How do I convert a URLpath to SysFilePath if I have the file's URL?

I'm in a writing mood, so decided to tackle this question:

One of your pages talks about how to get a/the filepath from a URL path; so if I know the URL where a file is, can I obtain the (absolute) path, on the server, where this file is? I will gladly supply more details, I just now would like to know if this is doable, in general. thanx!!

This is a hard question to address. First, I don't intimately remember all my 560 blog posts, and the user did not let me know which one he was referring to. Second, I am not aware which technology the user is referring to. Does he want an answer for Flex? Or AIR? Or ColdFusion?

I decided to tackle answers in all three technologies. Assuming you have a URL, how do you get the system path to the file?

In CF, I believe expandPath should give you the absolute file path. Just strip out the domain name of the URL before calling it. In Flex I do not believe you can access the file path of the server, nor the client. The security sandbox prevents such access.

In AIR, a URL to a local file is also the absolute path; but you wouldn't have access to the absolute path on the server.

So, in summary, for ColdFusion use the expandPath function. In Flex or AIR, you need a convoluted work around, such as a server side service or a desktop server piece like Merapi.

You can always ask me your question here, or stop by a Flextras Friday Lunch session and ask me in person.