ColdFusion Muse

Address Resolution, Networking, and Cfdocument

Among the things that can befuddle even experienced developers, domain resolution ranks up at the top. Usually this is because we don't spend a lot of time worrying about resolution on our desktop or laptop or Iphone. DNS is an extremely mature technology and for the most part it just works with few issues. When it comes to a server however, there are several things that can trip up resolution. Without an understanding of exactly what is going on under the hood, you will find yourself destroying yet another keyboard with the ball of your fist as you shout "why won't you just work!"

Domain resolution comes into play on most ColdFusion applications, even if you don't think so. Among other things, resolution is important for:

• Data Sources - how do you connect to an external server?
• Ecommerce - how do you connect to a Gateway?
• Web Services - how do you create your stub class?

So let's take a short journey down this path and see if we can uncover some of the general principles that will help us troubleshoot domain resolution issues.

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Ask-a-Muse: How Do I Upgrade the JVM?

I'm glad you asked this question because it reminds me that I sometimes give advice without any follow through - which is the same problem I have with my 8 iron. Upgrading the JVM on a windows installation is pretty easy. Just remember that you will need the correct Java Runtime for your platform and ColdFusion version. Rob specified Win2k3 x64 so I assume he means he is running ColdFusion 8 enterprise 64 bit - in which case the target version is 1.6 update 14 (or 1.6.0_14). I usually start at the Sun Java download page. Once you have the right version in hand the rest is easy.

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Certain JPGs Can Crash Your ColdFusion 8 Server

This issue was brought to my attention by Adrian Lynch on CF-Talk. It seems that if you use the new image functions in ColdFusion 8 against certain kinds of JPG images you can actually cause your JVM to crash. If you have code that uses the latest image functions to handle uploaded images you should definitely take note of this post. I cannot yet see how a user might take advantage of this bug to penetrate your server, but a malicious (or even non-malicious) user could easily perform a denial of service attack and cause your CF server to go up and down like Jack LaLanne doing jumping jacks. So if you fit into that category (handling uploaded images using CF 8 image functionality) here's the scoop.

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Connector Problems - Win2k8, IIS7 and Multi-Server ColdFusion 8 x 64 Bit

I have not yet had this problem specifically, but it was pointed out by CFG Tom Forrest who spent some time wrangling with it. He was trying to use the connector widget to connect IIS 7 sites to ColdFusion instances (running in Multi-Server Mode). He reports as follows:

According to Tom the fix is to install the IIS 6 Management Compatibility role service. This service allows an IIS 7 server to "act like" an IIS 6 server. Once installed the configuration tool began to work.

While I haven't had this specific problem, I have noticed that a number of other things are easier and more familiar with the IIS Management Compatibility installed. Thanks Tom.

Ask-a-Muse: Killing the Immortal Thread

Ah the immortal thread - like a god coming down from Mt. Olympus and laughing with his (or her) hands on his mighty hips (see why I chose "his"? ... "her mighty hips" ... well, I just didn't want to go there). Such threads are mind bogglingly frustrating. In actual fact, there are some requests spawned by ColdFusion that may not be able to be terminated by ColdFusion. For the long version read on McDuff.

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More Connection Magic

I outlined some issues in my last post on using CFHTTP and paying attention to connection issues. Muse reader Scott Pinkston posted a nice snippet of code that allows you to see what IP address is used to resolve a given domain name. Here it is complete with the function call (getHostAddress()) that gives you the IP address:

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Checking the Size of the Spool Directory on Windows

If you ever send out a few tens of thousands of messages using CF you know the spool directory can get pretty crowded. If you are like me you sometimes want to keep an eye on it as those messages clear out to make sure there is nothing funky going on. If you use Windows Explorer this can be a maddening experience. Windows doesn't just retrieve a count of files. It retrieves the entire file list and meta data and it redraws the explorer window. When you have 50k messages in the spool folder it can take 10 to 30 seconds just for Windows to refresh the count so you can know how many were added or deleted to the folder.

Instead, I use a little tool called "t4edirsize" from tools 4 Ever. I have a "show spool" batch file on my servers that looks like this:

The output gives me all sorts of information including the number of files in the directory - but it usually only takes 50-200 milliseconds to run. Tools 4 ever command line tools along with Sys-Internals tools (now owned by Microsoft) like "pslist" and "pskill" are essential to your arsenal as a troubleshooter.

Troubleshooting CFHTTP - 3 Tips

Hang around ColdFusion long enough and you will eventually find yourself making use of CFHTTP. The tag allows you to make an HTTP request from your Coldfusion server to an HTTP resource. Why would you want to do this? HTTP is a great low level protocol for data exchange. There's a reason why most web services run over HTTP - it is easy to understand and implement. As for CFHTTP, there are a great many examples, but here are a few.

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