How to generate unique username - PHP - php

Question

I have strings of usernames in array . I want to generate a unique string of username which do not exits in array.(probably with some numbers following the username)
How do I achieve this?
I have summarize the code:
function generate_unique_username(){
$firstname = "james";//data coming from user
$lastname = "oduro";//data coming from user
$new_username = $firstname.$lastname;
$usersnames = array("james39","oduro32","kwame93","elvisasante","frimpong32","edward32","jamesoduro");
//Loop through ARRAY usernames and check elements against VAR $new_username
if (in_array($new_username, $usersnames)) {
//generate new username which is not inside array
//the new generated string should also be check against array to ensure is doens not exit.
}else{
return $new_username;
}
}
Thank you.

Answer 1

Generating username from the stored array is not a good practice, I would suggest you to use the database.
If you are using the database instead of the array, you can use the best method to generate the unique username as following:
function generate_unique_username(){
$firstname = "james";//data coming from user
$lastname = "oduro";//data coming from user
$new_username = $firstname.$lastname;
/* Note: writing here pseudo sql code, replace with the actual php mysql query syntax */
$query = "SELECT COUNT(id) as user_count FROM user WHERE username like '%".$new_username."%'";
$result = mysql_query($query);
$count = $result['user_count'];
if(!empty($count)) {
$new_username = $new_username . $count;
}
return $new_username;
}

Answer 2

I think in this case you should first off try and assign cooler user names to the users then when that fails you go for a number suffix. This is an approach I may use. You may need to change the code to your more preferred and secured mysqli call like using the PDO or MySQLI prepared statement.
//function that will be used to figure out if the user name is available or not
function isAvailable($userName){
global $mysqli;
$result = $mysqli->query("SELECT id FROM users WHERE user_name='$userName'") or die($mysqli->error());
// We know username exists if the rows returned are more than 0
if ( $result->num_rows > 0 ) {
//echo 'User with this username already exists!';
return false;
}else{
return true;
}
}
function generate_unique_username($firstname, $lastname, $id){
$userNamesList = array();
$firstChar = str_split($firstname, 1)[0];
$firstTwoChar = str_split($firstname, 2)[0];
/**
* an array of numbers that may be used as suffix for the user names index 0 would be the year
* and index 1, 2 and 3 would be month, day and hour respectively.
*/
$numSufix = explode('-', date('Y-m-d-H'));
// create an array of nice possible user names from the first name and last name
array_push($userNamesList,
$firstname, //james
$lastname, // oduro
$firstname.$lastname, //jamesoduro
$firstname.'.'.$lastname, //james.oduro
$firstname.'-'.$lastname, //james-oduro
$firstChar.$lastname, //joduro
$firstTwoChar.$lastname, //jaoduro,
$firstname.$numSufix[0], //james2019
$firstname.$numSufix[1], //james12 i.e the month of reg
$firstname.$numSufix[2], //james28 i.e the day of reg
$firstname.$numSufix[3] //james13 i.e the hour of day of reg
);
$isAvailable = false; //initialize available with false
$index = 0;
$maxIndex = count($userNamesList) - 1;
// loop through all the userNameList and find the one that is available
do {
$availableUserName = $userNamesList[$index];
$isAvailable = isAvailable($availableUserName);
$limit = $index >= $maxIndex;
$index += 1;
if($limit){
break;
}
} while (!$isAvailable );
// if all of them is not available concatenate the first name with the user unique id from the database
// Since no two rows can have the same id. this will sure give a unique username
if(!$isAvailable){
return $firstname.$userId;
}
return $availableUserName;
}
//Get the unique user id from your database, for now let's go with 30
$userId = 30;
echo generate_unique_username('john', 'oduro', $userId);
Also, it would be nice to provide a fallback feature where the user can change their user name to any other unique value, in case they do not like the auto-generated value.