[LONG] Re: Illegal content in request

acassin@cs.mu.oz.au
Mon, 10 Nov 1997 11:55:59 +1100 (EST) 

[apologies for such a long-winded and cryptic bug report :) ]

On  7 Nov , Gisle Aas wrote:
>> I am having _some_ requests (sorry, I cant publish the code)
>> fail due to an 'Illegal content in request' and debugging in
>> LWP::Protocol::http::request() shows ref($contRef) eq 'LVALUE' 
> 
> Hard to tell without some code.  I have no idea what to do to get a
> reference to an LVALUE in perl.  I wish I did.

You and me both. I sure wish I knew what was going on. The program in
question obtains a set of urls (from ~/.netscape/bookmarks.html) and
visits them in turn checking to see if they have bytewise-changed
(using If-Modified-Since when possible). The following traces show
$content and $contRef in LWP::Protocol::http::request use'ing
Devel::Peek

Early on during the run, the requests proceed just fine:
--- HTTP::Request=HASH(0x140656cd8) ---
GET http://titan.lib.unimelb.edu.au/collections/mathematics/MSLib.html
Pragma: no-cache
Accept: text/html, image/*, www/unknown
Host: www.lib.unimelb.edu.au
If-Modified-Since: Thu, 30 Oct 1997 17:04:09 GMT

-----------------------------------

content is:
SV = PVIV(0x140683808)
  REFCNT = 2
  FLAGS = (PADBUSY,PADMY,POK,pPOK)
  IV = 0
  PV = 0x140692da8 ""
  CUR = 0
  LEN = 1
contRef is:
SV = RV(0x1406569b8)
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,ROK)
  RV = 0x14066aea8
SV = PVIV(0x140683808)
  REFCNT = 2
  FLAGS = (PADBUSY,PADMY,POK,pPOK)
  IV = 0
  PV = 0x140692da8 ""
  CUR = 0
  LEN = 1
LWP::IO::write: Write 277 bytes: 'GET http://titan.lib.unimelb.edu.au/collections
/mathematics/MSLib.html HTTP/1.0^M
Pragma: no-cache^M
Accept: text/html, image/*, www/unknown^M
From: acassin@cs.mu.oz.au^M
Host: titan.lib.unimelb.edu.au^M
If-Modified-Since: Thu, 30 Oct 1997 17:04:09 GMT^M
User-Agent: HotMarks/1.0^M
^M
'
LWP::IO::read: HTTP/1.0 304 Not modified
Date: Sun, 09 Nov 1997 23:47:50 GMT
Server: NCSA/1.5

but then, about halfway through the bookmarks this happens:
--- HTTP::Request=HASH(0x140707818) ---
GET http://www.troopers.demon.co.uk/text.htm
Accept: text/html, image/*, www/unknown
Host: www.troopers.demon.co.uk

-----------------------------------


content is:
SV = PVLV(0x140702908)
  REFCNT = 2
  FLAGS = (PADBUSY,PADMY,POK,pPOK)
  IV = 0
  NV = 0
  PV = 0x1406ddea8 ""
  CUR = 0
  LEN = 1
  TYPE =
  TARGOFF = 0
  TARGLEN = 0
  TARG = 0x0
SV = 0
contRef is:
SV = RV(0x1406569b8)
  REFCNT = 1
  FLAGS = (PADBUSY,PADMY,ROK)
  RV = 0x14066aea8
SV = PVLV(0x140702908)
  REFCNT = 2
  FLAGS = (PADBUSY,PADMY,POK,pPOK)
  IV = 0
  NV = 0
  PV = 0x1406ddea8 ""
  CUR = 0
  LEN = 1
  TYPE =
  TARGOFF = 0
  TARGLEN = 0
  TARG = 0x0
SV = 0

The debugging code in LWP::Protocol::http::request() looks like this:
    # If we're sending content we *have* to specify a content length
    # otherwise the server won't know a messagebody is coming.

    my $content = $request->content;

    # All this mess because we want to support content as both scalar,
    # ref to scalar and ref to code.
    my $contRef;
    if (defined $content){
    $contRef = ref($content) ? $content : \$content;
    print STDERR "content is:\n"; Dump($content);
    print STDERR "contRef is:\n"; Dump($contRef);
    if (ref($contRef) eq 'SCALAR') {
        $request->header('Content-Length', length $$contRef)
          if length $$contRef;
    } elsif (ref($contRef) eq 'CODE') {
        Carp::croak('No Content-Length header for request with content')
          unless $request->header('Content-Length');
    } else {
        Carp::croak("Illegal content in request ($content)");
    }
    }


Any ideas?

Andrew Cassin
acassin@cs.mu.oz.au