SYNOPSIS

use Data::Report;
# Create a new reporter.
my $rep = Data::Report::->create(type => "text"); # or "html", or "csv", ...
# Define the layout.
$rep->set_layout
([ { name => "acct", title => "Acct", width => 6 },
{ name => "desc", title => "Description", width => 40, align => "<" },
{ name => "deb", title => "Debet", width => 10, align => ">" },
{ name => "crd", title => "Credit", width => 10, align => ">" },
]);
# Start the reporter.
$rep->start;
# Add data, row by row.
$rep->add({ acct => 1234, desc => "Received", deb => "242.33" });
$rep->add({ acct => 5678, desc => "Paid", crd => "699.45" });
$rep->add({ acct => 1259, desc => "Taxes", deb => "12.00", crd => "244.00" });
$rep->add({ desc => "TOTAL", deb => "254.33", crd => "943.45" });
# Finish the reporter.
$rep->finish;

DESCRIPTION

Data::Report is a flexible, plugin-driven reporting framework. It makes it easy to define reports that can be produced in text, HTML and CSV. Textual ornaments like extra empty lines, dashed lines, and cell lines can be added in a way similar to HTML style sheets.

The Data::Report framework consists of three parts:

The plugins

Plugins implement a specific type of report. Standard plugins provided are "Data::Report::Plugin::Text" for textual reports, "Data::Report::Plugin::Html" for HTML reports, and "Data::Report::Plugin::Csv" for CSV (comma-separated) files.

Users can, and are encouraged, to develop their own plugins to handle different styles and types of reports.

The base class

The base class "Data::Report::Base" implements the functionality common to all reporters, plus a number of utility functions the plugins can use.

The factory

The actual "Data::Report" module is a factory that creates a reporter for a given report type by selecting the appropriate plugin and returning an instance thereof.

BASIC METHODS

Note that except for the "create" method, all other methods are actually handled by the plugins and their base class.

create

Reporter objects are created using the class method "create". This method takes a hash (or hashref) of arguments to initialise the reporter object.

The actual reporter object is implemented by one of the plugin modules, selected by the "type" argument. Standard plugins are provided for "text", "HTML" and "CSV" report types. The default type is "text".

When looking for a plugin to support report type "foo", the "create" method will first try to load a module "My::Package::Foo" where "My::Package" is the invocant class. If this module cannot be loaded, it will fall back to "Data::Report::Plugin::Foo". Note that, unless subclassed, the current class will be "Data::Report".

All other initialisation arguments correspond to attribute setting methods provided by the plugins. For example, the hypothetical call

  my $rpt = Data::Report->create(foo => 1, bar => "Hello!");

is identical to:

  my $rpt = Data::Report->create;
  $rpt->set_foo(1);
  $rpt->set_bar("Hello!");

You can choose any combination at your convenience.

start

This method indicates that all setup has been completed, and starts the reporter. Note that no output is generated until the "add" method is called.

"start" takes no arguments.

Although this method could be eliminated by automatically starting the reporter upon the first call to "add", it turns out that an aplicit "start" makes the API much cleaner and makes it easier to catch mistakes.

add

This method adds a new entry to the report. It takes one single argument, a hash ref of column names and the corresponding values. Missing columns are left blank.

In addition to the column names and values, you can add the special key "_style" to designate a particular style for this entry. What that means depends on the plugin that implements this reporter. For example, the standard HTML reporter plugin prefixes the given style with "r_" to form the class name for the row. The style name should be a simple name, containing letters, digits and underscores, starting with a letter.

Example

  $rpt->add({ date   => "2006-04-31",
              amount => 1000,
              descr  => "First payment",
              _style => "plain" });

finish

This method indicates that report generation is complete. After this, you can call "start" again to initiate a new report.

"finish" takes no arguments.

close

This is a convenience method. If the output stream was set up by the reporter itself (see "set_output", below), the stream will be closed. Otherwise, this method will be a no-op.

"close" takes no arguments.

ATTRIBUTE HANDLING METHODS

get_type

The reporter type.

set_layout

This is the most important attribute, since it effectively defines the report layout.

This method takes one argument, an array reference. Each element of the array is a hash reference that corresponds to one column in the report. The order of elements definines the order of the columns in the report, but see "set_fields" below.

The following keys are possible in the hash reference:

"name"

The name of this column. The name should be a simple name, containing letters, digits and underscores, starting with a letter.

The standard HTML reporter plugin uses the column name to form a class name for each cell by prefixing with "c_". Likewise, the classes for the table headings will be formed by prefixing the column names with "h_". See ``ADVANCED EXAMPLES'', below.

"title"

The title of this column. This title is placed in the column heading.

"width"

The width of this column. Relevant for textual reporters only.

By default, if a value does not fit in the given width, it will be spread over multiple rows in a pseudo-elegant way. See also the "truncate" key, below.

"align"

The alignment of this column. This can be either "<" for left-aligned columns, or ">" to indicate a right-aligned column.

"truncate"

If true, the values in this column will be truncated to fit the width of the column. Relevant for textual reporters only.

set_style

This method can be used to set an arbitrary style (a string) whose meaning depends on the implementing plugin. For example, a HTML plugin could use this as the name of the style sheet to use.

The name should be a simple name, containing letters, digits and underscores, starting with a letter.

get_style

Returns the style, or "default" if none.

set_output

Designates the destination for the report. The argument can be

a SCALAR reference

All output will be appended to the designated scalar.

an ARRAY reference

All output lines will be pushed onto the array.

a SCALAR

A file will be created with the given name, and all output will be written to this file. To close the file, use the "close" method described above.

anything else

Anything else will be considered to be a file handle, and treated as such.

set_stylist

The stylist is a powerful method to control the appearance of the report at the row and cell level. The basic idea is taken from HTML style sheets. By using a stylist, it is possible to add extra spaces and lines to rows and cells in a declarative way.

When used, the stylist should be a reference to a possibly anonymous subroutine with three arguments: the reporter object, the style of a row (as specified with "_style" in the "add" method), and the name of a column as defined in the layout. For table headings, the row name "_head" is used.

The stylist routine will be repeatedly called by the reporter to obtain formatting properties for rows and cells. It should return either nothing, or a hash reference with properties.

When called with only the "row" argument, it should return the properties for this row.

When called with row equal to ``*'' and a column name, it should return the properties for the given column.

When called with a row and a column name, it should return the properties for the given row/column (cell).

All appropriate properties are merged to form the final set of properties to apply.

The following row properties are recognised. Between parentheses the backends that support them.

"skip_before"

(Text) Produce an empty line before printing the current row.

"skip_after"

(Text) Produce an empty line after printing the current row, but only if other data follows.

"line_before"

(Text) Draw a line of dashes before printing the current row.

"line_after"

(Text) Draw a line of dashes after printing the current row.

"cancel_skip"

(Text) Cancel the effect of a pending "skip_after"

"ignore"

(All) Ignore this row. Useful for CSV backends where only the raw data matters, and not the totals and such.

The following cell properties are recognised. Between parentheses the backends that support them.

"indent"

(Text) Indent the contents of this cell with the given amount.

"wrap_indent"

(Text) Indent wrapped contents of this cell with the given amount.

"truncate"

(Text) If true, truncate the contents of this cell to fit the column width.

"line_before"

(Text) Draw a line in the cell before printing the current row. The value of this property indicates the symbol to use to draw the line. If it is 1, dashes are used.

"line_after"

(Text) Draw a line in the cell after printing the current row. The value of this property indicates the symbol to use to draw the line. If it is 1, dashes are used.

"raw_html"

(Html) Do not escape special HTML characters, allowing pre-prepared HTML code to be placed in the output. Use with care.

"ignore"

(All) Ignore this column. Note that to prevent surprising results, the column must be ignored in all applicable styles, including the special style "_head" that controls the heading.

"class"

(Html) Class name to be used for this cell. Default class name is ``h_CNAME'' for table headings and ``c_CNAME'' for table rows, where CNAME is the name of the column.

Example:

  $rep->set_stylist(sub {
    my ($rep, $row, $col) = @_;
    unless ( $col ) {
        return { line_after => 1 } if $row eq "total";
        return;
    }
    return { line_after => 1 } if $col eq "amount";
    return;
  });

Each reporter provides a standard (dummy) stylist called "_std_stylist". Overriding this method is equivalent to using "set_stylist".

get_stylist

Returns the current stylist, if any.

set_topheading

Headings consist of two parts, the top heading, and the standard heading. Bij default, the top heading is empty, and the standard heading has the names of the columns with a separator line (depnendent on the plugin used).

This method can be used to designate a subroutine that will provide the top heading of the report.

Example:

  $rpt->set_topheading(sub {
    my $self = shift;
    $self->_print("Title line 1\n");
    $self->_print("Title line 2\n");
    $self->_print("\n");
  });

Note the use of the reporter provided "_print" method to produce output.

When subclassing a reporter, a method "_top_heading" can be defined to provide the top heading. This is equivalent to an explicit call to "set_topheading", but doesn't need to be repeatedly and explicitly executed for each new reporter.

get_topheading

Returns the current top heading routine, if any.

set_heading

This method can be used to designate a subroutine that provides the standard heading of the report.

In normal cases using this method is not necessary, since setting the top heading will be sufficient.

Each reporter plugin provides a standard heading, implemented in a method called "_std_header". This is the default value for the "heading" attribute. A user-defined heading can use

  $self->SUPER::_std_header;

to still get the original standard heading produced.

Example:

  $rpt->set_heading(sub {
    my $self = shift;
    $self->_print("Title line 1\n");
    $self->_print("Title line 2\n");
    $self->_print("\n");
    $self->SUPER::_std_heading;
    $self->_print("\n");
  });

Note the use of the reporter provided "_print" method to produce output.

When subclassing a reporter, the method "_std_heading" can be overridden to provide a customized top heading. This is equivalent to an explicit call to "set_topheading", but doesn't need to be repeatedly and explicitly executed for each new reporter.

get_heading

Returns the current standard heading routine, if any.

set_fields

This method can be used to define what columns (fields) should be included in the report and the order they should appear. It takes an array reference with the names of the desired columns.

Example:

  $rpt->set_fields([qw(descr amount date)]);

get_fields

Returns the current set of selected columns.

set_width

This method defines the width for one or more columns. It takes a hash reference with column names and widths. The width may be an absolute number, a relative number (to increase/decrease the width, or a percentage.

Example:

  $rpt->set_width({ amount => 10, desc => '80%' });

get_widths

Returns a hash with all column names and widths.

ADVANCED EXAMPLES

This example subclasses Data::Report with an associated plugin for type "text". Note the use of overriding "_top_heading" and "_std_stylist" to provide special defaults for this reporter.

  package POC::Report;
  use base qw(Data::Report);
  package POC::Report::Text;
  use base qw(Data::Report::Plugin::Text);
  sub _top_heading {
      my $self = shift;
      $self->_print("Title line 1\n");
      $self->_print("Title line 2\n");
      $self->_print("\n");
  }
  sub _std_stylist {
      my ($rep, $row, $col) = @_;
      if ( $col ) {
          return { line_after => "=" }
            if $row eq "special" && $col =~ /^(deb|crd)$/;
      }
      else {
          return { line_after => 1 } if $row eq "total";
      }
      return;
  }

It can be used as follows:

  my $rep = POC::Report::->create(type => "text");
  $rep->set_layout
    ([ { name => "acct", title => "Acct",   width => 6  },
       { name => "desc", title => "Report", width => 40, align => "<" },
       { name => "deb",  title => "Debet",  width => 10, align => "<" },
       { name => "crd",  title => "Credit", width => 10, align => ">" },
     ]);
  $rep->start;
  $rep->add({ acct => "one", desc => "two", deb => "three", crd => "four", _style => "normal" });
  $rep->add({ acct => "one", desc => "two", deb => "three", crd => "four", _style => "normal" });
  $rep->add({ acct => "one", desc => "two", deb => "three", crd => "four", _style => "special"});
  $rep->add({ acct => "one", desc => "two", deb => "three", crd => "four", _style => "total"  });
  $rep->finish;

The output will look like:

  Title line 1
  Title line 2
  Acct                                      Report  Debet           Credit
  ------------------------------------------------------------------------
  one                                          two  three             four
  one                                          two  three             four
  one                                          two  three             four
                                                    ==========  ==========
  one                                          two  three             four
  ------------------------------------------------------------------------

This is a similar example for a HTML reporter:

  package POC::Report;
  use base qw(Data::Report);
  package POC::Report::Html;
  use base qw(Data::Report::Plugin::Html);
  sub start {
      my $self = shift;
      $self->{_title1} = shift;
      $self->{_title2} = shift;
      $self->{_title3} = shift;
      $self->SUPER::start;
  }
  sub _top_heading {
      my $self = shift;
      $self->_print("<html>\n",
                    "<head>\n",
                    "<title>", $self->_html($self->{_title1}), "</title>\n",
                    '<link rel="stylesheet" href="css/', $self->get_style, '.css">', "\n",
                    "</head>\n",
                    "<body>\n",
                    "<p class=\"title\">", $self->_html($self->{_title1}), "</p>\n",
                    "<p class=\"subtitle\">", $self->_html($self->{_title2}), "<br>\n",
                    $self->_html($self->{_title3}), "</p>\n");
  }
  sub finish {
      my $self = shift;
      $self->SUPER::finish;
      $self->_print("</body>\n</html>\n");
  }

Note that it defines an alternative "start" method, that is used to pass in additional parameters for title fields.

The method "_html" is a convenience method provided by the framework. It returns its argument with sensitive characters escaped by HTML entities.

It can be used as follows:

  package main;
  my $rep = POC::Report::->create(type => "html");
  $rep->set_layout
    ([ { name => "acct", title => "Acct",   width => 6  },
       { name => "desc", title => "Report", width => 40, align => "<" },
       { name => "deb",  title => "Debet",  width => 10, align => "<" },
       { name => "crd",  title => "Credit", width => 10, align => ">" },
     ]);
  $rep->start(qw(Title_One Title_Two Title_Three_Left&Right));
  $rep->add({ acct => "one", desc => "two", deb => "three", crd => "four", _style => "normal" });
  $rep->add({ acct => "one", desc => "two", deb => "three", crd => "four", _style => "normal" });
  $rep->add({ acct => "one", desc => "two", deb => "three", crd => "four", _style => "normal" });
  $rep->add({ acct => "one", desc => "two", deb => "three", crd => "four", _style => "total"  });
  $rep->finish;

The output will look like this:

  <html>
  <head>
  <title>Title_One</title>
  <link rel="stylesheet" href="css/default.css">
  </head>
  <body>
  <p class="title">Title_One</p>
  <p class="subtitle">Title_Two<br>
  Title_Three_Left&amp;Right</p>
  <table class="main">
  <tr class="head">
  <th align="left" class="h_acct">Acct</th>
  <th align="left" class="h_desc">Report</th>
  <th align="right" class="h_deb">Debet</th>
  <th align="right" class="h_crd">Credit</th>
  </tr>
  <tr class="r_normal">
  <td align="left" class="c_acct">one</td>
  <td align="left" class="c_desc">two</td>
  <td align="right" class="c_deb">three</td>
  <td align="right" class="c_crd">four</td>
  </tr>
  <tr class="r_normal">
  <td align="left" class="c_acct">one</td>
  <td align="left" class="c_desc">two</td>
  <td align="right" class="c_deb">three</td>
  <td align="right" class="c_crd">four</td>
  </tr>
  <tr class="r_normal">
  <td align="left" class="c_acct">one</td>
  <td align="left" class="c_desc">two</td>
  <td align="right" class="c_deb">three</td>
  <td align="right" class="c_crd">four</td>
  </tr>
  <tr class="r_total">
  <td align="left" class="c_acct">one</td>
  <td align="left" class="c_desc">two</td>
  <td align="right" class="c_deb">three</td>
  <td align="right" class="c_crd">four</td>
  </tr>
  </table>
  </body>
  </html>

See also the examples in "t/09poc*.t".

AUTHOR

Johan Vromans, "<jvromans at squirrel.nl>"

SUPPORT

You can find documentation for this module with the perldoc command.

    perldoc Data::Report          (user API)
    perldoc Data::Report::Base    (plugin writer documentation)

You can also look for information at:

• RT: CPAN's request tracker

  <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Data-Report>

• CPAN Ratings

  <http://cpanratings.perl.org/d/Data-Report>

• Search CPAN

  <http://search.cpan.org/dist/Data-Report>

ACKNOWLEDGEMENTS

COPYRIGHT & LICENSE

Copyright 2006,2008 Squirrel Consultancy, all rights reserved.

This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.