What are the architectural limitations of PHP? [closed]
I was reading the article "PHP Sucks, But It Doesn't Matter" by Jeff Atwood.
In the comments he writes:
That said, I absolutely think it's important for PHP devs to be aware开发者_StackOverflow of the architectural limitations of PHP, and understand the alternatives.
What are those limitations and how do they compare with other scripting / weakly typed languages?
Also, what are the alternatives in those conditions where limitations need to be avoided?
There are basically two real limitations I see:
PHP is a fully synchronous language. This has impact on which things you can easily implement in PHP and which not. For example implementing a Long Polling driven chat application isn't trivial, because PHP would need block one process per chatter. I'm not saying it's impossible, you can hack around this limitation using some PHP Daemon library. I'm just saying that this is one of the cases where other languages, like JavaScript, are more appropriate (NodeJS).
PHP is slow. Please don't understand this an an offense. It's a fact that PHP - as implemented by Zend - is slow compared to other scripting languages. This typically is no problem when building websites, but you obviously can't do certain things: Implementing a ray tracer in PHP is definitely a bad idea - whereas in JavaScript you could do this.
But apart from that, I think that PHP is pretty multi-purpose. You can use it for nearly anything - and I do ;)
Take a look at the date. The article was written in 2008.
It means, that if you'll see the PHP5.3 advantages, you'll find there many things, like closures and namespaces, which were in other languages before. Some of them is already affected the architecture of famous frameworks, like Symfony.
And that list will never be complete.
Meanwhile, I meet a lot of people who think that "weak typing" language is an architectural problem itself.
Then, some people think that inline regex syntax is good thing in, for example, JavaScript, but others think, that "different language" must be written down in string constants there, as in PHP. Etc.
I'll take a stab at this without getting too into the nitty gritty:
- The initial design of PHP as a collection of functions still shows through.
- Object-oriented patterns that have been implemented in the latest PHP 5 releases are still half-baked and lack multiple inheritance (or "mixins"), proper module support, and are designed to be backwards compatible with the CoF (collection of functions) design.
- Method overriding and callbacks are not supportive natively.
- Closures. They are there, but they are very weak.
- Errors vs Exceptions — methods are inconsistent in which they use (thanks again to CoF design), and error-handling is half-baked.
I'm sure I'm stepping on someone's toes here and I'll get any angry mob, but I'm also sure that I still didn't hit everything. It's largely subjective, but it's easy to see what is to dislike when you stack PHP up next to Ruby or Python.
I don't find it odd anymore that all of "PHP SUCKS" articles are coming from developers accustomed to established Microsoft technologies.
What I do find odd are statements that indicate that PHP is a spaghetti code. It's completely up to the author of the code whether the code will be spaghetti or if it'll use certain design rules when approaching the problem.
The reason a lot of PHP code out there is spaghetti code is because examples and tutorials are such that they don't teach beginners the good coding practices. Also, people are quick to grasp examples like hello world or connecting to MySQL, doing a query and looping over the result - but that's it, that's where ALL tutorials stop. I still haven't found a tutorial that covers the following:
- what is a framework and what it helps with
- what are data structures and data types (explained in a way a normal human can understand)
- what is an array, what are array dimensions, how do arrays work, what are arrays useful for
- what is object oriented code, why object oriented code, how does PHP do it, what is considered good, why are there patterns out there and so on
As you can see, a beginner programmer won't be bothered to learn all of those points outlined above, I know that because I was a beginner too and did all the mistakes beginners do. However, even if someone doesn't know how to program, they can still create useful applications.
Many popular scripts were written by people who knew WHAT they want to achieve, however they did not know HOW to properly design the environment (framework) in which they'll deploy their php code. That's why we see scripts that become incredibly popular due to the ease of their use as a regular user which are hard to extend looking at it as a developer, using weird function names, odd coding conventions and no commenting.
Also, what's ridiculous is saying PHP is slow which is absolute nonsense. When I come across such statement, I want to shoot myself in the head for reading such a blog entry.
One has to know several things before making such a statement:
PHP is a scripting language, that means the interpreter is invoked every time someone requests a PHP page which takes A LOT of CPU power. That has been addressed by using bytecode caching mechanisms such as APC which stores the copy of pre-interpreted piece of the script in memory. The results are impressive, and I kid you not - execution for some of my scripts goes from 20 milliseconds to 1 microsecond, where some benefit "only" 5 times. That's on a system that serves 1 thousand concurrent users. Now, if someone wants to tell me that 1 microsecond is slow (or 5 milliseconds) - I'll take that as bullshit.
PHP is not the only thing involved in serving a web page. There's also underlying server (Apache) which has its own issues, there's MySQL which runs queries - and who says all queries are optimal? There's the network, there's the hard disk, there's the CPU, there are tons of other processes. Configure Apache with PHP-FPM, optimize MySQL to perform good on 8 core machine with 16 gigs of ram, use APC, use Memcache - and voila, you're getting an incredibly fast, scalable system capable of serving an incredible amount of traffic. Languages that PHP is being compared to are often "compiled" into the bytecode and then executed by
You can extend PHP yourself. Assuming a PHP function is slow, NOTHING prevents anyone from creating a .so in C that is able to do the job faster and then hooking everything up trough extension in PHP. Not that I know what would such job be that would require that, but such a thing IS possible.
Sadly, and I say sadly because I respect certain programmers and admire their work (and I'm by no means a PHP fanboy) but it hurts me when I see uneducated, inexperienced and subjective comments about a tool which spreads misinformation.
As for why big websites use PHP - because it's fast. Because they laid proper foundations before starting the projects. Because it's free, extensible and scalable. Because it follows C syntax. Because you can extend it when you need it to be faster. Because it runs on a free operating system. Because it's easy to use.
PHP is improving everyday. It is open source and used all around the world. That said, when you have a problem, it is most probable that you will find your solution or get help faster than any other language.
The very reason of this article, I believe it is simple. If you (or in that matter any other programmer) used to code in C++, Java etc.. they had a lot of possibilities such as OOP coding and PHP was limited in the beginning.
It is a good thing that PHP has many built-in functions / methods / classes so you don't have to spend hours to code some function / class / method which PHP already has.
You don't have to (and you shouldn't) try to memorize all these functions. It is useless to memorize all of them (which one is doing what, how to use it etc). Imagine you are working on some project which took you 4-5 months to finish (yeah big one (: ) You are not going to use all these functions in all the projects and eventually you will forget what they were doing since you don't use them often.
The point is, you should know the syntax of PHP. When you need to do something, check first if PHP already has what you want to do in its library. Check the manual to see how to use it. This way, you will also LEARN (NOT MEMORIEZE) the ones you use often and this information will be hard to forget.
PHP or any other programming language is just like a normal language which we humans use daily to communicate with each other. If you don't use it, you will forget.
PHP 5.3 and above brought many features. Static feature is one of the biggest feature for me. It made my life so much easier that I can't even begin to describe.
Since PHP is that famous and open source web scripting language, Facebook developer team created HipHop.
What HipHop does is, takes the data from PHP and sends it to C++. C++ does all the process and sends back results to PHP for outputting.
The whole idea of HipHop was to make Facebook use less servers & improve the page display times.
Now you tell me if this seems limited and / or slow to you?
i dont think there is anything like 'architectural limitation' for php. developer knowledge limitation might be the reason. read this http://www.quora.com/What-is-Facebooks-architecture . most of the time, non-world-class developer does not know how they could use php to its full capabilities.
I would assume he is referring to the fact the the OOP portions of PHP are not the greatest compared to languages that are purely object oriented.
Architecture Limitations in Addition to nikic's answer
Writing extensions for PHP is a PITA. Not as bad as with Perl or Java, but not as easy as it could be. The ease of extensibility champion is still TCL which hails from the early 90's. Nearly any C function taking char* can be made into a TCL extension.
Embedding PHP in other systems. mod_php, gtk.php.net shows it can be done, but Guile and TCL are much easier to embed.
加载中,请稍侯......
精彩评论