308 lines
9.6 KiB
Perl
308 lines
9.6 KiB
Perl
|
package CGI::Push;
|
||
|
|
|
||
|
|
# See the bottom of this file for the POD documentation. Search for the
|
||
|
|
# string '=head'.
|
||
|
|
|
||
|
|
# You can run this file through either pod2man or pod2html to produce pretty
|
||
|
|
# documentation in manual or html file format (these utilities are part of the
|
||
|
|
# Perl 5 distribution).
|
||
|
|
|
||
|
|
# Copyright 1995,1996, Lincoln D. Stein. All rights reserved.
|
||
|
|
# It may be used and modified freely, but I do request that this copyright
|
||
|
|
# notice remain attached to the file. You may modify this module as you
|
||
|
|
# wish, but if you redistribute a modified version, please attach a note
|
||
|
|
# listing the modifications you have made.
|
||
|
|
|
||
|
|
# The most recent version and complete docs are available at:
|
||
|
|
# http://stein.cshl.org/WWW/software/CGI/
|
||
|
|
|
||
|
|
$CGI::Push::VERSION='1.01';
|
||
|
|
use CGI;
|
||
|
|
@ISA = ('CGI');
|
||
|
|
|
||
|
|
$CGI::DefaultClass = 'CGI::Push';
|
||
|
|
$CGI::Push::AutoloadClass = 'CGI';
|
||
|
|
|
||
|
|
# add do_push() and push_delay() to exported tags
|
||
|
|
push(@{$CGI::EXPORT_TAGS{':standard'}},'do_push','push_delay');
|
||
|
|
|
||
|
|
sub do_push {
|
||
|
|
my ($self,@p) = CGI::self_or_default(@_);
|
||
|
|
|
||
|
|
# unbuffer output
|
||
|
|
$| = 1;
|
||
|
|
srand;
|
||
|
|
my ($random) = sprintf("%16.0f",rand()*1E16);
|
||
|
|
my ($boundary) = "----------------------------------$random";
|
||
|
|
|
||
|
|
my (@header);
|
||
|
|
my ($type,$callback,$delay,$last_page,$cookie,$target,$expires,@other) =
|
||
|
|
$self->rearrange([TYPE,NEXT_PAGE,DELAY,LAST_PAGE,[COOKIE,COOKIES],TARGET,EXPIRES],@p);
|
||
|
|
$type = 'text/html' unless $type;
|
||
|
|
$callback = \&simple_counter unless $callback && ref($callback) eq 'CODE';
|
||
|
|
$delay = 1 unless defined($delay);
|
||
|
|
$self->push_delay($delay);
|
||
|
|
|
||
|
|
my(@o);
|
||
|
|
foreach (@other) { push(@o,split("=")); }
|
||
|
|
push(@o,'-Target'=>$target) if defined($target);
|
||
|
|
push(@o,'-Cookie'=>$cookie) if defined($cookie);
|
||
|
|
push(@o,'-Type'=>"multipart/x-mixed-replace; boundary=$boundary");
|
||
|
|
push(@o,'-Server'=>"CGI.pm Push Module");
|
||
|
|
push(@o,'-Status'=>'200 OK');
|
||
|
|
push(@o,'-nph'=>1);
|
||
|
|
print $self->header(@o);
|
||
|
|
print "${boundary}$CGI::CRLF";
|
||
|
|
|
||
|
|
# now we enter a little loop
|
||
|
|
my @contents;
|
||
|
|
while (1) {
|
||
|
|
last unless (@contents = &$callback($self,++$COUNTER)) && defined($contents[0]);
|
||
|
|
print "Content-type: ${type}$CGI::CRLF$CGI::CRLF"
|
||
|
|
unless $type eq 'dynamic';
|
||
|
|
print @contents,"$CGI::CRLF";
|
||
|
|
print "${boundary}$CGI::CRLF";
|
||
|
|
do_sleep($self->push_delay()) if $self->push_delay();
|
||
|
|
}
|
||
|
|
|
||
|
|
# Optional last page
|
||
|
|
if ($last_page && ref($last_page) eq 'CODE') {
|
||
|
|
print "Content-type: ${type}$CGI::CRLF$CGI::CRLF" unless $type =~ /^dynamic|heterogeneous$/i;
|
||
|
|
print &$last_page($self,$COUNTER),"$CGI::CRLF${boundary}$CGI::CRLF";
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
sub simple_counter {
|
||
|
|
my ($self,$count) = @_;
|
||
|
|
return (
|
||
|
|
CGI->start_html("CGI::Push Default Counter"),
|
||
|
|
CGI->h1("CGI::Push Default Counter"),
|
||
|
|
"This page has been updated ",CGI->strong($count)," times.",
|
||
|
|
CGI->hr(),
|
||
|
|
CGI->a({'-href'=>'http://www.genome.wi.mit.edu/ftp/pub/software/WWW/cgi_docs.html'},'CGI.pm home page'),
|
||
|
|
CGI->end_html
|
||
|
|
);
|
||
|
|
}
|
||
|
|
|
||
|
|
sub do_sleep {
|
||
|
|
my $delay = shift;
|
||
|
|
if ( ($delay >= 1) && ($delay!~/\./) ){
|
||
|
|
sleep($delay);
|
||
|
|
} else {
|
||
|
|
select(undef,undef,undef,$delay);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
sub push_delay {
|
||
|
|
my ($self,$delay) = CGI::self_or_default(@_);
|
||
|
|
return defined($delay) ? $self->{'.delay'} =
|
||
|
|
$delay : $self->{'.delay'};
|
||
|
|
}
|
||
|
|
|
||
|
|
1;
|
||
|
|
|
||
|
|
=head1 NAME
|
||
|
|
|
||
|
|
CGI::Push - Simple Interface to Server Push
|
||
|
|
|
||
|
|
=head1 SYNOPSIS
|
||
|
|
|
||
|
|
use CGI::Push qw(:standard);
|
||
|
|
|
||
|
|
do_push(-next_page=>\&next_page,
|
||
|
|
-last_page=>\&last_page,
|
||
|
|
-delay=>0.5);
|
||
|
|
|
||
|
|
sub next_page {
|
||
|
|
my($q,$counter) = @_;
|
||
|
|
return undef if $counter >= 10;
|
||
|
|
return start_html('Test'),
|
||
|
|
h1('Visible'),"\n",
|
||
|
|
"This page has been called ", strong($counter)," times",
|
||
|
|
end_html();
|
||
|
|
}
|
||
|
|
|
||
|
|
sub last_page {
|
||
|
|
my($q,$counter) = @_;
|
||
|
|
return start_html('Done'),
|
||
|
|
h1('Finished'),
|
||
|
|
strong($counter),' iterations.',
|
||
|
|
end_html;
|
||
|
|
}
|
||
|
|
|
||
|
|
=head1 DESCRIPTION
|
||
|
|
|
||
|
|
CGI::Push is a subclass of the CGI object created by CGI.pm. It is
|
||
|
|
specialized for server push operations, which allow you to create
|
||
|
|
animated pages whose content changes at regular intervals.
|
||
|
|
|
||
|
|
You provide CGI::Push with a pointer to a subroutine that will draw
|
||
|
|
one page. Every time your subroutine is called, it generates a new
|
||
|
|
page. The contents of the page will be transmitted to the browser
|
||
|
|
in such a way that it will replace what was there beforehand. The
|
||
|
|
technique will work with HTML pages as well as with graphics files,
|
||
|
|
allowing you to create animated GIFs.
|
||
|
|
|
||
|
|
=head1 USING CGI::Push
|
||
|
|
|
||
|
|
CGI::Push adds one new method to the standard CGI suite, do_push().
|
||
|
|
When you call this method, you pass it a reference to a subroutine
|
||
|
|
that is responsible for drawing each new page, an interval delay, and
|
||
|
|
an optional subroutine for drawing the last page. Other optional
|
||
|
|
parameters include most of those recognized by the CGI header()
|
||
|
|
method.
|
||
|
|
|
||
|
|
You may call do_push() in the object oriented manner or not, as you
|
||
|
|
prefer:
|
||
|
|
|
||
|
|
use CGI::Push;
|
||
|
|
$q = new CGI::Push;
|
||
|
|
$q->do_push(-next_page=>\&draw_a_page);
|
||
|
|
|
||
|
|
-or-
|
||
|
|
|
||
|
|
use CGI::Push qw(:standard);
|
||
|
|
do_push(-next_page=>\&draw_a_page);
|
||
|
|
|
||
|
|
Parameters are as follows:
|
||
|
|
|
||
|
|
=over 4
|
||
|
|
|
||
|
|
=item -next_page
|
||
|
|
|
||
|
|
do_push(-next_page=>\&my_draw_routine);
|
||
|
|
|
||
|
|
This required parameter points to a reference to a subroutine responsible for
|
||
|
|
drawing each new page. The subroutine should expect two parameters
|
||
|
|
consisting of the CGI object and a counter indicating the number
|
||
|
|
of times the subroutine has been called. It should return the
|
||
|
|
contents of the page as an B<array> of one or more items to print.
|
||
|
|
It can return a false value (or an empty array) in order to abort the
|
||
|
|
redrawing loop and print out the final page (if any)
|
||
|
|
|
||
|
|
sub my_draw_routine {
|
||
|
|
my($q,$counter) = @_;
|
||
|
|
return undef if $counter > 100;
|
||
|
|
return start_html('testing'),
|
||
|
|
h1('testing'),
|
||
|
|
"This page called $counter times";
|
||
|
|
}
|
||
|
|
|
||
|
|
You are of course free to refer to create and use global variables
|
||
|
|
within your draw routine in order to achieve special effects.
|
||
|
|
|
||
|
|
=item -last_page
|
||
|
|
|
||
|
|
This optional parameter points to a reference to the subroutine
|
||
|
|
responsible for drawing the last page of the series. It is called
|
||
|
|
after the -next_page routine returns a false value. The subroutine
|
||
|
|
itself should have exactly the same calling conventions as the
|
||
|
|
-next_page routine.
|
||
|
|
|
||
|
|
=item -type
|
||
|
|
|
||
|
|
This optional parameter indicates the content type of each page. It
|
||
|
|
defaults to "text/html". Normally the module assumes that each page
|
||
|
|
is of a homogenous MIME type. However if you provide either of the
|
||
|
|
magic values "heterogeneous" or "dynamic" (the latter provided for the
|
||
|
|
convenience of those who hate long parameter names), you can specify
|
||
|
|
the MIME type -- and other header fields -- on a per-page basis. See
|
||
|
|
"heterogeneous pages" for more details.
|
||
|
|
|
||
|
|
=item -delay
|
||
|
|
|
||
|
|
This indicates the delay, in seconds, between frames. Smaller delays
|
||
|
|
refresh the page faster. Fractional values are allowed.
|
||
|
|
|
||
|
|
B<If not specified, -delay will default to 1 second>
|
||
|
|
|
||
|
|
=item -cookie, -target, -expires
|
||
|
|
|
||
|
|
These have the same meaning as the like-named parameters in
|
||
|
|
CGI::header().
|
||
|
|
|
||
|
|
=back
|
||
|
|
|
||
|
|
=head2 Heterogeneous Pages
|
||
|
|
|
||
|
|
Ordinarily all pages displayed by CGI::Push share a common MIME type.
|
||
|
|
However by providing a value of "heterogeneous" or "dynamic" in the
|
||
|
|
do_push() -type parameter, you can specify the MIME type of each page
|
||
|
|
on a case-by-case basis.
|
||
|
|
|
||
|
|
If you use this option, you will be responsible for producing the
|
||
|
|
HTTP header for each page. Simply modify your draw routine to
|
||
|
|
look like this:
|
||
|
|
|
||
|
|
sub my_draw_routine {
|
||
|
|
my($q,$counter) = @_;
|
||
|
|
return header('text/html'), # note we're producing the header here
|
||
|
|
start_html('testing'),
|
||
|
|
h1('testing'),
|
||
|
|
"This page called $counter times";
|
||
|
|
}
|
||
|
|
|
||
|
|
You can add any header fields that you like, but some (cookies and
|
||
|
|
status fields included) may not be interpreted by the browser. One
|
||
|
|
interesting effect is to display a series of pages, then, after the
|
||
|
|
last page, to redirect the browser to a new URL. Because redirect()
|
||
|
|
does b<not> work, the easiest way is with a -refresh header field,
|
||
|
|
as shown below:
|
||
|
|
|
||
|
|
sub my_draw_routine {
|
||
|
|
my($q,$counter) = @_;
|
||
|
|
return undef if $counter > 10;
|
||
|
|
return header('text/html'), # note we're producing the header here
|
||
|
|
start_html('testing'),
|
||
|
|
h1('testing'),
|
||
|
|
"This page called $counter times";
|
||
|
|
}
|
||
|
|
|
||
|
|
sub my_last_page {
|
||
|
|
header(-refresh=>'5; URL=http://somewhere.else/finished.html',
|
||
|
|
-type=>'text/html'),
|
||
|
|
start_html('Moved'),
|
||
|
|
h1('This is the last page'),
|
||
|
|
'Goodbye!'
|
||
|
|
hr,
|
||
|
|
end_html;
|
||
|
|
}
|
||
|
|
|
||
|
|
=head2 Changing the Page Delay on the Fly
|
||
|
|
|
||
|
|
If you would like to control the delay between pages on a page-by-page
|
||
|
|
basis, call push_delay() from within your draw routine. push_delay()
|
||
|
|
takes a single numeric argument representing the number of seconds you
|
||
|
|
wish to delay after the current page is displayed and before
|
||
|
|
displaying the next one. The delay may be fractional. Without
|
||
|
|
parameters, push_delay() just returns the current delay.
|
||
|
|
|
||
|
|
=head1 INSTALLING CGI::Push SCRIPTS
|
||
|
|
|
||
|
|
Server push scripts B<must> be installed as no-parsed-header (NPH)
|
||
|
|
scripts in order to work correctly. On Unix systems, this is most
|
||
|
|
often accomplished by prefixing the script's name with "nph-".
|
||
|
|
Recognition of NPH scripts happens automatically with WebSTAR and
|
||
|
|
Microsoft IIS. Users of other servers should see their documentation
|
||
|
|
for help.
|
||
|
|
|
||
|
|
=head1 AUTHOR INFORMATION
|
||
|
|
|
||
|
|
Copyright 1995-1998, Lincoln D. Stein. All rights reserved.
|
||
|
|
|
||
|
|
This library is free software; you can redistribute it and/or modify
|
||
|
|
it under the same terms as Perl itself.
|
||
|
|
|
||
|
|
Address bug reports and comments to: lstein@cshl.org
|
||
|
|
|
||
|
|
=head1 BUGS
|
||
|
|
|
||
|
|
This section intentionally left blank.
|
||
|
|
|
||
|
|
=head1 SEE ALSO
|
||
|
|
|
||
|
|
L<CGI::Carp>, L<CGI>
|
||
|
|
|
||
|
|
=cut
|
||
|
|
|