From the former STOMP web site (at codehaus.org):
The STOMP project is the Streaming Text Orientated Messaging Protocol site (or the Protocol Briefly Known as TTMP and Represented by the symbol :ttmp). STOMP provides an interoperable wire format so that any of the available Stomp Clients can communicate with any STOMP Message Broker to provide easy and widespread messaging interop among languages, platforms and brokers.
The RPG client makes it possible to speak to messaging systems like ActiveMQ, RabbitMQ, Apollo, Artemis ... natively.
The protocol is listed at github.
STOMP is a frame based protocol, with frames modelled on HTTP. A frame consists of a command, a set of optional headers and an optional body. STOMP is text based but also allows for the transmission of binary messages.
A frame contains data for the Message Queueing Server (command and headers) but also the data for the receiver of the message (body).
The client API is divided into many smaller modules:
- STOMP - main client module
- STOMPCMD - executing Stomp commands
- STOMPEXT - proxy/interface for RPG Stomp extension modules
- STOMPFRAME - building and working with frames
- STOMPINIT - initialization starter
- STOMPLOG - logging module
- STOMPPARSE - buiding a frame from its serialized state
- STOMPUTIL - utility procedures
Using this STOMP client starts with creating a client instance with the
stomp_create procedure which returns a handle which is used on every later call.
client = stomp_create('localhost' : 61613);
The socket to the client must be explicitly opened for communicating with the server.
stomp_open(client);
The client not only needs a connection to the server on a network level but also on an application level. The server expects a CONNECT STOMP frame.
stomp_command_connect(client);
After successfully connecting to the server it accepts messages from this client.
stomp_command_send(client : '/topic/retailprice' : '{ "id":5500 , "oldprice":1.23 , "newprice":1.59 }');
If no more messages are sent or received the client needs to disconnect from the server.
stomp_command_disconnect(client);
The allocated resources must be freed after finishing the communication with the server.
stomp_finalize(client);
For debugging purposes logging can be enabled by setting the environment variable
STOMP_DEBUG to '1'.
ADDENVVAR ENVVAR(STOMP_DEBUG) VALUE(1)
Note: Enableing logging results in many job log messages and should only be used for debugging.
Some message queuing systems implement the STOMP protocol differently or extending
the function set by adding new headers to the frames. There is an extension
mechanism for tweaking the STOMP frames for these systems (STOMPEXT). The
extension module must implement the stompext interface. For each call on a
procedure in the COMMAND module the corresponding procedure in the extension
module will be called.
For telling the client which extension to use the procedure stomp_setExtension must be called.
stomp_setExtension(client : stomp_ext_activemq_create());
This software package has the following dependencies:
For standard installation the tool make is used. The Makefile contains all
instructions for compilation.
make
will compile the module and bind the service program. You can specify the target library as following
make BIN_LIB=MYLIB compile
As this project depends on several other projects it needs the copybooks of
these projects. The Makefile assumes that the copybooks are placed in the
directory /usr/local/include. You can specify another directory like this
make INCDIR=/home/mihael/include
The API documentation is be available at ILEDocs hosted at rpgnextgen.com.