Mailing List Archive: ModPerl: ModPerl

Edit HTTP response headers

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jamuse at gmail

Apr 21, 2008, 1:30 PM

Post #1 of 6 (728 views)
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Edit HTTP response headers

I wrote a simple module that parses the HTTP response body and updates
certain text. I want the script to be able to parse and manipulate the HTTP
response headers as well. For example add secure and HttpOnly flags to
certain cookies, or add a redirection when a 500 error code is returned. The
code I have so far is:

======================================================================================
package TE::ST;
# $Header:$
use strict;
use warnings;

use Apache2::Filter ();
use Apache2::RequestRec ();
use APR::Table ();

use Apache2::Const -compile => qw(OK);

use constant BUFF_LEN => 1024;
no warnings qw(redefine);

sub handler {
my $f = shift;

while ($f->read(my $buffer, BUFF_LEN)) {
# Disable autocomplete
$buffer =~ s/login method="post"/login method="post"
autocomplete="off" /g;

$f->print($buffer);
}

return Apache2::Const::OK;
}
1;
======================================================================================

when using f->read it appears as though the HTTP headers are not including.
I know err_headers_out should have access to the headers, but is there a way
to force f->read to access the HTTP headers as well? I've seen the set and
add methods for err_headers_out, but can someone point me to a code example
of either editing the HTTP headers or rewriting the server response when
certain response codes are received?

Thanks.

perrin at elem

Apr 23, 2008, 7:28 AM

Post #2 of 6 (699 views)
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Re: Edit HTTP response headers [In reply to]

On Mon, Apr 21, 2008 at 4:30 PM, J Amuse <jamuse[at]gmail.com> wrote:
> when using f->read it appears as though the HTTP headers are not including.
> I know err_headers_out should have access to the headers, but is there a way
> to force f->read to access the HTTP headers as well?

No, the headers are not part of the response body.

> I've seen the set and
> add methods for err_headers_out, but can someone point me to a code example
> of either editing the HTTP headers or rewriting the server response when
> certain response codes are received?

http://perl.apache.org/docs/2.0/user/coding/coding.html#Generating_HTTP_Response_Headers
http://perl.apache.org/docs/2.0/user/handlers/filters.html#Introducing_Filters

- Perrin

torsten.foertsch at gmx

Apr 23, 2008, 8:48 AM

Post #3 of 6 (695 views)
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Re: Edit HTTP response headers [In reply to]

On Mon 21 Apr 2008, J Amuse wrote:
> I wrote a simple module that parses the HTTP response body and updates
> certain text. I want the script to be able to parse and manipulate the HTTP
> response headers as well. For example add secure and HttpOnly flags to
> certain cookies, or add a redirection when a 500 error code is returned.

You can modify outgoing headers up to the time they are sent. So, at the very
first call to your filter you can modify the status code as well as outgoing
headers. See Apache2::POST200 on CPAN.

Torsten

--
Need professional mod_perl support?
Just hire me: torsten.foertsch[at]gmx.net

jamuse at gmail

Apr 27, 2008, 6:18 AM

Post #4 of 6 (678 views)
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Re: Edit HTTP response headers [In reply to]

On Wed, Apr 23, 2008 at 5:28 PM, Perrin Harkins <perrin[at]elem.com> wrote:

> On Mon, Apr 21, 2008 at 4:30 PM, J Amuse <jamuse[at]gmail.com> wrote:
>
>
> http://perl.apache.org/docs/2.0/user/coding/coding.html#Generating_HTTP_Response_Headers
> <http://perl.apache.org/docs/2.0/user/handlers/filters.html#Introducing_Filters>

Thanks Perrin.
This link references the set method, which will overwrite the header value.
I want to append text (i.e. append a secure and httponly flag if there is a
Set-Cookie header in the HTTP response). Is this possible with the overlay
method? How can I extract the contents of the Set-Cookie header to modify
it?

Jay

perrin at elem

Apr 27, 2008, 6:28 AM

Post #5 of 6 (677 views)
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Re: Edit HTTP response headers [In reply to]

On Sun, Apr 27, 2008 at 9:18 AM, J Amuse <jamuse[at]gmail.com> wrote:
> This link references the set method, which will overwrite the header value.
> I want to append text (i.e. append a secure and httponly flag if there is a
> Set-Cookie header in the HTTP response). Is this possible with the overlay
> method? How can I extract the contents of the Set-Cookie header to modify
> it?

You can read the headers with $r->headers_out->get(). When you call
$r->headers_out() it gives you an APR::Table object which you can read
and write as much as you like:
http://perl.apache.org/docs/2.0/api/APR/Table.html

- Perrin

jamuse at gmail

Apr 28, 2008, 2:33 AM

Post #6 of 6 (659 views)
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Re: Edit HTTP response headers [In reply to]

On Wed, Apr 23, 2008 at 5:28 PM, Perrin Harkins <perrin[at]elem.com> wrote:

> On Mon, Apr 21, 2008 at 4:30 PM, J Amuse <jamuse[at]gmail.com> wrote:
> >
> >
> > http://perl.apache.org/docs/2.0/user/coding/coding.html#Generating_HTTP_Response_Headers
> > <http://perl.apache.org/docs/2.0/user/handlers/filters.html#Introducing_Filters>
> >
>
> Thanks Perrin.
> This link references the set method, which will overwrite the header
> value. I want to append text (i.e. append a secure and httponly flag if
> there is a Set-Cookie header in the HTTP response). Is this possible with
> the overlay method? How can I extract the contents of the Set-Cookie header
> to modify it?
>
>
For future reference, I was able to manipulate the HTTP headers via the
following code snippet:

sub handler
{
my $f = shift;

unless ($f->ctx)
{
my $SecureFlags = "\; secure\; HttpOnly\;";
my $Cookie = $f->r->headers_out->get("Set-Cookie");

if ($Cookie)
{
$Cookie .= $SecureFlags;
$f->r->headers_out->set("Set-Cookie" => "$Cookie");
}
$f->ctx(1);
}
}

Thanks again to Perrin for all his help.

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