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#
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# URLcache.pm
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#
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# Originally Written by Christopher Williams
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#
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# Description
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# -----------
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# Simple url->file lookup (persistent)
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#
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# Interface
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# ---------
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# new(cachedir) : A new URLcache object in a given directory
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# store(url,file) : store a url/file combination
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# file(url) : return the file for a given url
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# delete(url) : remove from cache url
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# clear() : clear cache
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# filestore() : Return the directory to download files to
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# filename(url) : return a unique file/dir in cache for the given url
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# updatenumber(int) : return an integer number changed with each store
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package URL::URLcache;
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require 5.004;
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use Utilities::HashDB;
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sub new {
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my $class=shift;
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$self={};
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bless $self, $class;
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$self->init(@_);
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return $self;
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}
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sub filestore {
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my $self=shift;
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return $self->{cachedir};
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}
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sub filename {
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my $self=shift;
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my $url=shift;
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my $filenumber;
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my $file=$self->file($url);
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if ( $file eq "" ) {
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# need to generate a new filename - a random number will do
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srand();
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do {
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$filenumber=int(rand 9999999)+1;
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$file=$self->filestore()."/".$filenumber;
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} until ( ! ( -e $file ) );
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}
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return $file;
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}
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sub init {
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my $self=shift;
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$self->{cachetop}=shift;
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$self->{cachedir}=$self->{cachetop}."/files";
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AddDir::adddir($self->{cachedir});
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$self->{cacheindex}=$self->{cachetop}."/index.db";
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$self->{cacheseqindex}=$self->{cachetop}."/seqnumb.db";
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$self->{urlDB}=Utilities::HashDB->new();
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$self->{urlDBupdate}=Utilities::HashDB->new();
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if ( -f $self->{cacheindex} ) {
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$self->{urlDB}->restore($self->{cacheindex});
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}
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else {
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AddDir::adddir($self->{cachedir});
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}
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if ( -f $self->{cacheseqindex} ) {
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$self->{urlDBupdate}->restore($self->{cacheseqindex});
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}
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}
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sub file {
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my $self=shift;
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my $url=shift;
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my @found=$self->{urlDB}->getdata($url);
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return ( ($#found == -1)?"":$found[0]);
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}
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sub delete {
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my $self=shift;
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my $url=shift;
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unlink ($self->{urlDB}->getdata($URL));
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$self->{urlDB}->deletedata($url);
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$self->{urlDB}->store($self->{cacheindex});
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}
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sub store {
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my $self=shift;
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my $url=shift;
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my $file=shift;
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$self->{urlDB}->deletedata($url);
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$self->{urlDB}->setdata($file,$url);
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$self->{urlDB}->store($self->{cacheindex});
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# Keep a track of changes
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my ($sequencenumber)=$self->{urlDBupdate}->getdata($url);
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if ( ! defined $sequencenumber ) { $sequencenumber=0 };
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$sequencenumber=$sequencenumber+1;
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$self->{urlDBupdate}->deletedata($url);
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$self->{urlDBupdate}->setdata($sequencenumber,$url);
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$self->{urlDBupdate}->store($self->{cacheseqindex});
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}
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sub updatenumber {
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my $self=shift;
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my $url=shift;
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return $self->{urlDBupdate}->getdata($url);
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}
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sub clear {
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my $self=shift;
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foreach $item ( $self->{urlDB}->match() ) {
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$self->delete($item->keys());
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}
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}
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