EventMachine::FileStreamer

Constants

MappingThreshold: Use mapped streamer for files bigger than 16k
BackpressureLevel: Wait until next tick to send more data when 50k is still in the outgoing buffer
ChunkSize: Send 16k chunks at a time

Public Class Methods

new(connection, filename, args = {}) click to toggle source

Stream a file over a given connection. An optional :http_chunks => true argument will use HTTP 1.1 style chunked-encoding semantics.

 module FileSender
   def post_init
     streamer = EventMachine::FileStreamer.new(self, '/tmp/bigfile.tar')
     streamer.callback{
       # file was sent successfully
       close_connection_after_writing
     }
   end
 end

    # File lib/em/streamer.rb, line 51
51:     def initialize connection, filename, args = {}
52:       @connection = connection
53:       @http_chunks = args[:http_chunks]
54: 
55:       if File.exist?(filename)
56:         @size = File.size?(filename)
57:         if @size <= MappingThreshold
58:           stream_without_mapping filename
59:         else
60:           stream_with_mapping filename
61:         end
62:       else
63:         fail "file not found"
64:       end
65:     end

Public Instance Methods

stream_one_chunk() click to toggle source

Used internally to stream one chunk at a time over multiple reactor ticks

     # File lib/em/streamer.rb, line 89
 89:     def stream_one_chunk
 90:       loop {
 91:         if @position < @size
 92:           if @connection.get_outbound_data_size > BackpressureLevel
 93:             EventMachine::next_tick {stream_one_chunk}
 94:             break
 95:           else
 96:             len = @size - @position
 97:             len = ChunkSize if (len > ChunkSize)
 98: 
 99:             @connection.send_data( "#{len.to_s(16)}\r\n" ) if @http_chunks
100:             @connection.send_data( @mapping.get_chunk( @position, len ))
101:             @connection.send_data("\r\n") if @http_chunks
102: 
103:             @position += len
104:           end
105:         else
106:           @connection.send_data "0\r\n\r\n" if @http_chunks
107:           @mapping.close
108:           succeed
109:           break
110:         end
111:       }
112:     end

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EventMachine::FileStreamer

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