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Useful PHP Tips for Beginners – Part 4

31. Make a portable function for executing shell commands

system , exec , passthru , shell_exec are the 4 functions that are available to execute system commands. Each has a slightly different behaviour. But the problem is that when you are working on shared hosting environments some of the functions are selectively disabled. Most newbie programmers tend to first find out which function is enabled and then use it.

A better solution :

The above function will execute the shell command using whichever function is available , keeping your code consistent.

32. Manage error reporting

error_reporting is the function to use to set the necessary level of error reporting required.
On a development machine notices and strict messages may be disabled by doing.

On production , the display should be disabled.

It is important to note that error_reporting should never be set to 0 on production machines. Atleast E_FATALs have to be known. Just switch off the display using the display_errors directive. If error_reporting is set to 0, errors wont be raised at all keeping all problems in the dark.

After the display is switched off, the errors should be logged to a file for later analysis. This can be done inside the script using init_set.

Note :

1. The path ‘/path/to/errors.txt’ should be writable by the web server for errors to be logged there.

2. A separate error file is specified , otherwise all logs would go inside the apache/web server error log and get mixed up with other apache errors.

3. Also since it is being setup in the current application , the error log will contain the errors of only the current application (there may be other applications running on the webserver).

4. The path can be somewhere inside the directory of the current application as well , so that the system directories like /var/log dont have to searched.

5. Dont set error_reporting to 0. It will not log anything then.

Alternatively set_error_handler should be used to set a custom user written function as the error handler. That particular function, for example can log all errors to a file.

Set ‘display_errors=On’ in php.ini on development machine

On development machine its important to enable display_errors right in the php.ini (and not rely on ini_set)
This is because any compile time fatal errors will now allow ini_set to execute , hence no error display
and a blank WHITE page.

Similarly when they are On in php.ini , switching it off in a script that has fatal errors will not work.

Set ‘display_errors=Off’ in php.ini on production machine

Do not rely on init_set(‘display_errors’ , 0); simply because it will not get executed if any compile time fatal errors come in the script , and errors will be displayed right away.

33. Be aware of platform architecture

The length of integers is different on 32 and 64 bit architectures. So functions like strtotime give different results.

On a 64 bit machine you can see such output.

But on a 32 bit machine all of them would give bool(false). Check here for more.

What would happen if an integer is left shifted more than 32 bits ? the result would be different on different machines.

34. Dont rely on set_time_limit too much

If you are limiting the maximum run-time of a script , by doing this :

It may not always work. Any execution that happens outside the script via system calls/os functions like socket operations, database operations etc. will not be under control of set_time_limit.

So if a database operation takes lot of time or “hangs” then the script will not stop. Dont be surprised then. Make better strategies to handle the run-time.

35. Localize your application

Localise your php application. Format dates and numbers with commas and decimals. Show the time according to timezone of the user.

36. Use a profiler like xdebug if you need to

Profilers are used to generate reports that show the time is taken by different parts of the code to execute. When writing large application where lots of libraries and other resources are working to do a cetain task, speed might be an important aspect to optimise.

Use profilers to check how your code is performing in terms of speed. Check out xdebug and webgrind.

37. Use plenty of external libraries

An application often needs more than what can be coded with basic php. Like generating pdf files, processing images, sending emails, generating graphs and documents etc. And there are lots of libraries out there for doing these things quickly and easily.

Few popular libraries are :

  • mPDF – Generate pdf documents, by converting html to pdf beautifully.
  • PHPExcel – Read and write Excel files
  • PhpMailer – Send html emails with attachments easily
  • pChart – Generate graphs in php

38. Have a look at phpbench for some micro-optimisation stats

If you really want to achieve optimisation at the level of microtime then check phpbench … it has some benchmarks for various syntax variations that can create significant difference.

39. Use an MVC framework

Its time to start using an MVC (Model view controller) framework like codeigniter. MVC does not make your code object oriented rightaway. The first thing they do is separate the php code from html code.

  • Clean separation of php and html code. Good for team work, when designers and coders are working together.
  • Functions and functionalities are organised in classes making maintenance easy.
  • Inbuilt libraries for various needs like email, string processing, image processing, file uploads etc.
  • Is a must when writing big applications
  • Lots of tips, techniques, hacks are already implemented in the framework

40. Read the comments on the php documentation website

The php documentation website has entries for each function, class and their methods. All those individual pages have got lots of user comments below them that contain a whole lot of valuable information from the community.

They contain user feedback, expert advice and useful code snippets. So check them out.

 

Prakash S

Prakash S

I would like to introduce myself as a Software professional opting for the career in software industry. I'm Prakash S, a MCA graduate and trained as industry level practice for Software technology. Basically I am a PHP Developer but now days exploring more in HTML5, CSS, AngularJS and jQuery libraries.