As a follow-up to recent postings about using Excel Web Query files (*.iqy) with Domino, here's the description of another problem I came across along with a solution.

It wasn't the problem Kathy was asking me about but it was a problem nonetheless. When I clicked the IQY link I saw this error:

The requested site is unavailable or cannot be found. Please try again later.

After trying lots of the obvious things I turned, once again, to HTTPWatch. After a bit of, ahem, sniffing about I noticed the problem. Compare these headers:

With those from a working .IQY form:

Notice the problematic IQY file doesn't cache. So IE downloads this executable "file", which is in fact a page of text, but doesn't store it on the hard drive. IE then tries to launch it, but can't as it doesn't exist on disk. Or at least that's my understanding of the problem. As a solution I added the following to the form's WebQueryOpen event:

I've no idea what significance the "private" bit has, but it's a legal value and seems to cause cacheing, which fixes the problem.

But why the different cache settings in the first place? Well, Kathy's form had some computed fields and @functions on it. My didn't. Nothing special at least. To be honest I can't work out exactly what Domino is doing. To cache or not to cache, that's Domino seemingly random decision. To add to the problem, an element of this behaviour is due to differing server versions. It's also down to Domino to decide whether to accept our new cache-control setting. I saw these headers on one server:

What am I getting at with all this? I'm not sure. Hopefully you've learnt something though. Whether it's how useful HTTP sniffing can be or that you can set headers when opening a form. Either way, it's been an interesting exercise for me. It's made me wary of using IQY files. Although I still think it's a handy little tool to have there's this quagmire of problems to navigate.

Another project I'm working on requires some cache magic and so it's high on my list of things to read up on. There might be more cache talk some time soon.