Welcome!

You will be redirected in 30 seconds or close now.

ColdFusion Authors: Yakov Fain, Jeremy Geelan, Maureen O'Gara, Nancy Y. Nee, Tad Anderson

Related Topics: ColdFusion

ColdFusion: Article

component.cfc: The Mother of All Components

component.cfc: The Mother of All Components

Yes, that's right, components have mommies and daddies. Well, not really, but that statement isn't too far from the truth. This article explains "component.cfc", a hidden gem in the ColdFusion Component architecture that is part of ColdFusion MX.

By now, everybody knows that the introduction of the component framework in ColdFusion MX was one of the most radical changes to CFML since its inception. Their introduction was significant for three primary reasons. First, they allow developers to expose functionality to the Flash Gateway and to any other Web service-enabled environment. Second, they offer a level of abstraction far superior to that of custom tags and user-defined functions. The third reason CFCs have made such an impact on CFML is that they offer ColdFusion developers the ability to implement object-oriented features.

These object-oriented features include new variable scopes with varying degrees of exposure outside the component; the "packaging" of functionality, introspection, and the generation of meta data; objectinstance- based programming; and inheritance. In traditional object-oriented programming languages, all objects inherit from a parent "Object" class. What many developers don't realize is that components, too, have a parent "class". Its name is "component.cfc" and it can be a very valuable tool when developing applications.

Where Can I Find component.cfc?
If you create a CFC that does not inherit from any other CFC and you view its meta data, you'll notice that the value for the "hierarchy" meta information defaults to "WEB-INF.cftags.component". You will find this file in the "CfusionMXWWWRootWEBINFcftags" directory if you're running the standalone version of ColdFusion, and in "JRun4servers{your_server_name}cfusion-earcfusion-warWEBINF cftags" if you're running the J2EE version (on top of JRun4). You can view the meta data for component.cfc on a server by browsing http://{server_domain}/CFIDE/componentutils/cfcexplorer.cfc?method=getcf cinhtml&name=WEB-INF.cftags.component, replacing "{server_domain}" with "localhost:8500" or whatever other URL you use to browse to that machine.

What Does component.cfc Do?
Well, nothing really. Not out of the box, anyway. The component.cfc file is empty by default in ColdFusion MX 6.1. In ColdFusion MX it had a tiny bit of encrypted data at the top of the file. As already discussed, all components inherit from component. cfc by default. Think of it as the Application.cfm of components - a place to put code that is implicitly included. The difference is that the code outside of any method in component.cfc is executed only when a ColdFusion Component is first initialized, and that its methods and meta data are inherited by other components. It gives you a single place to put code that must be common to all CFCs on your server.

Why Would I Want to Do That?
Having one place to put functionality and initialization code that will be available to all server components has two important uses. As already mentioned, you can think of it as similar to Application.cfm, which means that if you're running a server that's dedicated to hosting one application and the application is using CFCs for its business logic (as every application should be), it's a very good place to put functionality that all components need to have.

For example, if your server is hosting your company's public Web site, all of your components might need to have access to the current company catalog of products. Creating a method in component.cfc that retrieves the current catalog information from a database and returns it to the caller would ensure that all components have the ability to retrieve the catalog by calling that method. While this is a neat trick, it's not always terribly useful or desirable, especially when your application is running on a server that hosts other completely separate ColdFusion applications.

There's another use for component.cfc though - when wielded properly, it can be a powerful development tool. More than anything else, I like to put debugging methods in my component.cfc file so that they are available in any application I happen to be working on. Extending the component framework with development tools can make a developer's life a little bit easier, as we will soon see.

Coding with component.cfc
It's a little known fact that ColdFusion Components don't technically require a start and end <cfcomponent> tag… they will work without them. That said, without the <cfcomponent> tag, a CFC will not properly inherit from the base component. cfc file nor will it allow the use of <cfproperty> tags if you are defining meta information, so as a best practice, follow the standard recommended practices when creating components.

By default, component.cfc is an empty file. Because it does not inherit from any other component (after all, it is the mother of all components), you can code methods in the file without adding any <cfcomponent> tags. You can optionally add <cfcomponent> tags to component.cfc in order to generate meta data about the component or to enable the use of <cfproperty> tags before your methods. Like inheritence with other CFCs, any meta information, methods, and variables in the component are inherited by all other components on the server.

As you may have guessed, creating a method in one component with the same name as a method in component.cfc will override the method. The original method defined in component.cfc can be accessed with the "super" keyword as "super.methodName()", provided that the component you are in does not inherit from any other component. Let's examine one very practical use for this master component file.

Component.cfc Uses
If you're anything like me, you use <cfscript> a lot. As wonderful as <cfscript> is, it is not without limitations. In particular, the use of tags is strictly forbidden within a <cfscript> block. It is often necessary during the development process to view data in order to determine what's happening in your code. The <cfdump> tag is perfect for this, but wait - you cannot <cfdump> within a <cfscript> block. What to do?

Developers like me who use <cfscript> often, have made it a standard practice to create a function using <cffunction> that accepts a single argument of any data type, <cfdump> that variable, then <cfabort> the page. That function can then be called from <cfscript>, thus giving developers the ability to "see what's happening" within their <cfscript> code.

Here's the code I wrote inside of my component.cfc file so that I can dump a value from any ColdFusion Component <cfscript> block:

<cfcomponent displayname="Root" hint="Root CFC">
<!---:: function to dump then abort ::--->
<cffunction name="dumpIt" output="true" displayname="Dump It" hint="A
debugging tool" access="private" returntype="void">
<cfargument name="it" displayname="It" hint="The Thing To Dump"
required="true" type="any">
<cfdump var="#arguments.it#">
<cfabort>
</cffunction>
</cfcomponent>

You'll notice that the method is private because I do not need nor want to expose it to cfm pages that are instantiating my components. It also means that the method does not display along with the other methods of a component that's inherited it when that component's meta data is browsed.

The "dumpIt()" method is useful for developers who do not use <cfscript> as well. It is generally considered a best practice to encapsulate business logic with components. This means passing a value to a component method, operating on that value, and returning a value to the caller page or application. With this in mind, it's a safe assumption that the components in your application(s) aren't directly outputting anything to the HTTP output stream.

Pretty much every component I create not only uses <cfscript> heavily, but never outputs anything. To make sure nothing is output, I always set my <cffunction> tag "output" attributes to "false". This is definitely a best practice in most scenarios, but not being able to output directly from a component method also means you cannot <cfdump> the value of variables within the component when you're debugging your application. Once again, the "dumpIt()" method is a very handy tool, as from within a "silent" component, you can pass the suspicious variable to this method (which has the "output" attribute set to "true") in order to see what's going on in your code.

Where Do We Go from Here?
Component.cfc is a very practical debugging tool for developers and can also be a powerful part of your applications as well. We have looked at just one way that it can be used as an effective development tool. You could create variations of the "dumpIt()" function so that you have one method to dump and abort and another to dump and allow processing to continue. It wouldn't be difficult to add methods to your component.cfc that allow you to do other useful things such as time blocks of code using the getTickCount() function, for example.

Be forewarned that there are two major drawbacks to placing code, especially application rather than debugging/development code, in component.cfc. One is that from an architectural point of view, you are physically separating your code from the rest of your application business logic. The other is that you are making your code less portable - it's no longer a simple matter of copying a directory structure from one server to another in order to move your application when some of the logic is housed in component. cfc. Other than that, have fun and take advantage of it! The sky's the limit.

More Stories By Simon Horwith

Simon Horwith is the CIO at AboutWeb, LLC, a Washington, DC based company specializing in staff augmentation, consulting, and training. Simon is a Macromedia Certified Master Instructor and is a member of Team Macromedia. He has been using ColdFusion since version 1.5 and specializes in ColdFusion application architecture, including architecting applications that integrate with Java, Flash, Flex, and a myriad of other technologies. In addition to presenting at CFUGs and conferences around the world, he has also been a contributing author of several books and technical papers.

Comments (0)

Share your thoughts on this story.

Add your comment
You must be signed in to add a comment. Sign-in | Register

In accordance with our Comment Policy, we encourage comments that are on topic, relevant and to-the-point. We will remove comments that include profanity, personal attacks, racial slurs, threats of violence, or other inappropriate material that violates our Terms and Conditions, and will block users who make repeated violations. We ask all readers to expect diversity of opinion and to treat one another with dignity and respect.


@ThingsExpo Stories
"Dice has been around for the last 20 years. We have been helping tech professionals find new jobs and career opportunities," explained Manish Dixit, VP of Product and Engineering at Dice, in this SYS-CON.tv interview at 19th Cloud Expo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
More and more brands have jumped on the IoT bandwagon. We have an excess of wearables – activity trackers, smartwatches, smart glasses and sneakers, and more that track seemingly endless datapoints. However, most consumers have no idea what “IoT” means. Creating more wearables that track data shouldn't be the aim of brands; delivering meaningful, tangible relevance to their users should be. We're in a period in which the IoT pendulum is still swinging. Initially, it swung toward "smart for smar...
The Internet of Things will challenge the status quo of how IT and development organizations operate. Or will it? Certainly the fog layer of IoT requires special insights about data ontology, security and transactional integrity. But the developmental challenges are the same: People, Process and Platform and how we integrate our thinking to solve complicated problems. In his session at 19th Cloud Expo, Craig Sproule, CEO of Metavine, demonstrated how to move beyond today's coding paradigm and sh...
In his keynote at 18th Cloud Expo, Andrew Keys, Co-Founder of ConsenSys Enterprise, provided an overview of the evolution of the Internet and the Database and the future of their combination – the Blockchain. Andrew Keys is Co-Founder of ConsenSys Enterprise. He comes to ConsenSys Enterprise with capital markets, technology and entrepreneurial experience. Previously, he worked for UBS investment bank in equities analysis. Later, he was responsible for the creation and distribution of life sett...
We are always online. We access our data, our finances, work, and various services on the Internet. But we live in a congested world of information in which the roads were built two decades ago. The quest for better, faster Internet routing has been around for a decade, but nobody solved this problem. We’ve seen band-aid approaches like CDNs that attack a niche's slice of static content part of the Internet, but that’s it. It does not address the dynamic services-based Internet of today. It does...
The WebRTC Summit New York, to be held June 6-8, 2017, at the Javits Center in New York City, NY, announces that its Call for Papers is now open. Topics include all aspects of improving IT delivery by eliminating waste through automated business models leveraging cloud technologies. WebRTC Summit is co-located with 20th International Cloud Expo and @ThingsExpo. WebRTC is the future of browser-to-browser communications, and continues to make inroads into the traditional, difficult, plug-in web ...
20th Cloud Expo, taking place June 6-8, 2017, at the Javits Center in New York City, NY, will feature technical sessions from a rock star conference faculty and the leading industry players in the world. Cloud computing is now being embraced by a majority of enterprises of all sizes. Yesterday's debate about public vs. private has transformed into the reality of hybrid cloud: a recent survey shows that 74% of enterprises have a hybrid cloud strategy.
WebRTC is the future of browser-to-browser communications, and continues to make inroads into the traditional, difficult, plug-in web communications world. The 6th WebRTC Summit continues our tradition of delivering the latest and greatest presentations within the world of WebRTC. Topics include voice calling, video chat, P2P file sharing, and use cases that have already leveraged the power and convenience of WebRTC.
"We're a cybersecurity firm that specializes in engineering security solutions both at the software and hardware level. Security cannot be an after-the-fact afterthought, which is what it's become," stated Richard Blech, Chief Executive Officer at Secure Channels, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
The Internet of Things (IoT) promises to simplify and streamline our lives by automating routine tasks that distract us from our goals. This promise is based on the ubiquitous deployment of smart, connected devices that link everything from industrial control systems to automobiles to refrigerators. Unfortunately, comparatively few of the devices currently deployed have been developed with an eye toward security, and as the DDoS attacks of late October 2016 have demonstrated, this oversight can ...
Fact is, enterprises have significant legacy voice infrastructure that’s costly to replace with pure IP solutions. How can we bring this analog infrastructure into our shiny new cloud applications? There are proven methods to bind both legacy voice applications and traditional PSTN audio into cloud-based applications and services at a carrier scale. Some of the most successful implementations leverage WebRTC, WebSockets, SIP and other open source technologies. In his session at @ThingsExpo, Da...
Internet-of-Things discussions can end up either going down the consumer gadget rabbit hole or focused on the sort of data logging that industrial manufacturers have been doing forever. However, in fact, companies today are already using IoT data both to optimize their operational technology and to improve the experience of customer interactions in novel ways. In his session at @ThingsExpo, Gordon Haff, Red Hat Technology Evangelist, will share examples from a wide range of industries – includin...
We're entering the post-smartphone era, where wearable gadgets from watches and fitness bands to glasses and health aids will power the next technological revolution. With mass adoption of wearable devices comes a new data ecosystem that must be protected. Wearables open new pathways that facilitate the tracking, sharing and storing of consumers’ personal health, location and daily activity data. Consumers have some idea of the data these devices capture, but most don’t realize how revealing and...
Unless your company can spend a lot of money on new technology, re-engineering your environment and hiring a comprehensive cybersecurity team, you will most likely move to the cloud or seek external service partnerships. In his session at 18th Cloud Expo, Darren Guccione, CEO of Keeper Security, revealed what you need to know when it comes to encryption in the cloud.
"We build IoT infrastructure products - when you have to integrate different devices, different systems and cloud you have to build an application to do that but we eliminate the need to build an application. Our products can integrate any device, any system, any cloud regardless of protocol," explained Peter Jung, Chief Product Officer at Pulzze Systems, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
In his general session at 19th Cloud Expo, Manish Dixit, VP of Product and Engineering at Dice, discussed how Dice leverages data insights and tools to help both tech professionals and recruiters better understand how skills relate to each other and which skills are in high demand using interactive visualizations and salary indicator tools to maximize earning potential. Manish Dixit is VP of Product and Engineering at Dice. As the leader of the Product, Engineering and Data Sciences team at D...
Data is the fuel that drives the machine learning algorithmic engines and ultimately provides the business value. In his session at 20th Cloud Expo, Ed Featherston, director/senior enterprise architect at Collaborative Consulting, will discuss the key considerations around quality, volume, timeliness, and pedigree that must be dealt with in order to properly fuel that engine.
In addition to all the benefits, IoT is also bringing new kind of customer experience challenges - cars that unlock themselves, thermostats turning houses into saunas and baby video monitors broadcasting over the internet. This list can only increase because while IoT services should be intuitive and simple to use, the delivery ecosystem is a myriad of potential problems as IoT explodes complexity. So finding a performance issue is like finding the proverbial needle in the haystack.
According to Forrester Research, every business will become either a digital predator or digital prey by 2020. To avoid demise, organizations must rapidly create new sources of value in their end-to-end customer experiences. True digital predators also must break down information and process silos and extend digital transformation initiatives to empower employees with the digital resources needed to win, serve, and retain customers.
"Once customers get a year into their IoT deployments, they start to realize that they may have been shortsighted in the ways they built out their deployment and the key thing I see a lot of people looking at is - how can I take equipment data, pull it back in an IoT solution and show it in a dashboard," stated Dave McCarthy, Director of Products at Bsquare Corporation, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.