CommaHeaven

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

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