As a pre-requisite for this tutorial, you should be familiar with html, css and web technologies in general. You do not need to know any CFML (ColdFusion Markup Language). You should have an understanding of databases, particularly MySQL, which we will use in this example.
For this tutorial, we are using a virtual machine (using VirtualBox) running Windows 2003 Server Standard, IIS, MySQL 5.1, and Railo 3.1.
The code we will be writing is not platform specific. You can just as easily implement this on Linux or Mac OSX Server with MySQL and Apache.
Lets assume that we have the HTML layout code provided to us for our website, and that we need to make it “work” on the web server, pulling its page content from a MySQL database. In addition, we will add the capability for any page to render itself as a PDF for printing purposes.
You will want to make sure you have done a few things first:
- Make sure Railo and MySQL are running on your server (or VM)
- Make sure you created a MySQL database, and a user that has permission to use your database
For development (as opposed to production web servers), try running Railo Express, which runs in a terminal window. This allows you to see the templates it is running, and the full stack trace of errors when they occur.
Setup the Railo Datasource
The first thing we need to do is setup a Railo datasource. This named datasource will define our database credentials for our website.
Open a web browser to the Railo Server Administrator, which is usually located at: http://your.server.com/railo-context/admin/server.cfm. Check the Railo documentation if you have trouble opening up the administrator.
Enter your password to login. Once logged in, click on the Services / Datasource link in the left navigation.
At the bottom of this page is where you can create a new datasource. Enter a datasource name (Letters and numbers only, no spaces, and start with a letter) and select MySQL as the database type.
On the next screen, enter the MySQL server host name or ip address, and username and password for the user you created. All of the other settings can be kept with their default values.
Scroll to the bottom and click on the “Create” button to complete the datasource configuration. Railo Administrator will test your connection, so you can confirm that it is setup properly.
We created the datasource in the “server” context. When you deploy an application on a production server, you should create your datasources in the “web” context, so that it is only available to the website that needs it. Datasources created in the server context are accessible from any website on the same server.
Setup the website structure
In the document root of your website (or in the directory you choose for this tutorial), you will need a couple of files.
index.cfm – this is the default document, like index.html or default.htm header.cfm – this is the top portion of web pages, what appears above your page content. This is where you would put your html “design” code. footer.cfm – this is the bottom portion of your web pages, what shows up after your page content. This is where you would put your html “design” code. layout.css – the basic CSS layout for our pages styles.css – the CSS styles for your page content
Lets look first at header.cfm:
This file contains what you would expect to see at the top of a standard HTML web page, including head, title, meta tags, etc. There are a few different tags included in the content however. Any tags that begin with <cf…> are CFML language tags, that are processed by Railo and removed from the source code before the page is sent to your web browser. Just like PHP or ASP.net code, if somebody views the source of your web page, they won’t see your CFML code, but rather, they will see the html code, and any code that your CFML tags generate.
<cfparam name="title" default="Untitled" />
This tag defines and sets a default value for a variable named “title.” This value can be overridden using a <cfset …> tag which we will see later.
Any content inside <cfoutput>…</cfoutput> tags will be included in the output to your web browser. In this case, the title variable is written to the page output. As with all <cf..> tags, the <cfoutput> tags themselves will be removed from the web page output. Anything inside # characters will be evaluated as an expression. So if your code was <cfoutput>title</cfoutput>, then the literal word “title” would be included in your page output. When you put # characters around it, Railo will evaluate the expression and replace it with the result.</cfoutput></cf..>
header.cfm also includes the two .css files we need for our layout and styles. These are standard css which should be familiar to you, and won’t be covered in this article.
Lets look at index.cfm
<cfset title="Home Page">
This first tag sets a local variable called “title” and sets its value to “Home Page.”
This tag includes the file “header.cfm” into the current page, which means that any page output (the html, head, title, etc. tags) will be included in this page’s output. Notice that we set the local variable title in our page, and it gets used in the header.cfm file. Local variables are available to any pages that are included in the requested web page.
The “Hello World” content is the main textual content of this web page, and can be any html or CFML generated content you want.
After the main content, another <cfinclude…> tag includes footer.cfm, which includes the expected end of page tags such as </body> and </html>
Take A Look At It
If you open your web browser and browse to index.cfm, you will see your basic web page layout, with a page title, and Hello World content. If you view the page source, you should see the combined content of the header.cfm, index.cfm and footer.cfm, with no <cf…> tags in the output, only pure HTML.
You can easily organize and create static web pages like this, and like many other programming languages, structuring your website like this has many benefits. If you make a change to your header or footer, then all your pages inherit the change immediately. Likewise if you design a new layout or style for your site, applying it once to your header and footer then applies it to your entire website.
Displaying Dynamic Content From Your Database
For this tutorial, lets assume we have a very simple database, with one table called “Content.” Content has three database fields: