高质量PHP代码的50个实用技巧必备，上

require_once('../../lib/some_class.php');

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define('ROOT','/var/www/project/');

require_once(ROOT .'../../lib/some_class.php');

//rest of the code

//suppose your script is /var/www/project/index.php

//Then __FILE__ will always have that full path.

define('ROOT',pathinfo(__FILE__, PATHINFO_DIRNAME));

require_once(ROOT .'../../lib/some_class.php');

//rest of the code

require_once('lib/Database.php');

require_once('lib/Mail.php');

require_once('helpers/utitlity_functions.php');

functionload_class($class_name)

{

//path to the class file

$path= ROOT .'/lib/'.$class_name.'.php');

require_once($path);

}

load_class('Database');

load_class('Mail');

functionload_class($class_name)

{

//path to the class file

$path= ROOT .'/lib/'.$class_name.'.php');

if(file_exists($path))

{

require_once($path);

}

}

define('ENVIRONMENT','development');

if(!$db->query($query)

{

if(ENVIRONMENT =='development')

{

echo"$query failed";

}

else

{

echo"Database error. Please contact administrator";

}

}

define('ENVIRONMENT','production');

if(!$db->query($query)

{

if(ENVIRONMENT =='development')

{

echo"$query failed";

}

else

{

echo"Database error. Please contact administrator";

}

}

/**

Method to execute a command in the terminal

Uses :

1. system

2. passthru

3. exec

4. shell_exec

*/

functionterminal($command)

{

//system

if(function_exists('system'))

{

ob_start();

system($command,$return_var);

$output= ob_get_contents();

ob_end_clean();

}

//passthru

elseif(function_exists('passthru'))

{

ob_start();

passthru($command,$return_var);

$output= ob_get_contents();

ob_end_clean();

}

//exec

elseif(function_exists('exec'))

{

exec($command,$output,$return_var);

$output= implode("\n",$output);

}

//shell_exec

elseif(function_exists('shell_exec'))

{

$output= shell_exec($command) ;

}

else

{

$output='Command execution not possible on this system';

$return_var= 1;

}

returnarray('output'=>$output,'status'=>$return_var);

}

terminal('ls');

functionadd_to_cart($item_id,$qty)

{

$_SESSION['cart']['item_id'] =$qty;

}

add_to_cart('IPHONE3', 2 );

functionadd_to_cart($item_id,$qty)

{

if(!is_array($item_id))

{

$_SESSION['cart']['item_id'] =$qty;

}

else

{

foreach($item_idas$i_id=>$qty)

{

$_SESSION['cart']['i_id'] =$qty;

}

}

}

add_to_cart('IPHONE3', 2 );

add_to_cart(array('IPHONE3'=> 2 ,'IPAD'=> 5) );

<?php

echo"Hello";

//Now dont close this tag

<?php

classsuper_class

{

functionsuper_function()

{

//super code

}

}

?>

require_once('super_class.php');

//echo an image or pdf , or set the cookies or session data

<?php

classsuper_class

{

functionsuper_function()

{

//super code

}

}

//No closing tag

functionprint_header()

{

echo"<div >Site Log and Login links</div>";

}

functionprint_footer()

{

echo"<div >Site was made by me</div>";

}

print_header();

for($i= 0 ;$i< 100;$i++)

{

echo"I is :$i';

}

print_footer();

functionprint_header()

{

$o="<div >Site Log and Login links</div>";

return$o;

}

functionprint_footer()

{

$o="<div >Site was made by me</div>";

return$o;

}

echoprint_header();

for($i= 0 ;$i< 100;$i++)

{

echo"I is :$i';

}

echoprint_footer();

$xml = '<?xmlversion="1.0"encoding="utf-8"standalone="yes"?>';

$xml = "<response>

<code>0</code>

</response>";

//Send xml data

echo $xml;

$xml = '<?xmlversion="1.0"encoding="utf-8"standalone="yes"?>';

$xml = "<response>

<code>0</code>

</response>";

//Send xml data

header("content-type: text/xml");

echo $xml;

JavaScript

header("content-type: application/x-javascript");

echo"var a = 10";

CSS

header("content-type: text/css");

echo"#div id { background:#000; }";

//Attempt to connect to database

$c= mysqli_connect($this->host ,$this->username,$this->password);

//Check connection validity

if(!$c)

{

die("Could not connect to the database host: ". mysqli_connect_error());

}

//Set the character set of the connection

if(!mysqli_set_charset ($c,'UTF8'))

{

die('mysqli_set_charset() failed');

}

$value= htmlentities($this->value , ENT_QUOTES , CHARSET);

$images=array(

'myself.png','friends.png','colleagues.png'

);

$js_code='';

foreach($imagesas$image)

{

$js_code.="'$image' ,";

}

$js_code='var images = ['.$js_code.']; ';

echo$js_code;

//Output is var images = ['myself.png' ,'friends.png' ,'colleagues.png' ,];

更聪明的做法, 使用 json_encode:

$images=array(

'myself.png','friends.png','colleagues.png'

);

$js_code='var images = '. json_encode($images);

echo$js_code;

//Output is : var images = ["myself.png","friends.png","colleagues.png"]

$contents="All the content";

$file_path="/var/www/project/content.txt";

file_put_contents($file_path,$contents);

$contents="All the content";

$dir='/var/www/project';

$file_path=$dir."/content.txt";

if(is_writable($dir))

{

file_put_contents($file_path,$contents);

}

else

{

die("Directory $dir is not writable, or does not exist. Please check");

}

// Read and write for owner, read for everybody else

chmod("/somedir/somefile", 0644);

// Everything for owner, read and execute for others

chmod("/somedir/somefile", 0755);

if($_POST['submit'] =='Save')

{

//Save the things

}

if($_SERVER['REQUEST_METHOD'] =='POST'andisset($_POST['submit']) )

{

//Save the things

}

//Delay for some time

functiondelay()

{

$sync_delay= get_option('sync_delay');

echo"Delaying for $sync_delay seconds...";

sleep($sync_delay);

echo"Done ";

}

//Delay for some time

functiondelay()

{

static$sync_delay= null;

if($sync_delay== null)

{

$sync_delay= get_option('sync_delay');

}

echo"Delaying for $sync_delay seconds...";

sleep($sync_delay);

echo"Done ";

}

$_SESSION['username'] =$username;

$username=$_SESSION['username'];

define('APP_ID','abc_corp_ecommerce');

//Function to get a session variable

functionsession_get($key)

{

$k= APP_ID .'.'.$key;

if(isset($_SESSION[$k]))

{

return$_SESSION[$k];

}

returnfalse;

}

//Function set the session variable

functionsession_set($key,$value)

{

$k= APP_ID .'.'.$key;

$_SESSION[$k] =$value;

returntrue;

}

functionutility_a()

{

//This function does a utility thing like string processing

}

functionutility_b()

{

//This function does nother utility thing like database processing

}

functionutility_c()

{

//This function is ...

}

classUtility

{

publicstaticfunctionutility_a()

{

}

publicstaticfunctionutility_b()

{

}

publicstaticfunctionutility_c()

{

}

}

//and call them as

$a= Utility::utility_a();

$b= Utility::utility_b();

<span php string">"color:#333333;font-family:''Helvetica, Arial, sans-serif'';">if($a== true)$a_count++;</span>

<span php string">"color:#333333;font-family:''Helvetica, Arial, sans-serif'';">if($a== true)

{

$a_count++;

}</span>

foreach($arras$c=>$v)

{

$arr[$c] = trim($v);

}

$arr=array_map('trim',$arr);

$amount=intval($_GET['amount'] );

$rate= (int)$_GET['rate'];

$db_records_in_array_format;//This is a big array holding 1000 rows from a table each having 20 columns , every row is atleast 100 bytes , so total 1000 * 20 * 100 = 2MB

$cc=$db_records_in_array_format;//2MB more

some_function($cc);//Another 2MB ?

$a= get_large_array();

pass_to_function(&$a);

classA

{

functionfirst()

{

$this->a = get_large_array();

$this->pass_to_function();

}

functionpass_to_function()

{

//process $this->a

}

}

functionadd_to_cart()

{

$db=newDatabase();

$db->query("INSERT INTO cart .....");

}

functionempty_cart()

{

$db=newDatabase();

$db->query("DELETE FROM cart .....");

}