email_IsValid()

<?php
/**
 *
 * Validate an email address
 *
 * @author John B. Abela <github:johnabela>
 * @copyright 2019 https://4cm.com/
 * @created July 18, 2019
 * @version 1.0.0
 * @see https://gist.github.com/johnabela/9a41191e9946ed59addae447b3c72206
 * @param $email
 * @return bool
 * @usage if ( !email_IsValid($Email) ) { die('The email address you entered does not appear to be a valid email address.'); }
*/
function email_IsValid($email) {
    //
    //
    ///////////////////////////////////////////////////////////////////////
    //	Kill some email injection methods.
    //	The following characters are never used in an email address and are
    //	only used for email injections, which is vital we kill.
    ///////////////////////////////////////////////////////////////////////
    //
    $email = str_replace(';','', $email);  // Kill: Multiple Email Addresses
    $email = str_replace(',','', $email);  // Kill: Multiple Email Addresses
    $email = str_replace(' ','', $email);  // Kill: Spaces don't belong in emails
    $email = str_replace(':','', $email);  // Kill: Content-Type:multipart/mixed & header:
    $email = str_replace('/','', $email);  // Kill: Content-Type:multipart/mixed
    $email = str_replace('=','', $email);  // Kill: boundary=
    $email = str_replace('%','', $email);  // Kill: Carriage return (such as 0x0D/%0D in hexadecimal)
    $email = str_replace('\r','', $email); // Kill: Carriage returns
    $email = str_replace('\n','', $email); // Kill: Carriage returns
    $email = str_replace('&','', $email);  // Kill: @ character translation (such as &#64;)
    //
    //
    ///////////////////////////////////////////////////////////////////////
    //	Correct common tld typos
    ///////////////////////////////////////////////////////////////////////
    //
    if ( substr($email, -3) == 'cmo' ) {
        //
        $email = substr($email, 0, -3) . 'com';
        //
    }
    elseif ( substr($email, -3) == 'moc' ) {
        //
        $email = substr($email, 0, -3) . 'com';
        //
    }
    elseif ( substr($email, -3) == 'ocm' ) {
        //
        $email = substr($email, 0, -3) . 'com';
        //
    }
    elseif ( substr($email, -3) == 'nte' ) {
        //
        $email = substr($email, 0, -3) . 'net';
        //
    }
    elseif ( substr($email, -3) == 'etn' ) {
        //
        $email = substr($email, 0, -3) . 'net';
        //
    }
    elseif ( substr($email, -3) == 'ogr' ) {
        //
        $email = substr($email, 0, -3) . 'org';
        //
    }
    elseif ( substr($email, -3) == 'rog' ) {
        //
        $email = substr($email, 0, -3) . 'org';
        //
    }
    elseif ( substr($email, -3) == 'gor' ) {
        //
        $email = substr($email, 0, -3) . 'org';
        //
    }
    //
    //
    ///////////////////////////////////////////////////////////////////////
    //	Does email address have a @ and . symbol?
    ///////////////////////////////////////////////////////////////////////
    //
    if ((strpos($email,'@') === false) || (strpos($email,'.') === false)) {
        //
        return false;
        //
    }
    //
    //
    ///////////////////////////////////////////////////////////////////////
    //  Does email address have text between @ and .
    ///////////////////////////////////////////////////////////////////////
    //
    if (!trim(strstr(strstr($email,'@'),'.',true),'@.')) {
        //
        return false;
        //
    }
    //
    //
    ///////////////////////////////////////////////////////////////////////
    //  Does email address have text after period
    ///////////////////////////////////////////////////////////////////////
    //
    if ( !explode('.', substr($email, strrpos($email, '@')+1))[1] ) {
        //
        return false;
        //
    }
    //
    //
    ///////////////////////////////////////////////////////////////////////
    // Does email pass dns check?
    ///////////////////////////////////////////////////////////////////////
    //
    if (function_exists('idn_to_ascii') && defined('INTL_IDNA_VARIANT_UTS46')) {
        //
        $domain = idn_to_ascii(ltrim(stristr($email, '@'), '@') . '.', 0, INTL_IDNA_VARIANT_UTS46);
        //
        if ( !checkdnsrr($domain, 'ANY') ) {
            //
            return false;
            //
        }
        //
    }
    //
    return true;
    //
}