Username verification if already exists in the database using PHP CodeIgniter, JQuery, AJAX

Question

I am trying to check the username's validity first before the user hits the submit button using Codeigniter. The status of the username if it is taken or not will just appear beside it.

Here is the JS in the view:

<script type="text/javascript" src="../assets/js/jquery.min.js"></script>
<script type="text/javascript"><!--
 $(document).ready(function() {
    $("#username").blur(function() {
        //remove all the class add the messagebox classes and start fading
        $("#msgbox").removeClass().addClass('messagebox').text('Checking...').fadeIn("slow");
        //check the username exists or not from ajax


        $.post("addpatient/check_user_availability",{ username:$(this).val() } ,function(data) {
            if(data=='no') {
                $("#msgbox").fadeTo(200,0.1,function() {  //start fading the messagebox

                    //add message and change the class of the box and start fading
                    $(this).html('This User name Already exists').addClass('messageboxerror').fadeTo(900,1);
                });

            }
            else {
                $("#msgbox").fadeTo(200,0.1,function() {  //start fading the messagebox

                    //add message and change the class of the box and start fading
                    $(this).html('Username available to register').addClass('messageboxok').fadeTo(900,1);    
                });
            }
        });

    });

});  
</script>

Here is a part of the form in html:

<form method="post" action="addpatient/insert" name="register">
        <table id='addpatient'>
            <tr>    
                <td width=100> Username:
                <td width=150>  <input type='text' id='username' name='username' value="<?php if(isset($_POST['username'])) echo $_POST['username']; ?>" placeholder="5-15 char" pattern=".{5,15}" required>
                <td> <span id="msgbox" style="display:none"></span>
                <td><div id="msgbox"></div>
            </tr>...

Here is the controller:

function check_user_availability()
    {
        $username = $this->input->post('username');

        //  Developed by Roshan Bhattarai 
        //  Visit http://roshanbh.com.np for this script and more.
        //  This notice MUST stay intact for legal use


        //this varible contains the array of existing users
        $existing_users=$this->user->get_all_usernames();
        //value got from the get metho
        $user_name= $username;

        //checking weather user exists or not in $existing_users array
        if (in_array($user_name, $existing_users))
        {
            //user name is not availble
            echo "no";
        } 
        else
        {
            //user name is available
            echo "yes";
        }
    }

And this is a function in the model:

function get_all_usernames() {
    $this->db->select('username');
    $this->db->from('users');
    $query = $this->db->get();
    return $query->result();
 }

However, when I run it, it always says that the username is available to register even though the username has been taken already.

Another problem is that it doesn't check the username's validity as the user types in his/her desired username in "real time". What I mean is, the user has to click on the next textfields first before the code checks the validity.

Please help me solve these problems. Thank you!

Answer 1

Try this:

function check_user_availability()
{
    $username   = $this->input->post('username');
    $result     = $this->user->get_all_usernames( $username );  #send the post variable to the model
    //value got from the get metho
    $user_name= $username;

    if( $result ){
        echo "no";
    }else{
        echo "yes";
    }
}

function get_all_usernames( $username ) {
    $this->db->select('username');
    $this->db->where('username', $username)
    $this->db->from('users', 1);
    $query = $this->db->get();
    if( $query->num_rows() > 0 ){
        return 0;
    }else{
        return 1;
    }
}

Changes in the script:

$(document).ready(function() {
    $("#username").keyup(function() {
        //remove all the class add the messagebox classes and start fading
        $("#msgbox").removeClass().addClass('messagebox').text('Checking...').fadeIn("slow");
        //check the username exists or not from ajax

        var name    = $(this).val();
        $.ajax({
            url     : "<?=base_url()?>addpatient/check_user_availability",
            data    : { username : name },
            type    : 'POST',
            success : function(data){
                if( data == '0' ){
                    $("#msgbox").fadeTo(200,0.1,function() {  //start fading the messagebox

                        //add message and change the class of the box and start fading
                        $(this).html('This User name Already exists').addClass('messageboxerror').fadeTo(900,1);
                    });
                }else if( data == '1' ){
                    $("#msgbox").fadeTo(200,0.1,function() {  //start fading the messagebox

                        //add message and change the class of the box and start fading
                        $(this).html('Username available to register').addClass('messageboxok').fadeTo(900,1);    
                    });
                }else{
                    alert("Some error occured! Check Console");
                }
            }
        });
    });
}); 

Answer 2

Controller:

function check_user_availability() {
    $username = $this->input->post('username');

    $this->form_validation->set_rules('username', 'Username', 'required|is_unique[users.username]');

    if ($this->form_validation->run() == FALSE) {
        //user name is not availble
        echo "no";
    } else {
        //user name is available
        echo "yes";
    }
}

Replace your check_user_availability() in controller with above. no need of using your get_all_usernames model.

View documentation for Form_Validation, set_rules