اجتناب از 10 اشتباه ناخواسته در زبان پی اچ پی Are You Making These 10 PHP Mistakes?

[دانه کولانه]

اجتناب از 10 اشتباه ناخواسته در زبان پی اچ پی Are You Making These 10 PHP Mistakes

One of the best things about PHP is that it’s a great language to just “dive into”, thanks to its wide-ranging popularity. Anyone with the ability to hit “Search” on Google can quickly create a program. However, this also lends to a major criticism of PHP: it’s almost too easy to find and reproduce bad code.

Here are 10 PHP mistakes that any programmer, regardless of skill level, might make at any given time. Some of the mistakes are very basic, but trip up even the best PHP programmer. Other mistakes are hard to spot (even with strict error reporting). But all of these mistakes have one thing in common: They’re easy to avoid

Take the time and make sure that your PHP is secure, clean and running smoothly by checking your site for these common PHP blunders.
------------------------------------------------------

اشتباهات رایجی وجود دارند که گاها برنامه نویس های مبتدی حواسشون نیست و برنامه شون دچار اشکال میشه
که بعضا تقصیر خود برنامه نویس هم نیست بنابراین بهتره که به بعضی از رایج تریناش اشاره بشه



مثلا شما فرض کنید که توی پی اچ پی نسخه 4 و 5 در مورد کارکرد تابع

empty()

تفاوت هست مثلا :

کد PHP:

class Foo {
 function Foo() {
 }
 function bar() {
 }
 }
 $foo = new Foo();
 if (empty($foo)) {
 // this code executes in PHP4 (but NOT in PHP5)!
 } 


[دانه کولانه]

1. Single quotes, double quotes

It’s easy to just use double quotes when concatenating strings because it parses everything neatly without having to deal with escaping characters and using dot values. However, using single quotes has considerable performance gains, as it requires less processing.

Consider this string:

کد PHP:

# $howdy = 'everyone';   
# $foo = 'hello $howdy';   
# $bar = "hello $howdy"; 


$foo outputs to “hello $howdy” and $bar gives us “hello everyone”. That’s one less step that PHP has to process. It’s a small change that can make significant gains in the performance of the code.

اگر میخواهید مقدار متغیر هاتون در رشته جایگزین بشه از دابل کوتیشن استفاده کنید در غیر اینصورت میتونین با استفاده از سینگل کوتیشن علامت $ رو در رشته چاپ کنید و دنبال مقدار متغیر نخواهد بود .

[دانه کولانه]

2. Semicolon after a While

It’s funny how one little character can create havoc in a program, without even being reported to the PHP error logs! Such as it is with semicolons and While statements.

Codeutopia has an excellent example of this little error, showing that these nasty errors don’t even get reported (even to E_ALL!), as it quietly falls into a silent loop.

کد PHP:

$i = 0;  
while($i < 20); {    //some code here  
  $i++;  
} 


Omit the ; after the while statement, and your code is in the clear.

بدون هیچ پیغام خطایی برنامه میره رو هوا

[دانه کولانه]

استفاده از سیستم های کش دیتابیس در برنامه های php

What is Memcached?

Free & open source, high-performance, distributed memory object caching system, generic in nature, but intended for use in speeding up dynamic web applications by alleviating database load.

Memcached is an in-memory key-value store for small chunks of arbitrary data (strings, objects) from results of database calls, API calls, or page rendering.

Memcached is simple yet powerful. Its simple design promotes quick deployment, ease of development, and solves many problems facing large data caches. Its APIis available for most popular languages.

3. NOT Using database caching

If you're using a database in your PHP application, it is strongly advised that you at least use some sort of database caching. Memcached has emerged as the most poplar caching system, with mammoth sites likeFacebook endorsing the software.

Memcached is free and can provide very significant gains to your software. If your PHP is going into production, it's strongly advised to use the caching system.

کارشناسا توصیه اکید میکنند که حتما از یکی از سیستم های کش دیتابیس استفاده کنید
لیست مشتری های مثال فوق برق رو از سر ادم میپرونه ! .

[دانه کولانه]

4. Missing Semicolon After a Break or a Continue

Like #2, a misused semicolon can create serious problems while silently slipping off into the shadows, making it quite difficult to track the error down.

If you're using a semicolon after a "break" or "continue" in your code, it will convince the code to output a "0" and exit. This could cause some serious head scratching. You can avoid this by using braces with PHPcontrol structures (via CodeUtopia).

البته من بدون سیمی کالن تست کردم خطا میگیره .

[دانه کولانه]

فعال کردن سیستم گزارش خطا در پی اچ پی PHP Using E_ALL Reporting

5. Not Using E_ALL Reporting

Error reporting is a very handy feature in PHP, and if you're not already using it, you should really turn it on. Error reporting takes much of the guesswork out of debugging code, and speeds up your overall development time.

While many PHP programmers may use error reporting, many aren't utilizing the full extent of error reporting. E_ALL is a very strict type of error reporting, and using it ensures that even the smallest error is reported. (That's a good thing if you're wanting to write great code.)

When you're done developing your program, be sure to turn off your reporting, as your users probably won't want to see a bunch of error messages on pages that otherwise appear fine. (Even with the E_ALL error reporting on they hopefully won't see any errors anyway, but mistakes do happen.)

تمام جزئیات خطا ها رو نشون میده و هیچ چی رو جا نمیذاره و میتونین استفاده مفیدی ازش داشته باشین که عموما ازش غافل هستند .