#!/usr/bin/perl -w
# Copyright © 2001-2018 Jamie Zawinski <jwz@jwz.org>.
#
# Permission to use, copy, modify, distribute, and sell this software and its
# documentation for any purpose is hereby granted without fee, provided that
# the above copyright notice appear in all copies and that both that
# copyright notice and this permission notice appear in supporting
# documentation. No representations are made about the suitability of this
# software for any purpose. It is provided "as is" without express or
# implied warranty.
#
# This program chooses a random file from under the given directory, and
# prints its name. The file will be an image file whose dimensions are
# larger than a certain minimum size.
#
# If the directory is a URL, it is assumed to be an RSS or Atom feed.
# The images from that feed will be downloaded, cached, and selected from
# at random. The feed will be re-polled periodically, as needed.
#
# The various xscreensaver hacks that manipulate images ("jigsaw", etc.) get
# the image to manipulate by running the "xscreensaver-getimage" program.
#
# Under X11, the "xscreensaver-getimage" program invokes this script,
# depending on the value of the "chooseRandomImages" and "imageDirectory"
# settings in the ~/.xscreensaver file (or .../app-defaults/XScreenSaver).
# The screen savers invoke "xscreensaver-getimage" via utils/grabclient.c,
# which then invokes this script.
#
# Under Cocoa, this script lives inside the .saver bundle, and is invoked
# directly from utils/grabclient.c.
#
# Created: 12-Apr-01.
require 5;
#use diagnostics; # Fails on some MacOS 10.5 systems
use strict;
use POSIX;
use Fcntl;
use Fcntl ':flock'; # import LOCK_* constants
use POSIX ':fcntl_h'; # S_ISDIR was here in Perl 5.6
import Fcntl ':mode' unless defined &S_ISUID; # but it is here in Perl 5.8
# but in Perl 5.10, both of these load, and cause errors!
# So we have to check for S_ISUID instead of S_ISDIR? WTF?
use Digest::MD5 qw(md5_base64);
# Some Linux systems don't install LWP by default!
# Only error out if we're actually loading a URL instead of local data.
BEGIN { eval 'use LWP::Simple;' }
my $progname = $0; $progname =~ s@.*/@@g;
my ($version) = ('$Revision: 1.52 $' =~ m/\s(\d[.\d]+)\s/s);
my $verbose = 0;
# Whether to use MacOS X's Spotlight to generate the list of files.
# When set to -1, uses Spotlight if "mdfind" exists.
#
# (In my experience, this isn't actually any faster, and might not find
# everything if your Spotlight index is out of date, which happens often.)
#
my $use_spotlight_p = 0;
# Whether to cache the results of the last run.
#
my $cache_p = 1;
# Regenerate the cache if it is older than this many seconds.
#
my $cache_max_age = 60 * 60 * 3; # 3 hours
# Re-poll RSS/Atom feeds when local copy is older than this many seconds.
#
my $feed_max_age = $cache_max_age;
# This matches files that we are allowed to use as images (case-insensitive.)
# Anything not matching this is ignored. This is so you can point your
# imageDirectory at directory trees that have things other than images in
# them, but it assumes that you gave your images sensible file extensions.
#
my @good_extensions = ('jpg', 'jpeg', 'pjpeg', 'pjpg', 'png', 'gif',
'tif', 'tiff', 'xbm', 'xpm');
my $good_file_re = '\.(' . join("|", @good_extensions) . ')$';
# This matches file extensions that might occur in an image directory,
# and that are never used in the name of a subdirectory. This is an
# optimization that prevents us from having to stat() those files to
# tell whether they are directories or not. (It speeds things up a
# lot. Don't give your directories stupid names.)
#
my @nondir_extensions = ('ai', 'bmp', 'bz2', 'cr2', 'crw', 'db',
'dmg', 'eps', 'gz', 'hqx', 'htm', 'html', 'icns', 'ilbm', 'mov',
'nef', 'pbm', 'pdf', 'php', 'pl', 'ppm', 'ps', 'psd', 'sea', 'sh',
'shtml', 'tar', 'tgz', 'thb', 'txt', 'xcf', 'xmp', 'Z', 'zip' );
my $nondir_re = '\.(' . join("|", @nondir_extensions) . ')$';
# JPEG, GIF, and PNG files that are are smaller than this are rejected:
# this is so that you can use an image directory that contains both big
# images and thumbnails, and have it only select the big versions.
# But, if all of your images are smaller than this, all will be rejected.
#
my $min_image_width = 500;
my $min_image_height = 500;
my @all_files = (); # list of "good" files we've collected
my %seen_inodes; # for breaking recursive symlink loops
# For diagnostic messages:
#
my $dir_count = 1; # number of directories seen
my $stat_count = 0; # number of files/dirs stat'ed
my $skip_count_unstat = 0; # number of files skipped without stat'ing
my $skip_count_stat = 0; # number of files skipped after stat
my $config_file = $ENV{HOME} . "/.xscreensaver";
my $image_directory = undef;
sub find_all_files($);
sub find_all_files($) {
my ($dir) = @_;
print STDERR "$progname: + reading dir $dir/...\n" if ($verbose > 1);
my $dd;
if (! opendir ($dd, $dir)) {
print STDERR "$progname: couldn't open $dir: $!\n" if ($verbose);
return;
}
my @files = readdir ($dd);
closedir ($dd);
my @dirs = ();
foreach my $file (@files) {
next if ($file =~ m/^\./); # silently ignore dot files/dirs
if ($file =~ m/[~%\#]$/) { # ignore backup files (and dirs...)
$skip_count_unstat++;
print STDERR "$progname: - skip file $file\n" if ($verbose > 1);
}
$file = "$dir/$file";
if ($file =~ m/$good_file_re/io) {
#
# Assume that files ending in .jpg exist and are not directories.
#
push @all_files, $file;
print STDERR "$progname: - found file $file\n" if ($verbose > 1);
} elsif ($file =~ m/$nondir_re/io) {
#
# Assume that files ending in .html are not directories.
#
$skip_count_unstat++;
print STDERR "$progname: -- skip file $file\n" if ($verbose > 1);
} else {
#
# Now we need to stat the file to see if it's a subdirectory.
#
# Note: we could use the trick of checking "nlinks" on the parent
# directory to see if this directory contains any subdirectories,
# but that would exclude any symlinks to directories.
#
my @st = stat($file);
my ($dev,$ino,$mode,$nlink,$uid,$gid,$rdev,$size,
$atime,$mtime,$ctime,$blksize,$blocks) = @st;
$stat_count++;
if ($#st == -1) {
if ($verbose) {
my $ll = readlink $file;
if (defined ($ll)) {
print STDERR "$progname: + dangling symlink: $file -> $ll\n";
} else {
print STDERR "$progname: + unreadable: $file\n";
}
}
next;
}
next if ($seen_inodes{"$dev:$ino"}); # break symlink loops
$seen_inodes{"$dev:$ino"} = 1;
if (S_ISDIR($mode)) {
push @dirs, $file;
$dir_count++;
print STDERR "$progname: + found dir $file\n" if ($verbose > 1);
} else {
$skip_count_stat++;
print STDERR "$progname: + skip file $file\n" if ($verbose > 1);
}
}
}
foreach (@dirs) {
find_all_files ($_);
}
}
sub spotlight_all_files($) {
my ($dir) = @_;
my @terms = ();
# "public.image" matches all (indexed) images, including Photoshop, etc.
# push @terms, "kMDItemContentTypeTree == 'public.image'";
foreach (@good_extensions) {
# kMDItemFSName hits the file system every time: much worse than "find".
# push @terms, "kMDItemFSName == '*.$_'";
# kMDItemDisplayName matches against the name in the Spotlight index,
# but won't find files that (for whatever reason) didn't get indexed.
push @terms, "kMDItemDisplayName == '*.$_'";
}
$dir =~ s@([^-_/a-z\d.,])@\\$1@gsi; # quote for sh
my $cmd = "mdfind -onlyin $dir \"" . join (' || ', @terms) . "\"";
print STDERR "$progname: executing: $cmd\n" if ($verbose > 1);
@all_files = split (/[\r\n]+/, `$cmd`);
}
# If we're using cacheing, read the cache file and return its contents,
# if any. This also holds an exclusive lock on the cache file, which
# has the additional benefit that if two copies of this program are
# running at once, one will wait for the other, instead of both of
# them spanking the same file system at the same time.
#
my $cache_fd = undef;
my $cache_file_name = undef;
my $read_cache_p = 0;
sub read_cache($) {
my ($dir) = @_;
return () unless ($cache_p);
my $dd = "$ENV{HOME}/Library/Caches"; # MacOS location
if (-d $dd) {
$cache_file_name = "$dd/org.jwz.xscreensaver.getimage.cache";
} elsif (-d "$ENV{HOME}/.cache") { # Gnome "FreeDesktop XDG" location
$dd = "$ENV{HOME}/.cache/xscreensaver";
if (! -d $dd) { mkdir ($dd) || error ("mkdir $dd: $!"); }
$cache_file_name = "$dd/xscreensaver-getimage.cache"
} elsif (-d "$ENV{HOME}/tmp") { # If ~/tmp/ exists, use it.
$cache_file_name = "$ENV{HOME}/tmp/.xscreensaver-getimage.cache";
} else {
$cache_file_name = "$ENV{HOME}/.xscreensaver-getimage.cache";
}
print STDERR "$progname: awaiting lock: $cache_file_name\n"
if ($verbose > 1);
my $file = $cache_file_name;
open ($cache_fd, '+>>', $file) || error ("unable to write $file: $!");
flock ($cache_fd, LOCK_EX) || error ("unable to lock $file: $!");
seek ($cache_fd, 0, 0) || error ("unable to rewind $file: $!");
my $mtime = (stat($cache_fd))[9];
if ($mtime + $cache_max_age < time) {
print STDERR "$progname: cache is too old\n" if ($verbose);
return ();
}
my $odir = <$cache_fd>;
$odir =~ s/[\r\n]+$//s if defined ($odir);
if (!defined ($odir) || ($dir ne $odir)) {
print STDERR "$progname: cache is for $odir, not $dir\n"
if ($verbose && $odir);
return ();
}
my @files = ();
while (<$cache_fd>) {
s/[\r\n]+$//s;
push @files, "$odir/$_";
}
print STDERR "$progname: " . ($#files+1) . " files in cache\n"
if ($verbose);
$read_cache_p = 1;
return @files;
}
sub write_cache($) {
my ($dir) = @_;
return unless ($cache_p);
# If we read the cache, just close it without rewriting it.
# If we didn't read it, then write it now.
if (! $read_cache_p) {
truncate ($cache_fd, 0) ||
error ("unable to truncate $cache_file_name: $!");
seek ($cache_fd, 0, 0) ||
error ("unable to rewind $cache_file_name: $!");
if ($#all_files >= 0) {
print $cache_fd "$dir\n";
foreach (@all_files) {
my $f = $_; # stupid Perl. do this to avoid modifying @all_files!
$f =~ s@^\Q$dir/@@so || die; # remove $dir from front
print $cache_fd "$f\n";
}
}
print STDERR "$progname: cached " . ($#all_files+1) . " files\n"
if ($verbose);
}
flock ($cache_fd, LOCK_UN) ||
error ("unable to unlock $cache_file_name: $!");
close ($cache_fd);
$cache_fd = undef;
}
sub html_unquote($) {
my ($h) = @_;
# This only needs to handle entities that occur in RSS, not full HTML.
my %ent = ( 'amp' => '&', 'lt' => '<', 'gt' => '>',
'quot' => '"', 'apos' => "'" );
$h =~ s/(&(\#)?([[:alpha:]\d]+);?)/
{
my ($o, $c) = ($1, $3);
if (! defined($2)) {
$c = $ent{$c}; # for <
} else {
if ($c =~ m@^x([\dA-F]+)$@si) { # for A
$c = chr(hex($1));
} elsif ($c =~ m@^\d+$@si) { # for A
$c = chr($c);
} else {
$c = undef;
}
}
($c || $o);
}
/gexi;
return $h;
}
# Figure out what the proxy server should be, either from environment
# variables or by parsing the output of the (MacOS) program "scutil",
# which tells us what the system-wide proxy settings are.
#
sub set_proxy($) {
my ($ua) = @_;
my $proxy_data = `scutil --proxy 2>/dev/null`;
foreach my $proto ('http', 'https') {
my ($server) = ($proxy_data =~ m/\b${proto}Proxy\s*:\s*([^\s]+)/si);
my ($port) = ($proxy_data =~ m/\b${proto}Port\s*:\s*([^\s]+)/si);
my ($enable) = ($proxy_data =~ m/\b${proto}Enable\s*:\s*([^\s]+)/si);
if ($server && $enable) {
# Note: this ignores the "ExceptionsList".
my $proto2 = 'http';
$ENV{"${proto}_proxy"} = ("${proto2}://" . $server .
($port ? ":$port" : "") . "/");
print STDERR "$progname: MacOS $proto proxy: " .
$ENV{"${proto}_proxy"} . "\n"
if ($verbose > 2);
}
}
$ua->env_proxy();
}
sub init_lwp() {
if (! defined ($LWP::Simple::ua)) {
error ("\n\n\tPerl is broken. Do this to repair it:\n" .
"\n\tsudo cpan LWP::Simple LWP::Protocol::https Mozilla::CA\n");
}
set_proxy ($LWP::Simple::ua);
}
sub sanity_check_lwp() {
my $url1 = 'https://www.mozilla.org/';
my $url2 = 'http://www.mozilla.org/';
my $body = (LWP::Simple::get($url1) || '');
if (length($body) < 10240) {
my $err = "";
$body = (LWP::Simple::get($url2) || '');
if (length($body) < 10240) {
$err = "Perl is broken: neither HTTP nor HTTPS URLs work.";
} else {
$err = "Perl is broken: HTTP URLs work but HTTPS URLs don't.";
}
$err .= "\nMaybe try: sudo cpan -f Mozilla::CA LWP::Protocol::https";
$err =~ s/^/\t/gm;
error ("\n\n$err\n");
}
}
# If the URL does not already end with an extension appropriate for the
# content-type, add it after a "#" search.
#
# This is for when we know the content type of the URL, but the URL is
# some crazy thing without an extension. The files on disk need to have
# proper extensions.
#
sub force_extension($$) {
my ($url, $ct) = @_;
return $url unless (defined($url) && defined($ct));
my ($ext) = ($ct =~ m@^image/([-a-z\d]+)@si);
return $url unless $ext;
$ext = lc($ext);
$ext = 'jpg' if ($ext eq 'jpeg');
return $url if ($url =~ m/\.$ext$/si);
return "$url#.$ext";
}
# Returns a list of the image enclosures in the RSS or Atom feed.
# Elements of the list are references, [ "url", "guid" ].
#
sub parse_feed($);
sub parse_feed($) {
my ($url) = @_;
init_lwp();
$LWP::Simple::ua->agent ("$progname/$version");
$LWP::Simple::ua->timeout (10); # bail sooner than the default of 3 minutes
# Half the time, random Linux systems don't have Mozilla::CA installed,
# which results in "Can't verify SSL peers without knowning which
# Certificate Authorities to trust".
#
# In xscreensaver-text we just disabled certificate checks. However,
# malicious images really do exist, so for xscreensaver-getimage-file,
# let's actually require that SSL be installed properly.
print STDERR "$progname: loading $url\n" if ($verbose);
my $body = (LWP::Simple::get($url) || '');
if ($body !~ m@^\s*<(\?xml|rss)\b@si) {
# Not an RSS/Atom feed. Try RSS autodiscovery.
# (Great news, everybody: Flickr no longer provides RSS for "Sets",
# only for "Photostreams", and only the first 20 images of those.
# Thanks, assholes.)
if ($body =~ m/^\s*$/s) {
sanity_check_lwp();
error ("null response: $url");
}
error ("not an RSS or Atom feed, or HTML: $url")
unless ($body =~ m@<(HEAD|BODY|A|IMG)\b@si);
# Find the first <link> with RSS or Atom in it, and use that instead.
$body =~ s@<LINK\s+([^<>]*)>@{
my $p = $1;
if ($p =~ m! \b REL \s* = \s* ['"]? alternate \b!six &&
$p =~ m! \b TYPE \s* = \s* ['"]? application/(atom|rss) !six &&
$p =~ m! \b HREF \s* = \s* ['"] ( [^<>'"]+ ) !six
) {
my $u2 = html_unquote ($1);
if ($u2 =~ m!^/!s) {
my ($h) = ($url =~ m!^([a-z]+://[^/]+)!si);
$u2 = "$h$u2";
}
print STDERR "$progname: found feed: $u2\n"
if ($verbose);
return parse_feed ($u2);
}
'';
}@gsexi;
error ("no RSS or Atom feed for HTML page: $url");
}
$body =~ s@(<ENTRY|<ITEM)@\001$1@gsi;
my @items = split(/\001/, $body);
shift @items;
my @imgs = ();
my %ids;
foreach my $item (@items) {
my $iurl = undef;
my $id = undef;
# First look for <link rel="enclosure" href="...">
#
if (! $iurl) {
foreach my $link ($item =~ m@<LINK[^<>]*>@gsi) {
last if $iurl;
my ($href) = ($link =~ m/\bHREF\s*=\s*[\"\']([^<>\'\"]+)/si);
my ($type) = ($link =~ m/\bTYPE\s*=\s*[\"\']?([^<>\'\"]+)/si);
my ($rel) = ($link =~ m/\bREL\s*=\s*[\"\']?([^<>\'\"]+)/si);
$href = undef unless (lc($rel || '') eq 'enclosure');
$href = undef if ($type && $type !~ m@^image/@si); # omit videos
$iurl = html_unquote($href) if $href;
$iurl = force_extension ($iurl, $type);
}
}
# Then look for <media:content url="...">
#
if (! $iurl) {
foreach my $link ($item =~ m@<MEDIA:CONTENT[^<>]*>@gsi) {
last if $iurl;
my ($href) = ($link =~ m/\bURL\s*=\s*[\"\']([^<>\'\"]+)/si);
my ($type) = ($link =~ m/\bTYPE\s*=\s*[\"\']?([^<>\'\"]+)/si);
my ($med) = ($link =~ m/\bMEDIUM\s*=\s*[\"\']?([^<>\'\"]+)/si);
$type = 'image/jpeg' if (!$type && lc($med || '') eq 'image');
$href = undef if ($type && $type !~ m@^image/@si); # omit videos
$iurl = html_unquote($href) if $href;
$iurl = force_extension ($iurl, $type);
}
}
# Then look for <enclosure url="..."/>
#
if (! $iurl) {
foreach my $link ($item =~ m@<ENCLOSURE[^<>]*>@gsi) {
last if $iurl;
my ($href) = ($link =~ m/\bURL\s*=\s*[\"\']([^<>\'\"]+)/si);
my ($type) = ($link =~ m/\bTYPE\s*=\s*[\"\']?([^<>\'\"]+)/si);
$href = undef if ($type && $type !~ m@^image/@si); # omit videos
$iurl = html_unquote($href) if ($href);
$iurl = force_extension ($iurl, $type);
}
}
# Ok, maybe there's an image in the <url> field?
#
if (! $iurl) {
foreach my $link ($item =~ m@<URL\b[^<>]*>([^<>]*)@gsi) {
last if $iurl;
my $u2 = $1;
$iurl = html_unquote($u2) if ($u2 =~ m/$good_file_re/io);
if (! $iurl) {
my $u3 = $u2;
$u3 =~ s/#.*$//gs;
$u3 =~ s/[?&].*$//gs;
$iurl = html_unquote($u2) if ($u3 =~ m/$good_file_re/io);
}
}
}
# Then look for <content:encoded> or <description>... with an
# <img src="..."> inside. If more than one image, take the first.
#
foreach my $t ('content:encoded', 'description') {
last if $iurl;
foreach my $link ($item =~ m@<$t[^<>]*>(.*?)</$t>@gsi) {
last if $iurl;
my $desc = $1;
if ($desc =~ m@<!\[CDATA\[\s*(.*?)\s*\]\]>@gs) {
$desc = $1;
} else {
$desc = html_unquote($desc);
}
my ($href) = ($desc =~ m@<IMG[^<>]*\bSRC=[\"\']?([^\"\'<>]+)@si);
$iurl = html_unquote($href) if ($href);
# If IMG SRC has a bogus extension, pretend it's a JPEG.
$iurl = force_extension ($iurl, 'image/jpeg')
if ($iurl && $iurl !~ m/$good_file_re/io);
}
}
# Find a unique ID for this image, to defeat image farms.
# First look for <id>...</id>
($id) = ($item =~ m!<ID\b[^<>]*>\s*([^<>]+?)\s*</ID>!si) unless $id;
# Then look for <guid isPermaLink=...> ... </guid>
($id) = ($item =~ m!<GUID\b[^<>]*>\s*([^<>]+?)\s*</GUID>!si) unless $id;
# Then look for <link> ... </link>
($id) = ($item =~ m!<LINK\b[^<>]*>\s*([^<>]+?)\s*</LINK>!si) unless $id;
# If we only have a GUID or LINK, but it's an image, use that.
$iurl = $id if (!$iurl && $id && $id =~ m/$good_file_re/io);
if ($iurl) {
$id = $iurl unless $id;
my $o = $ids{$id};
if (! $o) {
$ids{$id} = $iurl;
my @P = ($iurl, $id);
push @imgs, \@P;
} elsif ($iurl ne $o) {
print STDERR "$progname: WARNING: dup ID \"$id\"" .
" for \"$o\" and \"$iurl\"\n";
}
}
}
return @imgs;
}
# Like md5_base64 but uses filename-safe characters.
#
sub md5_file($) {
my ($s) = @_;
$s = md5_base64($s);
$s =~ s@[/]@_@gs;
$s =~ s@[+]@-@gs;
return $s;
}
# expands the first URL relative to the second.
#
sub expand_url($$) {
my ($url, $base) = @_;
$url =~ s/^\s+//gs; # lose whitespace at front and back
$url =~ s/\s+$//gs;
if (! ($url =~ m/^[a-z]+:/)) {
$base =~ s@(\#.*)$@@; # strip anchors
$base =~ s@(\?.*)$@@; # strip arguments
$base =~ s@/[^/]*$@/@; # take off trailing file component
my $tail = '';
if ($url =~ s@(\#.*)$@@) { $tail = $1; } # save anchors
if ($url =~ s@(\?.*)$@@) { $tail = "$1$tail"; } # save arguments
my $base2 = $base;
$base2 =~ s@^([a-z]+:/+[^/]+)/.*@$1@ # if url is an absolute path
if ($url =~ m@^/@);
my $ourl = $url;
$url = $base2 . $url;
$url =~ s@/\./@/@g; # expand "."
1 while ($url =~ s@/[^/]+/\.\./@/@s); # expand ".."
$url .= $tail; # put anchors/args back
print STDERR "$progname: relative URL: $ourl --> $url\n"
if ($verbose > 1);
} else {
print STDERR "$progname: absolute URL: $url\n"
if ($verbose > 2);
}
return $url;
}
# Given the URL of an image, download it into the given directory
# and return the file name.
#
sub download_image($$$) {
my ($url, $uid, $dir) = @_;
my $url2 = $url;
$url2 =~ s/\#.*$//s; # Omit search terms after file extension
$url2 =~ s/\?.*$//s;
my ($ext) = ($url =~ m@\.([a-z\d]+)$@si);
($ext) = ($url2 =~ m@\.([a-z\d]+)$@si) unless $ext;
# If the feed hasn't put a sane extension on their URLs, nothing's going
# to work. This code assumes that file names have extensions, even the
# ones in the cache directory.
#
if (! $ext) {
print STDERR "$progname: skipping extensionless URL: $url\n"
if ($verbose > 1);
return undef;
}
# Don't bother downloading files that we will reject anyway.
#
if (! ($url =~ m/$good_file_re/io ||
$url2 =~ m/$good_file_re/io)) {
print STDERR "$progname: skipping non-image URL: $url\n"
if ($verbose > 1);
return undef;
}
my $file = md5_file ($uid);
$file .= '.' . lc($ext) if $ext;
# Don't bother doing If-Modified-Since to see if the URL has changed.
# If we have already downloaded it, assume it's good.
if (-f "$dir/$file") {
print STDERR "$progname: exists: $dir/$file for $uid / $url\n"
if ($verbose > 1);
return $file;
}
# Special-case kludge for Flickr:
# Their RSS feeds sometimes include only the small versions of the images.
# So if the URL ends in one of the "small-size" letters, change it to "b".
#
# _o orig, 1600 +
# _k large, 2048 max
# _h large, 1600 max
# _b large, 1024 max
# _c medium, 800 max
# _z medium, 640 max
# "" medium, 500 max
# _n small, 320 max
# _m small, 240 max
# _t thumb, 100 max
# _q square, 150x150
# _s square, 75x75
#
# Note: if we wanted to get the _k or _o version instead of the _b or _h
# version, we'd need to crack the DRM -- which is easy: see crack_secret
# in "https://www.jwz.org/hacks/galdown".
#
$url =~ s@_[sqtmnzc](\.[a-z]+)$@_b$1@si
if ($url =~ m@^https?://[^/?#&]*?flickr\.com/@si);
print STDERR "$progname: downloading: $dir/$file for $uid / $url\n"
if ($verbose > 1);
init_lwp();
$LWP::Simple::ua->agent ("$progname/$version");
$url =~ s/\#.*$//s; # Omit search terms
my $status = LWP::Simple::mirror ($url, "$dir/$file");
if (!LWP::Simple::is_success ($status)) {
print STDERR "$progname: error $status: $url\n"; # keep going
}
return $file;
}
sub mirror_feed($) {
my ($url) = @_;
if ($url !~ m/^https?:/si) { # not a URL: local directory.
return (undef, $url);
}
my $dir = "$ENV{HOME}/Library/Caches"; # MacOS location
if (-d $dir) {
$dir = "$dir/org.jwz.xscreensaver.feeds";
} elsif (-d "$ENV{HOME}/.cache") { # Gnome "FreeDesktop XDG" location
$dir = "$ENV{HOME}/.cache/xscreensaver";
if (! -d $dir) { mkdir ($dir) || error ("mkdir $dir: $!"); }
$dir .= "/feeds";
if (! -d $dir) { mkdir ($dir) || error ("mkdir $dir: $!"); }
} elsif (-d "$ENV{HOME}/tmp") { # If ~/tmp/ exists, use it.
$dir = "$ENV{HOME}/tmp/.xscreensaver-feeds";
} else {
$dir = "$ENV{HOME}/.xscreensaver-feeds";
}
if (! -d $dir) {
mkdir ($dir) || error ("mkdir $dir: $!");
print STDERR "$progname: mkdir $dir/\n" if ($verbose);
}
# MD5 for directory name to use for cache of a feed URL.
$dir .= '/' . md5_file ($url);
if (! -d $dir) {
mkdir ($dir) || error ("mkdir $dir: $!");
print STDERR "$progname: mkdir $dir/ for $url\n" if ($verbose);
}
# At this point, we have the directory corresponding to this URL.
# Now check to see if the files in it are up to date, and download
# them if not.
my $stamp = '.timestamp';
my $lock = "$dir/$stamp";
print STDERR "$progname: awaiting lock: $lock\n"
if ($verbose > 1);
my $mtime = ((stat($lock))[9]) || 0;
my $lock_fd;
open ($lock_fd, '+>>', $lock) || error ("unable to write $lock: $!");
flock ($lock_fd, LOCK_EX) || error ("unable to lock $lock: $!");
seek ($lock_fd, 0, 0) || error ("unable to rewind $lock: $!");
my $poll_p = ($mtime + $feed_max_age < time);
# --no-cache cmd line arg means poll again right now.
$poll_p = 1 unless ($cache_p);
# Even if the cache is young, make sure there is at least one file,
# and re-check if not.
#
if (! $poll_p) {
my $count = 0;
opendir (my $dirh, $dir) || error ("$dir: $!");
foreach my $f (readdir ($dirh)) {
next if ($f =~ m/^\./s);
$count++;
last;
}
closedir $dirh;
if ($count <= 0) {
print STDERR "$progname: no image files in cache of $url\n"
if ($verbose);
$poll_p = 1;
}
}
if ($poll_p) {
print STDERR "$progname: loading $url\n" if ($verbose);
my %files;
opendir (my $dirh, $dir) || error ("$dir: $!");
foreach my $f (readdir ($dirh)) {
next if ($f eq '.' || $f eq '..');
$files{$f} = 0; # 0 means "file exists, should be deleted"
}
closedir $dirh;
$files{$stamp} = 1;
# Download each image currently in the feed.
#
my $count = 0;
my @urls = parse_feed ($url);
print STDERR "$progname: " . ($#urls + 1) . " images\n"
if ($verbose > 1);
my %seen_src_urls;
foreach my $p (@urls) {
my ($furl, $id) = @$p;
$furl = expand_url ($furl, $url);
# No need to download the same image twice, even if it was in the feed
# multiple times under different GUIDs.
next if ($seen_src_urls{$furl});
$seen_src_urls{$furl} = 1;
my $f = download_image ($furl, $id, $dir);
next unless $f;
$files{$f} = 1; # Got it, don't delete
$count++;
}
my $empty_p = ($count <= 0);
# Now delete any files that are no longer in the feed.
# But if there was nothing in the feed (network failure?)
# then don't blow away the old files.
#
my $kept = 0;
foreach my $f (keys(%files)) {
if ($count <= 0) {
$kept++;
} elsif ($files{$f}) {
$kept++;
} else {
if (unlink ("$dir/$f")) {
print STDERR "$progname: rm $dir/$f\n" if ($verbose > 1);
} else {
print STDERR "$progname: rm $dir/$f: $!\n"; # don't bail
}
}
}
# Both feed and cache are empty. No files at all. Bail.
error ("empty feed: $url") if ($kept <= 1);
# Feed is empty, but we have some files from last time. Warn.
print STDERR "$progname: empty feed: using cache: $url\n"
if ($empty_p);
$mtime = time(); # update the timestamp
} else {
# Not yet time to re-check the URL.
print STDERR "$progname: using cache: $url\n" if ($verbose);
}
# Unlock and update the write date on the .timestamp file.
#
truncate ($lock_fd, 0) || error ("unable to truncate $lock: $!");
seek ($lock_fd, 0, 0) || error ("unable to rewind $lock: $!");
utime ($mtime, $mtime, $lock_fd) || error ("unable to touch $lock: $!");
flock ($lock_fd, LOCK_UN) || error ("unable to unlock $lock: $!");
close ($lock_fd);
$lock_fd = undef;
print STDERR "$progname: unlocked $lock\n" if ($verbose > 1);
# Don't bother using the imageDirectory cache. We know that this directory
# is flat, and we can assume that an RSS feed doesn't contain 100,000 images
# like ~/Pictures/ might.
#
$cache_p = 0;
# Return the URL and directory name of the files of that URL's local cache.
#
return ($url, $dir);
}
sub find_random_file($) {
my ($dir) = @_;
if ($use_spotlight_p == -1) {
$use_spotlight_p = 0;
if (-x '/usr/bin/mdfind') {
$use_spotlight_p = 1;
}
}
my $url;
($url, $dir) = mirror_feed ($dir);
if ($url) {
$use_spotlight_p = 0;
print STDERR "$progname: $dir is cache for $url\n" if ($verbose > 1);
}
@all_files = read_cache ($dir);
if ($#all_files >= 0) {
# got it from the cache...
} elsif ($use_spotlight_p) {
print STDERR "$progname: spotlighting $dir...\n" if ($verbose);
spotlight_all_files ($dir);
print STDERR "$progname: found " . ($#all_files+1) .
" file" . ($#all_files == 0 ? "" : "s") .
" via Spotlight\n"
if ($verbose);
} else {
print STDERR "$progname: recursively reading $dir...\n" if ($verbose);
find_all_files ($dir);
print STDERR "$progname: " .
"f=" . ($#all_files+1) . "; " .
"d=$dir_count; " .
"s=$stat_count; " .
"skip=${skip_count_unstat}+$skip_count_stat=" .
($skip_count_unstat + $skip_count_stat) .
".\n"
if ($verbose);
}
write_cache ($dir);
if ($#all_files < 0) {
print STDERR "$progname: no image files in $dir\n";
exit 1;
}
my $max_tries = 50;
my $total_files = @all_files;
my $sparse_p = ($total_files < 20);
# If the directory has a lot of files in it:
# Make a pass through looking for hirez files (assume some are thumbs);
# If we found none, then, select any other file at random.
# Otherwise if there are a small number of files:
# Just select one at random (in case there's like, just one hirez).
for (my $check_size_p = $sparse_p ? 0 : 1;
$check_size_p >= 0; $check_size_p--) {
for (my $i = 0; $i < $max_tries; $i++) {
my $n = int (rand ($total_files));
my $file = $all_files[$n];
if (!$check_size_p || large_enough_p ($file)) {
if (! $url) {
$file =~ s@^\Q$dir/@@so || die; # remove $dir from front
}
return $file;
}
}
}
print STDERR "$progname: no suitable images in " . ($url || $dir) . " -- " .
($total_files <= $max_tries
? "all $total_files images"
: "$max_tries of $total_files images") .
" are smaller than ${min_image_width}x${min_image_height}.\n";
# If we got here, blow away the cache. Maybe it's stale.
unlink $cache_file_name if $cache_file_name;
exit 1;
}
sub large_enough_p($) {
my ($file) = @_;
my ($w, $h) = image_file_size ($file);
if (!defined ($h)) {
# Nonexistent files are obviously too small!
# Already printed $verbose message about the file not existing.
return 0 unless -f $file;
print STDERR "$progname: $file: unable to determine image size\n"
if ($verbose);
# Assume that unknown files are of good sizes: this will happen if
# they matched $good_file_re, but we don't have code to parse them.
# (This will also happen if the file is junk...)
return 1;
}
if ($w < $min_image_width || $h < $min_image_height) {
print STDERR "$progname: $file: too small ($w x $h)\n" if ($verbose);
return 0;
}
print STDERR "$progname: $file: $w x $h\n" if ($verbose);
return 1;
}
# Given the raw body of a GIF document, returns the dimensions of the image.
#
sub gif_size($) {
my ($body) = @_;
my $type = substr($body, 0, 6);
my $s;
return () unless ($type =~ /GIF8[7,9]a/);
$s = substr ($body, 6, 10);
my ($a,$b,$c,$d) = unpack ("C"x4, $s);
return (($b<<8|$a), ($d<<8|$c));
}
# Given the raw body of a JPEG document, returns the dimensions of the image.
#
sub jpeg_size($) {
my ($body) = @_;
my $i = 0;
my $L = length($body);
my $c1 = substr($body, $i, 1); $i++;
my $c2 = substr($body, $i, 1); $i++;
return () unless (ord($c1) == 0xFF && ord($c2) == 0xD8);
my $ch = "0";
while (ord($ch) != 0xDA && $i < $L) {
# Find next marker, beginning with 0xFF.
while (ord($ch) != 0xFF) {
return () if (length($body) <= $i);
$ch = substr($body, $i, 1); $i++;
}
# markers can be padded with any number of 0xFF.
while (ord($ch) == 0xFF) {
return () if (length($body) <= $i);
$ch = substr($body, $i, 1); $i++;
}
# $ch contains the value of the marker.
my $marker = ord($ch);
if (($marker >= 0xC0) &&
($marker <= 0xCF) &&
($marker != 0xC4) &&
($marker != 0xCC)) { # it's a SOFn marker
$i += 3;
return () if (length($body) <= $i);
my $s = substr($body, $i, 4); $i += 4;
my ($a,$b,$c,$d) = unpack("C"x4, $s);
return (($c<<8|$d), ($a<<8|$b));
} else {
# We must skip variables, since FFs in variable names aren't
# valid JPEG markers.
return () if (length($body) <= $i);
my $s = substr($body, $i, 2); $i += 2;
my ($c1, $c2) = unpack ("C"x2, $s);
my $length = ($c1 << 8) | $c2;
return () if ($length < 2);
$i += $length-2;
}
}
return ();
}
# Given the raw body of a PNG document, returns the dimensions of the image.
#
sub png_size($) {
my ($body) = @_;
return () unless ($body =~ m/^\211PNG\r/s);
my ($bits) = ($body =~ m/^.{12}(.{12})/s);
return () unless defined ($bits);
return () unless ($bits =~ /^IHDR/);
my ($ign, $w, $h) = unpack("a4N2", $bits);
return ($w, $h);
}
# Given the raw body of a GIF, JPEG, or PNG document, returns the dimensions
# of the image.
#
sub image_size($) {
my ($body) = @_;
return () if (length($body) < 10);
my ($w, $h) = gif_size ($body);
if ($w && $h) { return ($w, $h); }
($w, $h) = jpeg_size ($body);
if ($w && $h) { return ($w, $h); }
# #### TODO: need image parsers for TIFF, XPM, XBM.
return png_size ($body);
}
# Returns the dimensions of the image file.
#
sub image_file_size($) {
my ($file) = @_;
my $in;
if (! open ($in, '<:raw', $file)) {
print STDERR "$progname: $file: $!\n" if ($verbose);
return ();
}
my $body = '';
sysread ($in, $body, 1024 * 50); # The first 50k should be enough.
close $in; # (It's not for certain huge jpegs...
return image_size ($body); # but we know they're huge!)
}
# Reads the prefs we use from ~/.xscreensaver
#
sub get_x11_prefs() {
my $got_any_p = 0;
if (open (my $in, '<', $config_file)) {
print STDERR "$progname: reading $config_file\n" if ($verbose > 1);
local $/ = undef; # read entire file
my $body = <$in>;
close $in;
$got_any_p = get_x11_prefs_1 ($body);
} elsif ($verbose > 1) {
print STDERR "$progname: $config_file: $!\n";
}
if (! $got_any_p && defined ($ENV{DISPLAY})) {
# We weren't able to read settings from the .xscreensaver file.
# Fall back to any settings in the X resource database
# (/usr/X11R6/lib/X11/app-defaults/XScreenSaver)
#
print STDERR "$progname: reading X resources\n" if ($verbose > 1);
my $body = `appres XScreenSaver xscreensaver -1`;
$got_any_p = get_x11_prefs_1 ($body);
}
}
sub get_x11_prefs_1($) {
my ($body) = @_;
my $got_any_p = 0;
$body =~ s@\\\n@@gs;
$body =~ s@^[ \t]*#[^\n]*$@@gm;
if ($body =~ m/^[.*]*imageDirectory:[ \t]*([^\s]+)\s*$/im) {
$image_directory = $1;
$got_any_p = 1;
}
return $got_any_p;
}
sub get_cocoa_prefs($) {
my ($id) = @_;
print STDERR "$progname: reading Cocoa prefs: \"$id\"\n" if ($verbose > 1);
my $v = get_cocoa_pref_1 ($id, "imageDirectory");
$v = '~/Pictures' unless defined ($v); # Match default in XScreenSaverView
$image_directory = $v if defined ($v);
}
sub get_cocoa_pref_1($$) {
my ($id, $key) = @_;
# make sure there's nothing stupid/malicious in either string.
$id =~ s/[^-a-z\d. ]/_/gsi;
$key =~ s/[^-a-z\d. ]/_/gsi;
my $cmd = "defaults -currentHost read \"$id\" \"$key\"";
print STDERR "$progname: executing $cmd\n"
if ($verbose > 3);
my $val = `$cmd 2>/dev/null`;
$val =~ s/^\s+//s;
$val =~ s/\s+$//s;
print STDERR "$progname: Cocoa: $id $key = \"$val\"\n"
if ($verbose > 2);
$val = undef if ($val =~ m/^$/s);
return $val;
}
sub error($) {
my ($err) = @_;
print STDERR "$progname: $err\n";
exit 1;
}
sub usage() {
print STDERR "usage: $progname [--verbose] [ directory-or-feed-url ]\n\n" .
" Prints the name of a randomly-selected image file. The directory\n" .
" is searched recursively. Images smaller than " .
"${min_image_width}x${min_image_height} are excluded.\n" .
"\n" .
" The directory may also be the URL of an RSS/Atom feed. Enclosed\n" .
" images will be downloaded and cached locally.\n" .
"\n";
exit 1;
}
sub main() {
my $cocoa_id = undef;
my $abs_p = 0;
while ($_ = $ARGV[0]) {
shift @ARGV;
if (m/^--?verbose$/s) { $verbose++; }
elsif (m/^-v+$/s) { $verbose += length($_)-1; }
elsif (m/^--?name$/s) { } # ignored, for compatibility
elsif (m/^--?spotlight$/s) { $use_spotlight_p = 1; }
elsif (m/^--?no-spotlight$/s) { $use_spotlight_p = 0; }
elsif (m/^--?cache$/s) { $cache_p = 1; }
elsif (m/^--?no-?cache$/s) { $cache_p = 0; }
elsif (m/^--?cocoa$/) { $cocoa_id = shift @ARGV; }
elsif (m/^--?abs(olute)?$/) { $abs_p = 1; }
elsif (m/^-./) { usage; }
elsif (!defined($image_directory)) { $image_directory = $_; }
else { usage; }
}
# Most hacks (X11 and Cocoa) pass a --directory value on the command line,
# but if they don't, look it up from the resources. Currently this only
# happens with "glitchpeg" which invokes xscreensaver-getimage-file
# directly instead of going through the traditional path.
#
if (! $image_directory) {
if (!defined ($cocoa_id)) {
# see OSX/XScreenSaverView.m
$cocoa_id = $ENV{XSCREENSAVER_CLASSPATH};
}
if (defined ($cocoa_id)) {
get_cocoa_prefs($cocoa_id);
error ("no imageDirectory in $cocoa_id") unless $image_directory;
} else {
get_x11_prefs();
error ("no imageDirectory in X11 resources") unless $image_directory;
}
}
usage unless (defined($image_directory));
$image_directory =~ s@^feed:@http:@si;
if ($image_directory =~ m/^https?:/si) {
# ok
} else {
$image_directory =~ s@^~/@$ENV{HOME}/@s; # allow literal "~/"
$image_directory =~ s@/+$@@s; # omit trailing /
if (! -d $image_directory) {
print STDERR "$progname: $image_directory not a directory or URL\n";
usage;
}
}
my $file = find_random_file ($image_directory);
# With --absolute return fully qualified paths instead of relative to --dir.
if ($abs_p &&
$file !~ m@^/@ &&
$image_directory =~ m@^/@s) {
$file = "$image_directory/$file";
$file =~ s@//+@/@gs;
}
print STDOUT "$file\n";
}
main;
exit 0;
