CGI + SSI = extra content-type header?

[Kozz]

Most esteemed monks:

I have been wrestling with a problem in a CGI script which is included in a .html file as #exec cgi="retrieve_password.pl". (".html" has been set to server-parsed html).

A form (method=GET) calls another html page, resulting in a GET query of "/retrieve_password.html?email=[e-mail]". Then the QUERY_STRING is passed along to retrieve_password.pl through the Apache sub-request.

However, upon output, the Content-type: text/html is visible on the webpage! I triple-checked, and I do not see my script outputting headers more than once. But if I edit the script and comment-out the line which prints the header, it produces an error.

It seems that if I comment-out my call to send_account() that the header no longer becomes visible. But why is this?

Any help you can provide would be most welcome.

#!/usr/bin/perl

# database names, emails, subjects have been changed
# to protect the innocent

use strict;
use CGI;
use CGI::Carp qw(fatalsToBrowser);
use Postgres; # old module, I know
use Mail::Send;

my $sql = db_connect("mydbname");
if (!$sql){ 
    die "Unable to open database: $!\n"; 
}
my $table  = 'users';

my $q = new CGI;

print $q->header;

if($q->param('email') eq ''){
    print $q->p(qq{<p>Please <a href="javascript:history.go(-1)">go ba
+ck</a> and provide your account email address.</p>\n});
    exit;
}

my $query = sprintf(q{SELECT email, namefirst, namelast, username, use
+rpass from %s WHERE email ~ %s}, 
        $table, qstr($q->param('email')) );
my $result = $sql->execute($query);
my  @data = $result->fetchrow();


my $email = $data[0];

if($email ne ''){
    send_account(\@data);
    print $q->p( "Thank you!  Your account information has been sent t
+o " . $email );
    print $q->p( qq{<a href="/login.php">Log In</a>} );
}else{
    print $q->p(qq{<p>Sorry!  No account found with that email address
+.  Please } . 
            qq{<a href="javascript:history.go(-1)">go back</a> and try
+ again.</p>\n});

}

sub qstr{
    # this old Postgres module does not have its own quote() method.
    # this is a weak implementation, but better than nothing. (I think
+)
    my ($str) = @_;
    $str =~ s#(\\)#/#sg; # replace backslashes with slashes
    $str =~ s/(['])/\\$1/; # escape single-quotes
    return qq{'$str'};
}

sub send_account{
    my ($matching_row) = @_;
    # Set Mail Headers
    my $mailout = new Mail::Send;
    $mailout->to( shift @{$matching_row} );
    $mailout->subject("Online Registration");
    $mailout->add('From', '[e-mail]');
    $mailout->add('Reply-To', '[e-mail]');

    # open up a mail filehandle
    my $mailfh = $mailout->open;

    # print mail body
    my $mailbody=<<END_OF_MAIL;
Dear %s %s:
  Thank you for registering.  Here is your
  account information:
USERNAME:  %s
PASSWORD:  %s
  Please keep this information safe.

  Your account is active, and you may log in any time to place your fi
+rst
  order. 

Sincerely,

Administrator
END_OF_MAIL

    printf $mailfh $mailbody, @{$matching_row};

    # close and send
    $mailfh->close;   
}

I realize that some of the code is not the most elegant, and you are welcome to provide corrections, but my most pressing need is this spurious display of the content-type header.

Oh, it may also be worth noting that there are other perl scripts included in the page in a similar fashion, and these do NOT show a visible content-type header, though they DO have a "print $q->header;" line.

[benn]

I think there must be more going on here - maybe something to do with the other scripts, or your SSI setup. As stated above, if the request was made to "my_html_form_with_execs.html", then Apache should spit out the right headers along with the parsed html, which will include *any* output from your script(s).

None of your scripts should need to print a header - I'm puzzled as to why the other scripts *don't* show the header, if they all have a "print $q->header" line. Have you looked at the source of the HTML to work out exactly what is printing what where and when?

Again, commenting out the "send_account()" line should make no difference, unless there's an error there somewhere - what do the logs say when you comment out the "print $q->header" line? Is it a "no headers" error or something to do with send_account()?

Personally, I'd drop the "exec-cgi-inside-server-parsed html" approach and use HTML::Template instead :)

Cheers,Ben.

[waswas-fng]

Isnt the server responsible for setting content type when parsing html like this?

-Waswas

[Kozz]

Well, if I omit the header line, it produces an error... However, if I leave the print header line in place and comment-out my send_account() line, it shows the rest of the output correctly but does not make a visible content-type header. See my confusion?

[Anonymous Monk]

If Mail::Send forks a new process to send the mail and your output buffer is not empty then whatever is in the output buffer will be printed twice. A $| = 1; should fix the problem if it is indeed the problem I described.