On Tue, Nov 25, 2008 at 11:13 AM, Lianghua <[EMAIL PROTECTED]> wrote:
> > I know that we can use HttpWebRequest to try to get the response, but > most of time, when the URL is not available, I need wait for a timeout > or 404 error. Is there any other way to complete this? Specially I > need a quick way to do so, instead of waiting for time out? > > thanks. > > Leon So change the timeout to a small value. You should also use the HEAD ( http://www.w3.org/Protocols/rfc2616/rfc2616-sec9.html) method. 9.4 HEAD The HEAD method is identical to GET except that the server MUST NOT return a message-body in the response. The metainformation contained in the HTTP headers in response to a HEAD request SHOULD be identical to the information sent in response to a GET request. This method can be used for obtaining metainformation about the entity implied by the request without transferring the entity-body itself. ****This method is often used for ***testing hypertext links for validity***, accessibility, and recent modification****. The response to a HEAD request MAY be cacheable in the sense that the information contained in the response MAY be used to update a previously cached entity from that resource. If the new field values indicate that the cached entity differs from the current entity (as would be indicated by a change in Content-Length, Content-MD5, ETag or Last-Modified), then the cache MUST treat the cache entry as stale.
