README for CGI::Application::Plugin::Output::XSV
INSTALLATION
To install this module, run the following commands:
perl Build.PL
./Build
./Build test
./Build install
Alternatively, if you do not have Module::Build but you do have 'make',
you can used the included Makefile.PL and run the following commands:
perl Makefile.PL
make
make test
make install
DEPENDENCIES
This module requires these other CPAN modules:
CGI::Application
Text::CSV_XS
NAME
CGI::Application::Plugin::Output::XSV - generate csv output from a
CGI::Application runmode
SYNOPSIS
use CGI::Application::Plugin::Output::XSV;
...
# in some runmode...
# $sth is a prepared DBI statement handle
my $members = $sth->fetchall_arrayref( {} );
my @headers = qw( member_id first_name last_name ... );
return $self->xsv_report_web({
fields => \@headers,
values => $members,
csv_opts => { sep_char => "\t" },
filename => 'members.csv',
});
# or, generate the list on the fly:
sub get_members { $sth->fetchrow_arrayref() }
return $self->xsv_report_web({
iterator => \&get_members,
csv_opts => { sep_char => "\t" },
filename => 'members.csv',
});
DESCRIPTION
"CGI::Application::Plugin::Output::XSV" provides csv-related routines
useful for web applications (via Text::CSV_XS).
A method, "xsv_report_web" is exported by default. Three other
functions, "xsv_report", "clean_field_names", and "add_to_xsv" are
available for optional export.
You may export all four routines by specifying the export tag ":all":
use CGI::Application::Plugin::Output::XSV qw(:all);
PURPOSE
On many websites, I had code to retrieve a list of data items for use in
an HTML::Template TMPL_LOOP. Usually this code would use the DBI routine
"fetchall_arrayref()" to get a list of hash references, one for each
data item.
my $users = $sth->fetchall_arrayref( {} );
my $template = $self->load_tmpl( ... );
$template->param( users => $users );
return $template->output;
At some point, it would become apparent that an "export to spreadsheet"
feature would be useful, so I'd add another runmode, which almost always
looked the same:
my @fields = qw(keys to each data item);
my $csv = Text::CSV_XS->new();
foreach my $user ( @{$users} ) {
$csv->combine( [ @{$user}{@fields} ] );
$output .= $csv->string() . "\n";
}
$self->header_props(
-type => 'application/x-csv',
'-content-disposition' => "attachment; filename=export.csv",
);
return $output;
The purpose of this module is to provide a simple method,
"xsv_report_web", that wraps the above code while offering a fair amount
of programmer flexibility.
For example, the programmer may control the naming of header columns,
filter each row of data before it is passed to Text::CSV_XS, and set the
filename that is supplied to the user's browser.
Please see the documentation below for "xsv_report_web" for a list of
available options.
METHODS
xsv_report_web
## METHOD 1. Pre-generated list of values for csv
# in a runmode
my @members = (
{ member_id => 1,
first_name => 'Chuck',
last_name => 'Berry', },
...
);
my @headers = ("Member ID", "First Name", "Last Name");
my @fields = qw(member_id first_name last_name);
return $self->xsv_report_web({
fields => \@fields,
headers => \@headers,
values => \@members,
csv_opts => { sep_char => "\t" },
filename => 'members.csv',
});
## METHOD 2. Generate list on the fly
# in a runmode
sub get_members { $sth->fetchrow_arrayref() }
my @headers = ("Member ID", "First Name", "Last Name");
return $self->xsv_report_web({
headers => \@headers,
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
web browser. It sets the content-type header to 'application/x-csv'
and sets the content-disposition header to 'attachment'.
It should be invoked through a CGI::Application subclass object.
It takes a reference to a hash of named parameters. All except for
"values" or "iterator" are optional:
csv_opts
csv_opts => { sep_char => "\t" },
A reference to a hash of options passed to the constructor
of Text::CSV_XS. The default is an empty hash.
fields
fields => [ qw(member_id first_name last_name) ],
# or array indices
fields => [ 1, 2, 0 ],
A reference to a list of field names or array indices. This
parameter specifies the order of fields in each row of
output.
If "fields" is not supplied, a list will be generated using
the first entry in the "values" list. Note, however, that in
this case, if the "values" parameter is a list of hashes,
the field order will be random because the field names are
extracted from a hash. If the "values" parameter is a list
of lists, the field order will be the same as the data
provided.
If "fields" is not supplied and "iterator" is used instead
of "values", the field list will be empty.
filename
filename => 'members.csv',
The name of the file which will be sent in the HTTP
content-disposition header. The default is "download.csv".
headers
headers => [ "Member ID", "First Name", "Last Name" ],
A reference to a list of column headers to be used as the
first row of the csv report.
If "headers" is not supplied (and "include_headers" is not
set to a false value), "headers_cb" will be called with
"fields" as a parameter to generate column headers.
headers_cb
# replace underscores with spaces
headers_cb => sub {
my $fields = shift;
# using temp var to avoid modifying $fields
my @fields_copy = @{$fields};
return [
map { tr/_/ /; $_ } @fields_copy
];
},
A reference to a subroutine used to generate column headers
from the field names.
A default routine is provided in "clean_field_names". This
function is passed a reference to the list of fields
("fields") as a parameter and should return a reference to a
list of column headers.
include_headers
include_headers => 1,
A true or false value indicating whether to include
"headers" (or automatically generated headers) as the first
row of output.
The default is true.
line_ending
line_ending => "\n",
The value appended to each line of csv output. The default
is "\n".
values
values => [
{ member_id => 1,
first_name => 'Chuck',
last_name => 'Berry', },
],
# or a list of lists
values => [
[ 1, 'Chuck', 'Berry', ],
],
A reference to a list of hash references (such as that
returned by the DBI "fetchall_arrayref( {} )" routine), or a
reference to a list of list references.
Either this argument or "iterator" must be provided.
iterator
iterator => sub { $sth->fetchrow_arrayref() },
A reference to a subroutine that is used to generate each
row of data. It is passed a reference to the list of fields
("fields") as a parameter and should return a reference to a
list (which will be passed to "add_to_xsv()").
It will be called repeatedly to generate each row of data
until it returns a false value.
This may be preferred to "values" when the data set is large
or expensive to generate up-front. Thanks to Mark Stosberg
for suggesting this option.
Either this argument or "values" must be provided.
maximum_iters
maximum_iters => 1_000_000,
This is the maximum number of times the "iterator" will be
called before an exception is raised. This is a basic
stopgap to prevent a runaway iterator that never returns
false.
The default is one million.
row_filter
# uppercase all values
# (each row is a list of hash references)
row_filter => sub {
my ($row, $fields) = @_;
return [ map { uc } @{$row}{@$fields} ];
},
A reference to a subroutine used to filter each row of data
(other than the header row) before it is passed to
"add_to_xsv". When the "values" parameter is supplied, a
default filter is provided that produces each row in the
order specified by "headers". For example, the default
filter for a "values" list of hash references is shown
below.
row_filter => sub {
my ($row, $fields) = @_;
return [ @{$row}{@$fields} ];
},
This subroutine is passed two parameters for each row:
* the current row (reference to a list of hashes
or lists)
* the field list ("fields" - reference to a list
of hash keys or array indices)
Note: This parameter used to be named "get_row_cb". That
name is deprecated and a warning will be issued if it is
used instead of "row_filter".
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
CGI::Application convention of returning generated content
from your runmodes rather than printing it yourself.
FUNCTIONS
add_to_xsv
# $sth is a prepared DBI statement handle
my $values = $sth->fetchall_arrayref( {} );
my @headers = qw/foo bar baz/;
my $output;
# $csv is a Text::CSV_XS object
foreach my $href ( @{$values} ) {
$output .= add_to_xsv( $csv, [ @{$href}{@headers} ], "\r\n" );
}
This function, used internally by "xsv_report"/"xsv_report_web",
formats a list of values for inclusion a csv file. The return value
is from "$csv->string()", where $csv is a Text::CSV_XS object.
It takes three parameters:
* A Text::CSV_XS object
* A reference to a list of values
* The line ending
On an error from Text::CSV_XS, the function raises an exception.
On receiving an empty list of values, the function returns the line
ending only.
clean_field_names
my $fields = [ qw/first_name foo bar baz/ ];
my $headers = clean_field_names( $fields );
# $headers is now [ 'First Name', 'Foo', 'Bar', 'Baz' ]
This function takes a reference to a list of strings and returns a
reference to a new list in which the strings are reformatted as
such:
1. Underscores ('_') are changed to spaces
2. The first letter of each word is capitalized
This function is used by "xsv_report" and "xsv_report_web" if the
"headers_cb" parameter is not supplied.
xsv_report
# $sth is a prepared DBI statement handle
my $members = $sth->fetchall_arrayref( {} );
my @headers = qw( member_id first_name last_name ... );
my $output = $self->xsv_report({
fields => \@headers,
values => $members,
csv_opts => { sep_char => "\t" },
});
# do something with $output
This function generates a string containing csv data and returns it.
This may be useful when you want to do some manipulation of the data
before sending it to the user's browser or elsewhere. It takes the
same named parameters (via a reference to a hash) as
"xsv_report_web" except for "filename", which is not applicable to
this function.
EXAMPLES
Specify (almost) everything
return $self->xsv_report_web({
values => [
{ first_name => 'Jack',
last_name => 'Tors',
phone => '555-1212' },
{ first_name => 'Frank',
last_name => 'Rizzo',
phone => '555-1515' },
],
headers => [ "First Name", "Last Name", "Phone" ],
fields => [ qw(first_name last_name phone) ],
include_headers => 1,
line_ending => "\n",
csv_opts => { sep_char => "\t" },
filename => 'download.csv',
});
__END__
"First Name" "Last Name" Phone
Jack Tors 555-1212
Frank Rizzo 555-1515
Use defaults
# ends up with same options and output as above
return $self->xsv_report_web({
values => [
{ first_name => 'Jack',
last_name => 'Tors',
phone => '555-1212' },
{ first_name => 'Frank',
last_name => 'Rizzo',
phone => '555-1515' },
],
headers => [ "First Name", "Last Name", "Phone" ],
fields => [ qw(first_name last_name phone) ],
});
Use header generation provided by module
# headers generated will be [ "First Name", "Last Name", "Phone" ]
# same output as above
return $self->xsv_report_web({
values => [
{ first_name => 'Jack',
last_name => 'Tors',
phone => '555-1212' },
{ first_name => 'Frank',
last_name => 'Rizzo',
phone => '555-1515' },
],
fields => [ qw(first_name last_name phone) ],
});
Use custom header generation
# headers generated will be [ "first", "last", "phone" ]
return $self->xsv_report_web({
values => [
{ first_name => 'Jack',
last_name => 'Tors',
phone => '555-1212' },
{ first_name => 'Frank',
last_name => 'Rizzo',
phone => '555-1515' },
],
fields => [ qw(first_name last_name phone) ],
headers_cb => sub {
my @h = @{ +shift };
s/_name$// foreach @h;
return \@h;
},
});
__END__
first,last,phone
Jack,Tors,555-1212
Frank,Rizzo,555-1515
If order of fields doesn't matter
# headers and fields will be in random order (but consistent
# throughout data processing) due to extraction from hash
# (headers will be generated automatically)
return $self->xsv_report_web({
values => [
{ first_name => 'Jack',
last_name => 'Tors',
phone => '555-1212' },
{ first_name => 'Frank',
last_name => 'Rizzo',
phone => '555-1515' },
],
});
__END__
Phone,"Last Name","First Name"
555-1212,Tors,Jack
555-1515,Rizzo,Frank
No header row
return $self->xsv_report_web({
values => [
{ first_name => 'Jack',
last_name => 'Tors',
phone => '555-1212' },
{ first_name => 'Frank',
last_name => 'Rizzo',
phone => '555-1515' },
],
fields => [ qw(first_name last_name phone) ],
include_headers => 0,
});
__END__
Jack,Tors,555-1212
Frank,Rizzo,555-1515
Filter data as it is processed
sub plus_one {
my ($row, $fields) = @_;
return [ map { $_ + 1 } @{$row}{@$fields} ];
}
# each row (other than header row) will be
# passed through plus_one()
return $self->xsv_report_web({
fields => [ qw(foo bar baz) ],
values => [ { foo => 1, bar => 2, baz => 3 }, ],
row_filter => \&plus_one,
});
__END__
Foo,Bar,Baz
2,3,4
Pass list of lists (instead of hashes)
# each row will be processed in order
# since fields parameter is omitted
$self->xsv_report_web({
include_headers => 0,
values => [
[ 1, 2, 3 ],
[ 4, 5, 6 ],
],
});
__END__
1,2,3
4,5,6
Generate each row on the fly
my @vals = qw(one two three four five six);
sub get_vals {
while ( @vals ) {
return [ splice @vals, 0, 3 ]
}
};
$self->xsv_report_web({
include_headers => 0,
iterator => \&get_vals,
});
__END__
one,two,three
four,five,six
Generate each row on the fly using a DBI iterator
my $get_vals = sub { $sth->fetchrow_arrayref() };
$self->xsv_report_web({
include_headers => 0,
iterator => $get_vals,
});
Use a DBI iterator, increment each value extracted
$self->xsv_report_web({
include_headers => 0,
iterator => sub { $sth->fetchrow_arrayref() };
row_filter => sub {
my $row = shift;
return [ map { $_ + 1 } @{$row} ];
},
});
ERROR HANDLING
The function "add_to_xsv" will raise an exception when
"Text::CSV_XS->combine" fails. Please see the Text::CSV_XS documentation
for details about what type of input causes a failure.
AUTHOR
Evan A. Zacks "<zackse@cpan.org>"
BUGS
Please report any bugs or feature requests to
"bug-cgi-application-plugin-output-xsv@rt.cpan.org", or through the web
interface at
<http://rt.cpan.org/NoAuth/ReportBug.html?Queue=CGI-Application-Plugin-O
utput-XSV>. I will be notified, and then you'll automatically be
notified of progress on your bug as I make changes.
SEE ALSO
Text::CSV_XS, CGI::Application
COPYRIGHT AND LICENSE
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.