PHP ON A FAST TRACK INTRODUCTION: ROADMAP BY JAROSLAW FRANCIK. Companion web site: php.francik.name

Transcription

1 PHP ON A FAST TRACK BY JAROSLAW FRANCIK Companion web site: php.francik.name Writing web based, database connected applications in PHP is not difficult, however many people get stuck on just the basic stuff, in the very beginning. Indeed, configuring the software, establishing the database connection and starting a simple server script may be troublesome for a not experienced user. This paper will guide you step by step to creating a very simple web application of a cart, which may be a starting point for an on-line shop project. It will lead you from finding the basic tools (web server, php module, MySql database), through the set-up process, up to writing the code. One fundamental aspect of the development process in IT is that you will always have to face the fact that there will be problems. Problems are a natural part of your job, and the lion share of what we call an IT profession is the ability to solve them. The solutions for some most common problems you will find below, but it is only a matter of time when you encounter a new one that you will have to solve on your own. Search and experiment are the most useful hints, and your most powerful friend is your favourite web search engine. INTRODUCTION: ROADMAP A usual choice for developers is to create a workplace on your own local computer. When your solution is completed and working you will then transmit files to a server. While at the development stage, you have all your files stored locally, available to be checked and tested in your browser right in the moment when you save them to the disk. Now, you have several ways you can go. Here are just some of them: Download your development tools. There are many packages that contain all the necessary tools, including, most usually, Apache web server, MySQL database server and PHP scripting language. Together with Windows operating system they are commonly named WAMP (Windows, Apache, MySQL, PHP), or LAMP if you prefer Linux than Windows, or even MAMP if you are a Mac user. Their common feature is that they come in a form of open source installers, and require next to no time to install and setup. They are much more reliable now than they used to be, and in most cases the whole installation process is trouble-free. Especially if you are not yet an experienced developer, this approach may be recommended to you. There are many WAMP/LAMP/MAMP packages and they are easy to find through a search engine. My favourite project is a cross-platform package named XAMPP, where X stands for Cross, and the additional P is for Perl. You can download XAMPP from If you have chosen to download your development tools, you can ignore the PART 1 of this document and go straight to the PART 2. Install and configure your PHP development environment all by yourself. It s a more difficult path, but in the same time more awarding. Doing everything by yourself you will better understand your installation and you will be by far better prepared to cope with any possible problems. And, most importantly, the PART 1 of this document will help you, guiding step by step through the whole process. Use a different technology. PHP is still the most commonly used server-side scripting technology, but there is a lot of alternative solutions. Personally, I don t like PHP too much: it s relatively easy, but it s definitely outdated and too much low-level, when compared with perl, python on ruby. If you think about the latter option, check my other site at Look for ready to use solutions. There are plenty of open source projects around. For example, if you need to build an on-line shop, instead of creating your own one from scratch, it may make much more sense to look at projects like Shopify, oscommerce, Magento or many, many others. They will save you a lot of programming time and allow to concentrate on what is really important in your project. But, this document does not cover this option.

2 PART 1: CONFIGURING YOUR WORKPLACE PREREQUISITES You will need at least 200MB free on your hard drive as the only prerequisite. I tested the software on several computers running Windows XP and it worked without significant problems; it should be also ok if you have Windows 2000 or Vista. You also need the Administrator privileges on your PC. If you have already installed IIS (Internet Information System, the Microsoft Web Server), it is strongly recommended that you uninstall or at least deactivate it prior to installing the Apache server. You could also try to use IIS instead of Apache however this option is not covered in this guide and is not guaranteed to succeed. If you have previously installed MySQL, you can either re-use this installation or remove it completely. In the latter case it may be useful to manually remove the c:\program Files\MySQL directory from your disk to avoid problems. Installation on Linux and other systems is similar however this document covers no issues specific for such installation. The troubleshooting sections will be displayed in green. If you are lucky you will find all your questions answered here. Generally, you shouldn't expect that installation will be smooth. Problems are the rule, not an exception. It is however very unlikely that you are the first living creature to experience a particular kind of problem. Solutions to most problems you could encounter are somewhere in the Internet use your favourite search engine! DOWNLOADS It is sometimes a good idea not to load the newest versions of everything. If you get stuck, and apparently nothing is working as supposed, you can consider a downgrade. I tested all the newest versions of the software, as listed below, and I can recommend them to use in this guide. There were some tricky moments, and in fact I got stuck for long with the newest PHP, but eventually solved all the problems and the solutions are included below. So, download the following: 1. Web Server: Apache/ (Win32): Look for Apache in Google or go directly to find HTTP Server project and choose the proper version and file. Download Win32 Binary without crypto (no mod_ssl) (MSI Installer): apache_ win32-x86-no_ssl.msi. 2. Server-side scripting: PHP 5.2.6: Again, google for PHP or go to choose Downloads and then download PHP installer. Until recently, PHP installers were infamous, and most developers chose to install manually, but it seems all problems with this installer are at last fixed. 3. Database System: MySQL: Click Downloads section, than Download button, then Windows. Windows Essentials (x86), at version (or newer), will do. If you cannot see light at tunnel's end or just prefer an easy path see this: "I tried everything it just did not work, eventually i took a short cut i went to downloaded and installed the easyphp 1.8 package, this included PHP, APACHE & MYSQL. It was a pretty easy installation and it works perfect." (thanks Babz Amusan for this feedback). If you are going to install oscommerce: please notice that oscommerce does not work with the newest version of PHP. The recommended set in this case is: Apache , PHP and MySQL 4.1. INSTALLING THE APACHE SERVER This step is quite straightforward: just run the Apache installer you have downloaded and go through the Installation Wizard. Use following settings: Network Domain: if your computer has a network domain (a URL name, e.g. mycomp.co.uk) put this name here. Otherwise you can type localhost or in fact anything else. Server Name: usually the same as above, preceded by the 'www', e.g. If you don't have a domain, typing localhost here should be enough. Administrator's Address: you can type here your address. Choose "for All Users, on Port 80 - as a Service" (the default option). Choose Typical as the Setup Type. Accept all the default settings.

3 After the successful set-up you will find an icon on your task manager (bottom-right corner of your screen). Double click on it to run the Apache Service Monitor. You will do it later to restart your Apache service. You will also find a new Apache HTTP Server 2.2 item in your Start/Programs menu. In the Configure submenu you will find the Edit the Apache httpd.conf Configuration File item which will help you in case of problems. To test your new Apache server run an Internet browser and type address. You should see a starting page of your new Apache-managed site. Your new web site files are located on your drive at the following path (unless you chose other installation location): C:\Program Files\Apache Software Foundation\Apache2.2\htdocs In your browser the same will be accessible as If your computer has a constant IP address or a domain name, this site may be accordingly visible worldwide. The Apache HTTP Server cannot start: This is usually connected with a problem with the '80' port usually used by the HTTP server. This may be due to a previous installation of a Microsoft IIS server. Open the configuration file (Start Menu, Apache HTTP Server, Configure..., Edit the Apache httpd.conf), locate the Listen directive and change it to Listen You have to restart Apache using Apache Service Monitor. Your start page will appear now as If the problem persists and no Appache2 service appears in Appache Server Monitor (problem known as "no installed service named Appache2"), follow a hint given on forums.devshed.com and install the service manually. From the Start menu choose Run and write a following command: C:\Program Files\Apache Group\Apache2\bin\apache" -k install -n "Apache2 Adjust the address to suit. INSTALLING PHP In the previous version of this guide I recommended not to use Windows installer. It used to create more problems than it solved. This fortunately seems to be the past. You can still find steps that will guide you through the manual process of installation if everything else fails. Installing PHP with Windows MSI file (php win32-installer.msi or newer) is generally straightforward, however there is a couple of tricky moments, so ensure you do everything required or turn to the manual process explained below. The installation wizard will ask you about the following things: Web Server Setup: check Apache 2.2.x Module (or whatever you installed). Apache Configuration Directory: you have to locate the directory within your Apache installation that contains httpd.conf file. In my computer it is: C:\Program Files\Apache Software Foundation\Apache2.2\conf\. Ensure you browsed to the correct location: this step is really essential unless you desire to test yourself with manual installation of PHP. Choose Items to Install. The default setting here is for those peculiar developers who are using PHP without MySQL. All the rest of the world has to click on Extensions and ensure you have chosen MySQL and MySQLi items. Without them you would get stuck trying to connect to a database. Probably in order just to confuse you, there is an item there called MSSQL. You don t want this. That s almost all... click Install and wait... Most problems with PHP installer fortunately have been fixed. Most doesn t however mean all. Therefore the following step is absolutely essential: at the current stage a bug prevents the PHP installer from doing this automatically: Locate the PHP Installation directory (usually C:\Program Files\PHP) and find a libmysql.dll file in it. Copy this file to your Windows System directory (usually C:\Windows\System32). Without this, you ll stuck trying to connect to your database! And last but not least:

4 Restart your Apache server: use icon on your task manager to launch Apache Service Monitor. By now, your PHP should be up and running. To test it, use notepad to create the following PHP script: phpinfo() Store the file in your htdocs directory as test.php (it should be something like this: C:\Program Files\Apache Software Foundation\Apache2.2\htdocs\test.php) and then point your browser to the You should see a set of tables full of technical information, just like this: Press Ctrl C and find the mysql selection. You should get something like this: If anything went wrong either you can t see the phptest table at all or just cannot locate mysql information in it check if you ve done all the steps required or use the troubleshooting below. In case of big problems you may decide to either re-install PHP manually, or downgrade to the version, which also involves manual installation (using a Windows installer for PHP 4 is not recommended). If you are using PHP 4.4.9, downgrade Apache to 2.0 version first. In either case, follow the following steps: Installing PHP manually: 1. Download a zip package (either PHP zip package or PHP zip package) 2. Unpack your PHP zip installation archive. 3. Move the unpacked directory to the C: volume root and rename it to php. After this is done, all the files should be located in C:\php. You can use a different location as well, just remember to apply appropriate correction whenever this path appears in this guide. 4. Find a file named php.ini-recommended and rename it to php.ini. 5. For PHP only: move all the files from c:\php\sapi to c:\php. With PHP 5 you don t have to do this. 6. Configure your Apache server for using PHP: edit the Apache configuration file (Start Menu, Apache HTTP Server, Configure..., Edit the Apache httpd.conf) and add the following lines: For PHP 5.2.6: LoadModule php5_module "c:/php/php5apache2_2.dll" AddType application/x-httpd-php.php PHPIniDir "C:/php" For PHP 4.4.9: LoadModule php4_module "c:/php/php4apache2.dll" AddType application/x-httpd-php.php PHPIniDir "C:/php" If you have chosen a directory other than c:\php as your PHP location, be particularly careful at this stage and correct all the pathnames appropriately. 7. Restart your Apache server.

5 INSTALLING MYSQL DATABASE The installation process of MySQL is also straightforward. Just run the mysql-essential win32.msi file that you downloaded and go through the Setup Wizard, mostly using default settings. If you have installed MySQL previously and do not want to reuse it, uninstall it completely and remove any remaining files at c:\program Files\MySQL manually. Setup Type: choose Typical. After the installation is complete, ensure that the Configure the MySQL Server box is checked. Immediately after installation the MySQL Configuration Wizard will launch. Go through it: Choose Standard Configuration - it's pretty enough for us! You can leave all the settings as they are by default - this will do in most cases - however it's up to you if you would like to tune-up anything. When prompted, type here your password for the Database Server root user account. This is a very important step --- do not forget your password for the root user account!. Something went wrong with the Configuration Wizard. Don't worry: it happens quite often at this stage. Try to step back and then once more step forward in the Wizard. If didn't help, restart the Configuration Wizard. You will find it in the Start Menu. Choose Reconfigure Instance and go once more through all the options. You can use this wizard whenever any problems occur.

6 PART 2: CREATING A CART WEB APPLICATION By now you should have the Appache, MySQL and PHP properly installed on your Windows machine. This type of configuration is called WAMP. The following part of the guide can also be successfully used with a Linux installation (LAMP). PREPARE THE DATABASE This is an easy step, but may be done in several different ways depending on the tools you have. If you installed MySQL manually, you may use the MySQL Command Line Client. If what you have is preinstalled WAMP solution, you can find using phpmyadmin tool easier. There are three simple steps to do: first you have to create a database named test (in some system there may already be a test database), then create a table, and finally populate it with some sample data. We will use some simple SQL commands you should be well familiar with. Just type them into your command line client or use import option in phpmyadmin: USE test; CREATE TABLE goods ( id int(6) unsigned NOT NULL auto_increment, item varchar(100) NOT NULL default '', price decimal(6,2) NOT NULL default '0.00', PRIMARY KEY (id) ); INSERT INTO goods VALUES (1, 'Soap', '4.99'); INSERT INTO goods VALUES (2, 'Stawberry Jam', '1.99'); INSERT INTO goods VALUES (3, 'Toothpaste', '2.49'); INSERT INTO goods VALUES (4, '8GB Memory Stick', '22.99'); You can now exit the database command client. CREATE CART.PHP FILE The first step is easy. Open notepad (or any other text editor) and type the text in the frame below. You can also download this file from What we have here is almost pure HTML. The only piece of PHP code is between and markers and this is what actually PHP code is; it s HTML with embedded PHP snippets. As you can notice, at this stage our PHP code section is empty; but this is a placeholder into which we ll add the code later on. <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" " <html> <head> <title>your Cart</title> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> </head> <body> <h1>your Cart</h1> </body> </html> Now, save the file in the htdocs directory of your Apache server, and name it cart.php. The htdocs is the directory created when you installed your Apache server. It is typically C:\Program Files\Apache Software Foundation\Apache2.2\htdocs.

7 To test your web application, go to in your web browser. You should see something similar to this: Your Cart Hints: 1. To edit your PHP file you can use any text editor, and for this example notepad will be quite enough. It is however essential not to use text processors, like Microsoft Word or Open Office, as they add formatting information that is not accepted by PHP Processor. 2. Keep your text editor and the browser open all time. When you change anything in your PHP script, you can just save it (Ctrl S) and reload the page in the browser (F5) you will see the results immediately! 3. It will happen that your web application is not working. In that case check carefully what is wrong or missing. The common errors are lacking quotation marks, semicolons or dollar signs. Check also spelling and keep in mind that PHP is case sensitive: echo is something completely different then Echo. HELLO WORLD To do a classical programming exercise, just put the following code into the and code snippet: echo "Hello, world!"; Save the file and check the result in the browser (don t forget to reload the page). You ve just done your first piece in PHP! DETERMINE WHAT THE APPLICATION SHOULD DO To tell what our application should do, we can use a special section added after the page URL. For example, to tell the application just to show the cart, we will use: This will tell our application that the action to do is show. We can also add items with the following URL: Now, the action to do is add, and additionally the id (of the item added) is 2. The syntax is simple, and also it is very easy to read the values the application gets from within your PHP code. All the values are stored in a predefined array variable $_GET, which can be indexed by the name of the properties: $action = $_GET['action']; $id = $_GET['id']; echo "<p>debug: Action to do is $action, and item id is $id.</p>"; All identifiers starting with $ sign (in the example above: $action and $id) are PHP variables. Save the file and test the application with several different URL s as shown above. MAKE THE INFORMATION PERSISTENT The information about the content of the cart needs to be persistent. If the user returns to the cart several times before leaving the site, each time the content must be kept consistent. It is difficult because the web http protocol is stateless it has no knowledge about any previous operations. Even if data is stored in a database, still an id must be somewhere stored between consecutive visits so that the relevant records are addressed in the database. Fortunately PHP offers a very powerful and easy-to-use tool called session variables.

8 In fact, we don t even have to use the database to keep track of the items in the cart everything we need is a session variable. To start using the sessions a single call must be done to function session_start(). All the session variables are stored in an array called $_SESSION. We will use a variable named 'cart' which will be available as $_SESSIONS['cart']. Oops, there is one more important detail: most servers will require the session_start() to be called before the whole file starts, before even the!doctype. Therefore, we have to split our... section into two, like this: session_start(); <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" " <html> <head> <title>your Cart</title> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> </head> <body> <h1>your Cart</h1> session_start(); $cart = $_SESSION['cart']; $action = $_GET['action']; $id = $_GET['id']; echo "<p>debug: Action to do is $action, and item id is $id.</p>"; if ($action == 'add') $cart = $cart. ",$id"; $_SESSION['cart'] = $cart; echo "<p>debug: Cart is: $cart</p>"; </body> </html> The new additions to the code are bolded. Notice, that each time executing the script the value of the session variable is first stored into a local $cart variable. Then, if the action to do is add, the id of the item is added to the content of the cart, and the new value is stored in a session variable. Id s are separated with commas. Therefore, after adding a three items your cart state may be like this:,1,2,3. CREATE THE SHOP HOME PAGE With rudimentary but functional cart we can make a home page for the shop. In a separate file (maybe index.html) write the following HTML code: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" " <html> <head> <title>your Shop</title> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> </head> <body> <h1>your Shop</h1> <ul> <li><a href="cart.php?action=add&id=1">add item #1 to the cart</a></li> <li><a href="cart.php?action=add&id=2">add item #2 to the cart</a></li> <li><a href="cart.php?action=add&id=3">add item #3 to the cart</a></li> <li><a href="cart.php?action=add&id=4">add item #4 to the cart</a></li> </ul> <p><a href="cart.php?action=show">show your cart</a></p> </body> </html>

9 DISPLAY YOUR CART So far, the only output are not very interesting DEBUG strings. Another great PHP tool we ll use now are: explode() this function can transform a comma separated list into an array of items; foreach a standard PHP loop that is capable to iterate through each item of an array. Together, they do exactly what we now need: session_start(); $cart = $_SESSION['cart']; $action = $_GET['action']; $id = $_GET['id']; if ($action == 'add') $cart = $cart. ",$id"; $_SESSION['cart'] = $cart; $myitems = explode(',', $cart); // explode using comma as a separator if (count($myitems) <= 1) echo "<p>your cart is empty.<p>"; else foreach ($myitems as $i) if ($i!= '') echo "<p>item id: $i</p>"; After exploding the cart we first check if the cart is empty. If it is not, the foreach iteration will substitute consecutive items to the variable $i. We also avoid displaying information in case the item id is an empty string. CONNECT TO THE DATABASE Time came to connect to the database. It is essential if we want to display the name and price of items rather than just the id number. The sequence of operations necessary to open the connection is as follows: $hostname = 'localhost'; $username = 'root'; $password = 'elvis'; // localhost is the URL of the server // the username in this example is root // put here your MySQL root password // connect to the database server $con = mysql_connect($hostname, $username, $password) or die ('Could not connect: '. mysql_error()); // display if connection failed mysql_select_db( test, $con); // choose the test database... Provide the proper username and password! You can add new user accounts using Priviliges option in phpmyadmin. mysql_connect(...) or die (...) creates a database server connection and displays a message if failed, mysql_select_db chooses a database within the server. Client does not support authentication protocol is a common error at this stage. It is due to a change in the way the passwords are stored in the newer versions of MySQL and causes PHP passwords to be incompatible. The

10 solution of the problem is easy type the error message in Google and you ll find it in the first result. Start the MySQL Command Line Client, login and type: SET PASSWORD FOR = OLD_PASSWORD('elvis'); replacing 'elvis' with your real password. Assure you terminate the SQL directive with a semicolon. That s all. DISPLAY YOUR CART IN A SMART WAY With a known id, and a database connection, we can now read the name and the price of each product from the database. To achieve it, just three steps are needed: Form a MySQL query using mysql_query() function and standard SQL syntax. Fetch the result using mysql_fetch_array() function. The value returned by this function is a database table row. The row may be directly indexed with the names of table columns like $row['item'] and $row['price']. The final part of the PHP code will now look like this:... foreach ($myitems as $i) if ($i!= '') $result = mysql_query("select * FROM goods WHERE id = $i"); $row = mysql_fetch_array($result); $item = $row['item']; $price = $row['price']; echo "<p>$item: $price</p>"; Notice the use of the $i variable in creating the SQL query. FINAL POLISHING As the final polishing some better formatting will be added (using HTML tables) and also the total price of the transaction will be calculated: <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" " <html> <head> <title>your title here</title> <meta http-equiv="content-type" content="text/html; charset=utf-8" /> <!--<link rel="stylesheet" type="text/css" href="style.css" />--> </head> <body> <h1>your Cart</h1> $hostname = 'localhost'; $username = 'root'; $password = 'elvis'; // localhost is the URL of the server // the username in this example is root // put here your MySQL root password // connect to the database server $con = mysql_connect($hostname, $username, $password) or die ('Could not connect: '. mysql_error()); // display if connection failed mysql_select_db("test", $con); // choose the test database session_start(); $cart = $_SESSION['cart']; $action = $_GET['action']; $id = $_GET['id'];

11 if ($action == 'add') $cart = $cart. ",$id"; $_SESSION['cart'] = $cart; $myitems = explode(',', $cart); // explode using comma as a separator if (count($myitems) <= 1) echo "<p>your cart is empty.<p>"; else echo "<table>"; $total = 0; foreach ($myitems as $i) if ($i!= '') $result = mysql_query("select * FROM goods WHERE id = $i"); $row = mysql_fetch_array($result); $item = $row['item']; $price = $row['price']; $total += $price; echo "<tr><td>$item</td><td> $price</td></tr>"; echo "<tr><td><strong>total</strong></td><td><strong> $total</strong></td>"; echo "</tr></table>"; </body> </html> SHORTCOMINGS AND POSSIBLE EXTENSIONS If you buy the same item twice, the script displays it in separate lines. It should be displayed in one line, with quantity and price indicated. There is no Delete function. When adding items, it is enough to reload the page to get the item added again. The home page of the shop is hard-coded; it should rather load all the information from a database.

12 APPENDIX: DEPLOYMENT ON KINGSTON UNIVERSITY SERVER Kingston University provides a special studentnet server which you can use to deploy your application. You are provided with your own private web space at where kxxxxxx stands for your university k-number. You also have regular ftp access there (your usual k-number username and password will work). You also have the unique access to the university mysql server! You can only login from within the university, and the address is Use your k-number as the username, but the password system is different from the university main one! At the first login, just pretend you ve forgot your password, and you ll get a new one to your mailbox. Notice that due to a small bug you will always have to login twice! To deploy your application, you actually will need to port it: all the host addresses, user accounts, password etc. must be fixed to comply with the new environment. These steps will guide you through the process: 1. Identify your source files: shop.php and cart.php. You can prefer to name the former one index.php. Alternatively, you can create empty files with these names and use php.francik.name site to populate them with the source code. 2. Paste your source code into the files. 3. Edit cart.php and make the following amendments: a. change the hostname from localhost to ftemysql b. change the username from root to your k-number based username c. change the password from elvis to your actual password at the ftemysql server d. change the database name from test to your k-number. This is in the mysql_select_db function call. 4. Use your favourite ftp client to send the files to the studentnet. 5. See the results. You will probably not be very much satisfied with the results. If you don t know the solution (which is likely), just copy the error message and paste it to the Google search box. Do some research. If you are still confused, check for the solution provided by Subwayman, read both his posts. You can use studentnet to develop your application, avoiding installing everything locally however you will need to ftp your files each time you change anything not a very good idea. You can also use or find a hosting company to get (buy) your own server space. You have to check if the server supports php and offers mysql database access. The steps required to port your application will be similar to those described above. APPENDIX: PROBLEMS WITH WINDOWS VISTA This guide was written with Windows XP as your operating system in mind. So WAMP stands here for W(XP)AMP. If you use a Windows Vista machine, in theory everything should work the same and ok. That s the theory. The practice is that, unless you are able to configure your security settings wisely (I am not I am a relatively happy user of XP system), your PHP installer will probably be banned to access Apache configuration file (httpd.conf usually located in C:\Program Files\Apache Software Foundation\Apache2.2\conf). This is because Vista has introduced a special security for all system folders, including Program Files. A quick solution, maybe not the best possible but working is as follows: 1. Create a directory in a freely accessible area of your disk (for example somewhere in My Documents or Desktop). Name it whatever you like. 2. Copy the httpd.conf from its usual location in Program Files to the newly created directory. 3. Install PHP as usually, but when asked about the Apache Configuration Directory provide the path to the directory you have created, instead of the real one. 4. After the successful installation, just copy the httpd.conf back to its normal location overriding the original. You can just do what the PHP installer is not allowed to do. That s all!