[2008] Is there an event when navigating in ASP.NET?

Yeah I know my title may be a little oversimplified.

What I want to know, is how can I detect when a user is naviating to a different page from my ASP.NET application, but them just clicking a standard anchor tag. There is no postback involved so I am not sure if there is actually a valid method without a bunch of weird client side JS wireup to the document unload or something.

The goal is to rewrite HTTPS as HTTP when navigating from a sercure section of the site, to a non secure section. The issue is that there are relative links on the page, so if you are on an HTTPS page, and there is a href link to "../home.htm" it will resolve to HTTPS, which I want to prevent.

Currently I had to change the hrefs all to fully qualified URLs, but that is not the best way to do it, so I want to know how I can do it with relative paths.

I tired some of the events in the global.asax, but they didn't seem to fire off, likely because there is no postback and the ASP.NET runtime is not being invoked for these simple a href links.

You should look into creating an HTTP handler which will look at the URL that has been requested, the Referrer URL and using 'whatever logic' perform the 301 or 302 as required.

I'll look into it, but I am not writing any more code unless this client pays me to do so :)

But it's quite simple. You only need to create a set of 'mappings' in your web.config (or somewhere else) to indicate whether your page is under https or http. When a request comes in, have your handler look at it, check the security level and redirect accordingly. Just a few lines...

does this also work when the navigation location will be outside the ASP.NET application?

For example, the app is at

https://www.somesite.com/aspnetapp/default.aspx

On that page is a standard anchor tag that links to

../somepage.htm

which will resolve to

https://www.somesite.com/somepage.htm
when I want it to be
http://www.somesite.com/somepage.htm

I just want to make sure it is not going to matter that where I am navigating to is not in the directory structure of the asp.net application.

It won't work for that, unfortunately. You'll need to create a separate HTTP Handler for the root of the site, mapping .html extension to the ASP.NET ISAPI DLL so that the HTTP Handler can hook into the process pipeline.

If this is too complicated, then there may be other equally obscure ways to do this. For example, you could run all of the .NavigateUrl assignments through a method before assigning them to hyperlinks, and letting the method resolve them to full URLs.

Another way would be to use javascript to attach a method (onclick) to all the hyperlinks on a page and everytime one is clicked, have it call a web service to perform the URL resolution for you. Slow.

yet another method was to hard code the 15 links on the page to http. ;)

Makes my life a bit harder between the dev and production site, but its just the links in this one template file, I never need to click them on the dev box.

Oh yeah, there's that too. :p