/[fuse_dbi]/trunk/DBI.pm

This is repository of my old source code which isn't updated any more. Go to git.rot13.org for current projects!

Diff of /trunk/DBI.pm

Parent Directory | Revision Log | View Patch Patch

-revision 24 by dpavlin,
Fri Oct  8 20:07:12 2004 UTC
+revision 28 by dpavlin,
Fri Oct  8 23:43:06 2004 UTC
 Line 13 
 use Carp;
  use Data::Dumper;
- our $VERSION = '0.03';
+ our $VERSION = '0.04';
  =head1 NAME
 Line 24 
 Fuse::DBI - mount your database as files
    use Fuse::DBI;
    Fuse::DBI->mount( ... );
- See C<run> below for examples how to set parametars.
+ See C<run> below for examples how to set parameters.
  =head1 DESCRIPTION
 Line 32 
 This module will use C<Fuse> module, par
  available at L<http://sourceforge.net/projects/avf> to mount
  your database as file system.
- That will give you posibility to use normal file-system tools (cat, grep, vi)
+ That will give you possibility to use normal file-system tools (cat, grep, vi)
  to manipulate data in database.
  It's actually opposite of Oracle's intention to put everything into database.
 Line 46 
 It's actually opposite of Oracle's inten
  Mount your database as filesystem.
+ Let's suppose that your database have table C<files> with following structure:
+  id:            int
+  filename:      text
+  size:          int
+  content:       text
+  writable:      boolean
+ Following is example how to mount table like that to C</mnt>:
    my $mnt = Fuse::DBI->mount({
-         filenames => 'select name from files_table as filenames',
+         'filenames' => 'select id,filename,size,writable from files',
-         read => 'sql read',
+         'read' => 'select content from files where id = ?',
-         update => 'sql update',
+         'update' => 'update files set content = ? where id = ?',
-         dsn => 'DBI:Pg:dbname=webgui',
+         'dsn' => 'DBI:Pg:dbname=test_db',
-         user => 'database_user',
+         'user' => 'database_user',
-         password => 'database_password'
+         'password' => 'database_password',
+         'invalidate' => sub { ... },
    });
+ Options:
+ =over 5
+ =item filenames
+ SQL query which returns C<id> (unique id for that row), C<filename>,
+ C<size> and C<writable> boolean flag.
+ =item read
+ SQL query which returns only one column with content of file and has
+ placeholder C<?> for C<id>.
+ =item update
+ SQL query with two pace-holders, one for new content and one for C<id>.
+ =item dsn
+ C<DBI> dsn to connect to (contains database driver and name of database).
+ =item user
+ User with which to connect to database
+ =item password
+ Password for connecting to database
+ =item invalidate
+ Optional anonymous code reference which will be executed when data is updated in
+ database. It can be used as hook to delete cache (for example on-disk-cache)
+ which is created from data edited through C<Fuse::DBI>.
+ =item fork
+ Optional flag which forks after mount so that executing script will continue
+ running. Implementation is experimental.
+ =back
  =cut
  my $dbh;
-Line 84 
 sub mount {
+Line 138 
 sub mount {
          # save (some) arguments in self
          foreach (qw(mount invalidate)) {
                  $self->{$_} = $arg->{$_};
-                 $fuse_self->{$_} = $arg->{$_};
          }
          foreach (qw(filenames read update)) {
-Line 105 
 sub mount {
+Line 158 
 sub mount {
          $dbh = DBI->connect($arg->{'dsn'},$arg->{'user'},$arg->{'password'}, {AutoCommit => 0, RaiseError => 1}) || die $DBI::errstr;
-         $sth->{filenames} = $dbh->prepare($arg->{'filenames'}) || die $dbh->errstr();
+         $sth->{'filenames'} = $dbh->prepare($arg->{'filenames'}) || die $dbh->errstr();
          $sth->{'read'} = $dbh->prepare($arg->{'read'}) || die $dbh->errstr();
          $sth->{'update'} = $dbh->prepare($arg->{'update'}) || die $dbh->errstr();
+         $self->{'sth'} = $sth;
+         $self->{'read_filenames'} = sub { $self->read_filenames };
          $self->read_filenames;
+         $self->{'mounted'} = 1;
+         $fuse_self = \$self;
          Fuse::main(
                  mountpoint=>$arg->{'mount'},
                  getattr=>\&e_getattr,
-Line 123 
 sub mount {
+Line 184 
 sub mount {
                  utime=>\&e_utime,
                  truncate=>\&e_truncate,
                  unlink=>\&e_unlink,
+                 rmdir=>\&e_unlink,
                  debug=>0,
          );
+         $self->{'mounted'} = 0;
          exit(0) if ($arg->{'fork'});
-Line 146 
 database to filesystem.
+Line 210 
 database to filesystem.
  sub umount {
          my $self = shift;
-         system "fusermount -u ".$self->{'mount'} || croak "umount error: $!";
+         if ($self->{'mounted'}) {
+                 system "fusermount -u ".$self->{'mount'} || croak "umount error: $!";
+         }
          return 1;
  }
- #$SIG{'INT'} = sub {
+ $SIG{'INT'} = sub {
- #       print STDERR "umount called by SIG INT\n";
+         print STDERR "umount called by SIG INT\n";
- #       umount;
+         umount;
- #};
+ };
  sub DESTROY {
          my $self = shift;
+         return if (! $self->{'mounted'});
          print STDERR "umount called by DESTROY\n";
          $self->umount;
  }
-Line 169 
 Checks if C<fuse> module is loaded in ke
+Line 236 
 Checks if C<fuse> module is loaded in ke
    die "no fuse module loaded in kernel"
          unless (Fuse::DBI::fuse_module_loaded);
- This function in called by L<mount>, but might be useful alone also.
+ This function in called by C<mount>, but might be useful alone also.
  =cut
-Line 189 
 my %dirs;
+Line 256 
 my %dirs;
  sub read_filenames {
          my $self = shift;
+         my $sth = $self->{'sth'} || die "no sth argument";
          # create empty filesystem
          (%files) = (
                  '.' => {
-Line 295 
 sub read_content {
+Line 364 
 sub read_content {
          $sth->{'read'}->execute($id) || die $sth->{'read'}->errstr;
          $files{$file}{cont} = $sth->{'read'}->fetchrow_array;
+         $files{$file}{ctime} = time();
          print "file '$file' content [",length($files{$file}{cont})," bytes] read in cache\n";
  }
-Line 368 
 sub update_db {
+Line 438 
 sub update_db {
                  }
                  print "updated '$file' [",$files{$file}{id},"]\n";
-                 $fuse_self->{'invalidate'}->() if (ref $fuse_self->{'invalidate'});
+                 $$fuse_self->{'invalidate'}->() if (ref $$fuse_self->{'invalidate'});
          }
          return 1;
  }
-Line 428 
 sub e_statfs { return 255, 1, 1, 1, 1, 2
+Line 498 
 sub e_statfs { return 255, 1, 1, 1, 1, 2
  sub e_unlink {
          my $file = filename_fixup(shift);
-         return -ENOENT() unless exists($files{$file});
+         if (exists( $dirs{$file} )) {
+                 print "unlink '$file' will re-read template names\n";
-         print "unlink '$file' will invalidate cache\n";
+                 print Dumper($fuse_self);
+                 $$fuse_self->{'read_filenames'}->();
-         read_content($file,$files{$file}{id});
+                 return 0;
+         } elsif (exists( $files{$file} )) {
+                 print "unlink '$file' will invalidate cache\n";
+                 read_content($file,$files{$file}{id});
+                 return 0;
+         }
-         return 0;
+         return -ENOENT();
  }
 ;
  __END__
-Line 448 
 Nothing.
+Line 523 
 Nothing.
  C<FUSE (Filesystem in USErspace)> website
  L<http://sourceforge.net/projects/avf>
+ Example for WebGUI which comes with this distribution in
+ directory L<examples/webgui.pl>. It also contains a lot of documentation
+ about design of this module, usage and limitations.
  =head1 AUTHOR
  Dobrica Pavlinusic, E<lt>dpavlin@rot13.orgE<gt>

 Legend:



Removed from v.24
 


changed lines


 
Added in v.28
 Legend:



Removed from v.24
 


changed lines


 
Added in v.28
-Removed from v.24
+Added in v.28

	ViewVC Help
Powered by ViewVC 1.1.26