On Mon Oct 25 17:33:43 2010, RHESA wrote:
Show quoted text> The iterator support would be a tad more useful if the output were
> streamed row by row, rather than the current behavior where output is
> collected until the iterator is exhausted.
>
> Attached is a patch that makes this happen.
>
> Rhesa
Hello Rhesa,
Thanks for the suggestion and the patch! I elected to go with a separate option to the
xsv_report/xsv_report_web routines to indicate that streaming is desired. That way,
backwards-compatibility is retained. When the option is supplied, it applies to all uses of the
routines, not just when an iterator is used.
A patch is attached, please let me know what you think.
Thanks,
-Evan
diff --git a/XSV.pm b/XSV.pm
index 3e66166..d98590b 100644
--- a/XSV.pm
+++ b/XSV.pm
@@ -1,5 +1,3 @@
-# $Id: XSV.pm 43 2006-10-13 15:45:07Z zackse $
-
package CGI::Application::Plugin::Output::XSV;
use strict;
@@ -25,7 +23,7 @@ our %EXPORT_TAGS= (
all => [ @EXPORT, @EXPORT_OK ],
);
-our $VERSION= '1.00';
+our $VERSION= '1.01';
##
@@ -46,10 +44,15 @@ sub xsv_report {
line_ending => "\n",
csv_opts => {},
maximum_iters => 1_000_000, # XXX reasonable default?
+ stream => 0,
);
my %opts = ( %defaults, %$args );
+ my $was_buffering = $|;
+ local $| = $was_buffering;
+ $| = 1 if $opts{stream};
+
# deprecated option
if ( $opts{get_row_cb} ) {
if ( $opts{row_filter} ) {
@@ -127,7 +130,7 @@ sub xsv_report {
}
my $csv = Text::CSV_XS->new( $opts{csv_opts} );
- my $output;
+ my $output = '';
if ( $opts{include_headers} ) {
if ( ! $opts{headers} ) {
@@ -146,14 +149,26 @@ sub xsv_report {
croak "return value from headers_cb is not an array reference, aborting"
if ref ( $readable_headers ) ne 'ARRAY';
- $output .= add_to_xsv( $csv, $readable_headers, $opts{line_ending} );
+ if ( $opts{stream} ) {
+ print add_to_xsv( $csv, $readable_headers, $opts{line_ending} );
+ }
+ else {
+ $output .= add_to_xsv( $csv, $readable_headers, $opts{line_ending} );
+ }
}
if ( $opts{values} ) {
foreach my $list_ref ( @{ $opts{values} } ) {
- $output .= add_to_xsv(
- $csv, $row_filter->($list_ref, $fields), $opts{line_ending}
- );
+ if ( $opts{stream} ) {
+ print add_to_xsv(
+ $csv, $row_filter->($list_ref, $fields), $opts{line_ending}
+ );
+ }
+ else {
+ $output .= add_to_xsv(
+ $csv, $row_filter->($list_ref, $fields), $opts{line_ending}
+ );
+ }
}
}
# using iterator
@@ -168,9 +183,16 @@ sub xsv_report {
croak "iterator exceeded maximum iterations ($opts{maximum_iters})"
if ++$iterations > $opts{maximum_iters};
- $output .= add_to_xsv(
- $csv, $row_filter->($list_ref, $fields), $opts{line_ending}
- );
+ if ( $opts{stream} ) {
+ print add_to_xsv(
+ $csv, $row_filter->($list_ref, $fields), $opts{line_ending}
+ );
+ }
+ else {
+ $output .= add_to_xsv(
+ $csv, $row_filter->($list_ref, $fields), $opts{line_ending}
+ );
+ }
}
}
@@ -193,11 +215,20 @@ sub xsv_report_web {
my %opts = ( %defaults, %$args );
- $self->header_props(
+ my %headers = (
-type => 'application/x-csv',
'-content-disposition' => "attachment; filename=$opts{filename}",
);
+ # we're doing our own output
+ if ( $opts{stream} ) {
+ $self->header_type('none');
+ print $self->query->header( %headers );
+ }
+ else {
+ $self->header_props( %headers );
+ }
+
# consider use of magic goto in case of croak() inside xsv_report
return xsv_report( \%opts );
}
@@ -314,7 +345,7 @@ looked the same:
-type => 'application/x-csv',
'-content-disposition' => "attachment; filename=export.csv",
);
-
+
return $output;
The purpose of this module is to provide a simple method, C<xsv_report_web>,
@@ -371,6 +402,7 @@ available options.
iterator => \&get_members,
csv_opts => { sep_char => "\t" },
filename => 'members.csv',
+ stream => 1,
});
This method generates a csv file that is sent directly to the user's
@@ -554,6 +586,22 @@ Note: This parameter used to be named C<get_row_cb>. That name is
deprecated and a warning will be issued if it is used instead of
C<row_filter>.
+=item stream
+
+ stream => 1,
+
+This flag controls whether or not output is printed immediately or
+collected and returned to the caller. Set to a true value to remove
+buffering on STDOUT and to emit output as it is generated. This can
+save memory in the case of a large document, for example.
+
+The default is false to retain backwards-compatibility. In general, it
+is probably more efficient to set this to a true value, but note that it
+breaks with the standard L<CGI::Application|CGI::Application(3)>
+convention of returning generated content from your runmodes rather than
+printing it yourself.
+
+
=back
=back
@@ -811,7 +859,7 @@ which is not applicable to this function.
1,2,3
4,5,6
-=item Generate each row on the fly (streaming)
+=item Generate each row on the fly
my @vals = qw(one two three four five six);
@@ -876,13 +924,9 @@ L<Text::CSV_XS>, L<CGI::Application>
=head1 COPYRIGHT AND LICENSE
-Copyright (c) 2006 CommonMind, LLC. All rights reserved.
+Copyright (c) 2006,2010 CommonMind, LLC. All rights reserved.
This program is free software; you can redistribute it
and/or modify it under the same terms as Perl itself.
-=head1 REVISION
-
-$Id: XSV.pm 43 2006-10-13 15:45:07Z zackse $
-
=cut
