PHP Form Validation - Deprecated Function eregi()

Question

I've just raised a separate question on a problem with an enquiry form that had a deprecated eregi PHP function. Unfortunately, there's another file I missed that validates the form which is riddled with them :(

Here's the code below:

   /* ERRORS */
    function error($str) // private
    {
        $this->error = true;
        $this->error_string .= $str;
    } 
    /* VALIDATE FIELD AGAINST TYPE */
    function checkit($value, $type) // private
    {
        $length = "";
        if (eregi("^MIN[0-9]+$", $type)) {
            $tmp = explode(":", $type);
            $length = $tmp[1];
            $type = "MINLENGTH";
        } 
        if (eregi("^MAX[0-9]+$", $type)) {
            $tmp = explode(":", $type);
            $length = $tmp[1];
            $type = "MAXLENGTH";
        } 

        switch ($type) {
            case "NOT_EMPTY":
                $this->error_tmp = "string cannot be empty";
                return $this->not_empty($value);
                break;

            case "MINLENGTH":
                if (strlen($value) < $length) {
                    $this->error_tmp = "string to short";
                    return false;
                } else {
                    return true;
                } 
                break;

            case "MAXLENGTH":
                if (strlen($value) > $length) {
                    $this->error_tmp = "string to long";
                    return false;
                } else {
                    return true;
                } 
                break;

            case "ALPHA":
                $exp = "^[a-z]+$";
                if ($this->not_empty($value) && eregi($exp, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "string not alpha";
                    return false;
                } 
                break;

            case "ALPHASPACE":
                $exp = "^[a-z ]+$";
                if ($this->not_empty($value) && eregi($exp, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "string not alphaspace";
                    return false;
                } 
                break;

            case "ALPHANUM":
                $exp = "^[a-z0-9]+$";
                if ($this->not_empty($value) && eregi($exp, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "string not alphanum";
                    return false;
                } 
                break;

            case "ALPHANUMSPACE":
                $exp = "^[a-z0-9 ]+$";
                if ($this->not_empty($value) && eregi($exp, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "string not alphanumspace";
                    return false;
                } 
                break;

            case "NUMERIC":
                $exp = "^[0-9]+$";
                if ($this->not_empty($value) && eregi($exp, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "string not numeric";
                    return false;
                } 
                break;

            case "NUMERICPLUS":
                $exp = "^[0-9+-.]+$";
                if ($this->not_empty($value) && eregi($exp, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "string not numericplus";
                    return false;
                } 
                break;

            case "EMAIL":
                $exp = "^[A-Z0-9._%-]+@[A-Z0-9.-]+\.[A-Z]{2,4}$";
                if ($this->not_empty($value) && eregi($exp, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "not a valid email";
                    return false;
                } 
                break;

            case "YYYYMMDD":
                $exp = "^(19|20)[0-9][0-9][- /.](0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])$";
                if ($this->not_empty($value) && eregi($exp, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "string not YYYYMMDD";
                    return false;
                } 
                break;

            case "DDMMYYYY":
                $exp = "^(0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[012])[- /.](19|20)[0-9][0-9]$";
                if ($this->not_empty($value) && eregi($exp, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "string not DDMMYYYY";
                    return false;
                } 
                break;

            case "MMDDYYYY":
                $exp = "^(0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])[- /.](19|20)[0-9][0-9]$";
                if ($this->not_empty($value) && eregi($exp, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "string not MMDDYYYY";
                    return false;
                } 
                break;

            default:
                if ($this->not_empty($value) && $this->regex($type, $value)) {
                    return true;
                } else {
                    $this->error_tmp = "string not valid";
                    return false;
                } 
        } 
    } 
    /* NOT_EMPTY */
    function not_empty($value) // private
    {
        if (trim($value) == "") {
            return false;
        } else {
            return true;
        } 
    } 

    /* REGULAR EXPRESSION */
    function regex($regex, $value) // private
    {
        $the_regex = 'ereg("' . $regex . '", "' . $value . '")';
        $the_code = '<?php if(' . $the_regex . ') { return true; } else { return false; } ?>';
        if (!eval('?>' . $the_code . '<?php ')) {
            return false;
        } else {
            return true;
        } 
    } 
}

Are there too many to change?

I hope someone can help?

Thanks in advance, kind regards

Brian

Answer 1

Regex has the "case-insensitive" way to match a string. If you put the letter "i" at the end of the regular expression, the function preg_match() will match the string even if you are searching a lowercase sentence in an uppercase string.

In the case ALPHA, you can use this regular expression:

$exp = "/^[a-z]+$/i";

instead of

$exp = "^[a-z]+$";

Using this, you can change the PHP functions from eregi($exp, $value) to preg_match($exp, $value), which will return TRUE if there are matches.

You can read the related documentation of preg_match() function here: https://www.php.net/manual/en/function.preg-match.php

Andrea