Slither
by Ryan Wood http://ryanwood.com
Documentation: https://www.rubydoc.info/gems/slither
Description:
A simple, clean DSL for describing, writing, and parsing fixed-width text files.
Features:
- Easy DSL syntax
- Can parse and format fixed width files
- Templated sections for reuse
- Helpful error messages for invalid data
Synopsis:
Create a Slither::Defintion to describe a file format
Slither.define :simple, :by_bytes => false do |d|
# This is a template section that can be reused in other sections
d.template :boundary do |t|
t.column :record_type, 4
t.column :company_id, 12
end
# Create a header section
# alternatively, you can define the section on the fly by using metaprogramming
# ex: d.header(:align => :left) { |header| ... }
d.section(:header, :align => :left) do |header|
# The trap tells Slither which lines should fall into this section
header.trap { |line| line[0,4] == 'HEAD' }
# Use the boundary template for the columns
header.template :boundary
end
d.section(:body) do |body|
body.trap { |line| line[0,4] =~ /[^(HEAD|FOOT)]/ }
body.column :id, 10, :type => :integer
body.column :name, 10, :align => :left
body.spacer 3
body.column :state, 2
end
d.section(:footer) do |footer|
footer.trap { |line| line[0,4] == 'FOOT' }
footer.template :boundary
footer.column :record_count, 10
end
endSupported types are: string, integer, date, float, money, and money_with_implied_decimal.
Use :by_bytes => true (default) to allow newlines within rows and specify length in bytes.
Use :by_bytes => false to support sections of different lengths and length specification
in number of characters.
Then either feed it a nested struct with data values to create the file in the defined format:
test_data = {
:body => [
{ :id => 12, :name => "Ryan", :state => 'SC' },
{ :id => 23, :name => "Joe", :state => 'VA' },
{ :id => 42, :name => "Tommy", :state => 'FL' },
],
:header => { :record_type => 'HEAD', :company_id => 'ABC' },
:footer => { :record_type => 'FOOT', :company_id => 'ABC' }
}
# Generates the file as a string
puts Slither.generate(:simple, test_data)
# =>
# HEAD ABC
# 12Ryan SC
# 23Joe VA
# 42Tommy FL
# FOOT ABC
# Writes the file
Slither.write(output_filename, :simple, test_data)or parse files already in that format into a nested hash:
parsed_data = Slither.parse(input_filename, :simple)
parsed_data = Slither.parseIo(io_object, :simple)The gem is available as open source under the terms of the MIT License.
Code of Conduct
Everyone interacting in the Slither project's codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.