validate username

[nathj]

Hi,

I'm working on a registration form and one of the checks I need to perform as the form is used is on the username. I need to ensure that it is not already in use. I am getting a little stuck. Here's the code involved (sorry there's quite a bit) and then I'll explain the problem.

HTML (relevant sample)

    <div class="row">
        <span class="label" id="usernamelabel">
            <span class="warninglabel">Username:</span>
        </span>
        <span class="formw">
            <input id="username" type="text" size="47" onchange="validateItem('usernamelabel',this.value,'Username:',4,false,5,true);" title="Username, for use on the Forum" />
            (6-18 alpha numeric characters)
        </span>
    </div>
 

Javascript (3 functions involved)

function stateChanged() 
{ 
    if (goXMLHTTP.readyState==4 || goXMLHTTP.readyState=="complete")
    { 
    document.getElementById(gcItemID).innerHTML=goXMLHTTP.responseText; 
    } 
} 
 
function GetXmlHttpObject()
{ 
    if (window.XMLHttpRequest)
    {
        goXMLHTTP=new XMLHttpRequest()
    }
    else if (window.ActiveXObject)
    {
        goXMLHTTP=new ActiveXObject("Microsoft.XMLHTTP")
    }     
    if (goXMLHTTP==null)
    {
        alert ("Browser does not support HTTP Request")
         return    
    } 
} 
 
 
function validateItem(pcID,pcItem,pcDisplay,pnType,plPopulateExtra,pnNumberOfItems,plCheckDatabase)    
{    
    var lcRegExp, llIsValid, llUseRegExp
    llIsValid = false 
    llUseRegExp = false
    switch (pnType)
    {
        case 1:    // UK postcode
            pcItem = pcItem.toUpperCase()     
            lcRegExp = '^[A-PR-UWYZ0-9][A-HK-Y0-9][AEHMNPRTVXY0-9]?[ABEHMNPRVWXY0-9]? {1,2}[0-9][ABD-HJLN-UW-Z]{2}|GIR 0AA$' 
            llUseRegExp = true
            break;
        case 2: // email address
            lcRegExp = '^[_A-Za-z0-9-]+(\\.[_A-Za-z0-9-]+)*@[A-Za-z0-9-]+(\\.[A-Za-z0-9-]+)*$'
            llUseRegExp = true            
            break;
        case 3: // number of set length - basic telephone number check
            lcRegExp = '^[0-9]{6,11}$'                                            
            llUseRegExp = true            
            break;
        case 4: // username and password validation - alpha numeric characters 6-18 characters long
            lcRegExp = '^[A-Za-z0-9]{6,18}$' 
            llUseRegExp = true            
            break;                             
    }
 
    if (llUseRegExp)
    {
        if (pcItem.match(lcRegExp))
        {    
            if(plCheckDatabase)
            {    
                GetXmlHttpObject() // sets the global variable
                gcItemID = pcID
                gcUrl = "../lib/datacheck.php?check=1&tocheck='" + pcItem + "'"
                goXMLHTTP.onreadystatechange=stateChanged 
                goXMLHTTP.open("GET",gcUrl,true)
                goXMLHTTP.send(null)
 
            }
            else
            {
                llIsValid = true
            }
        }
        else
        {              
            llIsValid = false
        }
    }    
    else
    {                 
        if (pcItem == null||pcItem == ""||pcItem.length < 2)
        {
            llIsValid = false
        }
        else
        {
            llIsValid = true
        }     
    }
 
    if (!plCheckDatabase)
    {
        if (llIsValid)                                
        {                
            document.getElementById(pcID).innerHTML = pcDisplay
            if (gnValidationCount >= 1)
            {
                gnValidationCount = gnValidationCount - 1
            }
        }
        else
        {    
            document.getElementById(pcID).innerHTML = "<span class='warninglabel'>" + pcDisplay + "</span>"
            if (gnValidationCount <= pnNumberOfItems)
            {
                gnValidationCount = gnValidationCount + 1
            }
        }     
    }
 
    if (gnValidationCount == 0)    
    {
        hideOrShowInput("complete",false)    
    }
    else
    {
        hideOrShowInput("complete",true)    
    }    
    if (plPopulateExtra)
    {
         populateExtra(lcSource, lcDestination, true, true)
    }  
}
 

PHP (the page referenced in validateItem())

<?php    
 
    // establish what is being checked via the $_REQUEST variable
    $lnCheckType    = $_REQUEST['check'];
    $lcItemToCheck    = $_REQUEST['tocheck'];    
    switch($lnCheckType)
    {
        case 1: // check for presence of username, will only ever be one match
            $lcCheckSQL = 
            "SELECT 1 as test
            FROM credential 
            WHERE username like '$lcItemToCheck'" ; 
 
            $laResult = $loDB->queryGetData($lcCheckSQL); 
 
            foreach($laResult as $lcTest)
            {
                $llAvailable = $lcTest['test'];
                if($llAvailable > 0)
                {
                    echo "<span class='warninglabel'>Username in use:</span>";
                }
                else
                {
                    echo "Username:";
                }
            }    
            break;    
 
        case 2:// just to show that we can expand this system should we ever need to 
            echo "case = 2";
            break;
    }
?>
 

The Problem

The php will echo the tow variables from $_REQUEST, and the $lcCheckSQL is defined correctly. However, there appears to be a problem with the way the SQL is executing as all that happens is the label that is supposed to change is blanked.

I believe the connection to the database is available, this is set at the top of the page that has the form on it and so should be available. Even if I add a connection to this page the behaviour is the same.

This is really frustrating now and I'd love some help with this.

Thanks for reading (I know it was long)

nathj

[ronnil]

try this query

"SELECT COUNT(*) as test FROM credential WHERE username='$IcItemToCheck'";

(note that i put single quotationmarks around the variable

another to check would be to just select everything WHERE username='yourvar' and test if the $result has any rows in it. If it has, the username or whatever is ofcourse illegal :)

[nathj]

try this query

"SELECT COUNT(*) as test FROM credential WHERE username='$IcItemToCheck'";

(note that i put single quotationmarks around the variable

another to check would be to just select everything WHERE username='yourvar' and test if the $result has any rows in it. If it has, the username or whatever is ofcourse illegal :)

Thanks for the help, I have further tracked down the trouble with this. If i change the php file to:

-->        
<?php    
    // establish what is being checked via the $_REQUEST variable
    $lnCheckType    = $_REQUEST['check'];
    $lcItemToCheck    = $_REQUEST['tocheck'];     
 
    //establish connection - using dataobject.php did not work?
    $lvCon = mysql_connect('server', 'user', 'password');
    if (!$lvCon)
    {
        die('Could not connect: ' . mysql_error());
    }
    mysql_select_db("clfdb", $lvCon);
 
    // branch the code
    switch($lnCheckType)
    {
        case 1: // check for presence of username, will only ever be one match or no match
            $lcToDisplay = "Username:";
 
            $lcCheckSQL = 
            "SELECT 1 as test 
            FROM credential 
            WHERE username like $lcItemToCheck" ; 
 
            $result = mysql_query($lcCheckSQL);
 
            while ($row = mysql_fetch_array($result))
            {
                $lnAvailable = $row['test'];
                if ($lnAvailable = 1)
                 {
                     $lcToDisplay = "<span class='warninglabel'>Username in use:</span>";
                 }
            }
 
            echo $lcToDisplay;
            break;    
 
        case 2:// just to show that we can expand this system should we ever need to 
            echo "case = 2";
            break;
    }            
?>
 

it works just fine. This indicates that there is some problem in the way I was attempting to use the data abstraction layer I have developed.

I have changed the SQL to your suggested use of COUNT(*) as this makes more sense when reading. Otherwise I will leave it as it is shown above for the time being and try to figure out a way of not duplicating code later on.

Thanks for the help.
nathj

[pbmods]

Heya, nathj.

Thanks for using CODE tags! Did you know that you can specify a language for your CODE tags to make your source code easier to read?

You will still need to use [/code] to close your code blocks, regardless of the language, but you can the use one of these tags to open your code block:

[code=html]
[code=javascript]
[code=php]

and so on.

Thanks!

MODERATOR

[nathj]

Heya, nathj.

Thanks for using CODE tags! Did you know that you can specify a language for your CODE tags to make your source code easier to read?

You will still need to use [/code] to close your code blocks, regardless of the language, but you can the use one of these tags to open your code block:

[code=html]
[code=javascript]
[code=php]

and so on.

Thanks!



MODERATOR

I did not know all that, I will make use of this in future - thanks for the pointer.

I should also say thanks for the help, I have now got this working. The relevant controls validated based on a regular expression and on the database as I wanted them to and the form works a treat.

Many thanks
Nathan