Catalyst: stash vs. flash

roho has asked for the wisdom of the Perl Monks concerning the following question:

I am working through the example in Jonathan Rockway's Catalyst book on pp. 43-49 to add a search function to the AddressBook application. Running the sample code from the book (with mods to switch from FormBuilder to FormFu) displays search results, but leaves the wrong URL in the address bar.

Stash Example (see lines 28, 31, 33, 37)

 1 package AddressBook::Controller::Search;
 2 use strict;
 3 use warnings;
 4 use Text::CSV_XS;
 5 use parent qw(Catalyst::Controller::HTML::FormFu);
 6 
 7 sub search : Global FormConfig {
 8     my ($self, $c, $query) = @_;
 9     my $form = $c->stash->{form};
10 
11     # Get query from search form
12     if ($form->submitted_and_valid) {
13         $query = $c->request->param('query');
14     }
15     return unless $query; # No query? We're done
16     $c->stash->{query} = $query;
17 
18     # Parse query into tokens
19     my $csv = Text::CSV_XS->new();
20     $csv->parse($query) or die "Error parsing query";
21     my @tokens = $csv->fields();
22 
23     # Process query from search form and stash results
24     my $result;
25     if ($form->submitted_and_valid) {
26         if ($c->request->param('domain') eq 'Names') {
27             $result = $c->forward('search_names', \@tokens);
28             $c->stash->{template} = 'search/name_results.tt2';
29         } else {
30             $result = $c->forward('search_addresses', \@tokens);
31             $c->stash->{template} = 'search/address_results.tt2';
32         }
33         $c->stash->{result} = $result;
34         my $page = $c->request->param('page');
35         $page = 1 if ($page !~ /^\d+$/);
36         my $page_result = $result->page($page);
37         $c->stash->{pager} = $page_result->pager;
38     }
39 }
40 
41 sub search_names : Private {
42     my ($self, $c, @tokens) = @_;
43     my @people_fields = qw/firstname lastname/;
44     @people_fields    = cross(\@people_fields, \@tokens);
45     return $c->model('AddressDB::People')->search(\@people_fields);
46 }
47 
48 sub search_addresses : Private {
49     my ($self, $c, @tokens) = @_;
50     my @address_fields = qw/postal phone email location/;
51     @address_fields = cross(\@address_fields, \@tokens);
52     return $c->model('AddressDB::Addresses')->search(\@address_fiel
+ds);
53 }
54 
55 sub cross {
56     my $columns = shift || [];
57     my $tokens  = shift || [];
58     map {s/%/\\%/g} @$tokens;
59     my @result;
60     foreach my $column (@$columns){
61         push @result, (map +{$column => {-like => "%$_%"}}, @$token
+s);
62     }
63     return @result;
64 }
65 
66 1;
[download]

Previously (pp. 39-40) the book showed how to use sessions to leave the correct URL in the address bar by using redirect as follows:
$c->response->redirect($c->uri_for('<URL path>'));

This worked fine for the "edit" and "delete" actions previously in the application, but is not working for "search".

I replaced $c->stash->{template} = '<template-name>' with $c->flash->{template} = '<template-name>' and $c->stash->{result} = $result with $c->flash->{result} = $result, and $c->stash->{pager} with $c->flash->{pager}, which generated the following error message from DBIx::Class:
undef error - Can't call method "select" on an undefined value at: C;/Perl/site/lib/DBIx/Class/ResultSet.pm line 670

Flash Example (see lines 28, 31, 33, 37)

 1 package AddressBook::Controller::Search;
 2 use strict;
 3 use warnings;
 4 use Text::CSV_XS;
 5 use parent qw(Catalyst::Controller::HTML::FormFu);
 6 
 7 sub search : Global FormConfig {
 8     my ($self, $c, $query) = @_;
 9     my $form = $c->stash->{form};
10 
11     # Get query from search form
12     if ($form->submitted_and_valid) {
13         $query = $c->request->param('query');
14     }
15     return unless $query; # No query? We're done
16     $c->stash->{query} = $query;
17 
18     # Parse query into tokens
19     my $csv = Text::CSV_XS->new();
20     $csv->parse($query) or die "Error parsing query";
21     my @tokens = $csv->fields();
22 
23     # Process query from search form and flash results
24     my $result;
25     if ($form->submitted_and_valid) {
26         if ($c->request->param('domain') eq 'Names') {
27             $result = $c->forward('search_names', \@tokens);
28             $c->flash->{template} = 'search/name_results.tt2';
29         } else {
30             $result = $c->forward('search_addresses', \@tokens);
31             $c->flash->{template} = 'search/address_results.tt2';
32         }
33         $c->flash->{result} = $result;
34         my $page = $c->request->param('page');
35         $page = 1 if ($page !~ /^\d+$/);
36         my $page_result = $result->page($page);
37         $c->flash->{pager} = $page_result->pager;
38         if ($c->request->param('domain') eq 'Names') {
39             $c->response->redirect($c->uri_for('name_results/'));
40         } else {
41             $c->response->redirect($c->uri_for('address_results/'))
+;
42         }
43     }
44 }
45 
46 sub search_names : Private {
47     my ($self, $c, @tokens) = @_;
48     my @people_fields = qw/firstname lastname/;
49     @people_fields    = cross(\@people_fields, \@tokens);
50     return $c->model('AddressDB::People')->search(\@people_fields);
51 }
52 
53 sub search_addresses : Private {
54     my ($self, $c, @tokens) = @_;
55     my @address_fields = qw/postal phone email location/;
56     @address_fields = cross(\@address_fields, \@tokens);
57     return $c->model('AddressDB::Addresses')->search(\@address_fiel
+ds);
58 }
59 
60 sub cross {
61     my $columns = shift || [];
62     my $tokens  = shift || [];
63     map {s/%/\\%/g} @$tokens;
64     my @result;
65     foreach my $column (@$columns){
66         push @result, (map +{$column => {-like => "%$_%"}}, @$token
+s);
67     }
68     return @result;
69 }
70 
71 1;
[download]

I changed flash back to stash for {result} and the DBIx::Class error goes away and the correct URL is displayed in the address bar on the search results page, however no search results are displayed.

It almost seems like a catch-22 situation, where stash is needed for {result} to make DBIx::Class work, but flash is needed for {result} to make $c->response->redirect... work.

I tried using BOTH stash and flash but got the same error I received when using flash only.

Any ideas on how this problem might be resolved?
TIA

"Its not how hard you work, its how much you get done."

Comment on Catalyst: stash vs. flash Select or Download Code

Replies are listed 'Best First'.
Re: Catalyst: stash vs. flash by ikegami (Patriarch) on Apr 26, 2010 at 05:03 UTC
In the handler to which you redirect, get the stuff from the flash and put it in the stash. There's even something called `flash_to_stash` that can do that for you. I don't remember the details, so Google for it.	[reply] [d/l]
Re^2: Catalyst: stash vs. flash by roho (Bishop) on Apr 26, 2010 at 14:32 UTC
I have flash_to_stash enabled. It is enabled in the main AddressBook.pm module as follows: __PACKAGE__->config( session => {dbic_class => 'AddressDB::Session', flash_to_stash => 1 }); I cannot get the stuff from flash because when I store the search results in flash I get the DBIx::Class error. "Its not how hard you work, its how much you get done."	[reply]