将所有请求的URL重写为ASP.NET 3.5中的文件夹-IIS 7

Question

We have a number of existing clients that point to urls like:

http://sub1.site.com/images/image1.jpg

/images is a virutal directory that points to a directory that actually contains image1.jpg on that server.

We're moving all of the files out of this directory and onto a separate server that will not run this same application.

The file will now only be available at:

http://sub2.site.com/image1.jpg

What is the best way to make it so clients requesting http://sub1.site.com/images/image1.jpg will get the content that now resides at http://sub2.site.com/image1.jpg ?

A few requirements:

• We need the actual content to be returned through that url - not a 302 response.
• We cannot modify the IIS server configuration - only the web.config for the site
• Again, we're running asp.net 3.5

Thanks.

Answer 1

Not totally sure this would work, but you could setup URL Routing on the old site so all requests are sent to a handler and within that handler you could do a web request to get the file from it's new location.

I use a variation of the process to map image URLs to different locations and my handler does some database queries to get the mapped relationship and provide the correct image. I don't see why you could do a web request to get the image.

Answer 2

Since you are using IIS7, you can use the built in URL rewrite module .

You would want an inbound and an outbound rule to change \\images\\image1.jpg to \\image1.jpg

It can get pretty involved, but this should be rather simple.

Answer 3

Assuming you can add handlers to your site (as in add a DLL to your /bin directory in the site) and with the restriction that you can't send 302 responses for better performance, then alternatively you could write a custom handler to grab all requests that match that URL pattern, do the web request for the sub2.site image from the original site via web client code, then serve it back out of the original site, sub1.site.com.

See How To Create an ASP.NET HTTP Handler by Using Visual C# .NET for the very basics of creating and setting up a custom handler. Then use the HttpWebRequest to make the request of sub2.site.com, as in the guide A Deeper Look at Performing HTTP Requests in an ASP.NET Page . Plus a little other code to handle errors, timeouts, passing the image through with as little processing and memory usage as possible, etc.

Depending on the response time/lag between the two servers, this may be slow, but it would fit all your requirements. But if the point of moving the images to site 2 was for performance (CPU or memory) or bandwidth limitations, then this solution would nullify any gains — and would actually make things worse. But if they were moved for other business or technical reasons though, then this solution might be helpful still.

Answer 4

If you have other control over the server or anything upstream from the server, you could use mod_proxy (or similar Windows/IIS tool) to intercept those URLs and forward them to another server and respond back with the real request. Depending on your network configuration and available servers, this could be the simplest, best performing solution.

Can IIS be configure to forward request to another web server? on serverfault has a quick process and link for an IIS 7.5 solution.