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)
[CODE=html]
<div class="row">
<span class="label" id="usernamelab el">
<span class="warningl abel">Username: </span>
</span>
<span class="formw">
<input id="username" type="text" size="47" onchange="valid ateItem('userna melabel',this.v alue,'Username: ',4,false,5,tru e);" title="Username , for use on the Forum" />
(6-18 alpha numeric characters)
</span>
</div>
[/CODE]

Javascript (3 functions involved)
[CODE=javascript]
function stateChanged()
{
if (goXMLHTTP.read yState==4 || goXMLHTTP.ready State=="complet e")
{
document.getEle mentById(gcItem ID).innerHTML=g oXMLHTTP.respon seText;
}
}

function GetXmlHttpObjec t()
{
if (window.XMLHttp Request)
{
goXMLHTTP=new XMLHttpRequest( )
}
else if (window.ActiveX Object)
{
goXMLHTTP=new ActiveXObject(" Microsoft.XMLHT TP")
}
if (goXMLHTTP==nul l)
{
alert ("Browser does not support HTTP Request")
return
}
}


function validateItem(pc ID,pcItem,pcDis play,pnType,plP opulateExtra,pn NumberOfItems,p lCheckDatabase)
{
var lcRegExp, llIsValid, llUseRegExp
llIsValid = false
llUseRegExp = false
switch (pnType)
{
case 1: // UK postcode
pcItem = pcItem.toUpperC ase()
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(l cRegExp))
{
if(plCheckDatab ase)
{
GetXmlHttpObjec t() // sets the global variable
gcItemID = pcID
gcUrl = "../lib/datacheck.php?c heck=1&tocheck= '" + pcItem + "'"
goXMLHTTP.onrea dystatechange=s tateChanged
goXMLHTTP.open( "GET",gcUrl,tru e)
goXMLHTTP.send( null)

}
else
{
llIsValid = true
}
}
else
{
llIsValid = false
}
}
else
{
if (pcItem == null||pcItem == ""||pcItem.leng th < 2)
{
llIsValid = false
}
else
{
llIsValid = true
}
}

if (!plCheckDataba se)
{
if (llIsValid)
{
document.getEle mentById(pcID). innerHTML = pcDisplay
if (gnValidationCo unt >= 1)
{
gnValidationCou nt = gnValidationCou nt - 1
}
}
else
{
document.getEle mentById(pcID). innerHTML = "<span class='warningl abel'>" + pcDisplay + "</span>"
if (gnValidationCo unt <= pnNumberOfItems )
{
gnValidationCou nt = gnValidationCou nt + 1
}
}
}

if (gnValidationCo unt == 0)
{
hideOrShowInput ("complete",fal se)
}
else
{
hideOrShowInput ("complete",tru e)
}
if (plPopulateExtr a)
{
populateExtra(l cSource, lcDestination, true, true)
}
}
[/CODE]

PHP (the page referenced in validateItem())
[CODE=php]
<?php

// establish what is being checked via the $_REQUEST variable
$lnCheckType = $_REQUEST['check'];
$lcItemToCheck = $_REQUEST['tocheck'];
switch($lnCheck Type)
{
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($laResu lt as $lcTest)
{
$llAvailable = $lcTest['test'];
if($llAvailable > 0)
{
echo "<span class='warningl abel'>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;
}
?>
[/CODE]

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='$IcIt emToCheck'";

(note that i put single quotationmarks around the variable

another to check would be to just select everything WHERE username='yourv ar' 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='$IcIt emToCheck'";

(note that i put single quotationmarks around the variable

another to check would be to just select everything WHERE username='yourv ar' 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:
[CODE=php]
-->
<?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($lnCheck Type)
{
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" ;

$result = mysql_query($lc CheckSQL);

while ($row = mysql_fetch_arr ay($result))
{
$lnAvailable = $row['test'];
if ($lnAvailable = 1)
{
$lcToDisplay = "<span class='warningl abel'>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;
}
?>
[/CODE]

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