Class: Dreader::Engine

Inherits:
Object
  • Object
show all
Defined in:
lib/dreader.rb

Overview

This is where the real stuff begins

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Engine 



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# File 'lib/dreader.rb', line 47

def initialize
  @options = {}
  @colspec = []
end

Instance Attribute Details

#array ⇒ Object (readonly)

the data we read



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# File 'lib/dreader.rb', line 45

def array
  @array
end

#colspec ⇒ Object (readonly)

the specification of the columns to process



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# File 'lib/dreader.rb', line 43

def colspec
  @colspec
end

#options(&block) ⇒ Object (readonly)

define a DSL for options any string is processed as an option and it ends up in the



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# File 'lib/dreader.rb', line 41

def options
  @options
end

Instance Method Details

#column(name, &block) ⇒ Object

define a DSL for column specification

  • ‘name` is the name of the column

  • ‘block` contains two declarations, `process` and `check`, which are used, respectively, to make a cell into the desired data and to check whether the desired data is ok



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# File 'lib/dreader.rb', line 67

def column name, &block
  column = Column.new
  column.instance_eval(&block)

  @colspec << column.to_hash.merge({name: name})
end

#errors ⇒ Object

return an array of strings with all the errors we have encounterd an empty array is a good news



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# File 'lib/dreader.rb', line 122

def errors
  @errors
end

#mapping(&block) ⇒ Object

define what we do with each line we read

  • ‘block` is the code which takes as input a `row` and processes `row` is a hash in which each spreadsheet cell is accessible under the column names. Each cell has the following values: :value, :error, :row_number, :col_number



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# File 'lib/dreader.rb', line 79

def mapping &block
  @mapping = block
end

#process ⇒ Object

apply the mapping code to the array it makes sense to invoke it only



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# File 'lib/dreader.rb', line 128

def process
  @array.each do |r|
    @mapping.call(r)
  end
end

#read(filename = nil) ⇒ Object

read a file and store it internally return the data we read in the form of an array of hashes



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# File 'lib/dreader.rb', line 85

def read filename=nil
  spreadsheet = self.open_spreadsheet filename || @options[:filename]
  sheet = spreadsheet.sheet(@options[:sheet] || 0)

  @array = Array.new
  @errors = Array.new
  first_row = @options[:start_at] || 1
  (first_row..spreadsheet.last_row).each do |row_number|
    row = spreadsheet.row(row_number)

    r = Hash.new
    @colspec.each_with_index do |colspec, index|
      colname = colspec[:name]

      r[colname] = Hash.new

      r[colname][:row_number] = row_number
      r[colname][:col_number] = index + 1

      r[colname][:value] = value = colspec[:process] ? colspec[:process].call(row[index]) : row[index]

      if colspec[:check] and not colspec[:check].call(value) then
        r[colname][:error] = true
        @errors << "Error: value \"#{row[index]}\" for #{colname} at row #{row_number} (col #{index + 1}) is incorrect"
      else
        r[colname][:error] = false
      end
    end

    @array << r
  end

  @array
end

#to_s ⇒ Object 



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# File 'lib/dreader.rb', line 134

def to_s
  @array.to_s
end