/[fuse_dbi]/trunk/examples/webgui.pl
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, Sun Aug 29 20:12:37 2004 UTC revision 27 by dpavlin, Fri Oct 8 22:56:55 2004 UTC
# Line 3  Line 3 
3  use strict;  use strict;
4  use blib;  use blib;
5  use Fuse::DBI;  use Fuse::DBI;
6    use lib '/data/WebGUI/lib/';
7    use Data::Config;
8    
9  my $sql_filenames = q{  =head1 NAME
         select  
                 oid as id,  
                 namespace||'/'||name||' ['||oid||']' as filename,  
                 length(template) as size,  
                 iseditable as writable  
         from template ;  
 };  
10    
11  my $sql_read = q{  webgui.pl - mount WebGUI templates as filesystem
12          select template  
13                  from template  =head1 SYNOPSIS
                 where oid = ?;  
 };  
14    
15  my $sql_update = q{   webgui.pl /data/WebGUI/etc/webgui.conf /mnt
16          update template  
17                  set template = ?          =head1 DESCRIPTION
18                  where oid = ?;  
19    With this script, you can utilize C<Fuse> and C<Fuse::DBI> modules to mount
20    templates from WebGUI and edit them using command-line utilities (like C<vi>
21    or C<ftp>).
22    
23    It will present templates in WebGUI as directory tree consisting of
24    directories (which represent template's namespace) and files (which are
25    templates from database). If template name has slash (C</>) in name, deeper
26    directories will be created.
27    
28    Template files will have correct lengths and write permissions which are
29    specified in WebGUI database.
30    
31    =head2 Fuse module
32    
33    C<Fuse::DBI> module (which is core of this utility) uses C<Fuse> perl
34    bindings. Perl bindings are rather new addition to C<Fuse>, so
35    you will need recent CVS version of C<Fuse>. Current stable version doesn't
36    include perl binding, so you will probably have to compile C<Fuse> yourself
37    (see FUSE documentation for details about compilation and installation).
38    
39    After compilation and installation of C<fuse> kernel module and C<Fuse> perl
40    bindings for it, you will have to load C<fuse> module into kernel. For that,
41    you will have to be root. If you are not administrator on particular
42    machine, ask your admin to install and load C<fuse> module for you.
43    
44    If you used C<fusermount> command before running this script, module will be
45    already loaded.
46    
47    =head2 unsupported operations
48    
49    There is no support for creation of new templates, renaming, or deleting.
50    Although those operations map nicely to file system semantics there are still
51    possible only using WebGUI web interface.
52    
53    =head2 unlink to invalidate cache
54    
55    Unlink command (C<rm>) is implemented on files with special function: it
56    will remove in-memory cache of particular template and reload it from
57    database. That enables usage of web interface to make small changes and then
58    continuing editing using this script without restarting it.
59    
60    In-memory cache is populated with data about available templates when you
61    start this script. Currently only way to refresh template list (after you
62    create copy of template through web interface) is to remove directory using
63    C<rmdir> or C<rm -rf>.
64    
65    B<Don't panic!> Destructive operations in filesystem (C<rm> and C<rmdir>)
66    just invalidate in-memory cache and re-read data from database (this will
67    also change ctime of file, so your editor will probably notice that file has
68    changed).
69    
70    In-memory cache is used to speed up operations like grep on templates. If it
71    wasn't there, grep wouldn't be useful at all. I think this is acceptable
72    compromise.
73    
74    =head2 invalidating of on-disk templates
75    
76    Every write operation will erase all templates on disk (so that next reload
77    on browser will show your changes). It would be better if just changed
78    template is erased, but this works well enough. You might notice performance
79    penalty of this simplification if you are running very loaded production
80    site.
81    
82    You have to have write permission on C<uploads/temp/templates/> directory
83    for your WebGUI instance for this to work. If you don't C<Fuse::DBI> will
84    complain.
85    
86    =head2 supported databases
87    
88    This script have embedded SQL queries for MySQL and PostgreSQL. Other databases
89    could be supported easily. Contributions are welcomed.
90    
91    =head2 database transactions
92    
93    C<Fuse::DBI> uses transactions (if your database supports them) to prevent
94    accidental corruption of data by reading old version. Depending on type of
95    database back-end, MySQL users might be out of luck.
96    
97    =head2 recovering from errors
98    
99    B<Transport endpoint is not connected> is very often error when Fuse perl
100    bindings exit without clean umount (through C<Fuse::DBI> C<umount> method or
101    with C<fusermount -u /mnt> command).
102    
103    This script will automatically run C<fusermount -u /mnt> if it receives
104    above error on startup. If it fails, mount point is still in use (that
105    happens if you changed directory to mount point in other shell). Solution is
106    simple, just change directory in other back to C<$HOME> (with just C<cd>)
107    and re-run this script.
108    
109    =head2 missing Data::Config
110    
111    If this script complains about missing C<Data::Config> module, you will have
112    to point path at top which points to lib directory of WebGUI installation.
113    By default it points to C</data/WebGUI>:
114    
115     use lib '/data/WebGUI/lib/';
116    
117    =cut
118    
119    my ($config_file,$mount) = @ARGV;
120    
121    unless ($config_file && $mount) {
122            print STDERR <<_USAGE_;
123    usage: $0 /data/WebGUI/etc/webgui.conf /mnt
124    
125    For more information see perldoc webgui.pl
126    _USAGE_
127            exit 1;
128    }
129    
130    system "fusermount -u $mount" unless (-w $mount);
131    
132    unless (-w $mount) {
133            print STDERR "Current user doesn't have permission on mount point $mount: $!";
134            exit 1;
135    }
136    
137    my $config = new Data::Config $config_file || "can't open config $config_file: $!";
138    
139    my $sql = {
140            'pg' => {
141                    'filenames' => q{
142                            select
143                                    oid as id,
144                                    namespace||'/'||name||' ['||oid||']' as filename,
145                                    length(template) as size,
146                                    iseditable as writable
147                            from template ;
148                    },
149                    'read' => q{
150                            select template
151                                    from template
152                                    where oid = ?;
153                    },
154                    'update' => q{
155                            update template
156                                    set template = ?        
157                                    where oid = ?;
158                    },
159            },
160            'mysql' => {
161                    'filenames' => q{
162                            select
163                                    concat(templateid,name) as id,
164                                    concat(namespace,'/',name,'.html') as filename,
165                                    length(template) as size,
166                                    iseditable as writable
167                            from template ;
168                    },
169                    'read' => q{
170                            select template
171                                    from template
172                                    where concat(templateid,name) = ?;
173                    },
174                    'update' => q{
175                            update template
176                                    set template = ?        
177                                    where concat(templateid,name) = ?;
178                    },
179            },
180  };  };
181    
182    my $dsn = $config->param('dsn');
183    my $db;
184    
185    if ($dsn =~ m/DBI:(mysql|pg):/) {
186            $db = $1;
187    } else {
188            print STDERR "can't find supported database (mysql/pg) in dsn: $dsn\n";
189            exit 1;
190    }
191    
192    my $template_dir = $config->param('uploadsPath') . '/temp/templates/';
193    
194    print "using database '$db', template dir '$template_dir' and mountpoint $mount\n";
195    
196  my $mnt = Fuse::DBI->mount({  my $mnt = Fuse::DBI->mount({
197          filenames => $sql_filenames,          filenames => $sql->{$db}->{'filenames'},
198          read => $sql_read,          read => $sql->{$db}->{'read'},
199          update => $sql_update,          update => $sql->{$db}->{'update'},
200          dsn => 'DBI:Pg:dbname=webgui',          dsn => $config->param('dsn'),
201          mount => '/mnt2',          user => $config->param('dbuser'),
202            password => $config->param('dbpass'),
203            mount => $mount,
204            fork => 1,
205            invalidate => sub {
206                    print STDERR "invalidating content in $template_dir\n";
207                    opendir(DIR, $template_dir) || die "can't opendir $template_dir: $!";
208                    map { unlink "$template_dir/$_" || warn "can't remove $template_dir/$_: $!" } grep { !/^\./ && -f "$template_dir/$_" } readdir(DIR);
209                    closedir DIR;
210            },
211  });  });
212    
213  print "Press enter to exit...";  print "Press enter to exit...";
214  my $foo = <STDIN>;  my $foo = <STDIN>;
215    
216  $mnt->umount;  $mnt->umount;
217    
218    =head1 SEE ALSO
219    
220    C<Fuse::DBI> website
221    L<https://www.rot13.org/~dpavlin/fuse_dbi.html>
222    
223    C<FUSE (Filesystem in USErspace)> website
224    L<http://sourceforge.net/projects/avf>
225    
226    =head1 AUTHOR
227    
228    Dobrica Pavlinusic, E<lt>dpavlin@rot13.orgE<gt>
229    
230    =head1 COPYRIGHT AND LICENSE
231    
232    Copyright (C) 2004 by Dobrica Pavlinusic
233    
234    This library is free software; you can redistribute it and/or modify
235    it under the same terms as Perl itself, either Perl version 5.8.4 or,
236    at your option, any later version of Perl 5 you may have available.
237    
238    =cut
239    
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