Here is my sample code:

<cfftp action="open"
    connection="test"
    server="ftp.osric.com"
    username="chris"
    password="********************"
    timeout="60"
    stoponerror="yes">
<cfftp
    connection = "test"
    action = "getFile"
    name = "downloadFile"
    transferMode = "binary"
    localFile = "S:\chris\handlebar-moustache.jpg"
    remoteFile = "handlebar-moustache.jpg"
    timeout="60">

Here’s the error message it produced:
An error occurred during the FTP getFile operation.
Error: getFile operation exceeded timeout.

However, the local file was still created (as a zero-byte file).

The solution, in my case, was to turn on passive mode (add attribute passive="yes" to the cfftp tag).

Active FTP vs. Passive FTP, a Definitive Explanation has a brief explanation of the differences between active and passive FTP.

The reviewers had clearly spent some time with the application, reviewing both the code and the interface. (I asked about this after the review, and one reviewer said he had spent 2-3 hours reviewing what was a relatively short and simple application. It is telling, I think, that attendance was voluntary–the reviewers in attendance were keen reviewers.) They got down to the level of detail where they brought up the date format (e.g. why did the developer use dd-mmm-yyyy instead of mm/dd/yyyy?).

The review was relatively structured while remaining casual in tone. They discussed CFCs, followed by other ColdFusion code, followed by user interface concerns and SQL. Each suggestion was backed up with a reason, e.g. avoid using evaluate() because it can lead to performance issues, or use mm/dd/yyyy because ~60% of the intended audience is most familiar with that format. In general, the topics covered fell into these categories: security, speed, standards/best practices, readability/maintainability, and user interface concerns.

It really seemed like a useful process to me. True, it added 12-18 developer hours to the project, but that is a small price to pay to avoid a possible security breach or server crash (not that any such vulnerabilities or flaws were found). The key, it seemed to me, was in the preparedness of the reviewers, who each came with comments in hand. Their preparedness, in turn, was helped by having basic guidelines as to what issues to look for.

This is peculiar, as my address is not the organizer specified in the iCal file, it is only the recipient of the iCal attachment. I’m going to keep looking into it, but I thought I’d mention it here in case anyone else is running into the same issue.

The two functions I’ve found online to assist in generating iCal files are:

• iCalUS (via CFLib.org)
• CF_ICAL (via Planet Source Code.

There are 5 unique conflicts possible, and it seems like I’m always forgetting one.

Here’s a ColdFusion function that I’ve been using to check the database for conflicts:

<cffunction name="hasConflicts" access="private" output="false" returntype="boolean" hint="Determines whether the specified start and end times have any conflicts">
<cfargument name="startTime" type="date" required="true" hint="Start datetime timestamp">
<cfargument name="endTime" type="date" required="true" hint="End datetime timestamp">
	
	<cfset var getConflicts = "">
	<cfset var myResult = TRUE>
	
	<cfquery name="getConflicts" datasource="#THIS.ds#">
		SELECT id
		FROM reservations
		WHERE (
			(
				start_timestamp >= <cfqueryparam value="#ARGUMENTS.startTime#" cfsqltype="cf_sql_timestamp"> AND
				end_timestamp <= <cfqueryparam value="#ARGUMENTS.endTime#" cfsqltype="cf_sql_timestamp">
			) OR (
				start_timestamp <= <cfqueryparam value="#ARGUMENTS.startTime#" cfsqltype="cf_sql_timestamp"> AND
				end_timestamp >= <cfqueryparam value="#ARGUMENTS.endTime#" cfsqltype="cf_sql_timestamp">
			) OR (
				start_timestamp < <cfqueryparam value="#ARGUMENTS.endTime#" cfsqltype="cf_sql_timestamp"> AND
				end_timestamp >= <cfqueryparam value="#ARGUMENTS.endTime#" cfsqltype="cf_sql_timestamp">
			) OR (
				start_timestamp <= <cfqueryparam value="#ARGUMENTS.startTime#" cfsqltype="cf_sql_timestamp"> AND
				end_timestamp > <cfqueryparam value="#ARGUMENTS.startTime#" cfsqltype="cf_sql_timestamp">
			)
		)
	</cfquery>
	
	<cfif getConflictingReservations.recordCount EQ 0>
		<cfset myResult = FALSE>
	</cfif>
	
	<cfreturn myResult>
</cffunction>

There might be a more elegant query, but this one works. I’m posting it here for my own future reference, and anyone else that might find it useful.

The application is a room reservation tool. The interface displays a table/grid of rooms and their availability throughout the day. The grid is a object, each room within the grid is an object, and each reservation within the room is an object. With 20 rooms and up to 4 reservations per room, there were easily up to 81 complex objects instantiated per page load. During testing, the pages often took 5-10 seconds to load. Under load, the pages took minutes to load. Memory use skyrocketed, and I had to run garbage collection manually via the ColdFusion server monitor to get it to respond to further requests.

I found Robert Munn’s series of blog posts:

• Object instantiation and heap size in ColdFusion
• Object instantiation and heap size in ColdFusion – Part II
• Object instantiation and heap size in ColdFusion – Part III
• Object instantiation and heap size in ColdFusion – Part IV

His observations are very similar to mine (although the decline in server performance, in my experience, was far more drastic).

I haven’t yet addressed the all the issues in the room reservation application, but as a proof-of-concept I re-created the interface using a single object—a ColdFusion query object—rather than the original hierarchy of objects-within-objects-within-objects. The new page loaded 10 times faster than the original.

I was concerned that I hadn’t really found the problem, though. My new code was circumventing all the object instantiation, but it was circumventing a lot of other logic, too. Before starting a major revision, I needed more evidence that object overhead was indeed one of the performance issues.

I created 2 pages that do exactly the same thing: one page reads an XML file of U.S. state data and loops through it to find the Great Lakes State (Michigan) and the Keystone State (Pennsylvania). One page creates a state object for each record in the XML, and the other just works with the XML data directly:

• Using objects: 129 milliseconds
• Without objects: 1006 milliseconds

(Times listed are averages for 1000 runs. The file are here: ColdFusion objects performance test)

Does this mean developers should avoid object-oriented code in ColdFusion? I don’t think so. But I don’t think developers should create objects willy-nilly when they aren’t necessary. The room reservation system, for example, doesn’t need to create 80 reservation objects just to display a list, but it makes sense to create a single reservation object once the user drills down to view or edit the specifics of a single reservation.