Class: QueryBuilder::Processor

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

Constant Summary collapse

OPERATOR_TO_METHOD =

class << self

{
  :"!" => :not,
  :"@-" => :change_sign, :"@~" => :invert_bits,
  :"^" => :bitwise_xor,
  :* => :times, :/ => :division, :DIV => :integer_division, :% => :modulo, :mod => :modulo,
  :- => :minus, :+ => :addition,
  :<< => :left_shift, :>> => :right_shift,
  :& => :bitwise_and,
  :| => :bitwise_or,
  :eq => :equal, :ge => :greater_or_equal,
  :gt => :greater, :le => :less_or_equal, :lt => :less, :ne => :not_equal,
  :"=" => :equal, :"<=>" => :null_safe_equal, :>= => :greater_or_equal,
  :> => :greater, :<= => :less_or_equal, :< => :less, :"<>" => :not_equal, :"!=" => :not_equal,
  :"&&" => :and,
  :"||" => :or,
  :":=" => :assign
}
METHOD_TO_OPERATOR = 
{
  :greater => :>, :greater_or_equal => :>=,
  :equal   => :'=',
  :less_or_equal => :<=, :less => :<,
  :not_equal => :'<>'
}

Class Attribute Summary collapse

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(source, opts = {}) ⇒ Processor

Returns a new instance of Processor.



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# File 'lib/query_builder/processor.rb', line 140

def initialize(source, opts = {})
  @default = opts.delete(:default) || {}
  @opts = opts
  @rubyless_helper  = @opts[:rubyless_helper]

  if source.kind_of?(Processor)
    # experimental: class change
    @context  = source.context
    @query    = source.query
    @sxp      = source.sxp
    @ancestor = source # used during class change to return back to previous 'this'
  elsif source.kind_of?(String)
    @sxp = Parser.parse(source)

    @context = opts.merge(:first => true, :last => true)
    @query = Query.new(self.class)
    @query.main_class = @opts[:main_class] || resolve_main_class(self.class.main_class)
    before_process

    process_all

    after_process

    if limit = @opts[:limit]
      @query.limit = " LIMIT #{limit}"
    end
  else
    raise QueryBuilder::Error.new("Cannot use #{source.class} as source: expected a String or QueryBuilder::Processor")
  end
rescue QueryBuilder::Error => err
  raise err
rescue Exception => err
  raise QueryBuilder::Error.new("Exception raised while processing '#{source}' (#{err.message})")
end

Class Attribute Details

.after_process_callbacks ⇒ Object

Returns the value of attribute after_process_callbacks.



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# File 'lib/query_builder/processor.rb', line 11

def after_process_callbacks
  @after_process_callbacks
end

.before_process_callbacks ⇒ Object

Returns the value of attribute before_process_callbacks.



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# File 'lib/query_builder/processor.rb', line 11

def before_process_callbacks
  @before_process_callbacks
end

.custom_queries ⇒ Object

class variable



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# File 'lib/query_builder/processor.rb', line 9

def custom_queries
  @custom_queries
end

.custom_query_files ⇒ Object

class variable



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# File 'lib/query_builder/processor.rb', line 9

def custom_query_files
  @custom_query_files
end

.defaults ⇒ Object

Returns the value of attribute defaults.



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# File 'lib/query_builder/processor.rb', line 10

def defaults
  @defaults
end

.main_class ⇒ Object

class variable



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# File 'lib/query_builder/processor.rb', line 9

def main_class
  @main_class
end

.main_table ⇒ Object

class variable



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# File 'lib/query_builder/processor.rb', line 9

def main_table
  @main_table
end

Instance Attribute Details

#ancestor ⇒ Object (readonly)

Returns the value of attribute ancestor.



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# File 'lib/query_builder/processor.rb', line 5

def ancestor
  @ancestor
end

#context ⇒ Object (readonly)

Returns the value of attribute context.



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# File 'lib/query_builder/processor.rb', line 5

def context
  @context
end

#query ⇒ Object (readonly)

Returns the value of attribute query.



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# File 'lib/query_builder/processor.rb', line 5

def query
  @query
end

#sxp ⇒ Object (readonly)

Returns the value of attribute sxp.



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# File 'lib/query_builder/processor.rb', line 5

def sxp
  @sxp
end

Class Method Details

.after_process(callback) ⇒ Object 



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# File 'lib/query_builder/processor.rb', line 30

def after_process(callback)
  (self.after_process_callbacks ||= []) << callback
end

.before_process(callback) ⇒ Object 



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# File 'lib/query_builder/processor.rb', line 26

def before_process(callback)
  (self.before_process_callbacks ||= []) << callback
end

.insert_bind(str) ⇒ Object 



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# File 'lib/query_builder/processor.rb', line 34

def insert_bind(str)
  if str.kind_of?(::RubyLess::TypedString)
    ::RubyLess::TypedString.new("[[#{str}]]", str.opts)
  else
    "[[#{str}]]"
  end
end

.load_custom_queries(directories) ⇒ Object

Load prepared SQL definitions from a set of directories. If the file does not contain “group” or “groups” keys, the filename is used as group.

Parameters

query<String>

Path to list of custom queries yaml files.

Examples

DummyQuery.load_custom_queries("/path/to/some/*/directory")

The format of a custom query definition is:

groups:
  - test.host
DummyQuery:      # QueryBuilder class
  abc:           # query's relation name
    select:      # selected fields
      - 'a'
      - '34 AS number'
      - 'c'
    tables:      # tables used
      - 'test'
    join_tables: # joins
      test:
        - LEFT JOIN other ON other.test_id = test.id
    where:    # filters
      - '1'
      - '2'
      - '3'
    order:  'a DESC' # order clause

Once loaded, this ‘custom query’ can be used in a query like:

"images from abc where a > 54"



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# File 'lib/query_builder/processor.rb', line 74

def load_custom_queries(directories)
  # lazy loading (evaluation happens on first query)
  self.custom_query_files ||= []
  self.custom_query_files << directories
end

.load_custom_queries! ⇒ Object 



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# File 'lib/query_builder/processor.rb', line 80

def load_custom_queries!
  return unless list = self.custom_query_files
  klass = nil
  self.custom_queries ||= {'all' => {}}
  Dir.glob(list.flatten).each do |dir|
    if File.directory?(dir)
      Dir.foreach(dir) do |file|
        next unless file =~ /(.+).yml$/
        custom_query_groups = $1
        definitions = YAML::load(File.read(File.join(dir,file)))
        custom_query_groups = [definitions.delete('groups') || definitions.delete('group') || custom_query_groups].flatten
        definitions.each do |klass, query_list|
          begin
            klass = QueryBuilder.resolve_const(klass)
            klass = klass.query_compiler if klass.respond_to?(:query_compiler)
            raise ArgumentError.new("Invalid Processor class '#{klass}' in '#{file}' custom query. Should be a descendant of QueryBuilder::Processor or respond to query_compiler.") unless klass.ancestors.include?(Processor)
          rescue NameError
            raise ArgumentError.new("Unknown Processor class '#{klass}' in '#{file}' custom query.")
          end
          custom_queries = klass.custom_queries
          custom_query_groups.each do |custom_query_group|
            custom_queries[custom_query_group] ||= {}
            klass_queries = custom_queries[custom_query_group]
            query_list.each do |query_name, query|
              klass_queries[query_name] = query
            end
          end
        end
      end
    end
  end
  self.custom_query_files = nil
end

.set_default(key, value) ⇒ Object 



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# File 'lib/query_builder/processor.rb', line 21

def set_default(key, value)
  self.defaults ||= {}
  self.defaults[key] = value
end

.set_main_class(klass) ⇒ Object 



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# File 'lib/query_builder/processor.rb', line 17

def set_main_class(klass)
  self.main_class = klass
end

.set_main_table(table_name) ⇒ Object 



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# File 'lib/query_builder/processor.rb', line 13

def set_main_table(table_name)
  self.main_table = table_name
end