/[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!
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revision 26 by dpavlin, Fri Oct 8 22:55:36 2004 UTC revision 51 by dpavlin, Sat Nov 27 14:02:18 2004 UTC
# Line 13  use Carp; Line 13  use Carp;
13  use Data::Dumper;  use Data::Dumper;
14    
15    
16  our $VERSION = '0.03';  our $VERSION = '0.07';
17    
18  =head1 NAME  =head1 NAME
19    
# Line 24  Fuse::DBI - mount your database as files Line 24  Fuse::DBI - mount your database as files
24    use Fuse::DBI;    use Fuse::DBI;
25    Fuse::DBI->mount( ... );    Fuse::DBI->mount( ... );
26    
27  See C<run> below for examples how to set parametars.  See C<run> below for examples how to set parameters.
28    
29  =head1 DESCRIPTION  =head1 DESCRIPTION
30    
31  This module will use C<Fuse> module, part of C<FUSE (Filesystem in USErspace)>  This module will use C<Fuse> module, part of C<FUSE (Filesystem in USErspace)>
32  available at L<http://sourceforge.net/projects/avf> to mount  available at L<http://fuse.sourceforge.net/> to mount
33  your database as file system.  your database as file system.
34    
35  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)
36  to manipulate data in database.  to manipulate data in database.
37    
38  It's actually opposite of Oracle's intention to put everything into database.  It's actually opposite of Oracle's intention to put everything into database.
# Line 46  It's actually opposite of Oracle's inten Line 46  It's actually opposite of Oracle's inten
46    
47  Mount your database as filesystem.  Mount your database as filesystem.
48    
49    Let's suppose that your database have table C<files> with following structure:
50    
51     id:            int
52     filename:      text
53     size:          int
54     content:       text
55     writable:      boolean
56    
57    Following is example how to mount table like that to C</mnt>:
58    
59    my $mnt = Fuse::DBI->mount({    my $mnt = Fuse::DBI->mount({
60          filenames => 'select name from files_table as filenames',          'filenames' => 'select id,filename,size,writable from files',
61          read => 'sql read',          'read' => 'select content from files where id = ?',
62          update => 'sql update',          'update' => 'update files set content = ? where id = ?',
63          dsn => 'DBI:Pg:dbname=webgui',          'dsn' => 'DBI:Pg:dbname=test_db',
64          user => 'database_user',          'user' => 'database_user',
65          password => 'database_password'          'password' => 'database_password',
66            'invalidate' => sub { ... },
67    });    });
68    
69    Options:
70    
71    =over 5
72    
73    =item filenames
74    
75    SQL query which returns C<id> (unique id for that row), C<filename>,
76    C<size> and C<writable> boolean flag.
77    
78    =item read
79    
80    SQL query which returns only one column with content of file and has
81    placeholder C<?> for C<id>.
82    
83    =item update
84    
85    SQL query with two pace-holders, one for new content and one for C<id>.
86    
87    =item dsn
88    
89    C<DBI> dsn to connect to (contains database driver and name of database).
90    
91    =item user
92    
93    User with which to connect to database
94    
95    =item password
96    
97    Password for connecting to database
98    
99    =item invalidate
100    
101    Optional anonymous code reference which will be executed when data is updated in
102    database. It can be used as hook to delete cache (for example on-disk-cache)
103    which is created from data edited through C<Fuse::DBI>.
104    
105    =item fork
106    
107    Optional flag which forks after mount so that executing script will continue
108    running. Implementation is experimental.
109    
110    =back
111    
112  =cut  =cut
113    
114  my $dbh;  my $dbh;
# Line 78  sub mount { Line 132  sub mount {
132    
133          print Dumper($arg);          print Dumper($arg);
134    
135            unless ($self->fuse_module_loaded) {
136                    print STDERR "no fuse module loaded. Trying sudo modprobe fuse!\n";
137                    system "sudo modprobe fuse" || die "can't modprobe fuse using sudo!\n";
138            }
139    
140          carp "mount needs 'dsn' to connect to (e.g. dsn => 'DBI:Pg:dbname=test')" unless ($arg->{'dsn'});          carp "mount needs 'dsn' to connect to (e.g. dsn => 'DBI:Pg:dbname=test')" unless ($arg->{'dsn'});
141          carp "mount needs 'mount' as mountpoint" unless ($arg->{'mount'});          carp "mount needs 'mount' as mountpoint" unless ($arg->{'mount'});
142    
# Line 98  sub mount { Line 157  sub mount {
157                  die "fork() failed: $!" unless defined $pid;                  die "fork() failed: $!" unless defined $pid;
158                  # child will return to caller                  # child will return to caller
159                  if ($pid) {                  if ($pid) {
160                          return $self;                          my $counter = 4;
161                            while ($counter && ! $self->is_mounted) {
162                                    select(undef, undef, undef, 0.5);
163                                    $counter--;
164                            }
165                            if ($self->is_mounted) {
166                                    return $self;
167                            } else {
168                                    return undef;
169                            }
170                  }                  }
171          }          }
172    
# Line 115  sub mount { Line 183  sub mount {
183          $self->{'read_filenames'} = sub { $self->read_filenames };          $self->{'read_filenames'} = sub { $self->read_filenames };
184          $self->read_filenames;          $self->read_filenames;
185    
         $self->{'mounted'} = 1;  
   
186          $fuse_self = \$self;          $fuse_self = \$self;
187    
188          Fuse::main(          Fuse::main(
# Line 134  sub mount { Line 200  sub mount {
200                  debug=>0,                  debug=>0,
201          );          );
202                    
         $self->{'mounted'} = 0;  
   
203          exit(0) if ($arg->{'fork'});          exit(0) if ($arg->{'fork'});
204    
205          return 1;          return 1;
206    
207  };  };
208    
209    =head2 is_mounted
210    
211    Check if fuse filesystem is mounted
212    
213      if ($mnt->is_mounted) { ... }
214    
215    =cut
216    
217    sub is_mounted {
218            my $self = shift;
219    
220            my $mounted = 0;
221            my $mount = $self->{'mount'} || confess "can't find mount point!";
222            if (open(MTAB, "/etc/mtab")) {
223                    while(<MTAB>) {
224                            $mounted = 1 if (/ $mount fuse /i);
225                    }
226                    close(MTAB);
227            } else {
228                    warn "can't open /etc/mtab: $!";
229            }
230    
231            return $mounted;
232    }
233    
234    
235  =head2 umount  =head2 umount
236    
237  Unmount your database as filesystem.  Unmount your database as filesystem.
# Line 156  database to filesystem. Line 246  database to filesystem.
246  sub umount {  sub umount {
247          my $self = shift;          my $self = shift;
248    
249          if ($self->{'mounted'}) {          if ($self->{'mount'} && $self->is_mounted) {
250                  system "fusermount -u ".$self->{'mount'} || croak "umount error: $!";                  system "fusermount -u ".$self->{'mount'}." 2>&1 >/dev/null" ||
251                            system "sudo umount ".$self->{'mount'} ||
252                            return 0;
253                    return 1;
254          }          }
255    
256          return 1;          return 0;
257  }  }
258    
259  $SIG{'INT'} = sub {  $SIG{'INT'} = sub {
260          print STDERR "umount called by SIG INT\n";          if ($fuse_self && $$fuse_self->umount) {
261          umount;                  print STDERR "umount called by SIG INT\n";
262            }
263    };
264    
265    $SIG{'QUIT'} = sub {
266            if ($fuse_self && $$fuse_self->umount) {
267                    print STDERR "umount called by SIG QUIT\n";
268            }
269  };  };
270    
271  sub DESTROY {  sub DESTROY {
272          my $self = shift;          my $self = shift;
273          return if (! $self->{'mounted'});          if ($self->umount) {
274          print STDERR "umount called by DESTROY\n";                  print STDERR "umount called by DESTROY\n";
275          $self->umount;          }
276  }  }
277    
278  =head2 fuse_module_loaded  =head2 fuse_module_loaded
# Line 182  Checks if C<fuse> module is loaded in ke Line 282  Checks if C<fuse> module is loaded in ke
282    die "no fuse module loaded in kernel"    die "no fuse module loaded in kernel"
283          unless (Fuse::DBI::fuse_module_loaded);          unless (Fuse::DBI::fuse_module_loaded);
284    
285  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.
286    
287  =cut  =cut
288    
# Line 197  sub fuse_module_loaded { Line 297  sub fuse_module_loaded {
297  }  }
298    
299  my %files;  my %files;
 my %dirs;  
300    
301  sub read_filenames {  sub read_filenames {
302          my $self = shift;          my $self = shift;
# Line 210  sub read_filenames { Line 309  sub read_filenames {
309                          type => 0040,                          type => 0040,
310                          mode => 0755,                          mode => 0755,
311                  },                  },
312                    '..' => {
313                            type => 0040,
314                            mode => 0755,
315                    },
316          #       a => {          #       a => {
317          #               cont => "File 'a'.\n",          #               cont => "File 'a'.\n",
318          #               type => 0100,          #               type => 0100,
# Line 233  sub read_filenames { Line 336  sub read_filenames {
336                          # first, entry is assumed to be file                          # first, entry is assumed to be file
337                          if ($d) {                          if ($d) {
338                                  $files{$d} = {                                  $files{$d} = {
                                                 size => $dirs{$d}++,  
339                                                  mode => 0755,                                                  mode => 0755,
340                                                  type => 0040                                                  type => 0040
341                                  };                                  };
# Line 251  sub read_filenames { Line 353  sub read_filenames {
353                  }                  }
354          }          }
355    
356          print "found ",scalar(keys %files)-scalar(keys %dirs)," files, ",scalar(keys %dirs), " dirs\n";          print "found ",scalar(keys %files)," files\n";
357  }  }
358    
359    
# Line 267  sub e_getattr { Line 369  sub e_getattr {
369          $file =~ s,^/,,;          $file =~ s,^/,,;
370          $file = '.' unless length($file);          $file = '.' unless length($file);
371          return -ENOENT() unless exists($files{$file});          return -ENOENT() unless exists($files{$file});
372          my ($size) = $files{$file}{size} || 1;          my ($size) = $files{$file}{size} || 1024;
373          my ($dev, $ino, $rdev, $blocks, $gid, $uid, $nlink, $blksize) = (0,0,0,1,0,0,1,1024);          my ($dev, $ino, $rdev, $blocks, $gid, $uid, $nlink, $blksize) = (0,0,0,int(($size+1023)/1024),0,0,1,1024);
374          my ($atime, $ctime, $mtime);          my ($atime, $ctime, $mtime);
375          $atime = $ctime = $mtime = $files{$file}{ctime} || $ctime_start;          $atime = $ctime = $mtime = $files{$file}{ctime} || $ctime_start;
376    
# Line 276  sub e_getattr { Line 378  sub e_getattr {
378    
379          # 2 possible types of return values:          # 2 possible types of return values:
380          #return -ENOENT(); # or any other error you care to          #return -ENOENT(); # or any other error you care to
381          #print(join(",",($dev,$ino,$modes,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,$blksize,$blocks)),"\n");          print "getattr($file) ",join(",",($dev,$ino,$modes,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,$blksize,$blocks)),"\n";
382          return ($dev,$ino,$modes,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,$blksize,$blocks);          return ($dev,$ino,$modes,$nlink,$uid,$gid,$rdev,$size,$atime,$mtime,$ctime,$blksize,$blocks);
383  }  }
384    
# Line 288  sub e_getdir { Line 390  sub e_getdir {
390          my %out;          my %out;
391          foreach my $f (sort keys %files) {          foreach my $f (sort keys %files) {
392                  if ($dirname) {                  if ($dirname) {
393                          if ($f =~ s/^\E$dirname\Q\///) {                          if ($f =~ s/^\Q$dirname\E\///) {
394                                  $out{$f}++ if ($f =~ /^[^\/]+$/);                                  $out{$f}++ if ($f =~ /^[^\/]+$/);
395                          }                          }
396                  } else {                  } else {
# Line 310  sub read_content { Line 412  sub read_content {
412    
413          $sth->{'read'}->execute($id) || die $sth->{'read'}->errstr;          $sth->{'read'}->execute($id) || die $sth->{'read'}->errstr;
414          $files{$file}{cont} = $sth->{'read'}->fetchrow_array;          $files{$file}{cont} = $sth->{'read'}->fetchrow_array;
415          $files{$file}{ctime} = time();          # I should modify ctime only if content in database changed
416            #$files{$file}{ctime} = time() unless ($files{$file}{ctime});
417          print "file '$file' content [",length($files{$file}{cont})," bytes] read in cache\n";          print "file '$file' content [",length($files{$file}{cont})," bytes] read in cache\n";
418  }  }
419    
# Line 356  sub clear_cont { Line 459  sub clear_cont {
459          print "invalidate all cached content\n";          print "invalidate all cached content\n";
460          foreach my $f (keys %files) {          foreach my $f (keys %files) {
461                  delete $files{$f}{cont};                  delete $files{$f}{cont};
462                    delete $files{$f}{ctime};
463          }          }
464          print "begin new transaction\n";          print "begin new transaction\n";
465          #$dbh->begin_work || die $dbh->errstr;          #$dbh->begin_work || die $dbh->errstr;
# Line 439  sub e_utime { Line 543  sub e_utime {
543          return 0;          return 0;
544  }  }
545    
546  sub e_statfs { return 255, 1, 1, 1, 1, 2 }  sub e_statfs {
547    
548            my $size = 0;
549            my $inodes = 0;
550    
551            foreach my $f (keys %files) {
552                    if ($f !~ /(^|\/)\.\.?$/) {
553                            $size += $files{$f}{size} || 0;
554                            $inodes++;
555                    }
556                    print "$inodes: $f [$size]\n";
557            }
558    
559            $size = int(($size+1023)/1024);
560    
561            my @ret = (255, $inodes+1000, $inodes, $size, $size-10, 1024);
562    
563            print "statfs: ",join(",",@ret),"\n";
564    
565            return @ret;
566    }
567    
568  sub e_unlink {  sub e_unlink {
569          my $file = filename_fixup(shift);          my $file = filename_fixup(shift);
570    
571          if (exists( $dirs{$file} )) {  #       if (exists( $dirs{$file} )) {
572                  print "unlink '$file' will re-read template names\n";  #               print "unlink '$file' will re-read template names\n";
573                  print Dumper($fuse_self);  #               print Dumper($fuse_self);
574                  $$fuse_self->{'read_filenames'}->();  #               $$fuse_self->{'read_filenames'}->();
575                  return 0;  #               return 0;
576          } elsif (exists( $files{$file} )) {          if (exists( $files{$file} )) {
577                  print "unlink '$file' will invalidate cache\n";                  print "unlink '$file' will invalidate cache\n";
578                  read_content($file,$files{$file}{id});                  read_content($file,$files{$file}{id});
579                  return 0;                  return 0;
# Line 464  __END__ Line 588  __END__
588    
589  Nothing.  Nothing.
590    
591    =head1 BUGS
592    
593    Size information (C<ls -s>) is wrong. It's a problem in upstream Fuse module
594    (for which I'm to blame lately), so when it gets fixes, C<Fuse::DBI> will
595    automagically pick it up.
596    
597  =head1 SEE ALSO  =head1 SEE ALSO
598    
599  C<FUSE (Filesystem in USErspace)> website  C<FUSE (Filesystem in USErspace)> website
600  L<http://sourceforge.net/projects/avf>  L<http://fuse.sourceforge.net/>
601    
602    Example for WebGUI which comes with this distribution in
603    directory C<examples/webgui.pl>. It also contains a lot of documentation
604    about design of this module, usage and limitations.
605    
606  =head1 AUTHOR  =head1 AUTHOR
607    
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