Posifile
This library is intended to make it easier to read/write any kind of position file. All you have to do is write in the model how each position will be associated to each objects attributes.
Instalation
gem install posifile
Usage
The most difficult thing to do is figure out how the file is laid out. Once you can ‘see’ the fields, using this library is easy.
One line file
This is the case where there is only one line per file, and each file constains one register. You need to tell your model wich position is what, like: # client.rb require ‘rubygems’ require ‘posifile’
class Client < Posifile set_specification(“name”=“0..10”, “city”=>“11..31”, “country”=>“32..50”)
#you can put here any other method you’d like
end
And you will get as object attributes every key you specified in the above hash:
client = Client.new(“path/to/file.txt”) client.name client.city cliennt.country
Note that every key in the hash needs to be all downcase, because they’r gonna be method’s names.
Multi-line file
When the file you need to read has many sections and many registers in only one file, you can use some code (generally specified in some kind of document layout, and known as “section code”) to be able to tell to wich section some register belongs to. Here this code is in first three positions of the file.
# car require ‘rubygems’ require ‘posifile’
class Client < Posifile lines_where 0..2, “001” do # this is some header of the file, and commonly has just one register set_specification( “file_name”=>3..20, “date”=>21..29) set_attr_name :file_name end
lines_where 0..2, “002” do set_specification( “color”=>25..29,“brand”=>3..16, “model”=>17..24) set_attr_name :model end end
Using lines_where you can have different specifications for different kinds of registers. But in this situation, the attribute’s names of the object doesn’t follow the same rules as before. The set_attr_name will tell what to use as attribute names. So, supposing the file is something like:
001first_file.txt 05052011 002Wolksvagen Golf red
002Renault Vivasix blue 002Porsche Boxter black
We would do:
client = Client.new(“path/to/file.txt”) client.boxter # => ‘black’ client.boxter # =>‘Porsche’ client.boxter # =>‘Boxter’ cliennt.golf # => ‘red’
Notice that in multi-lin files, the method’s names will always be the downcased version of the value found in the given position. Whenever set_attr_name is not specified, the method creation rules will be the same as in a one-line file.
To list every attribute created for your object, do: client.pos_attributes # => [‘boxter’, ‘golf’, ‘vivasix’]
The code used to identify between the two specifications (in the example above they are 001 and 002) are called “section code”, and is automatically included in tha specification hash, so if you need it:
Feedback
Email: [email protected] Any ideas on how we can make this better will be appreciated.