181477 - Page with Last-Modified and no Etag HTTP header halts when reloaded

Status: RESOLVED WORKSFORME

(Core :: Networking: Cache, defect)

Description

[Sérgio Siegrist]

User-Agent:       Mozilla/4.0 (compatible; MSIE 5.5; Windows 95)
Build Identifier: Mozilla/5.0 (Windows; U; Win95; en-US; rv:1.2b) Gecko/20021016

I will explain what happens, at the next fields. Please, read them. The ASP 
code of the page follows. You don't need do know ASP to understand the code, 
I'm sure.

<%
Sub GravaLog(x)
Set fs = CreateObject("Scripting.FileSystemObject")
Set f = fs.OpenTextFile("c:\teste.txt", 8, True)
f.WriteLine x
f.Close
Set f = Nothing
Set fs = Nothing
End Sub


NovaData = "Thu, 06 Jun 2002 17:10:00 GMT"

If NovaData = Request.ServerVariables("HTTP_IF_MODIFIED_SINCE") Then
	Response.Status = "304 Not Modified"
	GravaLog "No need to serve."
	Response.End
End If

Response.AddHeader "Pragma", "no-cache"
Response.Expires = 0
Response.AddHeader "Cache-Control", "private, must-revalidate"
Response.AddHeader "Last-Modified", NovaData
GravaLog Now

For Each Campo in Request.ServerVariables
	Response.write "<p>" & Campo & " = " & Request.ServerVariables(Campo)
Next
Response.Write "<hr>" & Now
Response.Write "<hr>" & Request.ServerVariables("HTTP_CACHE_CONTROL")
%>

Reproducible: Always

Steps to Reproduce:
1. Call the url. The page is stored at the cache.
2. Reload the first time. Last-Modified date hasn't changed, thus the server 
sends "304 Not Modified" status to the browser with no content, and the page is 
displayed from the cache. Correct.
3. Reload the second time. Wait forever...
4. Reload once again. A new page is retrieved from the server, and stored at 
the cache. You may now repeat the step 2 and so on.
Actual Results:  
Probably, after the first reload (step 2), the page is displayed from the cache 
and the file at the cache is cleared (I don't know how to check this). The 
second reload (step 3) retrieves the cleared file from the cache, and halts.

Expected Results:  
Mozilla should display the file from the cache at each reload, without clearing 
the file at the cache.

This bug may affect other bugs I found at Bugzilla another day (I don't 
remember which) concerning images that don't display when reloaded or revisited.

This bug affects applications that have cache-control, that is, those that 
don't need to provide new data (such as requery databases) once the cached page 
contents are still valid. Isn't it important?

Comment 1

[Sérgio Siegrist]

Maybe this bug has something to do with 
http://bugzilla.mozilla.org/show_bug.cgi?id=121084

Comment 2

[Sérgio Siegrist]

I think I should add some information. The bug occurs as the web server runs 
Microsoft Personal Web Server. For instance, as the web server runs Microsoft 
IIS5 (W2K) there's no problem. 8¬p Maybe we should test a little more.

Comment 3

[Malcolm Rowe]

Dup of bug 231563?

Comment 4

[Wladimir Palant]

Confirmed. Mozilla always halts when reloading a page that has a Last-Modified
header but no Etag header. You have to press Reload twice to get a result.
AFAIKT this isn't related to bug 121084 or bug 231563.

Tweaking summary...

Comment 5

[Darin Fisher]

-> default owner