time = time(); $this->startSession(); } /** * startSession - Performs all the actions necessary to * initialize this session object. Tries to determine if the * the user has logged in already, and sets the variables * accordingly. Also takes advantage of this page load to * update the active visitors tables. */ function startSession(){ global $database; //The database connection session_start(); //Tell PHP to start the session /* Determine if user is logged in */ $this->logged_in = $this->checkLogin(); /** * Set guest value to users not logged in, and update * active guests table accordingly. */ if(!$this->logged_in){ $this->username = $_SESSION['username'] = GUEST_NAME; $this->userlevel = GUEST_LEVEL; $database->addActiveGuest($_SERVER['REMOTE_ADDR'], $this->time); } /* Update users last active timestamp */ else{ $database->addActiveUser($this->username, $this->time); } /* Remove inactive visitors from database */ $database->removeInactiveUsers(); $database->removeInactiveGuests(); /* Set referrer page */ if(isset($_SESSION['url'])){ $this->referrer = $_SESSION['url']; }else{ $this->referrer = "/"; } /* Set current url */ $this->url = $_SESSION['url'] = $_SERVER['PHP_SELF']; } /** * checkLogin - Checks if the user has already previously * logged in, and a session with the user has already been * established. Also checks to see if user has been remembered. * If so, the database is queried to make sure of the user's * authenticity. Returns true if the user has logged in. */ function checkLogin(){ global $database; //The database connection /* Check if user has been remembered */ if(isset($_COOKIE['cookname']) && isset($_COOKIE['cookid'])){ $this->username = $_SESSION['username'] = $_COOKIE['cookname']; $this->userid = $_SESSION['userid'] = $_COOKIE['cookid']; } /* Username and userid have been set and not guest */ if(isset($_SESSION['username']) && isset($_SESSION['userid']) && $_SESSION['username'] != GUEST_NAME){ /* Confirm that username and userid are valid */ if($database->confirmUserID($_SESSION['username'], $_SESSION['userid']) != 0){ /* Variables are incorrect, user not logged in */ unset($_SESSION['username']); unset($_SESSION['userid']); return false; } /* User is logged in, set class variables */ $this->userinfo = $database->getUserInfo($_SESSION['username']); $this->username = $this->userinfo['username']; $this->userid = $this->userinfo['userid']; $this->userlevel = $this->userinfo['userlevel']; return true; } /* User not logged in */ else{ return false; } } /** * login - The user has submitted his username and password * through the login form, this function checks the authenticity * of that information in the database and creates the session. * Effectively logging in the user if all goes well. */ function login($subuser, $subpass, $subremember){ global $database, $form; //The database and form object /* Username error checking */ $field = "user"; //Use field name for username if(!$subuser || strlen($subuser = trim($subuser)) == 0){ $form->setError($field, "* Username not entered"); } else{ /* Check if username is not alphanumeric */ if(!eregi("^([0-9a-z])*$", $subuser)){ $form->setError($field, "* Username not alphanumeric"); } } /* Password error checking */ $field = "pass"; //Use field name for password if(!$subpass){ $form->setError($field, "* Password not entered"); } /* Return if form errors exist */ if($form->num_errors > 0){ return false; } /* Checks that username is in database and password is correct */ $subuser = stripslashes($subuser); $result = $database->confirmUserPass($subuser, md5($subpass)); /* Check error codes */ if($result == 1){ $field = "user"; $form->setError($field, "* Username not found"); } else if($result == 2){ $field = "pass"; $form->setError($field, "* Invalid password"); } /* Return if form errors exist */ if($form->num_errors > 0){ return false; } /* Username and password correct, register session variables */ $this->userinfo = $database->getUserInfo($subuser); $this->username = $_SESSION['username'] = $this->userinfo['username']; $this->userid = $_SESSION['userid'] = $this->generateRandID(); $this->userlevel = $this->userinfo['userlevel']; /* Insert userid into database and update active users table */ $database->updateUserField($this->username, "userid", $this->userid); $database->addActiveUser($this->username, $this->time); $database->removeActiveGuest($_SERVER['REMOTE_ADDR']); /** * This is the cool part: the user has requested that we remember that * he's logged in, so we set two cookies. One to hold his username, * and one to hold his random value userid. It expires by the time * specified in constants.php. Now, next time he comes to our site, we will * log him in automatically, but only if he didn't log out before he left. */ if($subremember){ setcookie("cookname", $this->username, time()+COOKIE_EXPIRE, COOKIE_PATH); setcookie("cookid", $this->userid, time()+COOKIE_EXPIRE, COOKIE_PATH); } /* Login completed successfully */ return true; } /** * logout - Gets called when the user wants to be logged out of the * website. It deletes any cookies that were stored on the users * computer as a result of him wanting to be remembered, and also * unsets session variables and demotes his user level to guest. */ function logout(){ global $database; //The database connection /** * Delete cookies - the time must be in the past, * so just negate what you added when creating the * cookie. */ if(isset($_COOKIE['cookname']) && isset($_COOKIE['cookid'])){ setcookie("cookname", "", time()-COOKIE_EXPIRE, COOKIE_PATH); setcookie("cookid", "", time()-COOKIE_EXPIRE, COOKIE_PATH); } /* Unset PHP session variables */ unset($_SESSION['username']); unset($_SESSION['userid']); /* Reflect fact that user has logged out */ $this->logged_in = false; /** * Remove from active users table and add to * active guests tables. */ $database->removeActiveUser($this->username); $database->addActiveGuest($_SERVER['REMOTE_ADDR'], $this->time); /* Set user level to guest */ $this->username = GUEST_NAME; $this->userlevel = GUEST_LEVEL; } /** * register - Gets called when the user has just submitted the * registration form. Determines if there were any errors with * the entry fields, if so, it records the errors and returns * 1. If no errors were found, it registers the new user and * returns 0. Returns 2 if registration failed. */ function register($infoArray){ global $database, $form, $mailer; //The database, form and mailer object /* Username error checking */ $field = "user"; //Use field name for username if(!$infoArray['subuser'] || strlen($infoArray['subuser'] = trim($infoArray['subuser'])) == 0){ $form->setError($field, "* Username not entered"); } else{ /* Spruce up username, check length */ $infoArray['subuser'] = stripslashes($infoArray['subuser']); if(strlen($infoArray['subuser']) < 3){ $form->setError($field, "* Username below 3 characters"); } else if(strlen($infoArray['subuser']) > 30){ $form->setError($field, "* Username above 30 characters"); } /* Check if username is not alphanumeric */ else if(!eregi("^([0-9a-z])+$", $infoArray['subuser'])){ $form->setError($field, "* Username not alphanumeric"); } /* Check if username is reserved */ else if(strcasecmp($infoArray['subuser'], GUEST_NAME) == 0){ $form->setError($field, "* Username reserved word"); } /* Check if username is already in use */ else if($database->usernameTaken($infoArray['subuser'])){ $form->setError($field, "* Username already in use"); } /* Check if username is banned */ else if($database->usernameBanned($infoArray['subuser'])){ $form->setError($field, "* Username banned"); } } /* Password error checking */ $field = "pass"; //Use field name for password if(!$infoArray['subpass']){ $form->setError($field, "* Password not entered"); } else{ /* Spruce up password and check length*/ $infoArray['subpass'] = stripslashes($infoArray['subpass']); if(strlen($infoArray['subpass']) < 4){ $form->setError($field, "* Password too short"); } /* Check if password is not alphanumeric */ else if(!eregi("^([0-9a-z])+$", ($infoArray['subpass'] = trim($infoArray['subpass'])))){ $form->setError($field, "* Password not alphanumeric"); } /** * Note: I trimmed the password only after I checked the length * because if you fill the password field up with spaces * it looks like a lot more characters than 4, so it looks * kind of stupid to report "password too short". */ } /* Email error checking */ $field = "email"; //Use field name for email if(!$infoArray['subemail'] || strlen($infoArray['subemail'] = trim($infoArray['subemail'])) == 0){ $form->setError($field, "* Email not entered"); } else{ /* Check if valid email address */ $regex = "^[_+a-z0-9-]+(\.[_+a-z0-9-]+)*" ."@[a-z0-9-]+(\.[a-z0-9-]{1,})*" ."\.([a-z]{2,}){1}$"; if(!eregi($regex,$infoArray['subemail'])){ $form->setError($field, "* Email invalid"); } $infoArray['subemail'] = stripslashes($infoArray['subemail']); } /* Errors exist, have user correct them */ if($form->num_errors > 0){ return 1; //Errors with form } /* No errors, add the new account to the db*/ else{ $infoArray['subpass'] = md5($infoArray['subpass']); if($valKey = $database->addNewUser($infoArray)){ if(EMAIL_WELCOME){ $mailer->sendWelcome($infoArray['subuser'],$infoArray['subemail'],$infoArray['subpassc'], $valKey); } return 0; //New user added succesfully }else{ return 2; //Registration attempt failed } } } /** * editAccount - Attempts to edit the user's account information * including the password, which it first makes sure is correct * if entered, if so and the new password is in the right * format, the change is made. All other fields are changed * automatically. */ function editAccount($infoArray){ global $database, $form; //The database and form object /* New password entered */ if($infoArray[subnewpass]){ /* Current Password error checking */ $field = "curpass"; //Use field name for current password if(!$infoArray[subcurpass]){ $form->setError($field, "* Current Password not entered"); } else{ /* Check if password too short or is not alphanumeric */ $infoArray[subcurpass] = stripslashes($infoArray[subcurpass]); if(strlen($infoArray[subcurpass]) < 4 || !eregi("^([0-9a-z])+$", ($infoArray[subcurpass] = trim($infoArray[subcurpass])))){ $form->setError($field, "* Current Password incorrect"); } /* Password entered is incorrect */ if($database->confirmUserPass($this->username,md5($infoArray[subcurpass])) != 0){ $form->setError($field, "* Current Password incorrect"); } } /* New Password error checking */ $field = "newpass"; //Use field name for new password /* Spruce up password and check length*/ $subpass = stripslashes($infoArray[subnewpass]); if(strlen($infoArray[subnewpass]) < 4){ $form->setError($field, "* New Password too short"); } /* Check if password is not alphanumeric */ else if(!eregi("^([0-9a-z])+$", ($infoArray[subnewpass] = trim($infoArray[subnewpass])))){ $form->setError($field, "* New Password not alphanumeric"); } } /* Change password attempted */ else if($infoArray[subcurpass]){ /* New Password error reporting */ $field = "newpass"; //Use field name for new password $form->setError($field, "* New Password not entered"); } /* Email error checking $field = "email"; //Use field name for email if($subemail && strlen($subemail = trim($subemail)) > 0){ // Check if valid email address $regex = "^[_+a-z0-9-]+(\.[_+a-z0-9-]+)*" ."@[a-z0-9-]+(\.[a-z0-9-]{1,})*" ."\.([a-z]{2,}){1}$"; if(!eregi($regex,$subemail)){ $form->setError($field, "* Email invalid"); } $subemail = stripslashes($subemail); }*/ /* Errors exist, have user correct them */ if($form->num_errors > 0){ return false; //Errors with form } $database->updateUserField($this->username,"headline",$infoArray[subheadline]); $database->updateUserField($this->username,"ufname",$infoArray[subfname]); $database->updateUserField($this->username,"ulname",$infoArray[sublname]); $database->updateUserField($this->username,"gender",$infoArray[subgender]); $database->updateUserField($this->username,"phone",$infoArray[subphone]); $database->updateUserField($this->username,"deglvl",$infoArray[subdeglvl]); $database->updateUserField($this->username,"indlvl",$infoArray[subindlvl]); $database->updateUserField($this->username,"ececonc",$infoArray[subececonc]); $database->updateUserField($this->username,"site",$infoArray[subsite]); /* Update password since there were no errors */ if($infoArray[subcurpass] && $infoArray[subnewpass]){ $database->updateUserField($this->username,"password",md5($infoArray[subnewpass])); } /* Change Email if($subemail){ $database->updateUserField($this->username,"email",$subemail); }*/ /* Success! */ return true; } /** * isAdmin - Returns true if currently logged in user is * an administrator, false otherwise. */ function isAdmin(){ return ($this->userlevel == ADMIN_LEVEL || $this->username == ADMIN_NAME); } /** * generateRandID - Generates a string made up of randomized * letters (lower and upper case) and digits and returns * the md5 hash of it to be used as a userid. */ function generateRandID(){ return md5($this->generateRandStr(16)); } /** * generateRandStr - Generates a string made up of randomized * letters (lower and upper case) and digits, the length * is a specified parameter. */ function generateRandStr($length){ $randstr = ""; for($i=0; $i<$length; $i++){ $randnum = mt_rand(0,61); if($randnum < 10){ $randstr .= chr($randnum+48); }else if($randnum < 36){ $randstr .= chr($randnum+55); }else{ $randstr .= chr($randnum+61); } } return $randstr; } function verifyMemValKey($memName, $valKey) { global $database; //The database object $verifyResult = $database->verifyMemKey($memName, $valKey); if($verifyResult == 0) { $database->updateUserField($memName,"userlevel","2"); $database->updateUserField($memName,"key","fin"); echo("exit point\n"); return 0; } return $verifyResult; } }; /** * Initialize session object - This must be initialized before * the form object because the form uses session variables, * which cannot be accessed unless the session has started. */ $session = new Session; /* Initialize form object */ $form = new Form; ?>
    
 


  • Figure 1: HKN Crest

    Welcome to Eta Kappa Nu (Sigma Chapter), at Carnegie Mellon! We shorten our name to HKN, for brevity's sake. Chapters of Eta Kappa Nu, the Electrical and Computer Engineering Honor Society, exist at nearly 200 colleges and universities worldwide. Members of Sigma Chapter at Carnegie Mellon University strive to serve Carnegie Mellon's Department of Electrical and Computer Engineering and their fellow students through service projects, professional enhancement activities and social events. Sigma Chapter's goal is to provide Carnegie Mellon ECE students with opportunities to meaningfully interact with faculty members, industry leaders, and their peers.

    It is a distinctive honor to be recognized as a member of Eta Kappa Nu at Carnegie Mellon. Only the top one-fourth of juniors, one-third of seniors and select graduate students are offered admission to Eta Kappa Nu through Sigma Chapter.

    CMU's Sigma Chapter has over 295 current members. We are undergraduates, masters, and PhD students that strive to build a community within the ECE department -- uniting students, faculty members, industry leaders, and their peers. Through scholarship, character, and attitude, we uphold the highest standards to be the best engineers we can be.

    Membership requires a standing of top fourth in the junior class, top third in the senior class, and top third in the graduate students. Once inducted, the student is a member of HKN for life. HKN is very active on campus. Please take some time to view our activities, including mentoring events, corporate relations, student-led tours, and social happenings.

Welcome. members present, guests present.

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