/[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 31 by dpavlin, Sun Oct 10 19:33:23 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 = '0.04';
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    
# Line 32  This module will use C<Fuse> module, par Line 32  This module will use C<Fuse> module, par
32  available at L<http://sourceforge.net/projects/avf> to mount  available at L<http://sourceforge.net/projects/avf> 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 182  Checks if C<fuse> module is loaded in ke Line 236  Checks if C<fuse> module is loaded in ke
236    die "no fuse module loaded in kernel"    die "no fuse module loaded in kernel"
237          unless (Fuse::DBI::fuse_module_loaded);          unless (Fuse::DBI::fuse_module_loaded);
238    
239  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.
240    
241  =cut  =cut
242    
# Line 310  sub read_content { Line 364  sub read_content {
364    
365          $sth->{'read'}->execute($id) || die $sth->{'read'}->errstr;          $sth->{'read'}->execute($id) || die $sth->{'read'}->errstr;
366          $files{$file}{cont} = $sth->{'read'}->fetchrow_array;          $files{$file}{cont} = $sth->{'read'}->fetchrow_array;
367          $files{$file}{ctime} = time();          # I should modify ctime only if content in database changed
368            #$files{$file}{ctime} = time() unless ($files{$file}{ctime});
369          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";
370  }  }
371    
# Line 356  sub clear_cont { Line 411  sub clear_cont {
411          print "invalidate all cached content\n";          print "invalidate all cached content\n";
412          foreach my $f (keys %files) {          foreach my $f (keys %files) {
413                  delete $files{$f}{cont};                  delete $files{$f}{cont};
414                    delete $files{$f}{ctime};
415          }          }
416          print "begin new transaction\n";          print "begin new transaction\n";
417          #$dbh->begin_work || die $dbh->errstr;          #$dbh->begin_work || die $dbh->errstr;
# Line 469  Nothing. Line 525  Nothing.
525  C<FUSE (Filesystem in USErspace)> website  C<FUSE (Filesystem in USErspace)> website
526  L<http://sourceforge.net/projects/avf>  L<http://sourceforge.net/projects/avf>
527    
528    Example for WebGUI which comes with this distribution in
529    directory C<examples/webgui.pl>. It also contains a lot of documentation
530    about design of this module, usage and limitations.
531    
532  =head1 AUTHOR  =head1 AUTHOR
533    
534  Dobrica Pavlinusic, E<lt>dpavlin@rot13.orgE<gt>  Dobrica Pavlinusic, E<lt>dpavlin@rot13.orgE<gt>
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