CFLib.org – Common Function Library Project

Description:
randStr returns a randomly generated string using lowercase letters, and/or numbers and possible uppercase letters. The length of the string can be set specifically or the function can choose a random length within a specified range. eg: "8,16" will generate a string 8 to 16 characters long: "5" would only generate strings with 5 characters. The characters used are based on your own preference. You may build a 'charset' using any of the three words "alpha, numeric, and upper". Alpha = a-z Upper = A-Z Numeric = 0-9

Return Values:
Returns a string.

Example:

<cfoutput>
#randStr("8,16", "alphanumericupper")#
</cfoutput>

Parameters:

Full UDF Source:

/**
 * Returns a randomly generated string using the specified character sets and length(s)
 * 
 * @param strLen      Either a number of a list of numbers representing the range in size of the returned string. (Required)
 * @param charset      A string describing the type of random string. Can contain: alpha, numeric, and upper. (Required)
 * @return Returns a string. 
 * @author Bobby Hartsfield (bobby@acoderslife.com) 
 * @version 2, April 2, 2007 
 */
function randStr(strLen, charSet) {
    var usableChars = "";
    var charSets = arrayNew(1);
    var tmpStr = "";    
    var newStr = "";
    var i = 0;
    var thisCharPos = 0;
    var thisChar = "";
    
    charSets[1] = '48,57';    // 0-9
    charSets[2] = '65,90';    // A-Z
    charSets[3] = '97,122';    // a=z
    
    if (findnocase('alpha', charSet)) { usableChars = listappend(usableChars, 3); }
    
    if (findnocase('numeric', charSet)) { usableChars = listappend(usableChars, 1); }
    
    if (findnocase('upper', charSet)) { usableChars = listappend(usableChars, 2); }
    
    if (len(usableChars) is 0) { usableChars = '1,2,3'; }

    if(listlen(strLen) gt 1 and listfirst(strLen) lt listlast(strLen)) { strLen = randrange(listfirst(strLen), listlast(strLen)); }
    else if (val(strLen) is 0) { strLen = 8; }
    
    
    while (len(tmpStr) LE strLen-1)
    {
        thisSet = listFirst(usableChars);
        usableChars = listdeleteat(usableChars, 1);
        usableChars = listappend(usableChars, thisSet);
    
        tmpStr = tmpStr & chr(randrange(listfirst(charSets[thisSet]), listlast(charSets[thisSet])));
    }
    
    for (i=1; i lte strLen; i=i+1)
    {
        thisCharPos = randrange(1, len(tmpStr));
        thisChar = mid(tmpStr, thisCharPos, 1);
        tmpStr = removeChars(tmPStr, thisCharPos, 1);
        newstr = newstr & thisChar;
    }
    
    return newStr;
}