I am trying to achieve something that you might typically use a hosts file for, but that isn't suitable here.
I want a Windows PC to refer to a local file (I can serve it from a web server at localhost if needed) when it attempts to fetch a certain remote file via HTTP. However, I need other files from that particular remote web server to be fetched as usual.
Any help appreciated.
The specific case is that I'm customising a web application which I don't own and can't run locally. It is a hosted web app, and custom css is added through a standard html text field, which is immediately applied to your production site. This of course limits my testing options.
So, I have been testing by applying a user-specified css file from my local machine. This works great in browsers that allow it.
I want to test old browsers that don't allow user-specified css, so I want to intercept all outbound requests to the remote css file and redirect them to a local css file (which I can refer to using file://, http://, whatever - I will do what I have to do. If the recommended method requires the local file to be served using http, I don't mind firing up a quick instance of Python's SimpleHTTPServer on a local port).
I can't redirect the entire hostname, because then the third-party site won't load at all. I just want to intercept requests to one particular URL and instead point at my local file.
I should also note that the remote web app does not allow the use of css import statements, because that is the obvious solution to this problem.