1. Introduction and Overview

A brief introduction to the basics of PHP and building applications for the dynamic web.

Transcript

1. PHP101 A concise course in PHP web development.
2. About Me • Currently working for WeddingVenues.com Receives around 1,200,000 unique visits per month > 35,000 pages • Working with PHP professionally for 10+ years • 29,000+ reputation on StackOverflow (@benm) • Open Source advocate; find me on GitHub (benmajor88)
3. Course Overview 1. PHP Overview & Basics 2. Functions 3. Loops 4. MySQL and data-rich websites 5. Security and Good Practice 6. Working with JSON, XML and APIs 7. Object-Oriented PHP Development 8. Conclusion
4. Course Overview 1. PHP Overview & Basics 2. Functions 3. Loops 4. MySQL and data-rich websites 5. Security and Good Practice 6. Working with JSON, XML and APIs 7. Object-Oriented PHP Development 8. Conclusion
5. The “Stack” • Building blocks of the dynamic web • LAMP: • Linux - Server Operating System • Apache - Server Software • MySQL: Database Engine • PHP: Scripting Language
6. MAMP • Windows and Mac friendly • Includes Apache and MySQL • Bundled with phpMyAdmin • Much faster for development • Download online:
 https://www.mamp.info/en/
7. Komodo Edit IDE • Syntax highlighting • Autocomplete • Code hinting • Supports OOP PHP and jQuery
8. So, what is PHP? • Recursive acronym — PHP: Hypertext Preprocessor. • HTML-embedded scripting language, not a programming language! • Multi-paradigm: procedural and object-oriented. • Loosely-typed, highly coupled. • Syntax largely borrowed and adapted from C, Perl and Java. • Current stable version: 5.6.19.
9. RTFM! http://php.net/manual/en/
10. Basic Syntax • Code must be wrapped inside an opening and closing tag:
 <?php and ?> respectively. • Files must have a .php extension. • Lines should be terminated with the ; literal (except in some case). • Can be wrapped inside of HTML:
 
 <p>My  paragraph  here!</p>
 <?php  /*  Some  PHP  code  here.  */  ?>
 <p>Another  paragraph!</p>
11. Data Types $foo  =  ‘bar’;                    //  String
 $foo  =  1;                            //  Integer
 $foo  =  1.2;                        //  Float  (floating  point  number)
 $foo  =  true;                      //  Boolean
 $foo  =  array(1,2);          //  Array
 $foo  =  new  stdClass();  //  Object
 $foo  =  null;                      //  Null
12. Variables • Store values persistently during the script’s execution. • Defined using the $ literal, for example: $var, $myVar… • Cannot begin with a numerical character, or contain special punctuation marks (bangs, colons or other reserved chars), for example:
 
 $123 Bad! $var123 OK!
 $!myVar Bad! $myVar! Bad!
 $?myVar Bad! $_myVar OK!
13. Comments • Comments help to add context and explain what your code does. • Ignored by the PHP parser. • We can define comments in three ways: • //  Using  two  forward  slashes  (limited  to  only  one  line)   • /*  A  forward  slash  and  an  asterisk  
      Can  be  multiline.  Have  to  be  terminated
      with  an  asterisk  and  a  forward  slash  at  the  end  */   • #  Using  a  pound
 #  Sometimes  cleaner,  but  limited  to  a  single  line
14. Outputting Data • As well as controlling variables, we need to display and output them, too. • Achieved using language structs: • echo  ‘Hello,  World!’; • print  ‘Hello,  World!’;   • Or functions:   • echo(  ‘Hello,  World!’  );   • print(  ‘Hello,  World!’  );
15. Strings 101 • Strings are wrapped in single (‘string’) or double (“string”) quotes • Double quotes can be used to concatenate a string with another variable, for example:
 $myString  =  “string  $i”;  (will append $i  to the string)
 $myString  =  'string  $i’;  ($myString will be string $i)   • We must escape quote literals of the same type within a string using a backslash (\), for example:
 $myString  =  “string  \”$i\”.  Some  more.”;
16. Strings 102 • We can concatenate a string from other strings or variables, use the . or , literal: • $myString  =  “string  ”.”appended”;   • $myString  =  “string  ”,“appended”;   • We can also append characters to a string using the .= syntax: • $myString  =  “string”;
 $myString.=  ‘  appended’;
17. Strings 103 • In PHP, all strings are also arrays of characters. • Useful when you need to identify the character at a given index • $myString  =  “string”;
 $myChar      =  $myString[0];  //  “s”
 $myChar      =  $myString[5];  //  “g”
18. Strings 104 • String variables can be used as variable names! • Called ‘variable variables’. • Defined using the $$ syntax: • $myString    =  ‘foo’;
 $$myString  =  ‘bar’;    //  Create  $foo  variable
 echo  $foo                        //  Will  output  ‘bar’
19. Useful String Functions • strtoupper(  $string  )
 Converts all chars of $string to uppercase. • strtolower(  $string  )
 Converts all chars of $string to lowercase. • ucwords(  $string  )
 Will detect individual words in $string and covert the first character of each to uppercase. • substr(  $string,  INDEX,  LENGTH  )
 Extracts another string from $string at the given INDEX with a length of LENGTH
20. Integers 101 • Integers represent whole numbers only. • Signed integers only (e.g. 1 and -­‐1). • They have a minimum and maximum value, which is dependent upon the platform and hardware: • A 32-bit machine which uses signed integers has a max of ~ 2,000,000,000,000 (and a minimum of -2b) • A 64-bit machine which uses signed integers has a max of ~ 9e18 • Windows installations (prior to PHP7) always used 32-bit signed ints.
21. Integers 102 • By default, all integers in PHP are decimal (or base-10). • We can also work with other bases: • $i  =  123;                //  Decimal   • $i  =  -­‐123;              //  Negative   • $i  =  0123;              //  Octal  (==  83)   • $i  =  0x1A;              //  Hexadecimal  (==  26)   • $i  =  0b11111111;  //  Binary  (==  255)  
22. Useful Integer Functions • min(  $int1,  $int2,  $int3,  …  )
 Returns the minimum integer in the given collection. • max(  $int1,  $int2,  $int3,  …  )
 Returns the maximum integer in the given collection. • intval(  $var  )
 Returns the integer value of $var. • abs(  $var  )
 Returns the absolute value of $var: • $abs  =  abs(  -­‐1  );      //  $abs  =  1;
23. Floats • Floating point integers allow us to define values with decimal places. • They are always real numbers. • Numerous syntax for defining floats: • $a  =  1.234;  //  1.234   • $b  =  1.2e3;  //  1200   • $c  =  7E-­‐10;  //  Same  as  writing:  7-­‐10  :  0.0000000007
24. Useful Float Functions • round(  $float  )
 Rounds $float to the nearest integer value. • floor(  $float  )
 Rounds $float down to the nearest integer value. • ceil(  $float  )
 Rounds $float up to the nearest integer value. • floatval(  $var  )
 Returns the floating point value of $var: • $float  =  floatval(  ‘1.2345the’  );      //  $float  =  1.2345;
25. Booleans • Boolean values are either true or false:   • $truthy  =  true;   • $falsey  =  false; • Integers can sometimes be treated as booleans; be careful! • $int  =  1;    //  This  is  the  same  as  $int  =  true;   • $int  =  0;    //  This  is  the  same  as  $int  =  false;
26. Performing Operations • We can perform operations on variables in PHP. • Mathematical operations (assume that $i is set to 2): • $i  =  $i  +  2;    //  $i  now  =  4
 $i+=  2;              //  $i  now  =  4   • $i  =  $i  -­‐  1;    //  $i  now  =  1
 $i-­‐=  1;              //  $i  now  =  1   • $i  =  $i  *  2;    //  $i  now  =  4
 $i*=  2;              //  $i  now  =  4   • $i  =  $i  /  2;    //  $i  now  =  1
 $i/=  2;              //  $i  now  =  1 • $i  =  $i  %  2;    //  $i  now  =  0
 $i%=  2;              //  $i  now  =  0
27. Type Juggling • Allows us to modify the variable type ‘on the fly’. • PHP parser will automatically handle the type. • $str      =  0.’  string’;      //  Converts  0  into  a  string:  ‘0  string’   • $total  =  ‘2’  +  1;              //  Total  =  3   • $total  =  ‘2.1’  +  ‘2.3’;  //  Total  =  5.4   • $myVar  =  ‘1’;
 $total+=  $myVar;                //  Also  valid,  increments  $total  by  1
28. Type Casting • Useful if we need to explicitly set the data type. • We can tell PHP to cast one type to another: • $integer  =  (int)  ‘1’;        //  $integer  is  an  integer  with  value  1   • $string    =  (string)  123;  //  $string  is  a  string  with  value  ‘123’   • $absInt    =  (int)  ‘1.23’;  //  $absInt  is  an  integer  with  value  1
29. Arrays 101 • Hold a collection of values, which can be of mismatched types. • Can be 0-indexed, or associative: • Array values are accessed using the square bracket notation ([]). • May also contain other arrays, some called a multi-dimensional array. • Useful for storing options or other persistent data that needs to be stored in a structured manner.
30. Arrays 102 0-indexed arrays: • When we don’t specify keys for the array, the values are accessed using their index within it. • The index is always 0-based (start counting from 0). • $arr  =  array(  ‘foo’,  ‘bar’,  ‘hello’,  ‘world’  );   • $foo                =  $arr[0];                  //  $foo  =  ‘foo’  
 $bar                =  $arr[1];                  //  $bar  =  ‘bar’
 $helloWorld  =  $arr[2].$arr[3];  //  $helloWorld  =  ‘helloworld’
31. Arrays 103 Associative arrays: • We can specify array keys to add meaning to the values stored within it. • Values are then accessed by their respective keys: • $arr  =  array(    
        ‘foo’      =>  ‘bar’,
        ‘hello’  =>  ‘world’
 );   • $foo      =  $arr[‘foo’];        //  $foo  =  ‘bar’
 $hello  =  $arr[‘hello’];    //  $hello  =  ‘world’
32. Arrays 104 Multi-dimensional arrays: • $arr  =  array(    
      array(
              ‘foo’    =>  ‘bar’,
              ‘foo2’  =>  ‘bar2’
      ),
      array(
              ‘foo’    =>  ‘bar’,
              ‘foo2’  =>  ‘bar2’
      )
 );
33. Modifying Arrays • We can also modify and add to arrays using square bracket notation. • $myArray      =  array();
 $myArray[]  =  ‘foo’;
 $myArray[]  =  ‘bar’;
 
 //  $myArray  now  looks  like:  array(‘foo’,  ‘bar’)
34. Useful Array Functions • count(  $array  )
 Returns the number of elements inside of $array. • array_push(  $array,  $toAdd  )
 Pushes $toAdd to the end of $array. • array_pop(  $array  )
 Removes the last element from $array and returns it. Modifies $array by reference: • $myArr  =  array(  ‘foo’,  ‘bar’  );
 $foo      =  array_pop(  $myArr  );
 //  $foo  =  ‘bar’
 //  $myArr  =  array(‘foo’);
35. • Code samples are available on GitHub at the following URL:
 https://github.com/benmajor/php-lessons • Slideshows are available on SpeakerDeck at the following URL:
 https://speakerdeck.com/benmajor • If you need any help, email me:
 ben.major88@gmail.com
 Questions?