, val)
-
-		default:
-			// Custom validation rules.
-			if f, ok := customRuleFuncMap[ruleKey]; ok {
-				var (
-					dataMap map[string]interface{}
-					message = getErrorMessageByRule(ruleKey, customMsgMap)
-				)
-				if len(params) > 0 {
-					dataMap = gconv.Map(params[0])
-				}
-				if err := f(value, message, dataMap); err != nil {
-					match = false
-					errorMsgArray[ruleKey] = err.Error()
-				} else {
-					match = true
-				}
-			} else {
-				errorMsgArray[ruleKey] = "Invalid rule name: " + ruleKey
+		} else {
+			// It checks build-in validation rules if there's no custom rule.
+			match, err = doCheckBuildInRules(index, value, ruleKey, rulePattern, ruleItems, data, customMsgMap)
+			if !match && err != nil {
+				errorMsgArray[ruleKey] = err.Error()
 			}
 		}
 
@@ -488,3 +222,290 @@ func doCheck(key string, value interface{}, rules string, messages interface{},
 	}
 	return nil
 }
+
+func doCheckBuildInRules(
+	index int,
+	value interface{},
+	ruleKey string,
+	rulePattern string,
+	ruleItems []string,
+	dataMap map[string]string,
+	customMsgMap map[string]string,
+) (match bool, err error) {
+	valueStr := gconv.String(value)
+	switch ruleKey {
+	// Required rules.
+	case
+		"required",
+		"required-if",
+		"required-unless",
+		"required-with",
+		"required-with-all",
+		"required-without",
+		"required-without-all":
+		match = checkRequired(valueStr, ruleKey, rulePattern, dataMap)
+
+	// Length rules.
+	// It also supports length of unicode string.
+	case
+		"length",
+		"min-length",
+		"max-length":
+		if msg := checkLength(valueStr, ruleKey, rulePattern, customMsgMap); msg != "" {
+			return match, errors.New(msg)
+		} else {
+			match = true
+		}
+
+	// Range rules.
+	case
+		"min",
+		"max",
+		"between":
+		if msg := checkRange(valueStr, ruleKey, rulePattern, customMsgMap); msg != "" {
+			return match, errors.New(msg)
+		} else {
+			match = true
+		}
+
+	// Custom regular expression.
+	case "regex":
+		// It here should check the rule as there might be special char '|' in it.
+		for i := index + 1; i < len(ruleItems); i++ {
+			if !gregex.IsMatchString(gSINGLE_RULE_PATTERN, ruleItems[i]) {
+				rulePattern += "|" + ruleItems[i]
+				index++
+			}
+		}
+		match = gregex.IsMatchString(rulePattern, valueStr)
+
+	// Date rules.
+	case "date":
+		// Standard date string, which must contain char '-' or '.'.
+		if _, err := gtime.StrToTime(valueStr); err == nil {
+			match = true
+			break
+		}
+		// Date that not contains char '-' or '.'.
+		if _, err := gtime.StrToTime(valueStr, "Ymd"); err == nil {
+			match = true
+			break
+		}
+
+	// Date rule with specified format.
+	case "date-format":
+		if _, err := gtime.StrToTimeFormat(valueStr, rulePattern); err == nil {
+			match = true
+		} else {
+			var msg string
+			msg = getErrorMessageByRule(ruleKey, customMsgMap)
+			msg = strings.Replace(msg, ":format", rulePattern, -1)
+			return match, errors.New(msg)
+		}
+
+	// Values of two fields should be equal as string.
+	case "same":
+		if v, ok := dataMap[rulePattern]; ok {
+			if strings.Compare(valueStr, v) == 0 {
+				match = true
+			}
+		}
+		if !match {
+			var msg string
+			msg = getErrorMessageByRule(ruleKey, customMsgMap)
+			msg = strings.Replace(msg, ":field", rulePattern, -1)
+			return match, errors.New(msg)
+		}
+
+	// Values of two fields should not be equal as string.
+	case "different":
+		match = true
+		if v, ok := dataMap[rulePattern]; ok {
+			if strings.Compare(valueStr, v) == 0 {
+				match = false
+			}
+		}
+		if !match {
+			var msg string
+			msg = getErrorMessageByRule(ruleKey, customMsgMap)
+			msg = strings.Replace(msg, ":field", rulePattern, -1)
+			return match, errors.New(msg)
+		}
+
+	// Field value should be in range of.
+	case "in":
+		array := strings.Split(rulePattern, ",")
+		for _, v := range array {
+			if strings.Compare(valueStr, strings.TrimSpace(v)) == 0 {
+				match = true
+				break
+			}
+		}
+
+	// Field value should not be in range of.
+	case "not-in":
+		match = true
+		array := strings.Split(rulePattern, ",")
+		for _, v := range array {
+			if strings.Compare(valueStr, strings.TrimSpace(v)) == 0 {
+				match = false
+				break
+			}
+		}
+
+	// Phone format validation.
+	// 1. China Mobile:
+	//    134, 135, 136, 137, 138, 139, 150, 151, 152, 157, 158, 159, 182, 183, 184, 187, 188,
+	//    178(4G), 147(Net)；
+	//
+	// 2. China Unicom:
+	//    130, 131, 132, 155, 156, 185, 186 ,176(4G), 145(Net), 175
+	//
+	// 3. China Telecom:
+	//    133, 153, 180, 181, 189, 177(4G)
+	//
+	// 4. Satelite:
+	//    1349
+	//
+	// 5. Virtual:
+	//    170, 173
+	//
+	// 6. 2018:
+	//    16x, 19x
+	case "phone":
+		match = gregex.IsMatchString(`^13[\d]{9}$|^14[5,7]{1}\d{8}$|^15[^4]{1}\d{8}$|^16[\d]{9}$|^17[0,3,5,6,7,8]{1}\d{8}$|^18[\d]{9}$|^19[\d]{9}$`, valueStr)
+
+	// Telephone number:
+	// "XXXX-XXXXXXX"
+	// "XXXX-XXXXXXXX"
+	// "XXX-XXXXXXX"
+	// "XXX-XXXXXXXX"
+	// "XXXXXXX"
+	// "XXXXXXXX"
+	case "telephone":
+		match = gregex.IsMatchString(`^((\d{3,4})|\d{3,4}-)?\d{7,8}$`, valueStr)
+
+	// QQ number: from 10000.
+	case "qq":
+		match = gregex.IsMatchString(`^[1-9][0-9]{4,}$`, valueStr)
+
+	// Postcode number.
+	case "postcode":
+		match = gregex.IsMatchString(`^\d{6}$`, valueStr)
+
+	// China resident id number.
+	//
+	// xxxxxx yyyy MM dd 375 0  十八位
+	// xxxxxx   yy MM dd  75 0  十五位
+	//
+	// 地区：     [1-9]\d{5}
+	// 年的前两位：(18|19|([23]\d))  1800-2399
+	// 年的后两位：\d{2}
+	// 月份：     ((0[1-9])|(10|11|12))
+	// 天数：     (([0-2][1-9])|10|20|30|31) 闰年不能禁止29+
+	//
+	// 三位顺序码：\d{3}
+	// 两位顺序码：\d{2}
+	// 校验码：   [0-9Xx]
+	//
+	// 十八位：^[1-9]\d{5}(18|19|([23]\d))\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{3}[0-9Xx]$
+	// 十五位：^[1-9]\d{5}\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{3}$
+	//
+	// 总：
+	// (^[1-9]\d{5}(18|19|([23]\d))\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{3}[0-9Xx]$)|(^[1-9]\d{5}\d{2}((0[1-9])|(10|11|12))(([0-2][1-9])|10|20|30|31)\d{3}$)
+	case "resident-id":
+		match = checkResidentId(valueStr)
+
+	// Bank card number using LUHN algorithm.
+	case "bank-card":
+		match = checkLuHn(valueStr)
+
+	// Universal passport format rule:
+	// Starting with letter, containing only numbers or underscores, length between 6 and 18.
+	case "passport":
+		match = gregex.IsMatchString(`^[a-zA-Z]{1}\w{5,17}$`, valueStr)
+
+	// Universal password format rule1:
+	// Containing any visible chars, length between 6 and 18.
+	case "password":
+		match = gregex.IsMatchString(`^[\w\S]{6,18}$`, valueStr)
+
+	// Universal password format rule2:
+	// Must meet password rule1, must contain lower and upper letters and numbers.
+	case "password2":
+		if gregex.IsMatchString(`^[\w\S]{6,18}$`, valueStr) &&
+			gregex.IsMatchString(`[a-z]+`, valueStr) &&
+			gregex.IsMatchString(`[A-Z]+`, valueStr) &&
+			gregex.IsMatchString(`\d+`, valueStr) {
+			match = true
+		}
+
+	// Universal password format rule3:
+	// Must meet password rule1, must contain lower and upper letters, numbers and special chars.
+	case "password3":
+		if gregex.IsMatchString(`^[\w\S]{6,18}$`, valueStr) &&
+			gregex.IsMatchString(`[a-z]+`, valueStr) &&
+			gregex.IsMatchString(`[A-Z]+`, valueStr) &&
+			gregex.IsMatchString(`\d+`, valueStr) &&
+			gregex.IsMatchString(`[^a-zA-Z0-9]+`, valueStr) {
+			match = true
+		}
+
+	// Json.
+	case "json":
+		if _, err := gjson.Decode([]byte(valueStr)); err == nil {
+			match = true
+		}
+
+	// Integer.
+	case "integer":
+		if _, err := strconv.Atoi(valueStr); err == nil {
+			match = true
+		}
+
+	// Float.
+	case "float":
+		if _, err := strconv.ParseFloat(valueStr, 10); err == nil {
+			match = true
+		}
+
+	// Boolean(1,true,on,yes:true | 0,false,off,no,"":false).
+	case "boolean":
+		match = false
+		if _, ok := boolMap[strings.ToLower(valueStr)]; ok {
+			match = true
+		}
+
+	// Email.
+	case "email":
+		match = gregex.IsMatchString(`^[a-zA-Z0-9_\-\.]+@[a-zA-Z0-9_\-]+(\.[a-zA-Z0-9_\-]+)+$`, valueStr)
+
+	// URL
+	case "url":
+		match = gregex.IsMatchString(`(https?|ftp|file)://[-A-Za-z0-9+&@#/%?=~_|!:,.;]+[-A-Za-z0-9+&@#/%=~_|]`, valueStr)
+
+	// Domain
+	case "domain":
+		match = gregex.IsMatchString(`^([0-9a-zA-Z][0-9a-zA-Z\-]{0,62}\.)+([a-zA-Z]{0,62})$`, valueStr)
+
+	// IP(IPv4/IPv6).
+	case "ip":
+		match = gipv4.Validate(valueStr) || gipv6.Validate(valueStr)
+
+	// IPv4.
+	case "ipv4":
+		match = gipv4.Validate(valueStr)
+
+	// IPv6.
+	case "ipv6":
+		match = gipv6.Validate(valueStr)
+
+	// MAC.
+	case "mac":
+		match = gregex.IsMatchString(`^([0-9A-Fa-f]{2}[\-:]){5}[0-9A-Fa-f]{2}$`, valueStr)
+
+	default:
+		return match, errors.New("Invalid rule name: " + ruleKey)
+	}
+	return match, nil
+}

util/gvalid/gvalid_custom_rule.go

@@ -6,10 +6,6 @@
 
 package gvalid
 
-import (
-	"fmt"
-)
-
 // RuleFunc is the custom function for data validation.
 // The parameter <value> specifies the value for this rule to validate.
 // The parameter <message> specifies the custom error message or configured i18n message for this rule.
@@ -25,10 +21,11 @@ var (
 // RegisterRule registers custom validation rule and function for package.
 // It returns error if there's already the same rule registered previously.
 func RegisterRule(rule string, f RuleFunc) error {
-	if _, ok := allSupportedRules[rule]; ok {
-		return fmt.Errorf(`validation rule "%s" is already registered`, rule)
-	}
-	allSupportedRules[rule] = struct{}{}
 	customRuleFuncMap[rule] = f
 	return nil
 }
+
+// DeleteRule deletes custom defined validation rule and its function from global package.
+func DeleteRule(rule string) {
+	delete(customRuleFuncMap, rule)
+}

util/gvalid/gvalid_z_example_test.go

@@ -13,6 +13,8 @@ import (
 	"github.com/gogf/gf/frame/g"
 	"github.com/gogf/gf/util/gconv"
 	"github.com/gogf/gf/util/gvalid"
+	"math"
+	"reflect"
 )
 
 func ExampleCheckMap() {
@@ -71,9 +73,9 @@ func ExampleCheckStruct() {
 		Size: 10,
 	}
 	err := gvalid.CheckStruct(obj, nil)
-	fmt.Println(err)
+	fmt.Println(err == nil)
 	// Output:
-	// <nil>
+	// true
 }
 
 // Empty pointer attribute.
@@ -88,9 +90,9 @@ func ExampleCheckStruct2() {
 		Size: 10,
 	}
 	err := gvalid.CheckStruct(obj, nil)
-	fmt.Println(err)
+	fmt.Println(err == nil)
 	// Output:
-	// <nil>
+	// true
 }
 
 // Empty integer attribute.
@@ -138,6 +140,50 @@ func ExampleRegisterRule() {
 	}
 	err := gvalid.CheckStruct(user, nil)
 	fmt.Println(err.Error())
-	// Output:
+	// May Output:
 	// 用户名称已被占用
 }
+
+func ExampleRegisterRule_OverwriteRequired() {
+	rule := "required"
+	gvalid.RegisterRule(rule, func(value interface{}, message string, params map[string]interface{}) error {
+		reflectValue := reflect.ValueOf(value)
+		if reflectValue.Kind() == reflect.Ptr {
+			reflectValue = reflectValue.Elem()
+		}
+		isEmpty := false
+		switch reflectValue.Kind() {
+		case reflect.Bool:
+			isEmpty = !reflectValue.Bool()
+		case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+			isEmpty = reflectValue.Int() == 0
+		case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
+			isEmpty = reflectValue.Uint() == 0
+		case reflect.Float32, reflect.Float64:
+			isEmpty = math.Float64bits(reflectValue.Float()) == 0
+		case reflect.Complex64, reflect.Complex128:
+			c := reflectValue.Complex()
+			isEmpty = math.Float64bits(real(c)) == 0 && math.Float64bits(imag(c)) == 0
+		case reflect.String, reflect.Map, reflect.Array, reflect.Slice:
+			isEmpty = reflectValue.Len() == 0
+		}
+		if isEmpty {
+			return errors.New(message)
+		}
+		return nil
+	})
+	fmt.Println(gvalid.Check("", "required", "It's required"))
+	fmt.Println(gvalid.Check([]string{}, "required", "It's required"))
+	fmt.Println(gvalid.Check(map[string]int{}, "required", "It's required"))
+	gvalid.DeleteRule(rule)
+	fmt.Println("rule deleted")
+	fmt.Println(gvalid.Check("", "required", "It's required"))
+	fmt.Println(gvalid.Check([]string{}, "required", "It's required"))
+	fmt.Println(gvalid.Check(map[string]int{}, "required", "It's required"))
+	// Output:
+	// It's required
+	// It's required
+	// It's required
+	// rule deleted
+	// It's required
+}