Explain when to use GET or POST. Provide example for both the ways.

Correct Answer: PHP supports single level inheritance Inheriting a class would mean creating a new class with all functionality of the existing class in addition to some more The created class is called as a subclass of the parent class Parent is a keyword which we use to access members of a parent class Inheritance is usually defined by using the keyword ?Extend? $this is used a reference to the calling object Inheritance avoids redundancy of code Example: Class employee extends manager : Here Employee is a subclass of manager Echo $this->name can be used to echo variable name of the parent class

Correct Answer: Generating random passwords in PHP can be done in multiple ways depending on how much security the application demands:- Md5 function can be passed one parameter as uniqid() function which in turn generates a random number Passing the parameter as TRUE in uniqid() adds additional uniqueness

Correct Answer: A HTML form should be build before uploading the file The following HTML code is used for selecting the file that is to be uploaded The type attribute of input must be ?file?

Choose a file to upload:

At the time of executing uploaderphp, the uploaded file will be stored in a temporary storage are on the webserver An associative array $_FILES['uploadedfile']['name'] is used for uploading The ?name? is the original file that is to be uploaded Another associative array $_FILES['uploadedfile']['tmp_name'] is used for placing the uploaded file in a temporary location on the server and the file should be empty and should exist with the tmp_name The following code snippet is used for uploading the file $target_path = "uploads/"; // the target location of the file $target_path = $target_path basename( $_FILES['uploadedfile']['name']); if(move_uploaded_file($_FILES['uploadedfile']['tmp_name'], $target_path)) { echo "The file " basename( $_FILES['uploadedfile']['name']) " has been uploaded"; } else { echo ?There was an error while uploading the file?; } The function move_uploaded_file()is used to place the source file into the destination folder, which resides on the server If the uploading is successful, the message ?The file filename has been uploaded Otherwise the error message ?There was an error while uploading the file? would be displayed

Correct Answer: The mail() function of PHP is quite robust for sending bulk emails A SMTP server can also be directly used from the script PHPmailer class can be used for sending emails

Correct Answer: To access the global data which is originating externally, the super globals are used The superglobals are available as arrays These superglobals represents the data from URLs, HTML forms, cookies, sessions and also the web server For this purpose, $HTTP_GET_VARS, $HTTP_POST_VARS are used The super globals are pretty good enough to be used in functions The following are the list of super globals $_GET, $_POST, $_COOKIE;$_REQUEST, $_SERVER, $_SESSION, $_ENV, $_FILE Another PHP Superglobal, called $GLOBALS; is available for persisting every variable with global scope

Correct Answer: The function setcookie() is used to define a cookie that is to be sent along with HTTP headers The cookie must be sent prior to any output from the script as is the protocol restriction After setting the cookies, they can be used when the next page is loaded by using $_COOKIE or $HTTP_COOKIE_VARS arrays

Correct Answer: A PHP Session persist the user information to be used later For example, user name, password, shopping item details The session is temporary and will be removed soon after the user has left the web site The session can be persisted for long term usage on databases like MySQL Each session is identified by a unique Id number for every visitor The first step to use PHP session is to start the session The starting session must precede the operations like HTML or the other The statement session_start() starts the PHP session and registers the user?s information on the server

Correct Answer: User names and passwords in PHP can be encrypted using md5 function MD5 function calculates the md5 hash of a string It is basically used for encryption It is also used for digital signature applications, where a large file must be "compressed" in a secure manner Example: Md5($str); Crypt() function can also be used to encrypt a string, It used MD5, DES or blow fish algorithms for encryption Syntax: Crypt(str, salt) Salt is an optional parameter used to increase the number of characters encoded, to make the encoding more secure

Correct Answer: Chmod() is used for changing permissions on a file Syntax: Chmod(file, mode) Mode here specifies the permissions as follows: The first number is always zero The second number specifies permissions for the owner The third number specifies permissions for the owner's user group The fourth number specifies permissions for everybody else Possible values (to set multiple permissions, add up the following numbers) 1 = execute permissions 2 = write permissions 4 = read permissions Example: // everything for owner, read for owner's group chmod("testtxt",0740);

Correct Answer: Opendir():- It opens the directory This function returns a directory stream on success and FALSE and an error on failure Syntax: Opendir(directory, context) Context is a set of options that can modify the behavior of a stream Example: opens sample directory $dir = opendir("directory"); Readdir(): It returns an entry from a directory handle opened by opendir() Syntax: Readdir(dir_stream) Example: $file = readdir($dir); closedir(): It closes a directory handle opened by opendir() Syntax: closedir(dir_stream) Example: $file = close($dir);