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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