Javascript判断Crontab表达式是否合法

Posted 2020-09-29

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这段时间在做Quartz任务调度，使用的Crontab表达式实现的。Crontab由前端页面输入，作为参数穿入后台。
虽然Quartz具有校验Crontab表达式的方法，如下：

boolean cronExpressionFlag = CronExpression.isValidExpression(crontab);

但是我一直想在前端直接验证，即不需要通过异步的方式向后台获取验证结果，找了好久，发现没有现成的框架可以使用，于是自己根据网上搜索到的资料，写了这个js脚本。
这个脚本目前对日和星期的判断还有点小问题，不过不影响使用。
以后如果有时间，继续完善这个脚本，废话不多说了，上代码：

 function cronValidate() {
        var cron = $("#cron").val();
        var result = CronExpressionValidator.validateCronExpression(cron);
        if(result == true){
            alert("格式正确");  
        }
        else{
            alert("格式错误");
        }
        return CronExpressionValidator.validateCronExpression(cron);  
    } 
    function CronExpressionValidator() {  
    }  

    CronExpressionValidator.validateCronExpression = function(value) {  
        var results = true;  
        if (value == null || value.length == 0) {  
            return false;  
        }  

        // split and test length  
        var expressionArray = value.split(" ");  
        var len = expressionArray.length;  

        if ((len != 6) && (len != 7)) {  
            return false;  
        }  

        // check only one question mark  
        var match = value.match(/\?/g);  
        if (match != null && match.length > 1) {  
            return false;  
        }  

        // check only one question mark  
        var dayOfTheMonthWildcard = "";  

        // if appropriate length test parts  
        // [0] Seconds 0-59 , - * /  
        if (CronExpressionValidator.isNotWildCard(expressionArray[0], /[\*]/gi)) {  
            if (!CronExpressionValidator.segmentValidator("([0-9\\\\,-\\/])", expressionArray[0], [0, 59], "seconds")) {  
                return false;  
            }  
        }  

        // [1] Minutes 0-59 , - * /  
        if (CronExpressionValidator.isNotWildCard(expressionArray[1], /[\*]/gi)) {  
            if (!CronExpressionValidator.segmentValidator("([0-9\\\\,-\\/])", expressionArray[1], [0, 59], "minutes")) {  
                return false;  
            }  
        }  

        // [2] Hours 0-23 , - * /  
        if (CronExpressionValidator.isNotWildCard(expressionArray[2], /[\*]/gi)) {  
            if (!CronExpressionValidator.segmentValidator("([0-9\\\\,-\\/])", expressionArray[2], [0, 23], "hours")) {  
                return false;  
            }  
        }  

        // [3] Day of month 1-31 , - * ? / L W C  
        if (CronExpressionValidator.isNotWildCard(expressionArray[3], /[\*\?]/gi)) {  
            if (!CronExpressionValidator.segmentValidator("([0-9LWC\\\\,-\\/])", expressionArray[3], [1, 31], "days of the month")) {  
                return false;  
            }  
        } else {  
            dayOfTheMonthWildcard = expressionArray[3];  
        }  

        // [4] Month 1-12 or JAN-DEC , - * /  
        if (CronExpressionValidator.isNotWildCard(expressionArray[4], /[\*]/gi)) {  
            expressionArray[4] = CronExpressionValidator.convertMonthsToInteger(expressionArray[4]);  
            if (!CronExpressionValidator.segmentValidator("([0-9\\\\,-\\/])", expressionArray[4], [1, 12], "months")) {  
                return false;  
            }  
        }  

        // [5] Day of week 1-7 or SUN-SAT , - * ? / L C #  
        if (CronExpressionValidator.isNotWildCard(expressionArray[5], /[\*\?]/gi)) {  
            expressionArray[5] = CronExpressionValidator.convertDaysToInteger(expressionArray[5]);  
            if (!CronExpressionValidator.segmentValidator("([0-9LC#\\\\,-\\/])", expressionArray[5], [1, 7], "days of the week")) {  
                return false;  
            }  
        } else {  
            if (dayOfTheMonthWildcard == String(expressionArray[5])) {  
                return false;  
            }  
        }  

        // [6] Year empty or 1970-2099 , - * /  
        if (len == 7) {  
            if (CronExpressionValidator.isNotWildCard(expressionArray[6], /[\*]/gi)) {  
                if (!CronExpressionValidator.segmentValidator("([0-9\\\\,-\\/])", expressionArray[6], [1970, 2099], "years")) {  
                    return false;  
                }  
            }  
        }  
        return true;  
    }  

    // ----------------------------------  
    // isNotWildcard 静态方法;  
    // ----------------------------------  
    CronExpressionValidator.isNotWildCard = function(value, expression) {  
        var match = value.match(expression);  
        return (match == null || match.length == 0) ? true : false;  
    }  

    // ----------------------------------  
    // convertDaysToInteger 静态方法;  
    // ----------------------------------  
    CronExpressionValidator.convertDaysToInteger = function(value) {  
        var v = value;  
        v = v.replace(/SUN/gi, "1");  
        v = v.replace(/MON/gi, "2");  
        v = v.replace(/TUE/gi, "3");  
        v = v.replace(/WED/gi, "4");  
        v = v.replace(/THU/gi, "5");  
        v = v.replace(/FRI/gi, "6");  
        v = v.replace(/SAT/gi, "7");  
        return v;  
    }  

    // ----------------------------------  
    // convertMonthsToInteger 静态方法;  
    // ----------------------------------  
    CronExpressionValidator.convertMonthsToInteger = function(value) {  
        var v = value;  
        v = v.replace(/JAN/gi, "1");  
        v = v.replace(/FEB/gi, "2");  
        v = v.replace(/MAR/gi, "3");  
        v = v.replace(/APR/gi, "4");  
        v = v.replace(/MAY/gi, "5");  
        v = v.replace(/JUN/gi, "6");  
        v = v.replace(/JUL/gi, "7");  
        v = v.replace(/AUG/gi, "8");  
        v = v.replace(/SEP/gi, "9");  
        v = v.replace(/OCT/gi, "10");  
        v = v.replace(/NOV/gi, "11");  
        v = v.replace(/DEC/gi, "12");  
        return v;  
    }  

    // ----------------------------------  
    // segmentValidator 静态方法;  
    // ----------------------------------  
    CronExpressionValidator.segmentValidator = function(expression, value, range, segmentName) {  
        var v = value;  
        var numbers = new Array();  

        // first, check for any improper segments  
        var reg = new RegExp(expression, "gi");  
        if (!reg.test(v)) {   
            return false;  
        }  

        // check duplicate types  
        // check only one L  
        var dupMatch = value.match(/L/gi);  
        if (dupMatch != null && dupMatch.length > 1) {  
            return false;  
        }  

        // look through the segments  
        // break up segments on ‘,‘  
        // check for special cases L,W,C,/,#,-  
        var split = v.split(",");  
        var i = -1;  
        var l = split.length;  
        var match;  

        while (++i < l) {  
            // set vars  
            var checkSegment = split[i];  
            var n;  
            var pattern = /(\w*)/;  
            match = pattern.exec(checkSegment);  

            // if just number  
            pattern = /(\w*)\-?\d+(\w*)/;  
            match = pattern.exec(checkSegment);  

            if (match  
                    && match[0] == checkSegment  
                    && checkSegment.indexOf("L") == -1  
                    && checkSegment.indexOf("l") == -1  
                    && checkSegment.indexOf("C") == -1  
                    && checkSegment.indexOf("c") == -1  
                    && checkSegment.indexOf("W") == -1  
                    && checkSegment.indexOf("w") == -1  
                    && checkSegment.indexOf("/") == -1  
                    && (checkSegment.indexOf("-") == -1 || checkSegment  
                            .indexOf("-") == 0) && checkSegment.indexOf("#") == -1) {  
                n = match[0];  

                if (n && !(isNaN(n)))  
                    numbers.push(n);  
                else if (match[0] == "0")  
                    numbers.push(n);  
                continue;  
            }  
    // includes L, C, or w  
            pattern = /(\w*)L|C|W(\w*)/i;  
            match = pattern.exec(checkSegment);  

            if (match  
                    && match[0] != ""  
                    && (checkSegment.indexOf("L") > -1  
                            || checkSegment.indexOf("l") > -1  
                            || checkSegment.indexOf("C") > -1  
                            || checkSegment.indexOf("c") > -1  
                            || checkSegment.indexOf("W") > -1 || checkSegment  
                            .indexOf("w") > -1)) {  

                // check just l or L  
                if (checkSegment == "L" || checkSegment == "l")  
                    continue;  
                pattern = /(\w*)\d+(l|c|w)?(\w*)/i;  
                match = pattern.exec(checkSegment);  

                // if something before or after  
                if (!match || match[0] != checkSegment) {   
                    continue;  
                }  

                // get the number  
                var numCheck = match[0];  
                numCheck = numCheck.replace(/(l|c|w)/ig, "");  

                n = Number(numCheck);  

                if (n && !(isNaN(n)))  
                    numbers.push(n);  
                else if (match[0] == "0")  
                    numbers.push(n);  
                continue;  
            }  

            var numberSplit;  

            // includes /  
            if (checkSegment.indexOf("/") > -1) {  
                // take first #  
                numberSplit = checkSegment.split("/");  

                if (numberSplit.length != 2) {   
                    continue;  
                } else {  
                    n = numberSplit[0];  

                    if (n && !(isNaN(n)))  
                        numbers.push(n);  
                    else if (numberSplit[0] == "0")  
                        numbers.push(n);  
                    continue;  
                }  
            }  

            // includes #  
            if (checkSegment.indexOf("#") > -1) {  
                // take first #  
                numberSplit = checkSegment.split("#");  

                if (numberSplit.length != 2) {    
                    continue;  
                } else {  
                    n = numberSplit[0];  

                    if (n && !(isNaN(n)))  
                        numbers.push(n);  
                    else if (numberSplit[0] == "0")  
                        numbers.push(n);  
                    continue; 
                } 
            }  

    // includes -  
            if (checkSegment.indexOf("-") > 0) {  
                // take both #  
                numberSplit = checkSegment.split("-");  

                if (numberSplit.length != 2) {   
                    continue;  
                } else if (Number(numberSplit[0]) > Number(numberSplit[1])) {  
                    continue;  
                } else {  
                    n = numberSplit[0];  

                    if (n && !(isNaN(n)))  
                        numbers.push(n);  
                    else if (numberSplit[0] == "0")  
                        numbers.push(n);  
                    n = numberSplit[1];  

                    if (n && !(isNaN(n)))  
                        numbers.push(n);  
                    else if (numberSplit[1] == "0")  
                        numbers.push(n);  
                    continue;  
                }  
            }  

        }  
        // lastly, check that all the found numbers are in range  
        i = -1;  
        l = numbers.length;  

        if (l == 0)  
            return false;  

        while (++i < l) {  
            // alert(numbers[i]);  
            if (numbers[i] < range[0] || numbers[i] > range[1]) {  
                return false;  
            }  
        }  
        return true;  
    }

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