My First WebApp
This tutorial explains how to implement your first webapp on appserver.io from scratch using the Servlet-Engine mixed with Dependency Injection and Session-Bean integration.
Prerequisite First you will need a running installation of appserver.io (>= Version 1.0.0-rc3). If you are new to this project you can easily download and follow the installation guide for your specific OS.
Preparations At first switch to dev mode in our local appserver.io installation. This will set the correct filesystem permissions for your user account and also let the appserver process itself run as the current user. This will make it easy for local development. sudo /opt/appserver/server.php -s dev # Should return: Setup for mode 'dev' done successfully! Now you are ready to create the webapp called myapp
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# Goto appserver.io webapps folder cd /opt/appserver/webapps/ # Create myapp mkdir myapp # Go into myapp cd myapp # Open it with your favorite editor if you want to... pstorm . brackets . atom . Keep the webapp under version control from the early beginning, so that you always have a chance to rollback things and maybe push it finally to GitHub with all the history in it if you want to. git init # Some default git ignore stuff echo ".idea\n/vendor\ncomposer.lock" > .gitignore # Do initial commit git add . git commit -m "initial commit"
Hello-World Script The simplest way to echo things like Hello-World to the client is the way you already know. Using a simple PHP script. So check if that works in appserver and create
a
PHP
script
called
hello.php
directly
in
the
webapps
folder
/opt/appserver/webapps/myapp.
<?php echo "hello i'am a simple php script"; ?> Open the browser at [http://127.0.0.1:9080/myapp/hello.php] and you should get...
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Wooow it works... looks great :) # Commit the current state via git. git add . git commit -m "added hello-world script"
Hello-World Servlet Ok now do the same thing using the Servlet-Engine by creating your first simple
Hello-World Servlet. In the beginning create the WEB-INF/classes folder where all Servlets are. In this folder the namespaces and classes MUST follow an autoloading PSR: PSR-0.
PSR-4 support is comming in one of the next appserver.io releases. If
our
vendor
name
is
MyVendor
the
folder
should
look
like
WEB-
INF/classes/MyVendor/MyApp
mkdir -p WEB-INF/classes/MyVendor/MyApp Finally
we
introduce
our
servlet
by
creating
a
PHP
class
HelloServlet.php in that folder. <?php namespace MyVendor\MyApp; use AppserverIo\Psr\Servlet\Http\HttpServlet;
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file
called
/** * @Route(name="helloWorld", urlPattern={"/hello.do", "/hello.do*"}) */ class HelloServlet extends HttpServlet { public function doGet($servletRequest, $servletResponse) { $servletResponse->appendBodyStream("hello i'am a simple servlet"); } } Due to the reason that servlets are pre-initialised by the servlet-engine at the appserver.io startup it is necessary to restart the appserver every time it is needed to test the recent changes. Here is a short overview how to restart. # OSX sudo /opt/appserver/sbin/appserverctl restart # Debian / Ubuntu / CentOS sudo /etc/init.d/appserver restart # Fedora sudo systemctl restart appserver After the appserver has restarted goto [http://127.0.0.1:9080/myapp/hello.do] and you should get...
Strike! :) # Commit the current state via git. git add . git commit -m "added hello-world servlet"
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Using Services As the most business logic should be separated into services now implement a
simple HelloService which is getting inject into the HelloServlet via DependencyInjection. To use Dependency-Injection you have to put the service classes at METAINF/classes where the namespaces and classes MUST also follow an *autoloading PSR: PSR-0.
mkdir -p META-INF/classes/MyVendor/MyApp Let us introduce the HelloService which provides the getHelloMessage() method that returns the hello-world message that the servlet should serve to the client.
Create
a
PHP
class
file
called
HelloService.php
in
folder
META-
INF/classes/MyVendor/MyApp <?php namespace MyVendor\MyApp; /** * @Stateless */ class HelloService { public function getHelloMessage() { return "hello i'am a simple servlet with service usage"; } } To inject the HelloService into the HelloServlet add an annotated property $helloService and modify the doGet method to make use of the injected service instance. The HelloServlet should now look like this... <?php namespace MyVendor\MyApp; use AppserverIo\Psr\Servlet\Http\HttpServlet; /** * @Route(name="helloWorld", urlPattern={"/hello.do", "/hello.do*"}) */
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class HelloServlet extends HttpServlet { /** * @EnterpriseBean(name="HelloService") */ protected $helloService; public function doGet($servletRequest, $servletResponse) { $servletResponse->appendBodyStream( $this->helloService->getHelloMessage() ); } } Restart
the
appserver
again
and
refresh
the
browser
at
[http://127.0.0.1:9080/myapp/hello.do]. Here you go...
And here it is... Your First WebApp on appserver.io! # Commit the current state via git. git add . git commit -m "added hello-world service and enhanced servlet"
Feel free to enhance it and let us know what you have built upon the next PHP infrastructure!
Annotations! But why? To use servlets without configuration, it is necessary to add a @Route annotation so the servlet-engine is able to map a specific url to the servlet.
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<?php /** * @Route(name="helloWorld", urlPattern={"/hello.do", "/hello.do*"}) */ class HelloServlet extends HttpServlet This annotation maps the URL http://127.0.0.1:9080/myapp/hello.do and http://127.0.0.1:9080/myapp/hello.do/anything/you/want to the servlet. For more servelt details checkout out Servlet Engine section in our Documentation You also use annotations to use Dependency-Injection. To make our HelloService injectable add an annotation above the class definition. In this case we want to have a stateless Session-Bean so put @Stateless to class doc block. <?php /** * @Stateless */ class HelloService To inject our HelloService to the HelloServlet via Property-Injection we just have to put the annotation above the member property like this... <?php class HelloServlet extends HttpServlet { /** * @EnterpriseBean(name="HelloService") */ protected $helloService;
Okay, folks that is all! We hope this tutorial helps you to have a smooth start into the world of appserver.io webapps! Any feedback is appreciated so do not hesitate to share your experiences or any problems you encounter with us. Cheers! :)
Š appserver.io 2015 â&#x20AC;&#x201C; Eine eingetragene Marke und Produkt der TechDivision GmbH