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

A Closer Look at CFScript

A Closer Look at CFScript

Allaire's esteemed guru Ben Forta introduced CFSCRIPT to CFDJ readers last year with his article "Stick to the Script" (CFDJ, Vol. 2, issue 7). Hopefully, some of you absorbed the words of wisdom from our evangelist and gave CFSCRIPT a shot, but I suspect for most of you the lesson fell to the wayside when it came time to hit the code again. I can't blame you. Paltry documentation by Allaire on CFSCRIPT coupled with most CF developers' inexperience in scripting languages makes it easy to ignore.

Most ColdFusion developers don't have a scripting background. So why take up CFSCRIPT? It can't replace conventional CF tag structure. Although a modest performance gain can be seen in some circumstances, its exclusion of CF tags significantly limits its potential functionality. What does it offer most developers who are not seasoned scripters?

I believe it can make three compelling contributions to your repertoire. First, CFSCRIPT simplifies concatenation of strings and basic mathematical manipulation, even if you know little about scripting.

Second, and perhaps most important, CFSCRIPT offers an easy way to encapsulate business logic in a single location at the top of your page. Studio's coloring of scripting helps differentiate business logic from output, making it easy to find and address. It also rests in a more native state, devoid of some of the visual overhead tags create.

The third and rarely discussed reason, at least in my opinion, is that it serves as a great introduction to scripting languages. While most of us enjoy the ease of ColdFusion, we limit ourselves by not employing JavaScript, JSP, or other scripting languages. Indeed, next year Allaire will allow the cohabitation of JSP and ColdFusion in their NEO release (sixth generation ColdFusion). Future ColdFusion developers will really need to know JSP to extract the full potential of future CF applications, and what better way to cut their teeth than inside ColdFusion.

I must confess, jumping into CFSCRIPT may be a bit intimidating. Gone are meaningful plain English tags (CFSET, CFLOOP, etc.) that made developing so easy. Also, as I mentioned earlier, Allaire's normally strong documentation provides woeful coverage of CFSCRIPT. To help you along your daunting journey into the scary forest of scripting, I've prepared a large block of CFSCRIPT employing many of the basic constructs you'll want to use. I've chosen a credit card validation routine for a shopping cart. This doesn't expose all of CFSCRIPT's operations, but should provide enough examples to give you a jump start on your own projects. (Source code for this article can be found on the CFDJ Web site, www.coldfusionjournal.com.)

To start the process I open with a CFSCRIPT tag. There are no attributes for the tag, but I don't leave the Script block empty (ColdFusion doesn't like this and returns an error). Before I even get to the credit card validation, I'm taking advantage of the fact that I've started a CFSCRIPT block and set defaults for a page that would normally have been accomplished with CFSET or CFPARAM. By moving these sets into the CFSCRIPT, I'm reducing some visual and performance overhead. I identify the section with a comment that I start with two back slashes. These comment markers only comment out a line at a time and have no ending markers to stop the commenting (a bit weird for CF developers, but old hat for scripters).

The first three events are simple sets:

j=0; local.errM = ""; check = "";
(see Figure 1).

Note: Other than comment lines, CFSCRIPT ignores carriage returns. After making each assignment you must place a semicolon before addressing another operation. CFSCRIPT doesn't require any special word to make an assignment (like var or set); simply place a variable on the left, some expression on the right, and end it with a semicolon. Missing semicolons will be the primary cause of errors when you begin CFSCRIPTing, and they're generally not obvious. This single line of code replaces the following three conventional ColdFusion tags:

<CFSET local.errM = "">
<CFSET check = "">
Hopefully, you can recognize the "visual" advantage of making these settings inside of CFSCRIPT in conventional tags.

The next block of code drives navigation links on the page, and again bears no relation to the credit card routine. As I mentioned, you can't use ColdFusion tags inside CFSCRIPT. We can, however, re-create the functionality of some tags using ColdFusion functions. In this case I need to parameterize a form variable, which may or may not have been passed. Since I can't use CFPARAM, I'll have to mimic it with the IsDefined function and a simple assignment if the formfield doesn't exist:

if (Not IsDefined("form.carType")) form.carType = "Mondial t";
This introduces our first conditional statement, a simple if. JavaScripters take note, your favorite operators (!, ==, >=, etcŠ) are not available. You have to use ColdFusion operators (such as "NOT," "IS," "GTE," etc.), which can be a bit frustrating but are necessary nonetheless. To begin the "CFIF" simply type if, followed by the condition you wish to check enclosed in parentheses. In a simple conditional check, place the assignment or action right after the check and end it with a semicolon. In this case, if the condition is met (i.e., there's no form variable), I'd like to set it to a default of "Mondial t". We'll cover the if statements in more detail later, but I wanted to demonstrate that there are workarounds for some ColdFusion tags (although in this case, CFPARAM would have been easier).

Next, I moved some of the logic I employed in the navigation scheme into the CFSCRIPT block. This specific chunk of code occupied eight lines of code in my original template, so it was a prime candidate for moving into this block of CFSCRIPT. Again, we haven't hit the credit card validation yet, I'm just moving logic normally found throughout my page into a clean and more concise environment. This particular snippet peeks at the path to see if we're looking at Ferraris, Maseratis, or Ducatis (see Figure 2). For whichever one the script will set a nav count that will position one of those silly arrows the client absolutely must have:

if (cgi.Script_name CONTAINS "Fer") {local.navCount = 1; local.title = "Ferrari";}
else {if (cgi.Script_Name CONTAINS "Mas") {local.navCount = 16; local.title = "Maserati";}
else {local.navCount = 32; local.title = "Ducati";}}
In CFSCRIPT the braces allow you to perform multiple actions instead of a single set (much the same way parentheses work in ColdFusion or mathematics). Without the braces the if statement would end with the first semicolon. After the first set of braces, we have an else statement (just like CFELSE). I actually needed a CFELSEIF, but that's not directly available in CFSCRIPT so I simply embed another if statement inside the else. This block could have been accomplished with a switch statement (very similar to CFSWITCH), which Ben Forta covered in his CFSCRIPT article.

The final block of code I want to discuss prior to launching into the credit card validation is a simple banner rotator. Again, this logic would normally appear elsewhere on my template, but I'm moving it into the CFSCRIPT block to clean up my page. This gives us an opportunity to witness a simple concatenation and arithmetic operation, which CFSCRIPT performs so well. The snippet takes the title I set in the last section of code and appends a number (from 1 to 6) based on what minute it is. This essentially rotates through six different banners (named, for example, Ferrari1.gif, Ferrari2. gif, etc.) and will be used in the content after the CFSCRIPT block.

variables.mod = local.title & (Minute(now()) MOD 6) & ".gif";
You could extend this to create a string with the link and other HTML features as well. Whenever you have to assemble long strings (such as interaction with a COM object or other third-party software), always consider CFSCRIPT as an alternative to conventional CFSETs. JavaScripters should notice that ampersands, not the addition sign, concatenate strings.

Finally we're ready to play with the credit card validation. The first thing I must do is set some defaults that I'll manipulate further downstream. I could have separated these assignments with a carriage return, but I prefer keeping the simple ones in a single line for cleanliness. Next we see a new comment tag, this time in a multiline format. This comment resembles traditional ColdFusion REM statements in that content contained between the symbols is not executed (versus the single-line comments). To begin a multiline comment we employ a backslash and an asterisk /*; to end we reverse the order and employ an asterisk and a backslash */.

/* Required: local.CardNum, local.expYear, local.expMonth. PASSED: local.errM on exception */
As the comment suggests, we're now going to step through the card number and strip out any nonintegers the client may have provided us. This event gives us our first loop. Scripters will welcome CFSCRIPT's loops, but regular Cold-Fusion developers will probably find these a tad confusing. The looping syntax in CFSCRIPT bears no resemblance to its big brother, CFLOOP, and due to the requirement that CFSCRIPT employs ColdFusion operators, it's not a direct match with JavaScript or Java loops (but is familiarly close).

Loops come in a variety of flavors in CFSCRIPT; the while loop is the first one we'll discuss. It's not the most common loop (which is the for loop), but it's the first we see in this application. The while loop inspects the conditions specified in its parentheses and executes the operations inside its braces as long as the condition is met. This is very similar, yet distinct from a do..while loop, which checks for the condition only after executing each loop, allowing a minimum of one run through the loop. In this scenario we're going to progress through each element of the credit card string the client submitted and discard any characters that are not integers.

while (Len(trim(local.CardNum)) GT 0) { if(IsNumeric(mid(local.CardNum, 1, 1))) check = check & mid(local.CardNum, 1, 1); local.CardNum = RemoveChars(local.CardNum, 1, 1);}

The condition in this situation is the length of the variable we're manipulating. It'll shrink by one position each time through the loop. The trim function discards accidental spaces the client may have provided. As mentioned earlier, the operator must be a ColdFusion operator (in this case "GT") instead of a mathematical or JavaScript one. I have a simple if inquiry that, when true, appends that integer to a new string, cryptically named check. Subsequently, the RemoveChars function strips out the character we had just checked. The same snippet could have been accomplished with a conventional for loop, which I'll discuss soon, or through an REReplace() with regular expressions (a better idea, but it doesn't afford me the opportunity to talk about loops).

The next lines of script build error messages if the card number fails to meet certain basic criteria, specifically length, expiration, and whether the first digit is appropriate for the card type specified. The only thing worth noting here is the compound conditions for the first if statement.

if((Len(local.CardNum) LT 13) OR (Len(local.CardNum) GT 16)) local.errM = local.errM & "<li>Your credit card number must be between 13 and 16 characters long, and should only contain numbers.";
As with its elder brother the CFIF tag, if statements can check for multiple conditions (ranges of values, exclusion of ranges, or different strings).

Before the template evaluates the specifics of the number, it offers an opportunity to short-circuit if any of the earlier conditions uncovers an error. This prevents unnecessary processing of a card we won't accept anyway. To do this I simply wrap the remaining logic in an if statement.

First I perform some quick math and set a couple of defaults. These numbers will be used in the loop that follows.

local.lngth = Len(local.CardNum) - 1; tempCard = Left(local.CardNum,local.lngth); newNum = "";
The local.lngth is one less than the number of integers in the card, and tempCard is the card number stripped of the last digit. CFSCRIPT's variables are case insensitive, but minding case only helps build the coding discipline required in JSP or Java. Many developers prefer to employ more descriptive variables, but I've chosen to err on the side of brevity, due to the math I want to perform. For the same reason I've left the scope off tempCard, newNum, and Step1. In production I'd scope these variables to prevent possible problems.

The i=1; establishes the variable "i" as the index or incrementing variable. The second expression defines the condition under which the loop should continue (see Figure 3). In this case, as long as "i" is less than or equal to the value of local.lngth, the loop will process its contents. The last expression increments the variable. I need to step by two through the loop, thus I set "i" equal to itself plus 2. If I didn't want the step, I'd use the expression i=i+1. The CFLOOP equivalent of this for loop would be:

<CFLOOP from="1" to="#local.lngth#" step="2">
Since some credit cards are 16 digits while others are 15, I need two different operations with an if..else operation to direct each loop iteration. In the case of Visa, Discover, and MasterCard, I need to double the digit I'm currently viewing (specifically in the "i" position) and concatenate it with the next digit in line.
newNum = newNum & (2 * Mid(tempCard,i,1)) & (Mid(tempCard,nextNum,1));
For the American Express card the next digit in line must be doubled and concatenated to the first digit:
newNum = newNum & Mid(tempCard,i,1) & (2 * Mid(tempCard,nextNum,1));

Once I've built the new number I must sum all of its digits. For this a simple for loop can iterate through each number and add it to a variable I'll call sumNum:

for(j=1; j LTE Len(newNum); j=j+1) sumNum = sumNum + Int(Mid(newNum,j,1));
Given the simplicity of the operation, I've left the braces out of this for loop. If you perform more than one operation, however, you'll need braces (just as with if..else statements).

The final step compares the last digit of the credit card against the difference of the right-most digit of sumNum from 10. If it's not a match, I create an error message to display in the content.

In a real application this template would allow the client an opportunity to correct a mistaken entry before sending the card to a financial institution for verification. This template doesn't guarantee that the card submitted is valid, but that it conforms to industry standards. Performing such checks before interacting with third-party agents not only en-hances server performance (by preventing HTTP interaction for an event that was bound to fail), it also improves your chances of completing the transaction by providing the client with an opportunity to immediately correct a mistake. For best results this should be combined with a similar routine in JavaScript, providing instant feedback (if the client has JavaScript turned on) when the client has made a faulty entry.

This same application logic in traditional ColdFusion tags occupies more than twice the number of lines as its CFSCRIPT counterpart and is more difficult to read. By translating the functionality into CFSCRIPT I've made the business logic more transparent, transportable, and refined. Indeed, when I translated this logic, I uncovered several unnecessary redundancies and found a better progression for the logic simply because the operations were unencumbered by tags.

For those ColdFusion developers without scripting experience, I'd highly recommend some experimentation with CFSCRIPT in your next application. As a rule of thumb, anytime more than three consecutive CFSETs lie in a row, you'll benefit from moving them into a CFSCRIPT block. Start slow, making simple assignments in your templates. Next, for giggles, move a loop into CFSCRIPT. Finally, go back to some old business logic module and translate it into CFSCRIPT. Not only will your code be improved, you'll have gained invaluable experience in an important language family: scripting.


More Stories By Christopher Graves

Christopher Graves is president of RapidCF, a ColdFusion development
shop in Connecticut. In his prior "life" he was a Marine Corps
officer and graduate of the U.S. Naval Academy.

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
SYS-CON Events announced today that Dasher Technologies will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Dasher Technologies, Inc. ® is a premier IT solution provider that delivers expert technical resources along with trusted account executives to architect and deliver complete IT solutions and services to help our clients execute their goals, plans and objectives. Since 1999, we'v...
SYS-CON Events announced today that NetApp has been named “Bronze Sponsor” of SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. NetApp is the data authority for hybrid cloud. NetApp provides a full range of hybrid cloud data services that simplify management of applications and data across cloud and on-premises environments to accelerate digital transformation. Together with their partners, NetApp emp...
SYS-CON Events announced today that IBM has been named “Diamond Sponsor” of SYS-CON's 21st Cloud Expo, which will take place on October 31 through November 2nd 2017 at the Santa Clara Convention Center in Santa Clara, California.
SYS-CON Events announced today that TidalScale, a leading provider of systems and services, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. TidalScale has been involved in shaping the computing landscape. They've designed, developed and deployed some of the most important and successful systems and services in the history of the computing industry - internet, Ethernet, operating s...
Infoblox delivers Actionable Network Intelligence to enterprise, government, and service provider customers around the world. They are the industry leader in DNS, DHCP, and IP address management, the category known as DDI. We empower thousands of organizations to control and secure their networks from the core-enabling them to increase efficiency and visibility, improve customer service, and meet compliance requirements.
SYS-CON Events announced today that IBM has been named “Diamond Sponsor” of SYS-CON's 21st Cloud Expo, which will take place on October 31 through November 2nd 2017 at the Santa Clara Convention Center in Santa Clara, California.
Join IBM November 1 at 21st Cloud Expo at the Santa Clara Convention Center in Santa Clara, CA, and learn how IBM Watson can bring cognitive services and AI to intelligent, unmanned systems. Cognitive analysis impacts today’s systems with unparalleled ability that were previously available only to manned, back-end operations. Thanks to cloud processing, IBM Watson can bring cognitive services and AI to intelligent, unmanned systems. Imagine a robot vacuum that becomes your personal assistant tha...
In his Opening Keynote at 21st Cloud Expo, John Considine, General Manager of IBM Cloud Infrastructure, will lead you through the exciting evolution of the cloud. He'll look at this major disruption from the perspective of technology, business models, and what this means for enterprises of all sizes. John Considine is General Manager of Cloud Infrastructure Services at IBM. In that role he is responsible for leading IBM’s public cloud infrastructure including strategy, development, and offering ...
In a recent survey, Sumo Logic surveyed 1,500 customers who employ cloud services such as Amazon Web Services (AWS), Microsoft Azure, and Google Cloud Platform (GCP). According to the survey, a quarter of the respondents have already deployed Docker containers and nearly as many (23 percent) are employing the AWS Lambda serverless computing framework. It’s clear: serverless is here to stay. The adoption does come with some needed changes, within both application development and operations. Tha...
SYS-CON Events announced today that Avere Systems, a leading provider of enterprise storage for the hybrid cloud, will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 - Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Avere delivers a more modern architectural approach to storage that doesn't require the overprovisioning of storage capacity to achieve performance, overspending on expensive storage media for inactive data or the overbui...
Widespread fragmentation is stalling the growth of the IIoT and making it difficult for partners to work together. The number of software platforms, apps, hardware and connectivity standards is creating paralysis among businesses that are afraid of being locked into a solution. EdgeX Foundry is unifying the community around a common IoT edge framework and an ecosystem of interoperable components.
SYS-CON Events announced today that TidalScale will exhibit at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. TidalScale is the leading provider of Software-Defined Servers that bring flexibility to modern data centers by right-sizing servers on the fly to fit any data set or workload. TidalScale’s award-winning inverse hypervisor technology combines multiple commodity servers (including their ass...
SYS-CON Events announced today that N3N will exhibit at SYS-CON's @ThingsExpo, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. N3N’s solutions increase the effectiveness of operations and control centers, increase the value of IoT investments, and facilitate real-time operational decision making. N3N enables operations teams with a four dimensional digital “big board” that consolidates real-time live video feeds alongside IoT sensor data a...
As hybrid cloud becomes the de-facto standard mode of operation for most enterprises, new challenges arise on how to efficiently and economically share data across environments. In his session at 21st Cloud Expo, Dr. Allon Cohen, VP of Product at Elastifile, will explore new techniques and best practices that help enterprise IT benefit from the advantages of hybrid cloud environments by enabling data availability for both legacy enterprise and cloud-native mission critical applications. By rev...
With major technology companies and startups seriously embracing Cloud strategies, now is the perfect time to attend 21st Cloud Expo October 31 - November 2, 2017, at the Santa Clara Convention Center, CA, and June 12-14, 2018, at the Javits Center in New York City, NY, and learn what is going on, contribute to the discussions, and ensure that your enterprise is on the right path to Digital Transformation.
Join IBM November 1 at 21st Cloud Expo at the Santa Clara Convention Center in Santa Clara, CA, and learn how IBM Watson can bring cognitive services and AI to intelligent, unmanned systems. Cognitive analysis impacts today’s systems with unparalleled ability that were previously available only to manned, back-end operations. Thanks to cloud processing, IBM Watson can bring cognitive services and AI to intelligent, unmanned systems. Imagine a robot vacuum that becomes your personal assistant th...
Digital transformation is changing the face of business. The IDC predicts that enterprises will commit to a massive new scale of digital transformation, to stake out leadership positions in the "digital transformation economy." Accordingly, attendees at the upcoming Cloud Expo | @ThingsExpo at the Santa Clara Convention Center in Santa Clara, CA, Oct 31-Nov 2, will find fresh new content in a new track called Enterprise Cloud & Digital Transformation.
Most technology leaders, contemporary and from the hardware era, are reshaping their businesses to do software. They hope to capture value from emerging technologies such as IoT, SDN, and AI. Ultimately, irrespective of the vertical, it is about deriving value from independent software applications participating in an ecosystem as one comprehensive solution. In his session at @ThingsExpo, Kausik Sridhar, founder and CTO of Pulzze Systems, will discuss how given the magnitude of today's applicati...
Smart cities have the potential to change our lives at so many levels for citizens: less pollution, reduced parking obstacles, better health, education and more energy savings. Real-time data streaming and the Internet of Things (IoT) possess the power to turn this vision into a reality. However, most organizations today are building their data infrastructure to focus solely on addressing immediate business needs vs. a platform capable of quickly adapting emerging technologies to address future ...
SYS-CON Events announced today that Ryobi Systems will exhibit at the Japan External Trade Organization (JETRO) Pavilion at SYS-CON's 21st International Cloud Expo®, which will take place on Oct 31 – Nov 2, 2017, at the Santa Clara Convention Center in Santa Clara, CA. Ryobi Systems Co., Ltd., as an information service company, specialized in business support for local governments and medical industry. We are challenging to achive the precision farming with AI. For more information, visit http:...