I have a web role in which I have the following code snippet:
var webRequest = HttpWebRequest.Create(path);
webRequest.Timeout = 5000;
webRequest.Method = "GET";
It's requesting a resource from Azure CDN, so path is something like the following:
https://<uniqueString>.vo.msecnd.net/<container>/path/image.png
I noticed that the response I am getting is cached, because I checked in Fiddler, going directly to the resource, that I have different headers from the following webResponse.
var webResponse = (HttpWebResponse)webRequest.GetResponse();
So HttpRequest enforces some kind of CachePolicy here?
I tried replacing the first snippet with the following code but it didn't work:
WebRequest.DefaultCachePolicy = new RequestCachePolicy(RequestCacheLevel.NoCacheNoStore);
var webRequest = HttpWebRequest.Create(path);
webRequest.Timeout = 5000;
webRequest.Method = "GET";
Only when I did set the headers it did work, so the following code gives me the correct response:
var webRequest = HttpWebRequest.Create(path);
webRequest.Timeout = 5000;
webRequest.Method = "GET";
webRequest.Headers.Set(HttpRequestHeader.CacheControl, "max-age=0, no-cache, no-store");
Why HttpWebRequest was enforcing cache in the response and why the DefaultCachePolicy did not work after I tried to set it, except only explicitly setting the headers worked?
Note: The response was only caching when requesting the resource over HTTPS
Update
To be sure I've just added a query string parameter to the requested resource URI, putting the time ticks. Is this enough for me to not have cached responses?
