PHP Coding Horrors and Excuses for Poor Decisions

Few years back while attending a Python class a young chap put up his hand, introduced himself as a long time PHP developer and asked the lecturer a question. “What is the difference between Python’s dictionary & lists to PHP’s arrays.”. Bang. This is exactly why I do not want newbies to go down that route. Data structures are fundamental to any software design. PHP will NOT force you to think about data structures when coding.. instead just stick a boot in your face and say walk.

As a leader

As a smart fast paced technology leader, you should NOT be suggesting or advising PHP as the company’s “language of choice”. If a company is using optimized wordpress hosting it’s typically for its blog (yes WordPress rocks), due to legacy reasons (we all learn right) or a variant of it. PHP is not even a great presentation language (so famous for years ago) lacking good support for a real templating engine. Going LAMP stack, as in Linux stack, is not about moving to PHP. Matter of fact LAMP stack is an old, beaten, used & abused lingo which means little today with the range of open source stacks that run on the Linux OS.

Let’s first look at what makes a good language. And if you are a leader looking at starting or moving to a new language this post should be enough to tell you what to avoid. Learn from other’s mistakes so you don’t have to make them yourself.

What makes a good language

• Predictable
• Consistent
• Concise
• Reliable
• Debuggable

Check out the philosophies behind Python in Zen of Python on what a good language encourages.

PHP fails miserably here.

• PHP is full of surprises: mysql_real_escape_string, E_ALL
• PHP is inconsistent: strpos, str_rot13
• PHP requires boilerplate: error-checking around C API calls, ===
• PHP is flaky: ==, foreach ($foo as &$bar)
• PHP is opaque: no stack traces by default or for fatals, complex error reporting.

PHP is NOT an enterprise language

An enterprise language is one that has good corporate support. Best example is Microsoft and their .NET platform.

Look at the support behind the PHP language. No corporation supports PHP’s growth & maturity like Sun & Google do for Java, Google (Guido van Rossum) for Python (jnc Django framework), Ruby (inc RoR) by 37 signals etc…

PHP is not supported by Yahoo. They failed to launch a version with Unicode support in the hyped up PHP6. And the father of PHP Rasmus Lerdorf is no longer based at Yahoo. Nor is PHP supported by Facebook. Facebook has been trying hard to move away from it’s aged roots and now compile PHP into C via HipHop – more on that below.

The mess that is PHP

There are plenty of websites covering the mess that is PHP. Just go and read them if you are still doubtful.

• What are the horrors of PHP
• PHP Sadness.com
• PHP a fractal of bad design
• PHP turtles
• PHP WTF
• YourLanguageSucks
• PHP in contrast to Perl
• Pi’s dense, angry, inspirational rant
• PHP is not an acceptable COBOL
• Many hidden security vulnerabilities

Some of those nasty PHP horrors

• Unsatisfactory and inconsistent documentation at php.net.
• PHP is exceptionally slow unless you install a bytecode cache such as APC or eAccelerator, or use FastCGI. Otherwise, it compiles the script on each request. It’s the reason Facebook invented HipHop (PHP compiler) to increase speed by around 80% and offer a just-in-time (JIT) compilation engine.
• Unicode: Support for international characters (mbstring and iconv modules) is a hackish add-on and may or may not be installed. An afterthought.
• Arrays and hashes treated as the same type. Ref my short story above.
• No closures or first-class functions, until PHP 5.3. No functional constructs. such as collect, find, each, grep, inject. No macros (but complaining about that is like the starving demanding caviar.)  Iterators are present but inconsistently used.  No decorators, generators or list comprehension.
• The fact that == doesn’t always work as you’d expect, so they invented a triple-equals === operator that tests for true equality.
• include() can generate circular references and yield many unwanted and hard to debug problems. Not to mention its abuse to execute code that gets included.
• Designed to be run in the context of Apache. Any back-end scripts have to be written in a different language. Long-running background process in PHP have to overwrite the global php ini.
• PHP lacks standards and conventions.
• There’s no standard for processing background tasks, such as Python’s Celery.

PHP presents 4 challenges for Facebook.

• High CPU utilization.
• High memory usage.
• Difficult to use PHP logic in other systems.
• Extensions are hard to write for most PHP developers.

Dont use Facebook as an excuse to have PHP as your core language.

Excuses for poor decision to use PHP

“But Facebook is all PHP.”

Boo hoo. Is that what your decision was based on? Seriously? It is well documented that Facebook uses PHP due to legacy reasons. It is what Mark Zuckerberg used in his dorm nearly a decade ago and somehow it stuck around. Later a top FB engineer called Haiping Zhao released HipHop literally rewriting the entire PHP language thus avoiding the worst attributes of the language. Since 2007 alone, Haiping named four failed attempts to move to Python (twice), to Java, to C++. The reason this did not work is due to incumbent inertia (it’s what’s there).

So you see it is not the same PHP you are coding in but a far superior subset of it customized for Facebook process & development efforts. PHP at Facebook was a mistake that had been corrected to some degree. Today the preferred strategy at Facebook is to write new components in a de-coupled manner using a better language of choice (C++, python, Erlang, Java, etc); this is easily facilitated by Facebook’s early development of thrift, an efficient multi-language RPC framework.

“But Yahoo is all PHP.”

Seriously? Shall we even go into this. A sinking Titanic that started its life as a manually maintained directory site. Today’s online apps are more advanced, demand high concurrency and dynamic nature – something more advanced languages are capable of delivering.

 “But Zynga (a large gaming company) uses PHP.”

At the time Zynga started developing for the platform, there was no other official Facebook SDK available except for the PHP one. Naturally Zynga started its life on Facebook. The rest is history.

~ Ernest