|By Eben Hewitt||
|January 27, 2001 12:00 AM EST||
In recent years we've witnessed a trend in which organizations gather, codify, evaluate, and disseminate seemingly endless lists of "Best Practices" - guidelines that help promote the success of their business, the consistency of their actions and, presumably, the general cheerfulness of their employees.
Best Practices are cherished by neophytes and mentors alike for many reasons. For beginners (or those toiling fiendishly into the night, alone in their basements, who can't help but cackle, "It's alive!" every time their application runs without crashing), Best Practices offer a coherent and consistent mode of communication with fellow coders who might inherit their work. They also offer guidelines that hasten the debugging process, and they create a compendium of development tips and tricks that can be time consuming to find on your own. For more seasoned developers, Best Practices offer a refreshing prompt to review their habits - as Hal Helms suggested in "Making Assertions" (CFDJ, Vol. 2, issue 10) - and provide an excellent excuse for engaging in witty and urbane debate with one's peers.
These particular Best Practices are divided into five categories: General, Security, Portability/Modularity, Speed/Performance, and Teamwork/Readability. In the spirit of pursuing a provocative American trend, I offer this list of Best Practices for ColdFusion coding and development, which is the strange fruit of many conversations with many developers. My hope is to continue that conversation, and I invite your responses as well as your own Best Practices.
When debugging an application, set a simple variable and use <cfoutput> to display it on your processing page.
For instance, you might write <cfset Status = "Okay"> in the offending template, then write <cfoutput>#Status#</cfoutput> in the page in question. If you see the word "Okay" when you view your page in a browser, ColdFusion is processing your application at least up to that point. Move the <cfoutput> tags around within your application, and you can pinpoint exactly how far your application is processing, de-pending on whether or not your output is displayed.
This is also a good way to ensure compatibility of your applications across browsers. For instance, Internet Explorer 5.5 handles table display differently than IE 5.0 does. I've seen well-written applications that simply don't display in IE 5.5. This tip was the light at the end of the tunnel.
You can use a related technique within <cftransaction> blocks. For instance, set the status variable as above, and write a conditional clause around your <cftransaction> <cfquery> block. Set the status to "Not Okay" within a <cfcatch/cftry> block where the <cftransaction> is "Rollback".
<cfif status IS "Okay">
Your output will indicate the status of your database transaction.
Use the poor man's Spectra.
While this little idea certainly doesn't cover the many excellent features of Spectra, doing the following will help keep your clients - or your non-IT staff - happy when frequent content updates are an issue. Use a custom tag for formatting and general page display, and <cfinclude> all your content. For instance, when working on a page called "Aboutus.cfm", you might create a custom tag called <cf_layout> or <cf_table>, which allows easy and consistent specification of its attri-butes. You can title the headers of your tables, specify the colors and borders, and size them up. Then write a file called "AboutusContent.cfm", which is only plain text and no code. In a cell within your table call <cfinclude template= "Aboutus Content.cfm">. You can specify fonts with an external stylesheet or from within your custom tag, and you've got instant, consistent formatting and total separation of code from content. When it's time for others to update the content, they don't touch a line of code. Note that there's a slight performance penalty for using <cfinclude> as well as for any custom tag.
<td align="right"><font face=#font#" size=#medsize#">
</td><input type="Text" name="Username" size="#bigsize#"></td></cfoutput>
where the file LogoTable.cfm de-fines the fonts and sizes as cfparameters and also begins the table by defining a <tr> that contains the company logo, a background color, and more. It's a way of making a hybrid stylesheet/HTML that's easy to reuse.
You can also easily borrow Spectra's Universally Unique Identifier for Content Objects with the ColdFusion "CreateUUID" function as follows: <cfoutput>#CreateUUID()# </cfoutput>. It's also native to Transact-SQL as "NewID()". They both generate a 128-bit value, (almost) guar-anteed to be a unique value for any computer on a network because the last six digits are generated from the node number for the IEEE 802 identifier on your machine's NIC. Kewl! (Notice that there are a couple dozen CF functions like this one that have an exact counterpart in SQL. Use the CF functions when possible, however, for reasons that follow.)
Always scope your variables.
Perhaps it's a little thing, but I've found that referring to #Form.My Variable# rather than #MyVariable# makes it easier for other developers to follow your work, and it cuts down on debugging time. As a side note, remember that when working with <cfmodule>, the code of the module or custom tag is executed in its own process, outside the scope of the calling template. (Thus the module has no access to variables in the calling template.)
Don't use hidden fields to pass any sensitive or important variable (e.g., "price" or a limitation on record set returns).
While it's less of a problem with ColdFusion, it takes seconds to hack a page written in Perl or any CGI/server-side language that passes hidden form field variables. (Hacking 101: simply save the page source as an htm file, change the hidden variable to a price or limitation you like better, and pass your new local page to the absolute URL of the processing page.)
In guest book or other form, don't allow *<CF* as user input.
User input forms allow what my wife refers to as an "attractive nuisance"; hooligans have an opportunity to run code (cfdirectory, cffile) from your text fields. Make sure your application knows to return a tsk-tsk if it spots such input. Check for this by placing the following code at the top of your processing page:
<cfif Form.TextBody CONTAINS "%<cf%">
<cfabort showerror="You are very naughty.">
Thanks for your input. Etc...
Note that <cfexit> is a better choice than <cfabort> if you're running a custom tag.
Use the poor woman's dedicated SQL server.
You've heard it a hundred times. Put your databases on a different machine. But many maverick developers are unable to afford such a scheme. If you're in this valiant group, there is recourse. At the least make sure your databases aren't in the HTTP tree. If you have no control over this (if you're not hosting yourself), generate a random number to name your database with the following code:
If you do have a separate database machine and Web server but one is more powerful than the other, let the faster one be your SQL server. The sine qua non of many ColdFusion applications is a database; therefore, slow database = slow CFServer, but not the other way around.
Avoid proliferating <cfauthenticate> tags since you must specify the security context on the server.
If you move your app to another host or plug the module into an application on a host out of your control or reinstall ColdFusion server or make a significant upgrade, you'll likely have to rewrite your security context, forcing a potentially difficult migration. If you don't face these dilemmas, <cfauthenticate> is an otherwise handy tag.
Format data within your code, not your SQL data type.
For example, imagine you have a field named "Price". Rather than specifying the datatype "money" in your SQL database, specify INT and use the ColdFusion function Dollar format(#Price#). This practice allows you to follow the tradition that dictates one must separate display, action, and content. Also at issue here is portability/migration between database versions and database vendors. This may be more useful to independent developers looking to peddle their application wares than to job shops with their hosting routine down. Note that you'll take a slight performance hit in the (potentially lengthy) interim.
Use relative paths.
In the root of your applications create a folder called "files" or "general" to store single-page items such as "about" and "contactus" that may not merit an entire folder to themselves. Putting all pages in directories off the root maintains the relative paths for <cfincludes>, images, and Flash menu actions (such as GetURL). If you develop for a number of different clients, it's easy to move an application (or part of one) or reuse the entire app in another site. It makes later additions and changes easier to implement and gives you greater control of definitions and permissions in your Web server.
Refrain from running <cfloop>s and other complex logic within your <cfquery> tags.
Because the driver connection remains open for the duration of the code executing within <cfquery> tags, Allaire recommends keeping the executable code therein to a minimum. Anyway, you can accomplish the same task by separating out conditional queries to be run only in the event of a <cfswitch/case> clause as in Fusebox. This reduces to: never hit the database if you don't have to, never ask the database for one column or one row more than you need, and keep your conditional logic in Coldfusion where it belongs.
If database performance is an issue for you, keep this in mind: when designing your tables, accept NULL values sparingly, if at all. SQL Server stores a bitmap in every row to indicate whether a column set to accept NULL values is indeed NULL. By allowing NULLs you force SQL Server to decode this bitmap in each and every called row. This practice multiplies the complexity (read "proneness to bugs") of an application. The server logic em-ployed earns you a second performance penalty as well, as you must account for the allowed values throughout your code.
If you have more than one iteration of the <cfif, cfelseif, and cfelse> tag group, consider using <cfswitch> and <cfcase> to boost performance. In a <cfif/cfelse> scenario, ColdFusion must test against every condition before exiting the clause. If your expression matches the final condition in your series of if/elses, ColdFusion is forced to test and reject every condition. Switch/case is less code text than <cfif/cfelse>, making it easier to follow and debug, and since the conditional logic is more efficient, you can take home a performance boost.
Use nested <cfif> tags sparingly.
I state this as a corollary to the above, though the larger point has been made.
Use the function GetTickCount for testing slow or crashing templates implementing CFX tags or complex CFML logic to isolate the source of the problem.
GetTickcount returns a millisecond counter for timing the processing of ColdFusion markup. Try running the following example code. If this page returns slowly in a no-load environment, you can be confident your performance problem is server side and not due to poor coding or conditional logic. Then test it in a loaded environment, such as the suspect template, where your problem will be exacerbated.
<CFSET Count = 1000>
<CFLOOP Index = idxMyIndex From=1>
<CFSET Start = GetTickCount()>
<CFSET Stop = GetTickCount()>
<CFSET RoundTripTime = Stop - Start>
<CFOUTPUT>Round Trip time was #RoundTripTime# milliseconds</CFOUTPUT>
For Spectra developers, watch this count spiral past 3,000. Then have a heart to heart with your sys admin. (Remember, too, that the IIS 4 Management Console spawns a memory leak if left running. Windows 2000's IIS 5 sports a memory leak so exuberant that it will crash your entire system if you don't run the recently released service pack.)
Trick ColdFusion Studio into quickly saving files in your current project folder, rather than the default Studio folder, for speedy development.
Create a favorite with the following steps:
- In the Resource window navigate to your project folder.
- Right-click in the file list.
- Choose "favorite folders > Add current folder to favorites". Add your folder.
- Your subsequent effort to File > Save should result in your folder opening first.
Use lots of comments.
Everyone says this, but the resulting comments from such a vaguely stated rule are vague enough themselves. More important, who hasn't been set back days or weeks by poorly (or un-) commented code they've inherited? Coders must leave breadcrumbs, especially in a landscape where people typically stay at a job for no more than six months. In your application.cfm file, note the following: the author name and e-mail, the date, and a description of the application. As Ben Forta writes in "'The Ten Commandments' - Revisted" (CFDJ, Vol. 2, issue 10), "...every conditional statement, every loop, every set of variable assignments, and every include or component reference, must be commented with a simple statement explaining what's being done, and why."
To this I'd add that you note at the top of your list what other processes are dependent on the current process. This way, if I cut anything out of my app elsewhere, you'll be able to tell what else might unexpectedly fall apart. I even go so far as to include a "ReadMe.cfm" file in every application I write. When you comment heavily like this, however, I suggest you get rid of the resulting whitespace. In ColdFusion 4.5 you can do this by going to the Administration Page and enabling "Suppress whitespace by default". Refrain from ending a template with a comment if you choose this setting on the server. On a local level, you can also use the <cfprocessingdirective suppresswhitespace="Yes"> tag to handle it. The downside? You need this tag and its closing counterpart in all the templates you have to remove the spaces.
Use tab stops in your code to make it readable later - for yourself and others.
Validate at the top of the form so you can immediately see which fields contain a validation rule.
Use a standard, conventional nomenclature for your ColdFusion objects.
The Hungarian notation standard used in constructing Visual Basic and C applications offers some direction (see Table 1). So named because it was popularized at Microsoft by Hungarian programmer Charles Simonyi, Hungarian notation is a naming convention that allows the programmer to determine the type and use of an identifier (variable, function, constant, etc.)
If you don't like Hungarian notation, just make one up with the people on your team - and consider the following:
- Mnemonic value: Makes it easy to remember the name
- Suggestive value: So others can easily understand the name
- Consistency: Similar names for similar objects
Thank you to everyone who contributed suggestions, especially to Ben Forta for pointing me in good directions for research, and to my friend and colleague Garrick Brooks for contributing excellent ideas on security issues.
The Internet of Things can drive efficiency for airlines and airports. In their session at @ThingsExpo, Shyam Varan Nath, Principal Architect with GE, and Sudip Majumder, senior director of development at Oracle, discussed the technical details of the connected airline baggage and related social media solutions. These IoT applications will enhance travelers' journey experience and drive efficiency for the airlines and the airports.
Jan. 20, 2017 05:45 PM EST Reads: 2,085
With major technology companies and startups seriously embracing IoT strategies, now is the perfect time to attend @ThingsExpo 2016 in New York. Learn what is going on, contribute to the discussions, and ensure that your enterprise is as "IoT-Ready" as it can be! Internet of @ThingsExpo, taking place June 6-8, 2017, at the Javits Center in New York City, New York, is co-located with 20th Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry p...
Jan. 20, 2017 05:15 PM EST Reads: 3,801
"LinearHub provides smart video conferencing, which is the Roundee service, and we archive all the video conferences and we also provide the transcript," stated Sunghyuk Kim, CEO of LinearHub, in this SYS-CON.tv interview at @ThingsExpo, held November 1-3, 2016, at the Santa Clara Convention Center in Santa Clara, CA.
Jan. 20, 2017 03:00 PM EST Reads: 1,641
Things are changing so quickly in IoT that it would take a wizard to predict which ecosystem will gain the most traction. In order for IoT to reach its potential, smart devices must be able to work together. Today, there are a slew of interoperability standards being promoted by big names to make this happen: HomeKit, Brillo and Alljoyn. In his session at @ThingsExpo, Adam Justice, vice president and general manager of Grid Connect, will review what happens when smart devices don’t work togethe...
Jan. 20, 2017 02:15 PM EST Reads: 605
"There's a growing demand from users for things to be faster. When you think about all the transactions or interactions users will have with your product and everything that is between those transactions and interactions - what drives us at Catchpoint Systems is the idea to measure that and to analyze it," explained Leo Vasiliou, Director of Web Performance Engineering at Catchpoint Systems, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York Ci...
Jan. 20, 2017 01:30 PM EST Reads: 5,729
The 20th International Cloud Expo has announced that its Call for Papers is open. Cloud Expo, to be held June 6-8, 2017, at the Javits Center in New York City, brings together Cloud Computing, Big Data, Internet of Things, DevOps, Containers, Microservices and WebRTC to one location. With cloud computing driving a higher percentage of enterprise IT budgets every year, it becomes increasingly important to plant your flag in this fast-expanding business opportunity. Submit your speaking proposal ...
Jan. 20, 2017 01:30 PM EST Reads: 5,233
Discover top technologies and tools all under one roof at April 24–28, 2017, at the Westin San Diego in San Diego, CA. Explore the Mobile Dev + Test and IoT Dev + Test Expo and enjoy all of these unique opportunities: The latest solutions, technologies, and tools in mobile or IoT software development and testing. Meet one-on-one with representatives from some of today's most innovative organizations
Jan. 20, 2017 12:30 PM EST Reads: 1,650
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.
Jan. 20, 2017 12:30 PM EST Reads: 4,345
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.
Jan. 20, 2017 12:30 PM EST Reads: 3,186
SYS-CON Events announced today that Super Micro Computer, Inc., a global leader in Embedded and IoT solutions, will exhibit at SYS-CON's 20th International Cloud Expo®, which will take place on June 7-9, 2017, at the Javits Center in New York City, NY. Supermicro (NASDAQ: SMCI), the leading innovator in high-performance, high-efficiency server technology, is a premier provider of advanced server Building Block Solutions® for Data Center, Cloud Computing, Enterprise IT, Hadoop/Big Data, HPC and E...
Jan. 20, 2017 12:15 PM EST Reads: 5,836
Internet of @ThingsExpo, taking place June 6-8, 2017 at the Javits Center in New York City, New York, is co-located with the 20th International Cloud Expo and will feature technical sessions from a rock star conference faculty and the leading industry players in the world. @ThingsExpo New York Call for Papers is now open.
Jan. 20, 2017 10:45 AM EST Reads: 3,701
WebRTC sits at the intersection between VoIP and the Web. As such, it poses some interesting challenges for those developing services on top of it, but also for those who need to test and monitor these services. In his session at WebRTC Summit, Tsahi Levent-Levi, co-founder of testRTC, reviewed the various challenges posed by WebRTC when it comes to testing and monitoring and on ways to overcome them.
Jan. 20, 2017 10:45 AM EST Reads: 6,089
DevOps is being widely accepted (if not fully adopted) as essential in enterprise IT. But as Enterprise DevOps gains maturity, expands scope, and increases velocity, the need for data-driven decisions across teams becomes more acute. DevOps teams in any modern business must wrangle the ‘digital exhaust’ from the delivery toolchain, "pervasive" and "cognitive" computing, APIs and services, mobile devices and applications, the Internet of Things, and now even blockchain. In this power panel at @...
Jan. 20, 2017 09:45 AM EST Reads: 2,933
WebRTC services have already permeated corporate communications in the form of videoconferencing solutions. However, WebRTC has the potential of going beyond and catalyzing a new class of services providing more than calls with capabilities such as mass-scale real-time media broadcasting, enriched and augmented video, person-to-machine and machine-to-machine communications. In his session at @ThingsExpo, Luis Lopez, CEO of Kurento, introduced the technologies required for implementing these idea...
Jan. 20, 2017 08:30 AM EST Reads: 4,761
Buzzword alert: Microservices and IoT at a DevOps conference? What could possibly go wrong? In this Power Panel at DevOps Summit, moderated by Jason Bloomberg, the leading expert on architecting agility for the enterprise and president of Intellyx, panelists peeled away the buzz and discuss the important architectural principles behind implementing IoT solutions for the enterprise. As remote IoT devices and sensors become increasingly intelligent, they become part of our distributed cloud enviro...
Jan. 20, 2017 08:15 AM EST Reads: 4,955
"A lot of times people will come to us and have a very diverse set of requirements or very customized need and we'll help them to implement it in a fashion that you can't just buy off of the shelf," explained Nick Rose, CTO of Enzu, in this SYS-CON.tv interview at 18th Cloud Expo, held June 7-9, 2016, at the Javits Center in New York City, NY.
Jan. 20, 2017 08:15 AM EST Reads: 4,720
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 co...
Jan. 20, 2017 07:15 AM EST Reads: 2,982
In his keynote at @ThingsExpo, Chris Matthieu, Director of IoT Engineering at Citrix and co-founder and CTO of Octoblu, focused on building an IoT platform and company. He provided a behind-the-scenes look at Octoblu’s platform, business, and pivots along the way (including the Citrix acquisition of Octoblu).
Jan. 20, 2017 07:00 AM EST Reads: 9,083
For basic one-to-one voice or video calling solutions, WebRTC has proven to be a very powerful technology. Although WebRTC’s core functionality is to provide secure, real-time p2p media streaming, leveraging native platform features and server-side components brings up new communication capabilities for web and native mobile applications, allowing for advanced multi-user use cases such as video broadcasting, conferencing, and media recording.
Jan. 20, 2017 07:00 AM EST Reads: 6,875
Web Real-Time Communication APIs have quickly revolutionized what browsers are capable of. In addition to video and audio streams, we can now bi-directionally send arbitrary data over WebRTC's PeerConnection Data Channels. With the advent of Progressive Web Apps and new hardware APIs such as WebBluetooh and WebUSB, we can finally enable users to stitch together the Internet of Things directly from their browsers while communicating privately and securely in a decentralized way.
Jan. 20, 2017 03:00 AM EST Reads: 928