How to validate email address and website in commnet - php

Question

I want to validate email address and website in comment box. When someone writes comment in comment box and after submission check if email address or website found in comment remove that email and address.
I have put below regular expression for email.
"/(?:[a-z0-9!#$%&'*+=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+=?^_`{|}~-]+)*|\"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*\")#(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?\.)+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])/"
above expression validates email address but I want to validate like email[at]email[dot]com, email{at}email{dot}com, email(at)email(dot)com
Same for website validation I used below expression
"/((((http|https|ftp|ftps)\:\/\/)|www\.)[a-zA-Z0-9\-\.]+\.[a-zA-Z]{2,4}(\/\S*)?)/"
But I want to validate website like website[dot]com, www[dot]website[dot]com

Answer 1

Basically what you need to do is, where you have the validation of # and . character in email or . in weburl, you need to enhance your regex and put the alternatives to # character as you are expecting. So,
# should be written as (?:#|[[({]at[\]})])
And,
\. should be written as (?:\.|[[{(]dot[\]})])
wherever you have them in your regex and then it will also filter those strings as well.
Here is a modified regex for email.
(?:[a-z0-9!#$%&'*+=?^_`{|}~-]+(?:\.[a-z0-9!#$%&'*+=?^_`{|}~-]+)*|\"(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21\x23-\x5b\x5d-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])*\")(?:#|[[({]at[\]})])(?:(?:[a-z0-9](?:[a-z0-9-]*[a-z0-9])?(?:\.|[[{(]dot[\]})]))+[a-z0-9](?:[a-z0-9-]*[a-z0-9])?|\[(?:(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?)\.){3}(?:25[0-5]|2[0-4][0-9]|[01]?[0-9][0-9]?|[a-z0-9-]*[a-z0-9]:(?:[\x01-\x08\x0b\x0c\x0e-\x1f\x21-\x5a\x53-\x7f]|\\[\x01-\x09\x0b\x0c\x0e-\x7f])+)\])
Regex Demo for email
Same way you can replace . from your website regex and your modified regex becomes this,
(?:(?:(?:http|https|ftp|ftps)\:\/\/)|www(?:\.|[[{(]dot[\]})]))(?:[a-zA-Z0-9.-]|[[{(]dot[\]})])+(?:\.|[[{(]dot[\]})])[a-zA-Z]{2,4}(\/\S*)?
Regex Demo for web url
Now besides matching of [dot], {dot} and (dot), the regex will also match [dot} and similar and as you are trying to detect such strings further, hence matching these strings will be an added advantage, rather than a problem unless the context was otherwise.