|By Charlie Arehart||
|October 5, 2000 12:00 AM EDT||
We've all seen it: the dreaded "Error Occurred While Processing Request," which is the headline above a normal CF error message. As developers, of course, we relish the detail it offers: the CF error message, the line number and actual line of code in error, the name and path of the template in which it occurred, and so on. But is this the best thing to show our end users?
Probably not. What should they do with that information? Do they care about these details? Could a hacker use them for unintended purposes? And perhaps most important, how do you even know the error has occurred?
Several features - some old, some new in 4.5, but in either case often missed and misunderstood - can dramatically improve error handling in ColdFusion. In this series of articles I'll cover the basic solutions, CFTRY/CFCATCH, CFERROR (three forms of it) and Site Wide Error Handling, which may be new to you.
In this issue, though, we'll focus on some administrator settings that you may not have considered and that may be quite important to any effective error-handling strategy, depending on the other error-handling choices you make. I'll show how you can reduce the level of detail offered in error messages, as well as improve the ease with which errors may be reported to you when they occur. Along the way I'm confident even the most experienced CF coder will learn a thing or two as some aspects of these features are poorly documented and not obvious.
I'll discuss those other error-handling choices (CFTRY/CFCATCH, CFERROR, and Site Wide Error Handling) in forthcoming issues of CFDJ, and at the end I'll offer a clear list of things you should be doing to better handle errors in your applications.
By applying even one of these solutions, with just a few minutes work (or seconds, in some cases) you could dramatically improve not only your end users' experience, but also the security of your site and your awareness of errors that occur in your applications.
That Lovable, If Pesky, Error Message
The standard CF error message is a delight to the CF developer, with all that great detail. And if it's a SQL error, we even see the database error message, the name of the datasource in error and the SQL statement that was attempted. This is just great for debugging. An example is shown in Figure 1.
Clearly, the creators of CF were developers at heart and realized we'd need to see that info to solve problems. Quick Tip: When you get an error, do you jump back into the code and try to find and fix it? Most developers seem to...and fail to take full advantage of the text of the message. In some cases, though (see Figure 1), what's wrong isn't always obvious.
Even then, if you hop back into the code to scroll around looking for the line of code in error, you're missing a useful shortcut. Notice the line number that's offered (line 79 in this example). In Studio, type CTRL-G (or Edit>GoTo Line) to jump to that line of code. It's not a perfect solution, however; if you have any CFINCLUDEs above the line in error, the numbers in the Studio won't be in sync with the one reported in the error.
This detail is great for developers, but when you move your code to a production environment or, more simply, when an end user visits the site, is that error message an appropriate thing to offer them?
Is It the Right Thing for End Users?
There are several problems with letting users see an error message. First, of course, there's the compromise such errors make to your otherwise elegant user interface. How does it look when they go from your site's consistently blue background to the plain white CF error message page? And what are they going to do with this information? And again, how do you know the error has occurred for your users? Do you simply wait for a call and report it? And have you considered the security risks of showing the physical path of your templates and the SQL datasource name and statements of failed queries in this error message to users?
If you're like many CF developers, these are things you probably haven't thought about, or simply didn't know how to solve. As of Release 4.5, there are a host of options you can consider to limit, modify or hide the error message users see. You can even arrange to log the errors in a database and/or send your developers an e-mail indicating that an error has occurred.
But these enhancements generally require programming changes. We want to start off with some quick changes that can be made to assist the user in informing you that an error has occurred, as well as limiting what information is displayed.
Administrator Configuration Changes
In this article we'll consider three changes that can be made in the CF Administrator. They'll have an important impact on the information presented (or hidden) in the traditional CF error message.
Subsequent issues will cover modifying or completely hiding the display of the message as well as logging/e-mailing it to you automatically, with new "error-handling templates."
But even with those in place if you have them (or until we cover them next month), the changes discussed below have benefits. They'll improve both the ease of users reporting an error as well as the security of your site - especially if you won't be implementing error-handling templates.
The issues we'll cover are setting the administrator e-mail, hiding the SQL and datasource name for query errors, and hiding the template path to the template in error. Even if you think you understand these options, there's more to them than is documented. Let's look at them in detail.
Defining the Administrator E-Mail Error-Handling Address
Some experienced developers may be surprised by my pointing this out, but it's one of the simplest improvements you can make, in the right circumstances, and it's easily implemented.
In the CF Administrator there's a place where you can define the administrator e-mail address for the server:
- Take the "settings" link under the Logging area on the left nav bar.
- Enter an e-mail address that should receive e-mails sent by users choosing an option that will be presented to them to send such messages.
Please inform the site administrator that this error has occurred (be sure to include the contents of this page in your message to the administrator).
The "site administrator" link will now hold a hyperlink that when clicked will indicate to the browser that a mail message should be created to be sent to the e-mail address specified in that Administrator setting. (If the user's browser and e-mail client are properly configured to respond to such e-mail hyperlinks, the client's e-mail program will launch an e-mail message to the specified address - and the user can choose to fill in the subject and body of the message.)
Of course, we still have to hope they pay attention to the error message that states they should "include the contents of this page" in the message they send. And it's important to note that this doesn't mean that the "administrator e-mail" address will receive notification of every error that occurs - only when end users click the link offered in that message above. That's something we'll enable in the next issue.
Not Enough, But a Good First Step
This still doesn't solve the other problems of the less-than-attractive interface of the error message or getting an automatic notification. But it's a step in the right direction and, unless you're in a shared server environment where no one person is a suitable recipient of all notifications about error messages, it's probably the first thing you ought to do. (Just be sure to change that administrator setting should that person ever change or leave, lest messages be sent to someone who'll never get them.)
It's also useful when you do use site-wide error handling, as it becomes a variable you can refer to in the site-wide error template, covered next month.
Hiding the SQL and Datasource Name, and Template Path
I've already mentioned the potential security risk of showing the end user such details as the path to the template in error and the SQL code and datasource name in failed queries. In the next article I'll show how you can hide the entire error message from the user, so this point about hiding certain details of the message may become moot if you apply the other techniques. But it's important to understand, especially if you're not currently aware of the issue and may not soon implement those other techniques.
Let's look closely at the information shown in the normal CF error message, focusing just on the SQL and Datasource name of a failed query, and the path to the template in error (see Figure 1).
Could someone take advantage of knowing your Datasource name (SomeDSN, in the example) and the SQL code of the failed queries? Or the template path (C:\INETPUB\WWWROOT\SOMEDIR\) to the page in error?
Well, perhaps not if they're just a user of your Web site. Of course, if such a user could break in, they could certainly take advantage of the information. But such break-ins are unlikely, or at least well beyond the scope of this article.
But what if you're on a shared Web server with others who aren't related to your application but can also put CF code on the server in other directories? This is certainly an issue in a commercially hosted Web site on a server shared by many users. It's also a possible concern for users on a corporate Web site having multiple unrelated applications. (One solution to this problem is to use CF's Advanced Security, but this isn't a trivial exercise and is beyond the scope of this article.)
As for the SQL and Datasource Name, if someone can place CF code on the same server as you, have you considered the risk to your data if he or she knew the datasource name for your database? What's to stop someone from running a query against your database? If you're not password protecting your database, any CF template that's running on that same CF server can write a query against your datasource. Password protecting the file may be trivial or challenging in your environment, but explaining it is a subject for another article.
There is yet another risk, as described in Allaire Security Bulletins ASB99-04 and ASB99-09. It's possible in some situations (if not otherwise protected using the suggestions in the bulletins) for a Web visitor to append to the end of a URL (in certain rather unusual situations) extra SQL commands to be executed against your database. This isn't really a CF bug but rather a database driver issue.
In both these cases, if someone can see the SQL statements (including table and column names) shown in an error message, that makes it all the easier to take advantage of any security hole or weaknesses in your environment. So let's hide that information.
Hiding the SQL and Datasource Name in Query Errors
The good news is that it's easy to stop that information from showing in the standard error message (or the one available for display as a variable in one of the error-handling template approaches, discussed in the next issue). It's just a simple tick of a checkbox in the CF Administrator.
It may not be so easy to find, however. It's presented along with server-side debugging control options:
- Take the "debugging" link under the Miscellaneous area on the left nav bar.
- Make sure "Show SQL and data source name" is unchecked.
SQL = "select * from jobs where jobs.companyid = 499 and jobs.composite_ad_yn <> 1 and jobs.jobtitleid = jobtitles.jobtitleid and jobs.cityid = val_cities.cityid order by stateid,city, jobtitle, date_posted desc" Data Source = "SomeDSN"
That's another step in the right direction.
Now you might be worried about the loss of this useful information as a developer, but there's good news.
Interesting Behavior That May Confuse You
The text explaining this option in the Administrator screen suggests that it controls display, not only of the Datasource name but the SQL statement in error as well. You may find, however, that after doing this you'll still see the SQL statement in error. Is the feature broken? Will end users still see the SQL statement in error? That depends.
Although it's not documented anywhere, this option behaves in an interesting way, and it explains why this option is on the debugging options page. A user who can see the server-side debugging information will always see the SQL statement in error, regardless of whether the "show SQL and datasource name" is turned off.
This is a nice feature for developers as it gives them the detail they need. It's likely that you don't show end users the debugging information, so this makes it really safe to turn off the display of the SQL statement. Those who shouldn't see it won't, while those who should, will.
Hiding the Template Path
The security concerns don't stop there. Remember that display in the error message of the physical path to the template in error? That can also be used by hackers, or simply by others not associated with your project but located on the same server. A few tags available in CF, such as CFFILE and CFCONTENT, allow access to any file in the CF server.
The error occurred while processing an element with a general identifier of (CFQUERY), occupying document position (26:5) to (26:59).
If someone running code on your server (again, someone who has access to the server or, less likely, someone who's broken in) knows where your code resides, that person can use those tags to grab your source code...or possibly your database.
There are two broader solutions to that problem: one is to restrict access to those tags in the Administrator, which is an option under "Basic Security." Or you can configure Advanced Security, mentioned previously, to protect directories from access by other developers on the same server.
Beyond those security approaches, you can also lessen the risk caused by error messages showing the template path by simply preventing its display in the standard CF error message. Like the "SQL and Datasource Name" option, it too is embedded, curiously, among the server-side debugging control options:
- Take the "debugging" link under the Miscellaneous area on the left nav bar.
- Make sure "Display the template path in error messages" is unchecked.
The specific sequence of files included or processed is:
Sadly, this option doesn't respond the way the SQL and Datasource Name option does: even if you're authorized to see server-side debugging information, once this option is turned on, the template name and path will no longer be displayed in error messages. This will make it a little harder for a developer to determine a template in error.
If you have development and production environments, it's certainly worth considering whether you really want to use this option to hide the template path in the development environment.
Some errors (unless otherwise handled by error-handling strategies to be discussed in the next issue) will still show the template path anyway. Compilation errors are an example. Consider this example: turn off the display of the template path and run a template with the code:
This compilation error will display the complete path in the error message, after the details about the compilation error itself, as in:
This doesn't happen in all classes of errors, but it's something to keep in mind.
We've covered a lot of ground, and hopefully you've learned some things about configuring the Administrator to improve error handling.
Next month I'll explain further the opportunity to have even greater control over the display of errors, or hide them entirely and simply e-mail them automatically to a support person with no interaction by the user, or perhaps even log them to a database. I'll provide two of the three alternatives: Site Wide Error Handling (new to 4.5) and application-level error handling (which has changed significantly in 4.5). In the final part I'll cover CFTRY and CFCATCH, which offer even finer levels of control over error handling within your code.
As for the recommendations to take from this article, consider the following as a summary of the Administrator changes available to you:
- Set the Administrator e-mail address (if you're on a server where all the applications are related and one person is appropriately ready to handle all such messages).
- Turn off the display of the Datasource Name and SQL for queries in error, and the template path to the template in error, in anything other than a pure testing/development environment.
- Password protect your databases (even in Access) so users running code on a shared server with you need more than just the datasource name and knowledge of your tables and column names to access your data.
- Read the two Allaire security bulletins about further protecting your data from end users who might be able to take advantage of certain security issues in some database drivers and with some templates.
- Consider the "Tag Restriction" options in the Administrator to further prevent the likelihood of abuse among unrelated developers on a shared server.
- Set the Administrator debugging options to prevent server-side debug information from showing to your users, which allows the hide "SQL and Datasource Name" option described above to indeed hide the SQL in error.
SYS-CON Events announced today that Interoute, owner-operator of one of Europe's largest networks and a global cloud services platform, has been named “Bronze Sponsor” of SYS-CON's 18th Cloud Expo, which will take place on June 7-9, 2015 at the Javits Center in New York, New York. Interoute is the owner-operator of one of Europe's largest networks and a global cloud services platform which encompasses 12 data centers, 14 virtual data centers and 31 colocation centers, with connections to 195 ad...
Feb. 6, 2016 05:00 AM EST Reads: 312
Most people haven’t heard the word, “gamification,” even though they probably, and perhaps unwittingly, participate in it every day. Gamification is “the process of adding games or game-like elements to something (as a task) so as to encourage participation.” Further, gamification is about bringing game mechanics – rules, constructs, processes, and methods – into the real world in an effort to engage people. In his session at @ThingsExpo, Robert Endo, owner and engagement manager of Intrepid D...
Feb. 5, 2016 09:00 PM EST Reads: 753
With an estimated 50 billion devices connected to the Internet by 2020, several industries will begin to expand their capabilities for retaining end point data at the edge to better utilize the range of data types and sheer volume of M2M data generated by the Internet of Things. In his session at @ThingsExpo, Don DeLoach, CEO and President of Infobright, will discuss the infrastructures businesses will need to implement to handle this explosion of data by providing specific use cases for filte...
Feb. 5, 2016 03:00 PM EST
SYS-CON Events announced today that Fusion, a leading provider of cloud services, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Fusion, a leading provider of integrated cloud solutions to small, medium and large businesses, is the industry's single source for the cloud. Fusion's advanced, proprietary cloud service platform enables the integration of leading edge solutions in the cloud, including clou...
Feb. 5, 2016 02:30 PM EST Reads: 695
SYS-CON Events announced today that Commvault, a global leader in enterprise data protection and information management, has been named “Bronze Sponsor” of SYS-CON's 18th International Cloud Expo, which will take place on June 7–9, 2016, at the Javits Center in New York City, NY, and the 19th International Cloud Expo, which will take place on November 1–3, 2016, at the Santa Clara Convention Center in Santa Clara, CA. Commvault is a leading provider of data protection and information management...
Feb. 5, 2016 01:30 PM EST Reads: 329
SYS-CON Events announced today that Alert Logic, Inc., the leading provider of Security-as-a-Service solutions for the cloud, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. Alert Logic, Inc., provides Security-as-a-Service for on-premises, cloud, and hybrid infrastructures, delivering deep security insight and continuous protection for customers at a lower cost than traditional security solutions. Ful...
Feb. 5, 2016 01:15 PM EST Reads: 321
The cloud promises new levels of agility and cost-savings for Big Data, data warehousing and analytics. But it’s challenging to understand all the options – from IaaS and PaaS to newer services like HaaS (Hadoop as a Service) and BDaaS (Big Data as a Service). In her session at @BigDataExpo at @ThingsExpo, Hannah Smalltree, a director at Cazena, will provide an educational overview of emerging “as-a-service” options for Big Data in the cloud. This is critical background for IT and data profes...
Feb. 5, 2016 12:00 PM EST
SYS-CON Events announced today that VAI, a leading ERP software provider, will exhibit at SYS-CON's 18th International Cloud Expo®, which will take place on June 7-9, 2016, at the Javits Center in New York City, NY. VAI (Vormittag Associates, Inc.) is a leading independent mid-market ERP software developer renowned for its flexible solutions and ability to automate critical business functions for the distribution, manufacturing, specialty retail and service sectors. An IBM Premier Business Part...
Feb. 5, 2016 12:00 PM EST Reads: 519
Fortunately, meaningful and tangible business cases for IoT are plentiful in a broad array of industries and vertical markets. These range from simple warranty cost reduction for capital intensive assets, to minimizing downtime for vital business tools, to creating feedback loops improving product design, to improving and enhancing enterprise customer experiences. All of these business cases, which will be briefly explored in this session, hinge on cost effectively extracting relevant data from ...
Feb. 5, 2016 10:15 AM EST
As enterprises work to take advantage of Big Data technologies, they frequently become distracted by product-level decisions. In most new Big Data builds this approach is completely counter-productive: it presupposes tools that may not be a fit for development teams, forces IT to take on the burden of evaluating and maintaining unfamiliar technology, and represents a major up-front expense. In his session at @BigDataExpo at @ThingsExpo, Andrew Warfield, CTO and Co-Founder of Coho Data, will dis...
Feb. 5, 2016 10:00 AM EST
With the Apple Watch making its way onto wrists all over the world, it’s only a matter of time before it becomes a staple in the workplace. In fact, Forrester reported that 68 percent of technology and business decision-makers characterize wearables as a top priority for 2015. Recognizing their business value early on, FinancialForce.com was the first to bring ERP to wearables, helping streamline communication across front and back office functions. In his session at @ThingsExpo, Kevin Roberts...
Feb. 5, 2016 09:30 AM EST Reads: 305
Eighty percent of a data scientist’s time is spent gathering and cleaning up data, and 80% of all data is unstructured and almost never analyzed. Cognitive computing, in combination with Big Data, is changing the equation by creating data reservoirs and using natural language processing to enable analysis of unstructured data sources. This is impacting every aspect of the analytics profession from how data is mined (and by whom) to how it is delivered. This is not some futuristic vision: it's ha...
Feb. 2, 2016 02:00 PM EST Reads: 394
WebRTC has had a real tough three or four years, and so have those working with it. Only a few short years ago, the development world were excited about WebRTC and proclaiming how awesome it was. You might have played with the technology a couple of years ago, only to find the extra infrastructure requirements were painful to implement and poorly documented. This probably left a bitter taste in your mouth, especially when things went wrong.
Feb. 2, 2016 04:30 AM EST Reads: 822
Learn how IoT, cloud, social networks and last but not least, humans, can be integrated into a seamless integration of cooperative organisms both cybernetic and biological. This has been enabled by recent advances in IoT device capabilities, messaging frameworks, presence and collaboration services, where devices can share information and make independent and human assisted decisions based upon social status from other entities. In his session at @ThingsExpo, Michael Heydt, founder of Seamless...
Feb. 1, 2016 05:00 AM EST Reads: 909
The IoT's basic concept of collecting data from as many sources possible to drive better decision making, create process innovation and realize additional revenue has been in use at large enterprises with deep pockets for decades. So what has changed? In his session at @ThingsExpo, Prasanna Sivaramakrishnan, Solutions Architect at Red Hat, discussed the impact commodity hardware, ubiquitous connectivity, and innovations in open source software are having on the connected universe of people, thi...
Jan. 31, 2016 09:00 PM EST Reads: 705
WebRTC: together these advances have created a perfect storm of technologies that are disrupting and transforming classic communications models and ecosystems. In his session at WebRTC Summit, Cary Bran, VP of Innovation and New Ventures at Plantronics and PLT Labs, provided an overview of this technological shift, including associated business and consumer communications impacts, and opportunities it may enable, complement or entirely transform.
Jan. 31, 2016 07:15 PM EST Reads: 1,125
For manufacturers, the Internet of Things (IoT) represents a jumping-off point for innovation, jobs, and revenue creation. But to adequately seize the opportunity, manufacturers must design devices that are interconnected, can continually sense their environment and process huge amounts of data. As a first step, manufacturers must embrace a new product development ecosystem in order to support these products.
Jan. 31, 2016 10:00 AM EST Reads: 781
There are so many tools and techniques for data analytics that even for a data scientist the choices, possible systems, and even the types of data can be daunting. In his session at @ThingsExpo, Chris Harrold, Global CTO for Big Data Solutions for EMC Corporation, showed how to perform a simple, but meaningful analysis of social sentiment data using freely available tools that take only minutes to download and install. Participants received the download information, scripts, and complete end-t...
Jan. 31, 2016 10:00 AM EST Reads: 1,186
Manufacturing connected IoT versions of traditional products requires more than multiple deep technology skills. It also requires a shift in mindset, to realize that connected, sensor-enabled “things” act more like services than what we usually think of as products. In his session at @ThingsExpo, David Friedman, CEO and co-founder of Ayla Networks, discussed how when sensors start generating detailed real-world data about products and how they’re being used, smart manufacturers can use the dat...
Jan. 30, 2016 07:45 PM EST Reads: 743
When it comes to IoT in the enterprise, namely the commercial building and hospitality markets, a benefit not getting the attention it deserves is energy efficiency, and IoT’s direct impact on a cleaner, greener environment when installed in smart buildings. Until now clean technology was offered piecemeal and led with point solutions that require significant systems integration to orchestrate and deploy. There didn't exist a 'top down' approach that can manage and monitor the way a Smart Buildi...
Jan. 30, 2016 03:45 PM EST Reads: 1,246