Whenever I try to subscribe to a new newsletter I get the error:
" Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /home/jeremy/public_html/mailing_lists/user_transact.php on line 37

Warning: Cannot modify header information - headers already sent by (output started at /home/jeremy/public_html/mailing_lists/user_transact.php:37) in /home/jeremy/public_html/mailing_lists/user_transact.php on line 136"

My code for the page user_transact.php is:

<?php
require('config.php');

$conn = mysql_connect(SQL_HOST, SQL_USER, SQL_PASS)
 or die('Could not connect to MySQL database. ' . mysql_error());

mysql_select_db(SQL_DB,$conn);

if (isset($_REQUEST['action']))
{
 $headers = "From: " . ADMIN_E-MAIL . "\r\n";
 switch ($_REQUEST['action'])
 {
  case 'Remove':
   $sql = "SELECT user_id FROM ml_users " .
       "WHERE e-mail='" . $_POST['e-mail'] . "';";
   $result = mysql_query($sql,$conn);

   if (mysql_num_rows($result))
   {
    $row = mysql_fetch_array($result);
    $user_id = $row['user_id'];
    $url = "http://" . $_SERVER['HTTP_HOST'] .
       dirname($_SERVER['PHP_SELF']) .
       "/remove.php?u=" . $user_id .
       "&ml=" . $_POST['ml_id'];
    header("Location: $url");
    exit();
   }
   $redirect = 'user.php';
   break;
  case 'Subscribe':
   $sql = "SELECT user_id FROM ml_users " .
       "WHERE e-mail='" . $_POST['e-mail'] . "';";
   $result = mysql_query($sql,$conn);

   if (!mysql_num_rows($result))
   {
    $sql = "INSERT INTO ml_users " .
        "(firstname,lastname,e-mail) ".
        "VALUES ('" . $_POST['firstname'] . "'," .
        "'" . $_POST['lastname'] . "'," .
        "'" . $_POST['e-mail'] . "');";
    $result = mysql_query($sql, $conn);
    $user_id = mysql_insert_id($conn);
   }
   else
   {
    $row = mysql_fetch_array($result);
    $user_id = $row['user_id'];
   }

   $sql = "INSERT INTO ml_subscriptions (user_id,ml_id) " .
       "VALUES ('" . $user_id . "','" . $_POST['ml_id'] . "')";
   mysql_query($sql,$conn);

   $sql = "SELECT listname FROM ml_lists " .
       "WHERE ml_id=" . $_POST['ml_id'];
   $result = mysql_query($sql,$conn);
   $row = mysql_fetch_array($result);
   $listname = $row['listname'];

   $url = "http://" . $_SERVER['HTTP_HOST'] .
      dirname($_SERVER['PHP_SELF']) .
      "/user_transact.php?u=" . $user_id .
      "&ml=" . $_POST['ml_id'] . "&action=confirm";

   $subject = 'Mailing list confirmation';
   $body = "Hello " . $_POST['firstname'] . "\n" .
      "Our records indicate that you have subscribed to the " .
      $listname . " mailing list.\n\n" .
      "If you did not subscribe, please accept our apologies. " .
      "You will not be subscribed if you do not visit the " .
      "confirmation URL.\n\n" .
      "If you subscribed, please confirm this by visiting the " .
      "following URL:\n" . $url;

   mail($_POST['e-mail'],$subject,$body,$headers);

   $redirect = "thanks.php?u=" . $user_id . "&ml=" .
      $_POST['ml_id'] . "&t=s";
   break;


  case 'confirm':

   if (isset($_GET['u']) & isset($_GET['ml']))
   {
    $sql = "UPDATE ml_subscriptions SET pending=0 " .
        "WHERE user_id=" . $_GET['u'] .
        " AND ml_id=" . $_GET['ml'];
    mysql_query($sql, $conn);

    $sql = "SELECT listname FROM ml_lists " .
        "WHERE ml_id=" . $_GET['ml'];
    $result = mysql_query($sql,$conn);

    $row = mysql_fetch_array($result);
    $listname = $row['listname'];

    $sql = "SELECT * FROM ml_users " .
        "WHERE user_id='" . $_GET['u'] . "';";
    $result = mysql_query($sql,$conn);
    $row = mysql_fetch_array($result);
    $firstname = $row['firstname'];
    $e-mail = $row['e-mail'];

    $url = "http://" . $_SERVER['HTTP_HOST'] .
        dirname($_SERVER['PHP_SELF']) .
        "/remove.php?u=" . $_GET['u'] .
        "&ml=" . $_GET['ml'];

    // Send out confirmed e-mail
    $subject = 'Mailing List Subscription Confirmed';
    $body = "Hello " . $firstname . ",\n" .
       "Thank you for subscribing to the " .
       $listname . " mailing list. Welcome!\n\n" .
       "If you did not subscribe, please accept our apologies.\n".
       "You can remove this subscription immediately by ".
       "visiting the following URL:\n" . $url;

    mail($e-mail,$subject,$body,$headers);

    $redirect = "thanks.php?u=" . $_GET['u'] . "&ml=" .
       $_GET['ml'] . "&t=s";
   } else {
    $redirect = 'user.php';
   }
   break;

  default:
   $redirect = 'user.php';
 }
}

header('Location: ' . $redirect);

?>

Hi

I'm also receiving the same errors as Funky Monk from the user_transact script:

Warning: mysql_num_rows(): supplied argument is not a valid MySQL result resource in /hsphere/local/home/jamcp/jamesmcpherson.co.uk/kg_testing/user_transact.php on line 37

Warning: Cannot modify header information - headers already sent by (output started at /hsphere/local/home/jamcp/jamesmcpherson.co.uk/kg_testing/user_transact.php:37) in /hsphere/local/home/jamcp/jamesmcpherson.co.uk/kg_testing/user_transact.php on line 136


I've checked the Errata for the book and changed all occurances of $e-mail to $email as recommended.

As a newbie I'm unclear on how to implement the suggestions of Richard - can anyone suggest a solution to this problem?:(

TIA

The second error that you're seeing is a result of the first error. The header() function modifies the outgoing HTTP headers. The HTTP headers *must* go out before any content, e.g. the HTML document itself.

The first error that you're seeing is the real problem. mysql_num_rows is complaining that the resource handle passed to it isn't valid, this is the variable that's created when you call on mysql_query.

$result = mysql_query('Query stuff');

The $result variable is what's called a resource handle, it contains a pointer to the information contained in that query, but not the information itself. This pointer let's you call on functions like mysql_num_rows or mysql_fetch_array, which are functions that look at the information that pointer is referring to to tell you what you want to know about the query. When you see that error, then, that means that something went wrong with the creation of that resource pointer, most likely indicating an error in the SQL syntax used in the query. So adding a simple test of the pointer and functions that retrieve those potential errors tell you more about what went wrong and help you to correct the errors.

What's going on here is the $result variable is created after a call to mysql_query, directly after that call to mysql_query and the creation of the resource pointer, put in a check of that pointer to see if anything went wrong, if anything did tell the program to spit out some errors... this is done with the following snippet.

if (!$result)
{
    echo mysql_error()."<br />\n";

    // I'd even go so far as to dump out the $sql variable itself
    echo $sql."<br />\n";
}

This says if the resource pointer is FALSE, output some errors to find out what went wrong. If the resource was created successfully, it won't be FALSE and PHP will pass over this snippet of code. Does that make sense?

HTH!

Regards,
Rich

--
[http://www.smilingsouls.net]
[http://pear.php.net/Mail_IMAP] A PHP/C-Client/PEAR solution for webmail

I am new to Apache and php...
I followed the directions in the appendix and on pps. 15-16; after installation of Apache I got the success page. I customized the installation adding php with AddType statements (both of them), and then later on page 15 the instuctions state to enter LoadModule php4_module d:/php/sapi/php4apapche2.dll which I did, and then saved the changes. I made the changes stated on page 16, and I created a directory called test, entered the index.html text, but am unable to view the page. The error I get states that the module php4apache2.dll cannot be found, and yet when I checked in the files php/sapi/php4apache2.dll is just where it is supposed to be. Why can't the module be loaded and what must I do to get it to load? Thanks!

Hi saross, your question isn't on topic for this thread, please start a new thread or ask your question in a thread containing the same topic. Besides making more sense, this helps future forum visitors to find answers to their questions too.

That said, did you copy the php4ts.dll to the system32 directory?
http://www.php.net/manual/en/install.apache2.php

Regards,
Rich

--
[http://www.smilingsouls.net]
[http://pear.php.net/Mail_IMAP] A PHP/C-Client/PEAR solution for webmail

sorry, but I purchased the Beginning PHP, Apache, MySQL Web Development book by Wrox...I thought that this was the site to have those questions answered...

Well you have the right forum but how does this thread with the topic of *mailing lists - Chapter 13* fit the topic *installation problems*?!?

Regards,
Rich

--
[http://www.smilingsouls.net]
[http://pear.php.net/Mail_IMAP] A PHP/C-Client/PEAR solution for webmail

btw...Appendix I only mentions that the phpt4s.dll should be copied to d:/Program Files/Apache Group/Apache2/bin, which was what I did... After this post I promise I will find a thread on a similar subject or start a new one...

Thanks for the help Richard and taking time-out to explain the problem. After inserting the code you suggested I received this error:

unknown column 'e-mail' in 'where clause'

This pointed out that even though I had changed all instances of $e-mail to $email in my script I hadn't changed the name of the field in the database.

Once that was changed it works fine - thanks!

No worries ;) Glad to be of help!

Regards,
Rich

--
[http://www.smilingsouls.net]
[http://pear.php.net/Mail_IMAP] A PHP/C-Client/PEAR solution for webmail