Author: tpryan

Running a ColdFusion Shop 3

For Reference: Part 1 and Part2.

It’s been awhile, but I’ve finally got more to say about all this.

Backup

In the last one of these, I told you to back up your system. Maybe not directly, but it was there. Okay, so I didn’t say it. I’m saying it now. Backup your machines. Do a tape backup, export to an external drive, do anything. Just backup your machines.

Backup Configuration Files Separately

Independent of a backup solution that takes care of your whole system, I would also recommend backing up configurations to separate location, in their current format. Meaning, don’t put them on a tape, don’t ship them off site. Just keep them somewhere you can access them. Why? Coldfusion is pretty light. CFML sites are comprised of pretty small files. Odds are, if you have a systems failure, it very well may be faster to rebuild a system from scratch then it will be to get a system backup restored and working. Rebuild your server, reinstall your webserver, and reinstall ColdFusion, all while getting the CFML files from backup. Then use configuration files you’ve stored elsewhere to restore both your webserver and Coldfusion to its old state. By this point, the CFML files should be out from a restore.

There are other uses for these files. You can use this method to clone your boxes, for clustering for example. Additionally, the ways they are broken up make it easy to share certain areas of configuration between machines. The most useful of these is neo-query.xml, which has all of your datasources on it.

Anyway, you probably want to know where all of these are:

  • ColdFusion configuration information is stored in xml files, in [CfusionRoot]lib.
  • IIS XML configurations can be exported from the IIS Manager
    • Right Click website
    • Choose “All Tasks”
    • Choose “Save Configuration to file.”

I’m sure that Apache has something to handle this too. But I don’t have any experience with it.

Backup Certificates

If you are using SSL certificates, back them up. They are a pain in the ass to manage. If you lose one without a backup you have to depend on the Certificate Authority to get your SSL service back up. Better to just have them ready to go in case of a problem.

Again I can only speak authoritatively about IIS, but:

  • Go to IIS Manager
  • Right click your SSL secured site
  • Choose “Properties”
  • Go to “Directory Security”
  • Under “Secure Communication” hit the “View Certificate” button
  • Choose “Details” tab
  • At the bottom “Copy To File”

That will bring up the “Certificate Export Wizard.” I usually choose the default options, with one exception. I choose “Yes export the private key.” It’s less secure, so you want to make sure you store them somewhere safe, but you’ll be able to do this again with a certification created from a backup with the private key.

That’s all I got this time around. Sorry it’s all backup related. Nothing happened; I was just collating tips for building a new Coldfusion box in our environment, and realized that these were all pretty important to doing that

CFUse CFTry CFCatch

I was in a code review earlier last week, and someone said that they didn’t like using <cftry> and <cfcatch>. When we as a group investigated further it was revealed that they had used it “incorrectly,” experienced problems for doing so, and labeled the try catch model as bad, instead of the implementation. So I figured I would quickly go over my opinions of what you should be using them for.

To start with, the incorrect usage of <CFTry> was wrapping it around a troublesome page, so instead of visibly erroring, the page would just silently fail. To add insult to injury, there was an error in the cfcatch block which caused the whole thing to throw an application level error anyway. This was, to put it mildly, a flawed use of <cftry> and <cfcatch>.

In a nutshell, the <cftry> and <cfcatch> model in ColdFusion is for handling expected errors, as opposed to handling unexpected errors. ColdFusion has a pretty good system for handling unexpected errors – a combination of <cferror> tags, and use of onError in the application.cfc. So wrapping an entire page in <cftry> to catch any error that may come up is not only the wrong thing to do, it’s also pretty redundant.

In my opinion <cftry> and <cfcatch> should be used to handle errors around small pieces of code that have the potential to error in predictable ways. For example here is a line of code from one of my applications:

cfset Wsdl = “<webservice URL>” />

<cfset displayBrainstorm = FALSE />

<cftry>

    <cfinvoke timeout=“1” webservice=“#Wsdl#” method=“AuthorInfo” returnvariable=“BrainstormStruct”>
        <cfinvokeargument name=“username” value=“#url.username#” />
    </cfinvoke>

    <cfset displayBrainstorm = BrainstormStruct.IsAuthor />
    <cfcatch type=“any”>
        <cfif FindNoCase(“stub objects”, cfcatch.Message)>
            <cfset createObject(“java”,“coldfusion.server.ServiceFactory”) .XmlRpcService.refreshWebService(Wsdl) />

            <cftry>
                <cfinvoke timeout=“1” webservice=“#Wsdl#” method=“AuthorInfo” returnvariable=“BrainstormStruct”>
                    <cfinvokeargument name=“username” value=“#url.username#” />
                </cfinvoke>

                <cfset displayBrainstorm = BrainstormStruct.IsAuthor />

                <cfcatch type=“any”>
                    <cfrethrow />
                </cfcatch>

            </cftry>

        <cfelse>
            <cfrethrow />
        </cfif>

    </cfcatch>

</cftry>


In it you’ll notice I’m doing a webservice call. In my experience webservices can have issues with the skeleton ColdFusion creates to consume them, especially if details about the webservice change. However, my application has little control over this webservice. So I wrap the call to the webservice in a <cftry> block, and if my expected error condition occurs, (something with to do the skeleton, or “stub objects”) I reset the webservice and try again.

You’ll notice that if it isn’t a “stub objects” problem, it assumes that it is some other issue, and rethrows the error so the application error handlers can tackle the problem. Why, because it is an unexpected problem, not an expected one.

In conclusion, I’m not speaking for all programming languages, but at least in ColdFusion <cftry> and <cfcatch> should be used to handle error that you can predict. The shouldn’t be your default error handling technique, and like a <Cflock> or a <cftransaction> they should surround as little code as possible.

Whitespace – What’s the big deal?

This came up in a code review today. There were a couple misunderstandings about it, so I figured I would share the explanation publicly.

First, there are two types of whitespace what are in play here. Whitespace in your code for the purpose of properly formatting, and extra whitespace in your ultimate HTML output that comes from the various loops and other mysterious sources in ColdFusion. In simple terms, the first is good and the second is bad. However, you shouldn’t try and get rid of the first in order to get rid of the second.

First, to see a demonstration of what I am talking about, go to Wharton Computing’s Brainstorm. Once you’re there, “View Source” from your browser. At the top of the page, you’ll see a few lines of empty space before the DocType declaration. Select them with your cursor. You’ll see they’re not just page breaks, but spaces and tabs.

Now, go to the Wharton Wireless Troubleshooter (WWT). Do the same thing. You’ll notice a lot more whitespace at the top.

(I’m not picking on some random developer; I did both of these applications.)

That’s the easiest way to show you what I’m talking about. That whitespace makes the output HTML page bigger, as each piece of whitespace is a character that you are sending to you user.

Well how much of a problem is that little bit of whitespace? Well frankly not much, but if you understand how it gets created, you realize it can become a very big deal.

It gets created in loops that, in the case of the WWT, are being called before the header is rendered. (It can happen anywhere in a page, but that’s where it’s happening in this application.) So in the case of the WWT a few loops are generating say 1 character of whitespace per iteration. But suppose for a moment that you were doing hundreds or thousands of iterations… In multiple loops… with multiple characters per iteration… in multiple included files.

Like everything in coding, it’s not that one little thing is so bad, it’s that the little bad things tend to aggregate together, form large bad things, gain sentience and run amuck!

So what can you do to prevent whitespace? I could tell you. But Ray Camden does such a better job of it in his article about whitespace.

I would just add two things.

  1. Ray mentioned a whole bunch of techniques you can use to reduce whitespace, but he doesn’t say what not to do to reduce it. (Awkward sentence, but bear with me.) You should not start formatting your source code to reduce the number of lines you use, the number of tabs, or the number of spaces. Readability of your code is still extremely important. Don’t change your code formatting to fix your html formatting. Find the spots that generate the whitespace. Then utilize the techniques he mentions to treat the problem topically. (My favorite method is to insert the <yo /> tag randomly throughout the source.)
  2. If you’re not sure if you have this problem with your page, or if you’re not sure how big an impact the whitespace is having, use the tools at Web Site Optimization to see how big your output page is. Alternately this can be accessed via the Firefox Web Developer Toolbar.

Jupiter Rising

I have found reason 531 to be glad I switched to developing in CFEclipse. Its name is Jupiter. It’s a code review tool for Eclipse. I find myself in complete disbelief, but I think I love a code review tool.

Why? What does do that makes me love it?

  1. It links annotations directly to the code via line numbers.
  2. Because of that linkage, you can open the code directly from the code comments.
  3. It allows several levels of severity and categories of comments.
  4. It allows for teams to collaborate on code reviews.
  5. It saves notes in an easily parsed XML file for external reporting.

Dave and I are experimenting with it. It looks like it will make all of the code reviews we have to do a little easier.

I have to thank Kola Oyedeji who made some observations about a previous post of mine regarding code reviews.

Squidhead Swims On

I’ve done three updates to Squidhead since the last time I blogged about it. Two of them were pretty major so I figured I would squawk some more about it.

First, I haven’t forgotten about adding support for other DBMS’s other than Microsoft SQL. I haven’t done it, but I have re-architected Squidhead slightly to make it a bit more possible to do so down the road. There’s one more step I need to take to open that up, which is focusing on primary key’s rather than identity. I know it should work, but I’m just not ready to pull the trigger on it.

Second, I’ve added quite a few features around the main unique feature of Squidhead, stored procedures. The whole focus of Squidhead is pulling in user created stored procedures and creating the ColdFusion code to support them. The recent changes I made allow Squidhead to properly handle store procedures that return multiple result sets. Alternately it can handle multiple output parameters, from the stored procedures.

Third, I’ve got a Build a Blog in 15 minutes presentation in the works. It’s a respectful homage, to Joe Rinehart’s
YouTube presentation on ModelGlue. I figure it’s effective in getting the feature set across, and appropriate since Joe’s presentation got me into code generation and frameworks in the first place.

Finally, I have a pretty good idea of what’s coming down the pike for Squidhead. Before I add support for other DBMS, I’m going to try and flush out the feature set, so as to avoid writing multiple versions in tandem. I prefer to port over the full version to other databases. My current list of updates includes support for foreign and primary keys. I’m also looking to add some form validation. That being said, if anyone has any thoughts, I’m very open to them.

JVM Update and LDAP SSL

I had a problem this week due to recent updates for DST. LDAP over SSL stopped working. It took me a fair amount of time to track down the answer, so I figured I would share.

Basically, the secure certificates store is tied to the JVM, not to ColdFusion or even JRUN. So when you update the JVM you lose a bunch of Certificate Authorities in your keystore (I assume since the file is so much smaller) and you lose any custom Certificate Authorities you may have added.

I found the solution at via a Google search at sagewire.org (JVM upgrade breaks secure CFLDAP connections), but basically the solution is to copy your former copy of the cacerts files to the new JVM’s location, then restart ColdFusion.

Scorpio in August?

I don’t know if anyone checked out the new Scorpio wallpapers posted by Ben Forta, but in the lower right there is a line “<8 : 2007 >.” (See the blue wallpaper .)

I seem to remember reading this speculation somewhere else, but a quick Googling yielded nothing. I think that’s a pretty decent sign that Adobe is targeting August for ColdFusion 8. Woohoo. Good news to those of us that want to deploy apps for a new school year.

Either that or they’re screwing with us. If that is the case I say: “Shame on you, Tim Buntel. Shame.”

Poor, Slightly Misunderstood, Squidhead

I finally got around to listening to the ColdFusion Weekly Podcast on February 12th. Squidhead was mentioned – WoooHooo! Wait a minute from the description it seems like Squidhead just creates CRUD + list stored procedures. The key to my disappointment is the word “just.” Squidhead doesn’t just generate stored procedures. It also reads in stored procedures that you create. So sure, it scaffolds the basic CRUD and list actions building stored procedures and CFC’s but also builds CFML from user defined stored procedures.

So for example, you have a table, person, with columns personid, username, password, first and last name. You run Squidhead once, you get the 4 CRUD procs, plus a DAO CFC to call them, then you get a list proc, plus a gateway CFC to call them. But then you go back and write a procedure “usp_person_select_by_username” because you would rather do that then select by identity. You run Squidhead again; it adds “select_by_username” function to the person DAO CFC.

But let’s take it one step further, suppose you write a stored procedure named “usp_person_auth” that takes the username and password and checks them as an authentication routine. Run Squidhead again. You’ll now have an “auth” function in your person gateway CFC.

The idea here is to do the database work in the database, and not have to do the manual work of writing the cfml calling code. Sure, it creates stored procedures, and that is a leg up, but it also lets those of us that like starting in the database an even higher leg up… (not sure if that’s the right modification of that metaphor.)

Anyway, don’t take this as a swipe at Matt and Peter. I’m glad to have some exposure in the ColdFusion Weekly Podcast. It’s my bad that I haven’t been publicizing Squidhead better.