Php

Front 1

What is a key concept to server-side scripting languages?

Back 1

A web server will only ever return a web-page

Front 2

What do web servers respond to requests for?

Back 2

CGI scripts

Front 3

CGI engines have what passed to them?

Back 3

Requests for CGI scripts, with parameters

Front 4

What protocol do the Apache, IIS, MySQL, and MS-SQL servers have?

Back 4

TCP/IP

Front 5

What is the process for a web-client process?

Back 5

Client to server:

HTTP request -> server to scripting engine

parameters -> scripting to database

SQL query and parameters -> database to scripting

recordset -> scripting to server

HTML output -> server to client

HTTP response

Front 6

What tier is PHP?

Back 6

Middle tier, server-side scripting web technology

Front 7

What does PHP generate?

Back 7

HTML output, in response to requests from a browser

Front 8

How does PHP work?

Back 8

Code is saved on an Apache server

The code is input, parsed, compiled, executed, and its output is shown on a web browser through HTML code

Front 9

How is a PHP script cached?

Back 9

It is pre-compiled, zend-compiled, then the op-codes are stored

Front 10

What functions can be used for debugging?

Back 10

print_r()

var_dump()

var_export()

xdebug

Front 11

What does the PHP Formal Specification specify?

Back 11

How PHP should work, defines structure, syntax, grammar of the language

Front 12

What is a data structure?

Back 12

A way of storing and organising data in a computer so it can be used efficiently

Front 13

How is text outputted?

Back 13

Echo, print, print_r, var_dump

Front 14

How do the logical operators &&, AND, compare against ||?

Back 14

|| has a higher priority than AND, but less than &&

Front 15

What are the four scalar data types?

Back 15

boolean

integer

float

string

Front 16

What are the two compound data types?

Back 16

Array

object

Front 17

What are the two special data types?

Back 17

Resource

NULL

Front 18

What property does a variable in PHP have?

Back 18

Its name and the content it stores can be independent of each other

Front 19

How do arrays in PHP behave?

Back 19

They are ordered maps, maps being a type that associates values to keys

Front 20

How can multidimensional arrays and trees be initialised in PHP?

Back 20

Arrays values can be other arrays - an array within an array

Front 21

How do you create single line comments?

Back 21

// or CTRL + /

Front 22

How do you create multi-line comments

Back 22

/* */ or Shift + CTRL + /

Front 23

How do you create Doc Blocks

Back 23

/** */

Front 24

What are strings known as?

Back 24

Literals, distinguishing them from variables

Front 25

Why are strings in single quotes processed faster than double quotes?

Back 25

PHP evaluates strings in double quotes, inserting values stored in embedded variables, if there are any

Front 26

What are string blocks?

Back 26

Constructs that handle blocks of text

Front 27

How are string blocks defined?

Back 27

'<<<'

Front 28

What are the two main types of string blocks?

Back 28

'HEREDOC' and 'NOWDOC'

Front 29

What is the difference between the two string blocks?

Back 29

HEREDOC can embed variables

Front 30

What are the requirements for a block close statement?

Back 30

Must start in column 0,

Must have a ';'

Must be a new line after the block close statement

Front 31

How do you typecast a variable in PHP?

Back 31

(type) $variable

Front 32

How do you define a web page header in PHP?

Back 32

$page_header = <<< HEADER

Front 33

How do you define a web page body in PHP?

Back 33

$page_body = <<< BODY

Front 34

How do you define a web page footer?

Back 34

$page_footer = <<< FOOTER

Front 35

What command is used to include files?

Back 35

include_once

Issues a warning if the file is not available

Front 36

What command is used to require files?

Back 36

require_once

Fatal error if the file is not available

Front 37

What is Agile Software Development?

Back 37

A group of software development methods, based on iterative and incremental development

Front 38

Name some benefits of Agile Software Development

Back 38

Promotes adaptive planning, evolutionary development, and delivery

Encourages rapid, and flexible response to change,

Conceptual framework

Front 39

List some of the Agile Principles

Back 39

Customer satisfaction by rapid delivery of useful software

Welcome changing requirements, even late in development

Working software is delivered frequently

Front 40

In what way is Agile incremental?

Back 40

Tasks are broken down into small increments

Front 41

In what way is Agile iterative?

Back 41

Teams work in all functions, planning, requirement analysis, design, coding, testing, etc.

Front 42

What is the philosophy of Agile development?

Back 42

Agile development mainly targeted at complex systems and projects with dynamic undetermined, non-linear characteristics

Front 43

What are adaptive methods?

Back 43

Methods that focus on adapting quickly to changing realities

If the needs of the project change, the team changes too

Front 44

What is the downside of adaptive methods?

Back 44

An adaptive team struggles to describe what will happen in the future, to the point where they'd only describe the mission statement

Front 45

What are predictive methods?

Back 45

Methods that focus on analysing, planning for the future, catering for known risks

Front 46

What type of method are Agile methods?

Back 46

Adaptive

Front 47

What is the preference within the Agile manifesto - code or documentation?

Back 47

Code, working software more useful and welcome

Documentation not unnecessary, lack of documentation is a major problem

Front 48

What is a function?

Back 48

A named section of a program that performs a specific task

Front 49

What are two main types of function?

Back 49

Pre-written - set of functions in a library

User-defined - developer creates their own functions

Front 50

What are the benefits of functions?

Back 50

Allows developer to organise code to logical structure

Allows developer to allocate specific behaviour to code

Promotes the reuse of code

Front 51

What should a function achieve?

Back 51

The completion of a single outcome

The function may or may not return a result

Front 52

How are functions called?

Back 52

Functions are invoked by their names e.g.:

get_value()

Front 53

What can function parameters be?

Back 53

Data

Variable Names

Front 54

What does a function prototype define?

Back 54

The number, and type of, parameters

The data type of the returned value, if any

Front 55

How are user-defined functions defined?

Back 55

Defined in a function declaration

Front 56

What does PHP 7 add to functions?

Back 56

Return type declarations (return 'whatever')

Scalar Type Hinting (function doSomething(int $count, string $widgets))

Front 57

What are variable functions?

Back 57

Variables with parenthesis appended to them

PHP looks for function with same name as evaluation of variable, attempts to execute

Front 58

What are anonymous functions?

Back 58

Functions with no name, usually pass small sections of logic into functions

Can be assigned to variables

Front 59

What is the 'scope' of an identifier?

Back 59

The range of code statements where the identifier is valid

Three levels, global, class, function

Front 60

How can parameters be passed?

Back 60

Through value or reference

Front 61

What is a recursion function?

Back 61

One that calls itself

Front 62

What happens when a PHP script is executed?

Back 62

The PHP engine starts, reading script from file

Front 63

What is used to set or return location of PHP hosting system?

Back 63

setlocale()

Front 64

What are the first three in the OWASP list?

Back 64

A1 - Injection

A2 - Broken Authentication and Session Management

A3 - Cross-Site Scripting

Front 65

What are the next three in the OWASP list?

Back 65

A4 - Insecure Direct Object References

A5 - Security Misconfiguration

A6 - Sensitive Data Exposure

Front 66

What are the final four in the OWASP list?

Back 66

A7 - Missing Function Level Access Control

A8 - Cross-Site Request Forgery

A9 - Using Known Vulnerability Components

A10 - Unvalidated Redirects and Forwards

Front 67

What client-side attack vectors are there?

Back 67

Vulnerabilities in browsers via Javascript

Front 68

What server-side attack vectors are there?

Back 68

Web App

Database

Front 69

How could web forms suffer from buffer overflow?

Back 69

Input boxes take in long strings, could crash server

Front 70

What is a Denial Of Service attack?

Back 70

Overloading a server with too many service requests in a short space of time

The attack is successful because it takes a finite amount of time for a request to be processed

Front 71

What are SEO attacks?

Back 71

SEO poisoning attacks are primarily attacks on websites using XSS

Attackers exploit input and display vulnerabilities on sites

iframes then injected into sites, search will redirect to alternate site

Front 72

What do SEO attacks commonly use?

Back 72

iframes

Front 73

How do XSS attacks work?

Back 73

Script injection, usually Javascript, caused by lack of user input sanitisation

Browser often executes malicious script

Scripts access host file system

Front 74

What are the three types of XSS attacks?

Back 74

Stored

Reflected

DOM based XSS - rewrites HTML

Front 75

What are UK MoD Vas?

Back 75

Vulnerability Assessment Levels

Front 76

What are the Vulnerability Assessment Levels?

Back 76

Scanning

Automated probes

Penetration Test

Physical Test

Front 77

What attributes does the form element consist of?

Back 77

method

action

accept

accept-charset

enctype

Front 78

Give examples of form elements

Back 78

select

textarea

fieldset

label

Front 79

How would you have PHP process input forms?

Back 79

if($_POST['formSubmit']== "Submit")

Front 80

What do we think about User Input?

Back 80

EVIL.

Consider types of attack that involve user input

Front 81

What function does PHP have to filter data?

Back 81

filter_var()

Front 82

What argument does filter_var() need to filter a given string?

Back 82

FILTER_SANITIZE_STRING

Front 83

What argument does filter_var() need to filter a given (amount of) integer(s)?

Back 83

FILTER_VALIDATE_INT

Front 84

What argument does filter_var() need to filter a given IP address?

Back 84

FILTER_VALIDATE_IP

Front 85

What arguments are needed for filter_var() to both clean, and validate URLs and Emails?

Back 85

FILTER_SANITIZE_EMAIL/URL

FILTER_VALIDATE_EMAIL/URL

Front 86

What is an example of XSS?

Back 86

The web form has an input field, into which the user can type in something like a script

The PHP app computes the input, and a JS string (for example), is reflected to the browser

The browser accepts the JS from the trusted source, and the script is executed

Front 87

How can XSS be prevented?

Back 87

Never put untrusted data in:

Scripts

HTML comments

Attributes names

Tag names

Directly in CSS

Front 88

What was the main reason for OO design?

Back 88

To better model the real world

Front 89

What is OO

Back 89

The use of class and allied diagrams to create a system of reusable, inter-communicating objects

Front 90

What is one of the main properties of OO?

Back 90

Polymorphism - objects are reusable, with different parameters

Concepts of encapsulation and inheritance form from this

Front 91

What is encapsulation?

Back 91

An object knows about itself, in terms of its values and its behaviour

Front 92

What is inheritance?

Back 92

An object may inherit the values and behaviour of a parent object

Front 93

What is the S in the SOLID principles?

Back 93

S: single responsibility principle - an object has one purpose only

Front 94

What is the O in the SOLID principles?

Back 94

O: open/closed principle - software entities are open for extension, closed for modification

Front 95

What is the L in the SOLID principles?

Back 95

L: Liskov substitution principle - objects should be replaceable with instances of their subtypes, without altering the correctness of the program

Front 96

What is the I in the SOLID principles?

Back 96

I: interface segregation principles - many specific interfaces are better than one general purpose interface

Front 97

What is the D in the SOLID principles?

Back 97

D: dependency inversion principle - one should depend upon abstractions, not upon concretions

Front 98

How are objects created within PHP?

Back 98

new

Front 99

How are an object's attributes and accessor methods accessed?

Back 99

Using the keyword '$this', and the arrow operator '->'

Front 100

What are the three types of visibility for an object?

Back 100

public

protected

private

Front 101

What file format are classes saved as?

Back 101

.inc

More secure to use .php for all files though, which ensures that the files will be parsed by the PHP parser

Front 102

What should be given to the name of a class?

Back 102

The 'class.' prefix

class.Filename.php, for example

Front 103

How is a class file made available to a program?

Back 103

With either the 'include' or 'require' commands

Front 104

What is MySQL?

Back 104

Open source, multi-platform, client/server, ACID-compliant relational database

Front 105

What components does MySQL have with PHP?

Back 105

Information_schema, mysql and test

Front 106

What are PDOs?

Back 106

PHP Data Objects

Lightweight interface

Access to various databases

Front 107

What file format are PDOs in?

Back 107

.dll

Front 108

What is the advantage of using the .dll extension with PDOs?

Back 108

All databases accessed with same library functions

SQL injection attacks avoided

Front 109

How would you return information from MySQL

Back 109

list_dbs

Front 110

How would you connect to a database with a PHP script?

Back 110

Within a try/catch block

Variable assigned to a new PDO with host name, user name and password variables

Front 111

What is the database wrapper class?

Back 111

A class that incorporates some error handling

Used for connecting to the relevant database

Front 112

How is user data transmitted to PHP?

Back 112

Via a form

Front 113

What are ORMs?

Back 113

Object-Relational Mappings

Front 114

What is the purpose of an ORM?

Back 114

To map between the different data types - scalar values and data within objects

Front 115

What is the idea behind a Software Design Pattern?

Back 115

A general, reusable solution to a commonly occurring problem within a given context in software design

A template that can be used to solve problems, and can be used in many different situations

Front 116

What is the purpose of an OO Design Pattern?

Back 116

A pattern can show relationships and interactions between classes or objects

Front 117

What are web-application Design Patterns?

Back 117

Patterns used by PHP developers

Container, Factory, Observer, etc.

Front 118

What things should you consider when designing your application?

Back 118

Partition aspects of it logically

Use abstraction, implementing loose coupling between layers

Understand how components will communicate with each other

Reduce round trips

Front 119

What is the MVC pattern?

Back 119

Model, View, Controller

Front 120

What two ways can the model be considered as?

Back 120

Active - allows the model to inform the view and controller components of required changes

Passive - objects are completely unaware of being part of a larger application

Front 121

What is the third variation of the model?

Back 121

The Presentation Model

Front 122

What is the single point of entry for a PHP application?

Back 122

bootstrap.php

Front 123

How do you instantiate objects with autoloading?

Back 123

_autoload()

Front 124

What is the router class?

Back 124

The class responsible for instantiating the correct Controller class

Front 125

What is the config class?

Back 125

The class that stores any configurable values that will be used throughout the application

Could extend to storage of actual data in database

Front 126

What are the three As?

Back 126

Authentication - proving that you are who you claim to be

Authorisation - system decides what you're allowed to access

Accounting - keeping track of what you've done whilst using the system

Front 127

How is authentication achieved?

Back 127

Usually with a username and password

Modern systems starting to use biometrics, fingerprints

Front 128

What is two-factor authorisation?

Back 128

Any authentication process that requires two separate means of identification

Front 129

What can hash functions be used for?

Back 129

Authentication, but simpler functions have been broken many times

Front 130

How does MD5 work?

Back 130

A hash function takes an input string and transforms it into a fixed size string

One way function

Front 131

What is MD5 used for?

Back 131

Used to check the integrity of a file

Can be used to detect tampering of web application scripts

Front 132

What is SHA-1?

Back 132

Hashing function that produces a message digest of 160 bits

Has been cracked, SHA-2 developed

Front 133

What is salt?

Back 133

Passwords are encrypted with this

Salt is an extra piece of information, appended to the password, the string is then encrypted

Front 134

What is the DES algorithm?

Back 134

An algorithm based on transpositions, rearrangement of bits

An encryption algorithm

Front 135

What is Mcrypt?

Back 135

Encryption that uses PHP generic functions

Front 136

What happens when a script terminates?

Back 136

All variables declared are nullified

Allocated RAM returned to the heap

Contents lost

Front 137

How can the contents of variables be stored for use in later scripts?

Back 137

Store values in a special session file

Store values in alternative persistent storage

Front 138

What is SID?

Back 138

Session ID

Front 139

How are SIDs stored?

Back 139

Keys stored in session cookies on client machine

Can be a problem if client has cookies disabled as a security measure

Front 140

How are sessions created?

Back 140

session_start() function

Front 141

What happens when the session_start() function is called?

Back 141

Other than a session starting, looks for SID from client machine

If none exists, SID created and stored

Front 142

How are sessions removed?

Back 142

By PHP's garbage collector

Front 143

How are emails sent from within PHP scripts?

Back 143

mail() function

Email format must conform to RFC2822

Front 144

What is the purpose of the Sender Policy Framework?

Back 144

It attempts to authenticate an email to spam filters, prevents sender address forgery

Front 145

How does SPF work?

Back 145

Adds an SPF record to DNS domain of sender, contains policy of sender

Receiving email server checks if SPF record exists, and if message compiles with DNS record policy

Front 146

What should be done before optimisation of PHP code?

Back 146

Take snapshot of current performance

Allows improvements in performance to be measured

Front 147

What is memory caching also known as?

Back 147

Accelerators

Front 148

How does memory caching work?

Back 148

Cache compiled bytecode

Avoids processing overhead of parsing and compiling source code

Front 149

What is varnish?

Back 149

A caching server, HTTP accelerator

Front 150

What two variants of PHP scaling are there?

Back 150

Horizontal scaling - adding more servers

Vertical scaling - higher spec hardware

Front 151

What can be used to accelerate the processing of PHP scripts?

Back 151

Micro-optimisation

Front 152

What is Hoare's Law?

Back 152

Inside every large program is a small program struggling to get out,or

Premature optimisation is the root of all evil

Front 153

How would you implement micro-optimisation to your PHP scripts?

Back 153

Use ' instead of " to delineate Strings

Use the concatenation operator to insert variables into strings

Consider the performance of echo vs. print

Front 154

What is the main bottleneck of any web-application, usually?

Back 154

Retrieving data from the database

Front 155

What can you do to help reduce the bottleneck from the database?

Back 155

SQL optimiser package

Third party library

Front 156

Other than the server, what else causes web-page latency?

Back 156

Network latency,

Browser processing time, if their hardware is better then this will be faster

Front 157

What is a sprite?

Back 157

An image file that contains every image to be used on relevant web-pages

Front 158

What is code minification?

Back 158

The process of removing all extraneous characters, white spaces for example

Front 159

What is the GD Library?

Back 159

It's used to create images composed of lines, arcs, text, other images, multiple colours

Front 160

How do both PHP and GD2 relate?

Back 160

PHP can use the library to create graphics 'on-the-fly'

Front 161

What is LibChart?

Back 161

A simple-to-use library that produces horizontal and vertical bar, pie, and line charts

The output is rendered as a PNG image