1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
|
##############################################################################
# The Faq-O-Matic is Copyright 1997 by Jon Howell, all rights reserved. #
# #
# This program is free software; you can redistribute it and/or #
# modify it under the terms of the GNU General Public License #
# as published by the Free Software Foundation; either version 2 #
# of the License, or (at your option) any later version. #
# #
# This program is distributed in the hope that it will be useful, #
# but WITHOUT ANY WARRANTY; without even the implied warranty of #
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the #
# GNU General Public License for more details. #
# #
# You should have received a copy of the GNU General Public License #
# along with this program; if not, write to the Free Software #
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.#
# #
# Jon Howell can be contacted at: #
# 6211 Sudikoff Lab, Dartmouth College #
# Hanover, NH 03755-3510 #
# jonh@cs.dartmouth.edu #
# #
# An electronic copy of the GPL is available at: #
# http://www.gnu.org/copyleft/gpl.html #
# #
##############################################################################
use strict;
###
### The Slow module provides a mechanism for a long-running process to
### continue computing while letting the web browser get feedback sooner.
### An alternative would be nph-CGI (non-parsed headers, where flushed
### output is sent directly to the browser, rather than pausing in the
### server until it is complete), but
### (a) I don't know if browsers eventually give up on nph- input. (I don't
### think so, but it's an excuse. :v)
### (b) Using nph- would require that admin's web servers were configured
### to use it
### (c) admins would have to rename their CGI stub to nph-fom or somesuch;
### or have two CGI stubs, or something. What a mess.
package FAQ::OMatic::Slow;
use FAQ::OMatic;
use FAQ::OMatic::I18N;
my $reloadFrequency = 15; # seconds
my $tailSize = 20; # lines
sub split {
my $cgi = FAQ::OMatic::dispatch::cgi();
my $slowFile = "slow-output.".FAQ::OMatic::nonce();
my $slowPath = $FAQ::OMatic::Config::metaDir."/".$slowFile;
my $url = FAQ::OMatic::makeAref('-command'=>'displaySlow',
'-changedParams' => { 'slowFile' => $slowFile },
'-refType'=>'url');
#$url .= "#cursor"; # make browser snap to bottom of page
my $pid;
if (($pid = fork())==0) {
# child
# close stdio so httpd will not wait for me to get done
# and we'll let STDOUT go to the slow-output file, so we
# can watch what has been happening
open STDIN, "</dev/null";
open SLOWFILE, ">$slowPath";
open STDOUT, ">&SLOWFILE"; # redirect to $slowPath
open STDERR, ">&SLOWFILE";
# All "slow-capable" modules are expected to accept the filehandle
# we return, and print to that instead.
# This is because I thought mod_perl was somehow screwing up
# my prints to STDOUT. It turns out I was just never flushing
# them, and when the fork()ed child Apache::exit()ed, it went
# back to its main loop to handle web requests(!), and the
# file never got flushed. But this works pretty well, so we'll
# stick with it.
print SLOWFILE "<p>\n";
return *SLOWFILE;
} else {
# parent
# should display results in slowFile
FAQ::OMatic::redirect($cgi, $url);
}
}
sub childDone {
close STDOUT;
close STDERR;
# can't unlink the file, as user will load it one more time?
# But then he'll be gone -- what then? How to arrange for the
# unlink?
}
sub display {
my $params = shift;
if (not $params->{'slowFile'} =~ m/^(slow-output.[p\d]+)$/) {
FAQ::OMatic::gripe('error',
"Taint check failed on ".$params->{'slowFile'});
}
my $slowFile = $1;
my $url = FAQ::OMatic::makeAref('-command'=>'displaySlow',
'-changedParams' => { 'slowFile' => $slowFile },
'-refType'=>'url');
#$url .= "#cursor"; # make browser snap to bottom of page
# unfortunately, what appears to be a bug in Netscape foils
# that trick. So I'll only display the bottom n lines
# of the file, instead. Harrumph.
my $slowPath = $FAQ::OMatic::Config::metaDir."/".$slowFile;
if (not open SLOW, $slowPath) {
FAQ::OMatic::gripe('error', "can't open $slowFile: $!");
}
print "Content-type: text/html\n";
print "Refresh: $reloadFrequency; URL=$url\n";
print "\n";
my @tail = ();
my $cropped = '<pre>';
while (defined($_=<SLOW>)) {
if ((not $params->{'wholeFile'})
and (scalar(@tail) >= $tailSize)) {
shift(@tail);
$cropped = "<pre>...(cropped)...<br>\n";
}
push @tail, $_;
}
close(SLOW);
print "<title>Slow page</title>\n";
my $msg;
print gettexta("This page will reload every %0 seconds,", $reloadFrequency);
print " ";
if ($params->{'wholeFile'}) {
print gettexta("showing the entire process output.");
$msg = gettexta("Show the tail of the process log");
} else {
print gettexta("showing the last %0 lines of the process output.", $tailSize);
$msg = gettexta("Show the entire process log")
}
print "\n";
my $url2 = FAQ::OMatic::makeAref('-command'=>'displaySlow',
'-changedParams' => {'wholeFile' => !$params->{'wholeFile'}});
print "[".$url2.$msg."</a>]\n";
print "<hr>\n";
print $cropped;
print join('', @tail);
}
1;
|
