Archive for the ‘Web Development’ Category

We’ve been having some issues with people committing to the subversion server without entering a comment. Its easy to to require a comment using a “pre-commit” hook, which is a script that runs before someone’s changes are committed to the repository. A sample commit hook is supplied with subversion that you can enable to require comments. The problem is it doesn’t report back any error message (users will just get a generic “commit failed” in their svn client), and there is no provision for making sure the comment is a minimum length.

I tried to modify the example script, but I’m pretty bad with shell scripting. I looked for a perl one, which I knew I could easily modify, but couldn’t find any. So I whipped this one up:
Continue reading ‘Require subversion comments – a perl pre-commit hook’ »

I’ve used this trick several times when needing to sort data into groups. For example say you need to sort car classified listings by price. Some of the dealers enter a price of “0” for their listings. When sorting by lowest price, you want the listings that actually have a low price to come first, rather than than the cars costing $0 (hey, I’d like to buy your free car, thank you).
Continue reading ‘SQL CASE statement with NULLs’ »

In a couple application’s I’ve found it necessary to send a user to another ColdFusion server, but still maintain their current session. Usually this is for a payment gateway, or encryption process, or some other kind of functionality that only exists on that other server. In CF5 this was pretty straight forward. You set up both servers to access the same client variables database, then provide an HTML link (or a cflocation tag) that jumps the user to the other server, keeping their CFID and CFToken on the URL. The second server will see those URL values and use them, instead of generating new CFID/CFToken values as it normally would. I had both servers setup something like this:
Continue reading ‘Using CFID and CFToken to jump between ColdFusion servers’ »

I needed to clean out some orphaned records from a MySQL database today. I thought this would be as simple as

  SELECT subTable.ID from subTable
  LEFT OUTER JOIN parentTable ON subTable.parentID = parentTable.ID
  WHERE  parentTable.ID IS NULL

But this resulted in an error:
Continue reading ‘Cleaning up orphaned records in MySQL’ »

There has been some discussion on various ColdFusion discussion lists regarding the maximum heap size you can allocate to ColdFusion/Jrun. Windows allows a process to grab as much as 2GB of contiguous memory. Subtracting out memory for overhead, permgen memory, etc. you are left somewhere with 1.5-1.8GB available for general heap memory.

We were considering moving one of our clients to a Linux server if that would allow us to allocate more memory to the heap. In my research, it seemed the opinions were split about 50/50 as to if Linux would allow us to allocate more than 2GB of memory. So I decided to test for myself. I placed an order for 4GB of memory and waited for them to arrive.

Once I had swapped out my 4 256MB modules for the 4 1GB modules, I increased the heap size (Xms and Xmx options in jvm.config) to 2048 and restarted the server. No problems! I kept increasing by 100mb at a time until I reached 2600 – there it failed to start, so I backed it down to 2500mb. With the permgen and other overhead, Jrun was taking up about 2950Mb of memory – indicating a 3GB limit. I have been running this way for a few days now with no problems.

Your experience may vary of course, depending on what memory options you have in your jvm.config file. I did not need to do anything special other than bump up the Xms and Xmx values.

So the short answer is Yes, you can allocate about 1GB more memory to ColdFusion when running on Linux.

The command line statistics program supplied with ColdFusion, cfstat, has never worked for me. I’ve never tried it on Windows, but I have tried it on Linux on versions 6 and 7, and now version 8.

A little digging around told me why it never worked in CFMX 6-7. Apparently the cfstat script was looking for a particular jar file using a relative path – so it only worked if you were calling it from within the ColdFusion installation directory, which I guess I never did. Looking at the cfstat script in version 8, I can see they specify the full path.

But cfstat still wasn’t working for me in CF8, I got this error message:
Continue reading ‘Getting cfstat to work’ »

On a recent project I needed to be able to rotate PDF documents. I thought for sure there would be something like <cfpdf action="rotate"></cfpdf>, but I was surprised there was no such option. I came across ColdFusion 8’s built in DDX processing feature, and thought I would just do it with that. Turns out the limited DDX engine in ColdFusion does not include the ability to rotate.

But there is a way! The iText class libraries are bundled with ColdFusion, and they are capable of turning your PDFs on end.
Continue reading ‘Rotating PDFs in ColdFusion’ »

Today I needed to get the size of a file I’m working with. If the file was being uploaded from an html form, I can get the file size after calling <cffile action="upload"></cffile> by looking to the cffile.fileSize variable. But in this case, my file was uploaded long ago.

It is possible to get the file size by using <cfdirectory action="list" directory="parentDir"></cfdirectory>. This will return a query containing entries for each file in the directory. One of the columns in the query will be the file size. You can narrow it down to returning only your file by specifying a filter.

<cfdirectory action="list" directory="parentDir" filter="myfile.txt"></cfdirectory>

I don’t know if this filter is applied before or after the directory contents are read in. Anyway I didn’t really like this approach, maybe I’m just spoiled by Ruby’s simplicity ( File.size(“myfile.txt”) ), but this seems like the round about way to get a file’s size.

There is a more elegant way to do it with Java, and its very simple. If we create a Java “file” object, we can call the length() method on that object to get the size of the file in bytes. You can do it in one line.
Continue reading ‘Getting the size of a file in ColdFusion’ »

I was recently working with some java libraries that looked to a system property for a configuration setting. The sample Java app that came with the library was setting the system property on the command line. Their windows .bat file and Linux shell script both launched the java app like this:

java.exe -cp .;package1.jar SampleApp

Note the -D option, that sets the java system property to 500. If you are not familiar with java system properties – they are kind of like a global variable, accessible via any java code.

I didn’t want to have to edit my Jrun start up options and add the -D option on there. That option is not even possible for many ColdFusion users. But setting a system property via ColdFusion is actually very easy.
Continue reading ‘You *can* set Java system properties via ColdFusion’ »

I was creating a form the other day that had 3 form fields, layed out vertically on top of one another. I switched the first field to be a cfinput, so I could use the autosuggest feature:

cfinput example 1
Continue reading ‘ColdFusion 8 auto-suggest shows through other form fields’ »