Class: StoreHours::StoreHours

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

Overview

A very simple parser to parse text like

Mon-Fri:  9AM-5PM
Sat:      10AM-7PM
Sun:      closed

and build an internal data structure to enable possible formatting and queries.

This class is designed to use when (1) you like to use a single text field in database to store open hours, and (2) you would like to be able to check whether the store opens for a certain time, or to make sure inputs are valid, or to display the hours in a format different from user input (for example, take plain text from users, but to format the input in html to display).

Here is an example about how to use this class in rails. Suppose you have a model called “Store” with a text filed named normal_business_hours, you can add this validation method:

validate :normal_business_hours_must_be_in_valid_format
def normal_business_hours_must_be_in_valid_format
  hours_parser = ::StoreHours::StoreHours.new
  #check whether input is valid?
  success, error_message  = hours_parser.from_text(self.normal_business_hours)
  if !success
    #input is not valid
    errors.add(:normal_business_hours, error_message)
  end
end

Please refer to text_input_parser.rb and tree_transformer.rb to get some idea of what kinds of inputs are valid.

Instance Method Summary collapse

Constructor Details

#initialize ⇒ StoreHours

Returns a new instance of StoreHours.



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

def initialize
  @hours = []
end

Instance Method Details

#from_text(text) ⇒ Boolean, String

Try to parse the input text. the return value will be [false, “error message”]

This method will build the internal data structure for valid text argument.

Please don’t ignore the return value from this method as it is the only way to know whether input is valid.

Parameters:

  • text (String) —

    store hours text input, case-insensitive

Returns:

  • (Boolean, String) —

    returns [true, ”] if the text is valid, otherwise,



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# File 'lib/store_hours.rb', line 57

def from_text(text)
  text = '' if text == nil
  result = true
  error_message = ''

  begin
    # parse the text into an intermediary tree
    # this call may raise Parslet::ParseFailed exception
    tree = TextInputParser.new.parse(text.strip.downcase)

    # convert the tree into internal data structure
    # please refer to tree_transformer.rb for the details of this structure
    # this call may raise StoreHours::SemanticError exception
    @hours = TreeTransformer.new.apply(tree)

    result = true
  rescue Parslet::ParseFailed => e
    puts e.cause.ascii_tree
    puts e.cause.message
    puts text[0..e.cause.source.chars_left]

    result = false
    error_message = "syntax error: input is not in correct format"
  rescue ::StoreHours::SemanticError => e
    puts e.message

    result = false
    error_message = e.message
  end

  return [result, error_message]
end

#is_open?(t) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/store_hours.rb', line 117

def is_open?(t)
  @hours.each do |days_table|
    # days_table in the format of range(wday..wday) => [range(minutes..minutes),...]
    # only one key in the hash table
    days = days_table.keys.first
    if days.include?(t.wday == 0 ? 7 : t.wday)
      days_table[days].each do |min_range|
        minutes = t.hour * 60 + t.min

        if min_range.include?(minutes)
          return true
        end
      end
    end
  end

  return false
end

#to_text ⇒ Object

This is the method you can use to display store hours.



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# File 'lib/store_hours.rb', line 91

def to_text
  text = ''
  @hours.each do |days_table|
    days = days_table.keys.first  #days is the day range, for example, (1..5)
    if block_given?
      text += yield NUM_TO_WEEKDAY[days.first], NUM_TO_WEEKDAY[days.last], days_table[days]
    else
      text += NUM_TO_WEEKDAY[days.first].to_s
      text += "-" + NUM_TO_WEEKDAY[days.last].to_s if days.first != days.last
      text += ": "

      days_table[days].each_with_index do |minutes, index|
        text += ', ' if index > 0
        if minutes.first == -1  #closed days
          text += "closed"
        elsif
          text += ::StoreHours::from_minutes_to_time_str(minutes.first) + " - " + ::StoreHours::from_minutes_to_time_str(minutes.last)
        end
      end
      text += "\n"
    end
  end

  text.strip
end