Class: Protocol::Redis::Connection

Inherits:
Object
  • Object
show all
Defined in:
lib/protocol/redis/connection.rb

Overview

Represents a Redis protocol connection handling low-level communication.

Constant Summary collapse

CRLF = 
"\r\n".freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(stream) ⇒ Connection

Initialize a new connection with the provided stream.



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# File 'lib/protocol/redis/connection.rb', line 16

def initialize(stream)
	@stream = stream
	
	# Number of requests sent:
	@count = 0
end

Instance Attribute Details

#count ⇒ Object (readonly) 



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# File 'lib/protocol/redis/connection.rb', line 26

def count
  @count
end

#stream ⇒ Object (readonly)

Returns the value of attribute stream.



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# File 'lib/protocol/redis/connection.rb', line 23

def stream
  @stream
end

Instance Method Details

#close ⇒ Object

Close the underlying stream connection.



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# File 'lib/protocol/redis/connection.rb', line 29

def close
	@stream.close
end

#closed? ⇒ Boolean

Check if the connection is closed.

Returns:

  • (Boolean) 


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# File 'lib/protocol/redis/connection.rb', line 45

def closed?
	@stream.closed?
end

#flush ⇒ Object

Flush any buffered data to the stream.



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# File 'lib/protocol/redis/connection.rb', line 39

def flush
	@stream.flush
end

#read_data(length) ⇒ Object

Read data of specified length from the stream.



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# File 'lib/protocol/redis/connection.rb', line 92

def read_data(length)
	buffer = @stream.read(length) or @stream.eof!
	
	# Eat trailing whitespace because length does not include the CRLF:
	@stream.read(2) or @stream.eof!
	
	return buffer
end

#read_object ⇒ Object Also known as: read_response

Read and parse a Redis object from the stream.



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# File 'lib/protocol/redis/connection.rb', line 105

def read_object
	line = read_line or raise EOFError
	
	token = line.slice!(0, 1)
	
	case token
	when "$"
		length = line.to_i
		
		if length == -1
			return nil
		else
			return read_data(length)
		end
	when "*"
		count = line.to_i
		
		# Null array (https://redis.io/topics/protocol#resp-arrays):
		return nil if count == -1
		
		array = Array.new(count) {read_object}
		
		return array
	when ":"
		return line.to_i
		
	when "-"
		raise ServerError.new(line)
		
	when "+"
		return line
		
	else
		@stream.flush
		
		raise UnknownTokenError, token.inspect
	end
	
	# TODO: If an exception (e.g. Async::TimeoutError) propagates out of this function, perhaps @stream should be closed? Otherwise it might be in a weird state.
end

#write_array(array) ⇒ Object

Write a Redis array to the stream.



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# File 'lib/protocol/redis/connection.rb', line 81

def write_array(array)
	write_lines("*#{array.size}")
	
	array.each do |element|
		write_object(element)
	end
end

#write_object(object) ⇒ Object

Write a Redis object to the stream.



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# File 'lib/protocol/redis/connection.rb', line 64

def write_object(object)
	case object
	when String
		write_lines("$#{object.bytesize}", object)
	when Array
		write_array(object)
	when Integer
		write_lines(":#{object}")
	when nil
		write_lines("$-1")
	else
		write_object(object.to_redis)
	end
end

#write_request(arguments) ⇒ Object

The redis server doesn’t want actual objects (e.g. integers) but only bulk strings. So, we inline it for performance.



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# File 'lib/protocol/redis/connection.rb', line 50

def write_request(arguments)
	write_lines("*#{arguments.size}")
	
	@count += 1
	
	arguments.each do |argument|
		string = argument.to_s
		
		write_lines("$#{string.bytesize}", string)
	end
end