mail() inline error checking

[generic]

I have a basic PHP mail processor and I'm looking to add 'inline' error checking. First off, here's the basic code I'm using:

FORM.PHP:

<form method="post" action="mail.php">
Your Email:<br />
<input name="email" type="text" /><br />
Subject:<br />
<input name="subject" type="text" /><br />
Recipient:<br />
<select name="recipient" />
  <option selected>Recipient</option>
  <option value="[e-mail]">Guy #1</option>
  <option value="[e-mail]">Guy #2</option>
</select>
Message:<br />
<textarea name="message" rows="15" cols="40">
</textarea><br />
<input type="submit" />
</form>

MAIL.PHP:

<?
$email = $_REQUEST['email'] ;
$recipient = $_REQUEST['recipient'] ;
$subject = $_REQUEST['subject'] ;
$message = $_REQUEST['message'] ;

mail( "$recipient", "$subject",
$message, "From: $email" );
header( "Location: [url]http://www.blah.com/thankyou.html[/url]" );
?>

What I'd like to do is add error checking that will display an error for any null required fields beside the field in question (ie:

Your Email:
[email field here] *An Email Address Is Required

Also, I'm not sure if $recipient will work as I've obviously intended here. Anyway, I hope you guys n' gals know what I mean by all this and have some advice!

Thanks in advance,

• gen

[jpmoriarty]

just add if statements before it to test for the various conditions:

if(empty($_POST['email']))
{
  header("Location:error.php?missing=email");
}
elseif(empty($_POST['subject']))
{
  header("Location:error.php?missing=subject");
}
else
{
  mail(...);
  header...
}

not a problem

[amchargue]

A rather minor drawback with that approach is that it will only display the first error the script encounters rather
than all errors that might be present in the submitted form. And having an error.php page doesn't sound like what
you asked in your question, unless error.php would also include the form.

You could just have form.php submit to itself, do
error checking at the top, header to mail.php if no errors, else show form again with values and errors:

FORM.PHP:

<?
if (isset($_POST['submit'])) { //relies on submit button being named; maybe just if (isset($_POST))  ???

//set vars
$email = $_POST['email'] ; // you use $_REQUEST in your mail.php, I'm not familiar with that, so I'm using $_POST
$recipient = $_POST['recipient'] ;
$subject = $_POST['subject'] ;
$message = $_POST['message'] ;

//check vars
if (check_email($email)==0) $err_email = "Email error msg."; //check_email is a built-in PHP funciton
if (check_email($recipient)=="") $err_recipient = "Recipient error msg.";
if ($subject=="") $err_subject = "Subject error msg.";
if ($message=="") $err_message = "Message error msg.";

} //end if 

?>

<form method="post" action="mail.php">
Your Email:<br />
<input name="email" type="text" /><br /><? if (isset($err_email)) echo $err_email; ?>
Subject:<br />
<input name="subject" type="text" /><br /><? if (isset($err_subject)) echo $err_subject; ?>
Recipient:<br />
<select name="recipient" />
  <option selected>Recipient</option>
  <option value="[e-mail]">Guy #1</option>
  <option value="[e-mail]">Guy #2</option>
</select><? if (isset($err_recipient)) echo $err_recipient; //i guess an error here is rather unlikely
?>
Message:<br />
<textarea name="message" rows="15" cols="40">
</textarea><br /><? if (isset($err_message)) echo $err_message; ?>
<input type="submit" />
</form>

You could also write the values into those fields so the user wouldn't have to re-type. But I've cluttered up your code enough already ...

[generic]

Thanks! That's exactly what I needed. At least now I have a point of reference I can error check things on. The help is appreciated greatly amchargue! 🙂