Ruby Socket to Java Socket

Ruby
1

Hello !

I have some problem trying to establish dialog between a Ruby
socket(client) and a Java server socket (java.net.ServerSocket).

Everytime I try to write on the server socket I get an “Invalid stream
header” error from the server…

s = TCPSocket.open(“host”, 9061)
s.write(“test \n”);

=> Error

Can someone give a little hint on how to start inthe right way on this ?

Thx a lot !

Seurdge

2

Ok, I have experiment a lot and found that :

When the Java Server use :
in = requestSocket.getInputStream();

It works… I can read what the Ruby socket is sending…

But the real Java server that I have to talk with use :

in = new ObjectInputStream( new BufferedInputStream(

requestSocket.getInputStream() ) );

And in this case I get :

java.io.StreamCorruptedException: invalid stream header
at
java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:753)
at java.io.ObjectInputStream.(ObjectInputStream.java:268)
at project1.SergeServer1.main(SergeServer1.java:44)

The client can’t change the server so…

Is there a mean to force a header in a way that the ObjectInputStream
will be able to read what I send from Ruby ?

Here’s my test Ruby code :

addrinfo = Socket::getaddrinfo('localhost', 9501, nil,

Socket::SOCK_STREAM)
addrinfo.each do |af, port, name, addr|
begin
sock = TCPSocket.new(addr, port)
sock.send(“test”, 0)
rescue
end
end

Thx in advance !

Seurdge

Serge S. wrote:

Hello !

I have some problem trying to establish dialog between a Ruby
socket(client) and a Java server socket (java.net.ServerSocket).

Everytime I try to write on the server socket I get an “Invalid stream
header” error from the server…

s = TCPSocket.open(“host”, 9061)
s.write(“test \n”);

=> Error

Can someone give a little hint on how to start inthe right way on this ?

Thx a lot !

Seurdge

3

Serge S. wrote:

requestSocket.getInputStream() ) );

And in this case I get :

java.io.StreamCorruptedException: invalid stream header
at
java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:753)
at java.io.ObjectInputStream.(ObjectInputStream.java:268)
at project1.SergeServer1.main(SergeServer1.java:44)

The Java server is reading a Marshalled Java object, Usually that will
only be used for two Java
processes talking to each other.

If you are sending very simple Java Objects you could format it in Ruby
and transmit it, but it
would be messy. You will have to read the Sun documents on Java
serialized object formats, look at
the ObjectInputStream Javadoc for references to the required formats.

Try using JRuby instead and serialize the Java object in Java.

4

Thx jim…

we have finally made it by programming a little gateway that talk with
“ordinary” output stream to the outside world (Ruby) and translate to
his older brother that talk with pure Java stream…

Jim M. wrote:

Serge S. wrote:

requestSocket.getInputStream() ) );

And in this case I get :

java.io.StreamCorruptedException: invalid stream header
at
java.io.ObjectInputStream.readStreamHeader(ObjectInputStream.java:753)
at java.io.ObjectInputStream.(ObjectInputStream.java:268)
at project1.SergeServer1.main(SergeServer1.java:44)

The Java server is reading a Marshalled Java object, Usually that will
only be used for two Java
processes talking to each other.

If you are sending very simple Java Objects you could format it in Ruby
and transmit it, but it
would be messy. You will have to read the Sun documents on Java
serialized object formats, look at
the ObjectInputStream Javadoc for references to the required formats.

Try using JRuby instead and serialize the Java object in Java.

5

Serge,
Can you share this solution with us? I am stuck on exactly the same
thing. I cannot believe I cannot communicate over sockets to a java
server socket! Thanks SO much! -Janna B
Serge S. wrote:

Thx jim…

we have finally made it by programming a little gateway that talk with
“ordinary” output stream to the outside world (Ruby) and translate to
his older brother that talk with pure Java stream…

6

2008/9/25 Jim M. [email protected]:

The Java server is reading a Marshalled Java object, Usually that will only
be used for two Java processes talking to each other.

Exactly. Java and Ruby do not share a common serialization format.
You must take measures to explicitly handle serialization formats - or
more generally define the protocol you want to use on that connection.

If you are sending very simple Java Objects you could format it in Ruby and
transmit it, but it would be messy. You will have to read the Sun documents
on Java serialized object formats, look at the ObjectInputStream Javadoc for
references to the required formats.

Try using JRuby instead and serialize the Java object in Java.

There are more alternatives:

  • use one of the many XML serialization packages around,
  • generally use a SOAP API,
  • use YAML on both ends.

Kind regards

robert

7

Hello !

The trick is to use java.io.InputStream and java.io.OutputStream to
interface with Ruby socket, this work fine !

I have post the complete code to you Janna.

Hope this helps.

Serge

Robert K. wrote:

2008/9/25 Jim M. [email protected]:

The Java server is reading a Marshalled Java object, Usually that will only
be used for two Java processes talking to each other.

Exactly. Java and Ruby do not share a common serialization format.
You must take measures to explicitly handle serialization formats - or
more generally define the protocol you want to use on that connection.

If you are sending very simple Java Objects you could format it in Ruby and
transmit it, but it would be messy. You will have to read the Sun documents
on Java serialized object formats, look at the ObjectInputStream Javadoc for
references to the required formats.

Try using JRuby instead and serialize the Java object in Java.

There are more alternatives:

  • use one of the many XML serialization packages around,
  • generally use a SOAP API,
  • use YAML on both ends.

Kind regards

robert

8

Hi Serge,
I’m also looking for a solution to this problem. Can you provide me also
with the code?
Thanks

Serge S. wrote:

Hello !

The trick is to use java.io.InputStream and java.io.OutputStream to
interface with Ruby socket, this work fine !

I have post the complete code to you Janna.

Hope this helps.

Serge

Robert K. wrote:

2008/9/25 Jim M. [email protected]:

The Java server is reading a Marshalled Java object, Usually that will only
be used for two Java processes talking to each other.

Exactly. Java and Ruby do not share a common serialization format.
You must take measures to explicitly handle serialization formats - or
more generally define the protocol you want to use on that connection.

If you are sending very simple Java Objects you could format it in Ruby and
transmit it, but it would be messy. You will have to read the Sun documents
on Java serialized object formats, look at the ObjectInputStream Javadoc for
references to the required formats.

Try using JRuby instead and serialize the Java object in Java.

There are more alternatives:

  • use one of the many XML serialization packages around,
  • generally use a SOAP API,
  • use YAML on both ends.

Kind regards

robert