Checking if URL or email

[DeadlySin3]

What would be the best way to go about checking users input - to see if they entered an e-mail address or a URL?

[Weedpacket]

A couple of regular expressions; one to see if it looks like an email address, one that looks to see if it looks like a URL.

[DeadlySin3]

:eek:

Yeah, well PCRE's are Not my thing. heh. I'm still fairly new to php. An example of how new i am - the for-loop gives me headaches. :o

Think maybe i could get a snippet or a link to show how this is done?

[julesdw]

For emails you want to check if the key elements are present. You could go as far as to check the the SMTP (mail) host in question as an SMTP server will tell you if a user is valid. HTTP is somewhat easier then an email address I would think.

Of course, you may not be able to avoid the problem that the user enters a valid address syntax wise but not a real one.. eg. [e-mail].

There is a script here which will validate an email address. I don't know how well it works.

http://www.evilwalrus.com/viewcode/587.php

Jules...

[Norman_Graham]

Here are two examples taken from Wrox Beginning PHP4. A purchase I thoroughly recommend for other beginners.

The first is a simple e-mail check. It only checks whether an e-mail conforms to the rules of forming e-mail addresses. If you want to check if the address actually exists, you'll have to go a whole lot further.

<?php
//email_check.php
function emailcheck($intext) {
   $theresults = ereg("^[^@ ]+@[^@ ]+\.[^@ \.]+$", $intext, $trashed);
   if ($theresults) { $isamatch = "Yes"; } else { $isamatch = "No"; }
   echo("E-mail address check for \"$intext\": $isamatch<br>\n");
}

emailcheck("ImaUser18523");
emailcheck("[e-mail]");
emailcheck("Bogus [email][e-mail][/email]");
emailcheck("Bogus@User@[e-mail]");
emailcheck("[e-mail]");

?>

Obviously, you'll want to alter this to suit but the ereg routine covers things like missing domain names, spaces etc. It won't stop people from entering [e-mail]

Now here's a very simple ereg routine for checking URLs. Again, it doesn't cover every eventuality and it doesn't, of course, check whether the URL exists. Indeed, it only covers very few eventualities - an address like internet://wwww.nochance.com.com would be accepted. You'll have to extend the ereg to cover standard protocols (http, ftp) and search for typos like //wwww. or //ww. and a thousand other things. Wrox makes it clear that this is only an example.

<?php
//urlcheck.php

function urlcheck($intext) {
   $theresults = ereg("^[a-zA-Z0-9]+://[^ ]+$", $intext, $trashed);
   if ($theresults) { $isamatch = "Yes"; } else { $isamatch = "No"; }
   print ("URL check for \"$intext\": $isamatch<br>\n");
}

# Main
urlcheck("www.whateverhost.com");
urlcheck("http://www.whateverhost.com/");
urlcheck("http://www.bogus host with spaces.com/");
urlcheck("http://www.abcd.cc/filenames should lack spaces.html");
urlcheck("http://www.abcd.cc/filenames%20should%20lack%20spaces.html");
urlcheck("ftp://ftp2.somegiantcompany.com/pub/largefiles/");
urlcheck("telnet://mytelnethost.org:8888");

?>

In both cases, you'll want to add a loop so that the code checks lists of e-mails/URLs dynamically rather than actually typing in the real addresses. The purpose of both these snippets is purely to show how such code works.

Best of luck

Norman

[Duey]

he asked for simple didnt he?

$form_data = $_POST['var'];

if (strstr($form_data, "http://")){
$form_type = "url";
}
else{
$form_type = "email";
}

now thats a lot less code isnt it

[Norman_Graham]

OK, I didn't read the original thread properly. But just supposing Deadly did want to check whether the input was kosher ...

btw Deadly, you want to run a few htmlspecialchars() lines on your variables before you do anything else with them. There's no knowing what dastardly scripts people might enter into your form.

Norman

[DeadlySin3]

Originally posted by Norman Graham
OK, I didn't read the original thread properly. But just supposing Deadly did want to check whether the input was kosher ...


btw Deadly, you want to run a few htmlspecialchars() lines on your variables before you do anything else with them. There's no knowing what dastardly scripts people might enter into your form.

Norman

o.O

Thanks for all the replies! I was pretty much looking for a way to see if a field contained a url or an e-mail - looks like dueys way is definitely the easiest. Though, it would be great to validate the syntax as well.

Norman, I use strip_tags() when processing the input so html can't be used.

[planetsim]

To make it really simple.. if your checking for email and url see if theres an @ present if so its a email.. Then just make sure using regex.. then do the url stuff. Also make sure its a proper url..

[Duey]

theres many ways of checking emails you could just do it by checking if theres a "@" in it or you can do it by exploding "@" and getting the domain and making it a ip (forgot command) and if it works its a valid email, checking the front part is pointless these days as servers are advancing allowing more characters it just becomes in practiacal

[Weedpacket]

In the PEAR collection there is an RFC822-compliant address validator. Further checking beyond what is done there will be needed to see if the top-level domain is recognised (two-letter nation code or one of .com, .mil, .museum, etc.).

URL checking can be done with parse_url() and seeing if the resulting bits are valid.

I was thinking about a single RFC822 regexp, but research got me only as far as
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and it still does't cover things like comment strings. Needless to say, a staged approach like that used in PEAR's Mail/RFC822.php library is a better way to go. It depends on how careful you want to be.</sup>

[DeadlySin3]

heh.

As a coder, you'd have to appreciate the depth of that snippet.

To be honest w/you guys|gals, i'm working on a simple tagboard script [ Newest Version ] [ Stable Version ] and going that far might be a bit over doing it lol.

You see, what i'm trying to do, is allow a user to enter in either an email addy, or a URL in the url field: their preference.

With the advice & snippets handed to me, i'm more then sure I can accomplish that goal. I can't express my gratitude enough to those of you who contributed. Many thanks!

-Paul
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