On 06/03/2013 12:41 PM, Panagiotis Atmatzidis wrote:
>
> On 3 ϦԦ 2013, at 21:24 , Joel VanderWerf <joelvanderwerf / gmail.com> wrote:
>
>> On 06/03/2013 11:47 AM, Panagiotis Atmatzidis wrote:
>>> Hello,
>>>
>>> I'm writing a client/server application using TCPSocket and TCPServer. To serialize the objects at this point I use Marshal, since it comes handy.
>> ...
>>> What I notice is that connection ends when the '\n' character appears. I think that the issue is me using "@con.gets" method instead of something more appropriate. I tried @con.read but since 'read' method waits for the remote party to send an 'EOF' or close the connection stalls.
>>>
>>> Is there any other method I can use instead of gets? I did a 'methods.sort' but I can't see and I don't know how to read about these methods using "ri". 'ri TCPSocket::getc' for example doesn't work.
>>
>> You can try
>>
>> Marshal.load(conn)
>>
>> on the client side. The Marshal#load method determines just how many bytes to read.
>
>
> Worked fine! Thank you! I don't get it thought, could you elaborate a bit?

Sure (sorry to be cryptic!).

If you look at the format of marshalled objects, there is always a way 
to determine how many bytes to expect. In the case of fixed length data, 
there is a type field followed by the data (floats for example). In the 
case of strings, arrays, hashes, etc. there are type and length fields 
followed by the items (which themselves will have type and possibly 
length fields). So #load always knows either the number of bytes to read 
or the number of times to iterate to read all the items. Recursively 
build the object tree, and you're done.

However, Marshal#load can't know, until this recursion finishes, the 
total number of bytes. There is no length field for the whole serialized 
blob. That's why load(sock.read(n)) doesn't work well with marshal.

Btw, if your objects are just strings, numbers, booleans, hashes, and 
arrays, then msgpack is a great alternative to marshal. It's not ruby 
specific, it's fast and compact, and it plays well with non-blocking io.

Why non-blocking io? You'll notice that if you Marshal.load(conn) and 
conn takes a long time to send all the bytes, then the thread that 
called #load is blocked. So, just start a thread per connection. That's 
fine if you only need a few connections at a time. With msgpack's 
buffering, it's possible to read only the complete objects from the 
connection, and then the thread is free to go on to another connection 
and read. (See msgpack doc for examples.) Btw, the yajl JSON lib does 
something like this too.

Cheers!