Some frameworks (e.g. Merb) call `seek` and `rewind` on the input stream if it responds to these methods. In case of Phusion Passenger, the input stream is a socket, and altough socket objects respond to `seek` and `rewind`, calling these methods will raise an exception. We don't want this to happen so in AbstractRequestHandler we wrap the client socket into an UnseekableSocket wrapper, which doesn't respond to these methods.
We used to dynamically undef `seek` and `rewind` on sockets, but this blows the Ruby interpreter's method cache and made things slower. Wrapping a socket is faster despite extra method calls.
Furthermore, all exceptions originating from the wrapped socket will be annotated. One can check whether a certain exception originates from the wrapped socket by calling source_of_exception?
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 107 def addr @socket.addr rescue => e raise annotate(e) end
Already set to binary mode.
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 87 def binmode end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 203 def close @socket.close rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 209 def close_read @socket.close_read rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 215 def close_write @socket.close_write rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 197 def closed? @socket.closed? rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 183 def each(&block) return if @simulate_eof @socket.each(&block) rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 190 def eof? return true if @simulate_eof @socket.eof? rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 103 def fileno @socket.fileno end
Socket is sync'ed so flushing shouldn't do anything.
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 83 def flush end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 143 def gets return nil if @simulate_eof @socket.gets rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 137 def puts(*args) @socket.puts(*args) rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 150 def read(*args) if @simulate_eof length, buffer = args if buffer buffer.replace(binary_string("")) else buffer = binary_string("") end if length return nil else return buffer end end @socket.read(*args) rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 176 def readline raise EOFError, "end of file reached" if @simulate_eof @socket.readline rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 169 def readpartial(*args) raise EOFError, "end of file reached" if @simulate_eof @socket.readpartial(*args) rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 95 def simulate_eof! @simulate_eof = true end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 221 def source_of_exception?(exception) return exception.instance_variable_get(:"@from_unseekable_socket") == @socket.object_id end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 99 def stop_simulating_eof! @simulate_eof = false end
Don't allow disabling of sync.
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 79 def sync=(value) end
This makes select() work.
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 91 def to_io @socket end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 48 def wrap(socket) # Some people report that sometimes their Ruby (MRI/REE) # processes get stuck with 100% CPU usage. Upon further # inspection with strace, it turns out that these Ruby # processes are continuously calling lseek() on a socket, # which of course returns ESPIPE as error. gdb reveals # lseek() is called by fwrite(), which in turn is called # by rb_fwrite(). The affected socket is the # AbstractRequestHandler client socket. # # I inspected the MRI source code and didn't find # anything that would explain this behavior. This makes # me think that it's a glibc bug, but that's very # unlikely. # # The rb_fwrite() implementation takes an entirely # different code path if I set 'sync' to true: it will # skip fwrite() and use write() instead. So here we set # 'sync' to true in the hope that this will work around # the problem. socket.sync = true # There's no need to set the encoding for Ruby 1.9 because # abstract_request_handler.rb is tagged with 'encoding: binary'. @socket = socket return self end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 113 def write(string) @socket.write(string) rescue => e raise annotate(e) end
# File lib/phusion_passenger/utils/unseekable_socket.rb, line 119 def writev(components) @socket.writev(components) rescue => e raise annotate(e) end
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