ColdFusion is an application server. ColdFusion is also a web programming language that allows a web application communicate with various back end systems. Using ColdFusion, you can create dynamic web pages that offer user input, database lookups, time of day, or any other criteria you require. ColdFusion pages consist of standard HTML, together with its proprietary ColdFusion Markup Language (CFML).
Whenever a browser receives a request from a ColdFusion, the ColdFusion Application Server pre-processes the page. The server then instantly generates an HTML page, which the browser then displays.
Using ColdFusion, you can also perform the following:
- Rapidly create, test, and deploy applications since ColdFusion is scalable, multi-threaded, and service-oriented.
- Create custom functions and extend them across applications.
- Troubleshoot and debug applications via a debugger.
- Connect to most legacy and modern databases and external systems.
<!--- Get names sorted by department ---> <cfquery datasource="company" name="employees"> SELECT EmpName FROM EMPDATA ORDER BY DEPTT </cfquery> <!--- HTML page ---> <HTML> <HEAD> <TITLE>List of employees</TITLE> </HEAD> <BODY> <ul> <cfoutput query="employees"> <li>EmpName</li> </cfoutput> </ul> </BODY> </HTML>
When ColdFusion receives a request, the server parses the template looking for ColdFusion-specific tags (tags that start with CF) or ColdFusion variables and functions.
The HTML or plain text is ignored and is output as is in the browser. All ColdFusion constructs are processed, and the results are sent to the Web server. The Web server then sends the entire output back to the requester’s browser. All ColdFusion files have an extension of .cfm or .cfml. For example,
With every installation of ColdFusion, a built-in web server also gets installed. To avoid conflict with other web servers, ColdFusion's web servers (Apache or IIS) runs on port 8500 or any other specified port.
During ColdFusion installation, you can either opt to run ColdFusion in stand-alone mode (bound to the integrated Web server) or using an existing Web server. If you opt to use the internal Web server, specify the port number in all URLs.
ColdFusion Markup Language (CFML) is the scripting language used by ColdFusion. CFML supports standard HTML files with database commands, conditional operators, high-level formatting functions, and other elements to produce web applications.
ColdFusion tags have the same format as HTML tags. They are enclosed in angle brackets and can have zero or more named attributes. Many ColdFusion tags have bodies, that is, they have a start and end tags with text to be processed between them.
The pages in a ColdFusion application include the server-side CFML tags in addition to HTML tags.
CFML extends HTML to perform the following:
- Read and update data to databases and external applications like spreadsheets, flat files, or delimited files.
- Create dynamic data-driven pages and perform conditional processing.
- Populate forms with real-time data from back-end systems and then process form submissions.
- Generate and retrieve email messages.
- Interact with HTTP and FTP servers for accessing remote files.
- Secure an application with authentication tokens.
- Read and write client-side cookies.