CommaHeaven¶ ↑

CommaHeaven aims to be to CSV export what Searchlogic is to search.

<img src=“https://secure.travis-ci.org/sistrall/comma-heaven.png?branch=master” alt=“Build Status” />

Advice!¶ ↑

While in production on some project, CommaHeaven is young. Feature additions or bug fixes are welcome.

Install & use¶ ↑

Install the gem:

sudo gem install comma-heaven

Now just set it as a dependency in your project and you are ready to go.

Export with comma-heaven¶ ↑

Let me show how CommaHeaven works using an example. We have the following ActiveRecord models:

# Tree(id: integer, name: string, age: integer, gardener_id: integer)
# Leaf(id: integer, tree_id: integer, position: string, size: float, height_from_ground: float)

class Tree < ActiveRecord::Base
  has_many :leafs, :dependent => :destroy
end

class Leaf < ActiveRecord::Base
  belongs_to :tree
end

Tables contain:

# Trees:
+----+-------+-----+-------------+
| id | name  | age | gardener_id |
+----+-------+-----+-------------+
| 37 | Olmo  | 100 | 33          |
| 38 | Ulivo | 150 | 34          |
+----+-------+-----+-------------+

# Leaves:
+----+---------+----------+------+--------------------+
| id | tree_id | position | size | height_from_ground |
+----+---------+----------+------+--------------------+
| 81 | 37      | top      |      |                    |
| 82 | 37      | middle   |      |                    |
| 83 | 37      | bottom   |      |                    |
| 84 | 38      | 0        |      | 1.0                |
| 85 | 38      | 5        |      | 2.0                |
+----+---------+----------+------+--------------------+

CommaHeaven let you export CSV using:

Tree.to_comma_heaven(:export => { "name" => {"1" => {"as" => "", "include" => "1"} }, 
                                  "leafs" => {"2" => {"export" => { "position" => {"3" => {"as" => "", "include" => '1'} },
                                                                    "height_from_ground" => {"4" => {'as' => '', :include => '1'} } }, 'limit' => 2 } } }).to_csv

What you obtain is:

tree_name,leaf_0_position,leaf_0_height_from_ground,leaf_1_position,leaf_1_height_from_ground
Olmo,top,,middle,
Ulivo,0,1.0,5,2.0

The export hash explains what to export and how.

The @:by => ‘row’@ option gives the ability to denormalize table contents by rows. Using:

Tree.to_comma_heaven(:export => { "name" => {"1" => {"as" => "", "include" => "1"} }, 
                                  "leafs" => {"2" => {"export" => { "position" => {"3" => {"as" => "", "include" => '1'} },
                                                                    "height_from_ground" => {"4" => {'as' => '', :include => '1'} } }, 'by' => 'row' } } }).to_csv

You obtain:

tree_name,leaf_position,leaf_height_from_ground
Olmo,top,,
Olmo,middle,,
Olmo,bottom,,
Ulivo,0,1.0
Ulivo,5,2.0

Opinions¶ ↑

• CSV export is a common request and still hard to do

• Export parameters can be passed through an HTML form

• Use joins to produce the dataset to export

• Relationships are exported by row (see example above)

Note on Patches/Pull Requests¶ ↑

• Fork the project.

• Make your feature addition or bug fix.

• Add tests for it. This is important so I don’t break it in a future version unintentionally.

• Commit, do not mess with rakefile, version, or history. (if you want to have your own version, that is fine but bump version in a commit by itself I can ignore when I pull)

• Send me a pull request. Bonus points for topic branches.

Copyright¶ ↑

Copyright © 2009-2010 Silvano Stralla. See LICENSE for details.