Chris
Sun Nov 30 02:11:19 CST 2003
yeah, an image error / redirection should only affect that one image, even
if it fails...
unless maybe the load balancer is borked & mixing up responses.
very strange stuff...
When IIS sends a redirect, I guess it typically gets processed "invisibly"
by IE because a) the header of the HTTP response includes an "object moved"
status and a URL for the new location, so it knows that it's a redirect from
the beginning. b) the page does, however, also contain a tiny bit of
generic, IIS-generated HTML that, I think, includes a meta-refresh and/or a
link that says something like"click here to view what you were looking for".
I don't know, however, if a page had a redirect in the header AND contained
a large amount of data, such as a bunch of image tags, would IE attempt to
render / load the entire page and THEN redirect to the new location or would
it see the initial 302 and halt all content download / rendering.
The former, if the browser behaves that way, could cause a meta-refresh like
behaviour.
sorry, too much beer makes me ramble.
-Chris
<anonymous@discussions.microsoft.com> wrote in message
news:01b601c3b6b0$5ae8ee60$a101280a@phx.gbl...
> No, no custom errors, just the 500-100 script for
> trapping asp errors.
>
> I think we've narrowed this down to the load balancer. A
> test server, configured to run outside of the load
> balancing cluster doesn't exhibit any of these problems.
> Somehow I think requests are getting munged by the load
> balancer.
>
> But either way--if an image embedded on a web page
> returns any sort of 302 client-side redirect to any other
> page, error page or not, this shouldn't cause the entire
> web page to redirect should it? I thought browsers are
> be smart enough to ignore redirects from an image
> included on a web page, not try to redirect the whole
> browser...
>
> Scott
> >-----Original Message-----
> >Are your custom error pages also using images from a
> similar sort of
> >image/thumbnail setup.
> >
> >URL-based Custom Errors sent by ASP use a 302
> Redirection response to the
> >browser.
> >
> >--
> >//David
> >IIS
> >This posting is provided "AS IS" with no warranties, and
> confers no rights.
> >//
> ><anonymous@discussions.microsoft.com> wrote in message
> >news:004b01c3b5c5$9273c030$a101280a@phx.gbl...
> >Yes, hiding the actual location of images this way.
> >
> >The strange thing is that this is happening when the
> >images (thumbnails) are embedded onto another web page
> >(which loads fine - http 200 / ok). I would expect the
> >redirect to the "cannot find server" or whatever standard
> >built-in error page, but not when the image is embedded
> >into a web page which is loading fine.
> >>-----Original Message-----
> >>Sounds like a packet sniifer is in order to see if
> >there's any sort of
> >>redirection being passed in the HTTP headers.
> >>
> >>I assume you're using the ADO stream routine so that you
> >can protect/hide
> >>the actual thumb JPGs... I guess if that script broke
> >then the browser would
> >>get redirected to the standard error page (for that one
> >image element), but
> >>that should only show up as a familiar red-x icon.
> >>
> >>-chris
> >>
> >>
> >>
> >>"Scott" <anonymous@discussions.microsoft.com> wrote in
> >message
> >>news:017501c3b456$dc2e12e0$a501280a@phx.gbl...
> >>> This may or may not be an IIS issue.
> >>>
> >>> I provide an image hosting service, using an Coyote
> >e350
> >>> load balancer, and a cluster of 8 Windows 2003 Server
> >>> (standard) web servers.
> >>>
> >>> The website (www.domain.com) is set up on the load
> >>> balancer as a "sticky" cluster.
> >>>
> >>> Thumbnails are provided by a separate web site
> >>> (thumbs.domain.com), on a separate "virtual" cluster
> on
> >>> the load balancer that doesnt' provide sticky
> sessions.
> >>>
> >>> The problem we're running into is a handful of users
> >(10
> >>> out of 400,000 active users) are experiencing
> automatic
> >>> page refreshes when viewing "albums" which display
> >their
> >>> images using the thumbnail service.
> >>>
> >>> In most cases the entire HTML of the page will render,
> >and
> >>> a few thumbnails will display (there are up to 20 per
> >>> page), then the page refreshes itself, sometimes
> >>> repeatedly (we've been told 5-10 times by users), but
> >>> usually ending with a "server cannot be found page"
> >(this
> >>> is not a "friendly http" message, but the standard IE-
> >>> generated error page when a domain cannot be contacted
> >(so
> >>> disabling friendly HTTP errors has no effect).
> >>>
> >>> The thumbnail service (again, different site,
> >different IP
> >>> for the farm cluster), uses an ASP script to deliver
> >>> thumbnails, using response.binarywrite from an ADO
> >stream
> >>> object which reads/loads the thumbnail JPG. Nothing
> >>> fancy. Content types of the response are correctly
> set
> >>> to "image/jpeg". The thumbnails themselves are
> >requested
> >>> as an ASP script, like: IMG
> >>> SRC="thumbs.domain.com/index.asp?id=12345"
> >>> for example. The 12345 is a database identity
> >>> referencing the record that contains the local file
> >path
> >>> to the thumbnail. All errors are trapped on the
> >thumbnail
> >>> scripts, and text messages (with text/plain content
> >type)
> >>> are delivered when an error occurs.
> >>>
> >>> We have been able to reproduce this problem so far as
> >>> seeing the page refresh one time automatically.
> >>>
> >>> This happens with IE 5 to 6.
> >>>
> >>> There is no javascript that changes the current URL,
> >and
> >>> disabling "active scripting" seems to have no effect.
> >>>
> >>> There is javascript that adds a clipboard copy, and
> >>> a "select all/select none" functionality for
> checkboxes
> >>> for each thumbnail.
> >>>
> >>> Enabling/disabling cookies has no effect.
> >>>
> >>> We haven't had reports of this happening anywhere but
> >IE,
> >>> although 95% of our users are on IE, so that might
> >just be
> >>> a numbers game.
> >>>
> >>> I'm thinking that this is related to the way we
> request
> >>> thumbnails--that potential errors are "messing with"
> >the
> >>> current page rendering and tricking the browser into
> >>> trying to redirect to some unknown page or refresh.
> >But I
> >>> wouldn't think any type of response for an IMG SRC
> >request
> >>> could affect the entire web page.
> >>>
> >>> Sometimes this problem won't happen to a user, but
> then
> >>> after viewing 4 or 5 album pages, it starts in, and
> the
> >>> site basically becomes unusable.
> >>>
> >>> I've asked users to verify that they don't have a
> >virus,
> >>> ad-blocking software, spyware, etc. A few users have
> >been
> >>> unable to use our site because of this problem.
> >>>
> >>> Has anyone run into this before?
> >>
> >>
> >>.
> >>
> >
> >
> >.
> >