To understand why PHP is a suitable programming language for building microservices, we need to take a small peek into its history, where it comes from, which problems it was trying to solve, and the evolution of the language.
In 1994, Rasmus Lerdorf created what we can say was the first version of PHP. He built a small suite of Common Gateway Interfaces (CGIs) in the C programming language to maintain his personal web page. This suite of scripts was called Personal Home Page Tools, but it was more commonly referenced as PHP Tools.
Time passed and Rasmus rewrote and extended the suite so that it could work with web forms and have the ability to communicate with databases. This new implementation was called Personal Home Page/Forms Interpreter or PHP/FI and served as a framework upon which other developers could build dynamic web applications. In June 1995, the source code was opened to the public under the name of Personal Home Page Tools (PHP Tools) version 1.0, allowing developers from all over the world to use it, fix bugs and improve the suite.
The first idea around PHP/FI was not to create a new programming language, and Lerdorf let it grow organically, leading to some problems like the inconsistency of function names or their parameters. Sometimes the function names were the same as the low-level libraries that PHP was using.
In October 1995, Rasmus released a new rewrite of the code; this was the first release that was considered as an advanced scripting interface and PHP started to become the programming language that it is today.
As a language, PHP was designed to be very similar to C in structure so that it would be easier to be adopted by developers who were familiar with C, Perl, or similar languages. Along with the growth of the features of the language, the number of early adopters also began to grow. A Netcraft survey of May, 1998 indicated that nearly 60,000 domains had headers containing PHP (around 1% of the domains on the Internet at the time), which indicated that the hosting server had it installed.
One important point in PHP history was when Andi Gutmans and Zeev Suraski of Tel Aviv, Israel, joined the project in 1997. At this time, they did another complete rewrite of the parser and started the development of a new and independent programming language. This new language was named PHP, with the meaning becoming a recursive acronym---PHP (Hypertext Preprocessor).
The official release of PHP 3 was in June 1998, including a great number of features that made the language suitable for all kinds of projects. Some of the features included were a mature interface for multiple databases, support for multiple protocols and APIs, and the ease of extending the language itself. Among all the features, the most important ones were the inclusion of object-oriented programming and a more powerful and consistent language syntax.
Andi Gutmans and Zeev Suraski founded Zend Technologies and started the rewrite of PHP's core, creating the Zend Engine in 1999. Zend Technologies became the most important PHP company and the main contributor to the source code.
This was only the beginning and as years passed, PHP grew in features, language stability, maturity, and developer adoption.
Now that we have some historical background, we can focus on the main milestones achieved by PHP throughout the years. Each release increased the language stability and added more and more features.
PHP 4 was the first release, which included the Zend Engine. This engine increased the average performance of PHP. Along with the Zend Engine, PHP 4 included support for more web servers, HTTP sessions, output buffering, and increased security.
PHP 5 was released on July 13, 2004 using the Zend Engine II, which increased the language performance once again. This release included important improvements for object-oriented (OO) programming, making the language more flexible and robust. Now, users were able to choose between developing applications in a procedural or a stable OO way; they could have the best of both worlds. In this release, one of the most important extensions used to connect to data stores was also included---the PHP Data Objects (PDO) extension.
With PHP 5 becoming the most stable version in 2008, many open source projects started ending their support for PHP 4 in their new code.
This release was one of the most famous failures for PHP. The development of this major release started in 2005 but, in 2010, it was abandoned due to difficulties with the Unicode implementation. Not all the work was thrown away and most of the features, one of them being namespaces, were added to the previous releases. As a side note, version 6 is generally associated with a failure in the tech world: PHP 6, Perl 6, and even MySQL 6 were never released.
This was a long awaited release---one release to rule them all and a release with performance levels seen never before.
On December 3, 2015, version 7.0.0 was released with the last Zend Engine available. The performance increase obtained only by changing the running version on your machine reached up to 70%, with a very small memory footprint.
The language also evolved, and PHP now had a better 64-bit support and a secure random number generator. Now you could create anonymous classes or define return types among other major changes.
This release became serious competition to the other so-called enterprise languages.
PHP is one of the most used programming languages you can use to build your web projects. In case you are not yet sure if PHP is the appropriate language for your next application, let us now to tell you the main advantages of using PHP:
Big community: It's very easy to engage in conferences, events, and meetups all over the world with ZendCon, PHP[world], or International PHP Conference. Not only can you talk to other PHP developers at events and conferences, but you can join IRC/Slack channels or mailing lists to ask questions and keep yourself updated. One of the many locations where you can find events near your area is on the official site at http://php.net/cal.php.
Great documentation: The main point of information about the language is available on the PHP website (http://php.net/docs.php). This reference guide covers every aspect of PHP, from basic control flows to advanced topics. Do you want to read a book? No problem, it will be easy to find a suitable book among more than 15,000 Amazon references. Even if you need more information, a quick search on Google will give you more than 9,300,000,000 results.
Stable: The PHP project makes frequent releases and maintains several major releases at the same time until their scheduled End Of Life (EOL). Usually, the time between a release and its EOL is enough to move to the next mainstream version.
Easy to deploy: PHP is the most popular server-side programming language with an 81.8% usage in August 2016, so the market moves in the same direction. It is very easy to find a hosting provider with PHP preinstalled and ready to use, so you only need to deal with the deploy.
There are a number of ways of deploying your code into production. For instance, you can track your code in a Git repository and do a Git pull on your server later. You could also push your files through FTP to the public location.You can even build a Continuous Integration/Continuous Delivery (CI/CD) system with Jenkins, Docker, Terraform, Packer, Ansible, or other tools. The complexity of the deploy will always match the project complexity.
Easy to install: PHP has prebuilt packages for the major operating systems: it can be installed on Linux, Mac, Windows, or Unix. Sometimes the packages are available inside the package system (for instance, apt). In other cases, you need external tools to install it, such as Homebrew. In the worst case scenario, you can download the source code and compile it on your machine.
Open Source: All the PHP source code is available at GitHub, so it is really simple for any developer to take a deep look at how everything works. This openness allows a programmer to participate in the project, extending the language or fixing the bugs. The license used in PHP is a Berkeley Software Distribution (BSD) style license without the copyleft restrictions associated with GPL.
High running speed (PHP 7): In the past, PHP was not fast enough, but this situation changed completely with PHP 7. This major release is based on the PHP Next-Gen (PHPNG) project with Zend Technologies as the leader. The idea behind PHPNG was to speed up PHP applications and they did this very well. The performance gains can vary between 25% and 70% only by changing the PHP version.
High number of frameworks and libraries available: The PHP ecosystem is very rich in libraries and frameworks. The common way to find a suitable library for your project is using PEAR and PECL.
Regarding the available frameworks, you can use one of the best, for example Zend Framework, Symfony, Laravel, Phalcon, CodeIgniter, or you can build one from scratch if you can't find one that meets your requirements. The best part about this is that all of these are open source, so you can always extend them.
High development speed: PHP has a relatively small learning curve, which can help you start coding from the beginning. Also, the similarities in syntax with C, Perl, and other languages can make you understand how everything works in no time. PHP avoids wasting time waiting for the compiler to generate our build.
Easy to debug: As you probably know, PHP is an interpreted language. Therefore, when trying to solve an issue, you have multiple options to succeed. The easy way is dropping a few
var_dumporprint_rcalls to view what the code is doing. For a deeper view of the execution, you can link your IDE to Xdebug or Zend Debug and start tracing your application.Easy to test: No modern programming language will survive in the wild without an appropriate test suite, so you have to ensure that your application will continue running as expected. Don't worry, the PHP community has your back as you have available multiple tools to do any kind of tests. For instance, you can use PHPUnit for your Test Driven Development (TDD), or Behat if you are following a Behavior Driven Development (BDD).
You can do anything: PHP is a modern programming language with multiple applications in the real world. Therefore, only sky is the limit! You can build a GUI application using the GTK extension, or you can create a terminal command with all the required files in a phar archive. The language has no limitations, so anything can be built.
Like any programming language, PHP also has some disadvantages. Some of the most common mentioned disadvantages flagged are: security issues, unsuitable for large applications, and weak types. PHP started as a collection of CGIs and has become more modern and robust throughout the years, so it is pretty robust and flexible for a young programming language (in comparison with other languages).
In any case, an experienced developer will have no problem overcoming these disadvantages when building their application if they use the best practices.
As you can already see, the evolution of PHP was enormous. It has one of the most vibrant communities, was made for the web, and has all the power you need to create any kind of project. Without a doubt, PHP will be the right language for you to express your best ideas.