Class: ForestLiana::FiltersParser

Inherits:
Object
  • Object
show all
Defined in:
app/services/forest_liana/filters_parser.rb

Constant Summary collapse

AGGREGATOR_OPERATOR = 
%w(and or)

Instance Method Summary collapse

Constructor Details

#initialize(filters, resource, timezone) ⇒ FiltersParser

Returns a new instance of FiltersParser.



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# File 'app/services/forest_liana/filters_parser.rb', line 5

def initialize(filters, resource, timezone)
  begin
    @filters = JSON.parse(filters)
  rescue JSON::ParserError
    raise ForestLiana::Errors::HTTP422Error.new('Invalid filters JSON format')
  end

  @resource = resource
  @operator_date_parser = OperatorDateIntervalParser.new(timezone)
  @joins = []
end

Instance Method Details

#apply_filters ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 17

def apply_filters
  return @resource unless @filters

  where = parse_aggregation(@filters)
  return @resource unless where

  @joins.each do |join|
    current_resource = @resource.reflect_on_association(join.name).klass
    current_resource.include(ArelHelpers::Aliases)
    current_resource.aliased_as(join.name) do |aliased_resource|
      @resource = @resource.joins(ArelHelpers.join_association(@resource, join.name, Arel::Nodes::OuterJoin, aliases: [aliased_resource]))
    end
  end

  @resource.where(where)
end

#apply_filters_on_previous_interval(previous_condition) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 208

def apply_filters_on_previous_interval(previous_condition)
  # Ressource should have already been joined
  where = parse_aggregation_on_previous_interval(@filters, previous_condition)

  @resource.where(where)
end

#ensure_valid_aggregation(node) ⇒ Object

Raises:

  • (ForestLiana::Errors::HTTP422Error) 


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# File 'app/services/forest_liana/filters_parser.rb', line 253

def ensure_valid_aggregation(node)
  raise ForestLiana::Errors::HTTP422Error.new('Filters cannot be a raw value') unless node.is_a?(Hash)
  raise_empty_condition_in_filter_error if node.empty?
end

#ensure_valid_condition(condition) ⇒ Object

Raises:

  • (ForestLiana::Errors::HTTP422Error) 


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# File 'app/services/forest_liana/filters_parser.rb', line 258

def ensure_valid_condition(condition)
  raise_empty_condition_in_filter_error if condition.empty?
  raise ForestLiana::Errors::HTTP422Error.new('Condition cannot be a raw value') unless condition.is_a?(Hash)
  unless condition['field'].is_a?(String) and condition['operator'].is_a?(String)
    raise ForestLiana::Errors::HTTP422Error.new('Invalid condition format')
  end
end

#get_association_name_for_condition(field) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 168

def get_association_name_for_condition(field)
  field, subfield = field.split(':')

  association = @resource.reflect_on_association(field.to_sym)
  return nil if association.blank?

  @joins << association unless @joins.include? association

  association.name
end

#get_previous_interval_condition ⇒ Object

NOTICE: Look for a previous interval condition matching the following:

- If the filter is a simple condition at the root the check is done right away.
- There can't be a previous interval condition if the aggregator is 'or' (no meaning).
- The condition's operator has to be elligible for a previous interval.
- There can't be two previous interval condition.



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# File 'app/services/forest_liana/filters_parser.rb', line 184

def get_previous_interval_condition
  current_previous_interval = nil
  # NOTICE: Leaf condition at root
  unless @filters['aggregator']
    return @filters if @operator_date_parser.has_previous_interval?(@filters['operator'])
  end

  if @filters['aggregator'] === 'and'
    @filters['conditions'].each do |condition|
      # NOTICE: Nested conditions
      return nil if condition['aggregator']

      if @operator_date_parser.has_previous_interval?(condition['operator'])
        # NOTICE: There can't be two previous_interval.
        return nil if current_previous_interval

        current_previous_interval = condition
      end
    end
  end

  current_previous_interval
end

#is_belongs_to(field) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 164

def is_belongs_to(field)
  field.include?(':')
end

#parse_aggregation(node) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 34

def parse_aggregation(node)
  ensure_valid_aggregation(node)

  return parse_condition(node) unless node['aggregator']

  conditions = []
  node['conditions'].each do |condition|
    conditions.push(parse_aggregation(condition))
  end

  operator = parse_aggregation_operator(node['aggregator'])

  conditions.empty? ? nil : "(#{conditions.join(" #{operator} ")})"
end

#parse_aggregation_on_previous_interval(node, previous_condition) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 215

def parse_aggregation_on_previous_interval(node, previous_condition)
  raise_empty_condition_in_filter_error unless node

  return parse_previous_interval_condition(node) unless node['aggregator']

  conditions = []
  node['conditions'].each do |condition|
    if condition == previous_condition
      conditions.push(parse_previous_interval_condition(condition))
    else
      conditions.push(parse_aggregation(condition))
    end
  end

  operator = parse_aggregation_operator(node['aggregator'])

  conditions.empty? ? nil : "(#{conditions.join(" #{operator} ")})"
end

#parse_aggregation_operator(aggregator_operator) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 92

def parse_aggregation_operator(aggregator_operator)
  unless AGGREGATOR_OPERATOR.include?(aggregator_operator)
    raise_unknown_operator_error(aggregator_operator)
  end

  aggregator_operator.upcase
end

#parse_condition(condition) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 49

def parse_condition(condition)
  ensure_valid_condition(condition)

  operator = condition['operator']
  value = condition['value']
  field = condition['field']

  if @operator_date_parser.is_date_operator?(operator)
    condition = @operator_date_parser.get_date_filter(operator, value)
    return "#{parse_field_name(field)} #{condition}"
  end

  if is_belongs_to(field)
    association = field.partition(':').first.to_sym
    association_field = field.partition(':').last

    unless @resource.reflect_on_association(association)
      raise ForestLiana::Errors::HTTP422Error.new("Association '#{association}' not found")
    end

    current_resource = @resource.reflect_on_association(association).klass
  else
    association_field = field
    current_resource = @resource
  end

  # NOTICE: Set the integer value instead of a string if "enum" type
  # NOTICE: Rails 3 do not have a defined_enums method
  if current_resource.respond_to?(:defined_enums) && current_resource.defined_enums.has_key?(association_field)
    value = current_resource.defined_enums[association_field][value]
  end

  parsed_field = parse_field_name(field)
  parsed_operator = parse_operator(operator)
  parsed_value = parse_value(operator, value)

  if Rails::VERSION::MAJOR >= 5
    ActiveRecord::Base.sanitize_sql(["#{parsed_field} #{parsed_operator} ?", parsed_value])
  else
    "#{parsed_field} #{parsed_operator} #{ActiveRecord::Base.sanitize(parsed_value)}"
  end
end

#parse_field_name(field) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 141

def parse_field_name(field)
  if is_belongs_to(field)
    current_resource = @resource.reflect_on_association(field.split(':').first.to_sym)&.klass
    raise ForestLiana::Errors::HTTP422Error.new("Field '#{field}' not found") unless current_resource

    association = get_association_name_for_condition(field)
    quoted_table_name = ActiveRecord::Base.connection.quote_column_name(association)
    quoted_field_name = ActiveRecord::Base.connection.quote_column_name(field.split(':')[1])
  else
    quoted_table_name = @resource.quoted_table_name
    quoted_field_name = ActiveRecord::Base.connection.quote_column_name(field)
    current_resource = @resource
  end

  column_found = current_resource.columns.find { |column| column.name == field.split(':').last }

  if column_found.nil?
    raise ForestLiana::Errors::HTTP422Error.new("Field '#{field}' not found")
  end

  "#{quoted_table_name}.#{quoted_field_name}"
end

#parse_operator(operator) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 100

def parse_operator(operator)
  case operator
  when 'not'
    'NOT'
  when 'greater_than', 'after'
    '>'
  when 'less_than', 'before'
    '<'
  when 'contains', 'starts_with', 'ends_with'
    'LIKE'
  when 'not_contains'
    'NOT LIKE'
  when 'not_equal'
    '!='
  when 'equal'
    '='
  when 'blank'
    'IS'
  when 'present'
    'IS NOT'
  else
    raise_unknown_operator_error(operator)
  end
end

#parse_previous_interval_condition(condition) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 234

def parse_previous_interval_condition(condition)
  raise_empty_condition_in_filter_error unless condition

  parsed_condition = @operator_date_parser.get_date_filter_for_previous_interval(
    condition['operator'],
    condition['value']
  )

  "#{parse_field_name(condition['field'])} #{parsed_condition}"
end

#parse_value(operator, value) ⇒ Object 



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# File 'app/services/forest_liana/filters_parser.rb', line 125

def parse_value(operator, value)
  case operator
  when 'not', 'greater_than', 'less_than', 'not_equal', 'equal', 'before', 'after'
    value
  when 'contains', 'not_contains'
    "%#{value}%"
  when 'starts_with'
    "#{value}%"
  when 'ends_with'
    "%#{value}"
  when 'present', 'blank'
  else
    raise_unknown_operator_error(operator)
  end
end

#raise_empty_condition_in_filter_error ⇒ Object

Raises:

  • (ForestLiana::Errors::HTTP422Error) 


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# File 'app/services/forest_liana/filters_parser.rb', line 249

def raise_empty_condition_in_filter_error
  raise ForestLiana::Errors::HTTP422Error.new('Empty condition in filter')
end

#raise_unknown_operator_error(operator) ⇒ Object

Raises:

  • (ForestLiana::Errors::HTTP422Error) 


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# File 'app/services/forest_liana/filters_parser.rb', line 245

def raise_unknown_operator_error(operator)
  raise ForestLiana::Errors::HTTP422Error.new("Unknown provided operator '#{operator}'")
end