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From: Robert Chou rob_chou@bigfoot.com
To: "'java-apache-users@list.working-dogs.com'"  java-apache-users@list.working-dogs.com
Subject: getDateHeader("If-Modified-Since") always returns -1
Date: Wed, Jul 21, 1999, 8:49 PM


hi All,

I'm running Apache 1.3.6 and JServ 1.0b5 under Windows NT 4.0
and have noticed the following servlet behavior:

1. getHeader("If-Modified-Since") always returns null.
2. getDateHeader("If-Modified-Since") always returns -1.

I did a clean install of apache, jserv, and gnujsp 0.9.10 on a new machine and sent
the following request:

GET /webbuilder/snoop.jsp HTTP/1.0
Host: localhost2
If-Modified-Since: Sun, 06 Nov 1998 08:49:37 GMT
If-Modified-Since2: Sun, 06 Nov 1998 08:49:37 GMT

snoop.jsp is a sample jsp file included with gnujsp which happens to dumps headers.
For some strange reason, "Host" and "If-Modified-Since2" is printed, but not
"If-Modified-Since".  I then wrote a servlet to output this header with no luck.
getHeader always returns null.  I then sent the above request to a static html
file and got a 304, which seems to show that apache got it, at least.

Looking at the source, I found a line in apache which unset "If-Modified-Since",
but nothing else interesting (although my first time looking at the code, 
so no guru).

Anyone have seen this before?
thanks,
rob

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From: Henner Zeller zeller@stud.fh-heilbronn.de
To: Java Apache Users java-apache-users@list.working-dogs.com
Subject: Re: getDateHeader("If-Modified-Since") always returns -1
Date: Thu, Jul 22, 1999, 3:37 AM


The 'If-Modified-Since' header is evalutated by Apache itself and thus
your servlets do not get it. 

Basically, if Apache gets a request like this, it invokes the 
'long getLastModified()' - method of your servlet which must return the 
milliseconds since 1970 when the content (which would be generated) has 
last changed and invokes the doGet()/doPost() method only if the content
is newer. The default implementation of getLastModified() always returns a
value which requires to call do[Get/Post](). 

You find a longer descripton of this
behaviour at Jason Hunters Book pp 67,68

ciao,
  -hen
---
Henner Zeller                                 zeller@fh-heilbronn.de
 PGP pub key [77F75B39]: finger zeller@lemming.stud.fh-heilbronn.de 

 If Microsoft is the answer, it must have been a VERY silly question.