title: To understand PHP's include -command
body: <p>I would like to have all variables accessible of the file <em>handler_login.php</em> which I <code>include</code> in the file <em>handler_question.php</em>. The <em>handler_question.php</em> processes the data from the following form.</p>
  
  <p><strong>My form_question.php</strong></p>
  
  <pre><code>&lt;form method="post" action="handler-question.php"&gt;
      &lt;p&gt;Title:
          &lt;input name="question_title" type="text" cols="92" /&gt;
      &lt;/p&gt;
      &lt;p&gt;Question:
          &lt;div id="wmd-container" class="resizable-textarea"&gt;
                  &lt;textarea id="input" class="textarea" tabindex="101" rows="15" cols="92" name="question_body" /&gt;&lt;/textarea&gt;
          &lt;/div&gt;
      &lt;/p&gt;
  
      &lt;p&gt;Tags:
          &lt;input name="tags" type="text" cols="92" /&gt;
      &lt;/p&gt; 
  
      &lt;input type="submit" value="OK" /&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>The following file is what the last file includes</p>
  
  <p><strong>My handler_login.php</strong></p>
  
  <pre><code>&lt;?php
  
  // independent variables
  $dbHost = "localhost";
  $dbPort = 5432;
  $dbName = "masi";
  $dbUser = "masi";
  $dbPassword = "123456";
  
  $conn = "host=$dbHost port=$dbPort dbname=$dbName user=$dbUser password=$dbPassword";
  
  // you can store the username and password to $_SESSION variable
  $dbconn = pg_connect($conn);
  
  if(!$dbconn) {
      exit;
  }
  
  $sql = "SELECT username, passhash_md5, email
      FROM users
      WHERE username = '{$_POST['username']}'
      AND email = '{$_POST['email']}'
      AND passhash_md5 = '{$_POST['password']}';";
  
  $result = pg_query($dbconn, $sql);
  if(!$result) {
      exit;
  }
  
  $username = $_POST['username'];
  $passhash_md5 = md5($_POST['password']);
  
  
   // COOKIE setting /*{{{*/
  
   /* $cookie may look like this:
     variables
          $username = "username"
          $passhash_md5 = "password-in-md5"
     before md5:
          "usernamepasshash_md5"
     after md5:
          "a08d367f31feb0eb6fb51123b4cd3cb7"
   */
  
  $login_cookie = md5(
      $username .
      $passhash_md5
  );
  
  $sql3 = "SELECT passhash_md5
  
  
              FROM users
              WHERE username=$_POST['username'];";
  
  $password_data_original = pg_query($dbconn, $sql3);
  
  while ($row = pg_fetch_row($data)) {
      $password_original = $row[0];
  }
  
  $login_cookie_original = md5(
      $username .
      $password_original
  );
  
  
  // Check for the Cookie
  if (isset($_COOKIE['login']) )
  {
  
      // Check if the Login Form is the same as the cookie
      if ( $login_cookie_original == $login_cookie )
      {
          header("Location: index.php");
          die("logged in");
      }
      header("Location: index.php");
      die("wrong username/password");
  }
      // If no cookie, try logging them in
  else
  {
      //Get the Data
      // we do not want SQL injection so we use pg_escape_string
      $sql2 = sprintf("SELECT * from users
                      WHERE passhash_md5='%s',
                      pg_escape_string($login_cookie));
      $raw_user_list = pg_query($dbconn, $sql2);
  
      if ($user = pg_fetch_row($row_user_list)) {
          setcookie ("login", $login_cookie);
          header("Location: index.php");
          die("logged in");
      } else {
          header("Location: index.php");
          die("wrong username/password");
      }
  }
  
  pg_close($dbconn);
  ?&gt;
  </code></pre>
  
  <p><strong>and finally my handler_question.php where the problem occurs</strong></p>
  
  <pre><code>&lt;?php
  
  include 'handler-login.php';                         // This is the problem
  
  $question_body = '{$_POST['question_body']}'        // I get an error right from the beginning
  $question_title = '{$_POST['question_title']}'
  
  $sql_questions_question_id = "SELECT question_id FROM users 
                                WHERE username = $username;"
  // $username comes from handler_login.php
  
  $questions_question_id = pg_query($dbconn, $sql_questions_question_id);
  
  // to get tags to an array 
  $tags = '{$_POST['question_tags']}'; 
  $tags_trimmed = trim($tags);
  $tags_array = explode(",", $tags_trimmed);
  
  // to save the cells in the array to db
  $sql_tags_insert = "INSERT INTO tags (tag, questions_question_id)
                      VALUES (for ($i = 0; $i &lt; count($tags_array); $i++)"
  
  
  $sql = "SELECT username, passhash_md5, email
      FROM users
      WHERE username = '{$_POST['username']}'       
      AND email = '{$_POST['email']}' 
      AND passhash_md5 = '{$_POST['password']}';";
  
  $result = pg_query($dbconn, $sql);
  if(!$result) {
      exit;
  }
  
  $username = $_POST['username'];
  $passhash_md5 = md5($_POST['password']);
  
  
  pg_close($dbconn);
  
  ?&gt;
  </code></pre>
  
  <p><em>How can you have all variables of handler_login.php to be accessible by handler_question.php?</em></p>