详解Javascript判断Crontab表达式是否合法

Javascript判断Crontab表达式是否合法

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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