Introduction

WampEmb is a C++ 11 implementation of Wamp protocol, born for running on ARM mbed OS.

It can run also on Posix compliances OS (tested on Linux and OSX), with the primary purpose to achieve faster development time.

This library has been made for experimenting purpose and it's not complete and, probably, will be not maintained.

Anyway it is working and succesfully tested on Frescale Freedom K64f.

Features

• C++ 11 Wamp Library - built without using Exceptions to be mbed friendly
• Supporting MessagePack serialization
• Working on RawTransport and Websocket

Building

OSX and Linux

makedir build
cd build
cmake ..

mbed

yotta build

Programming

Initializing

First create a Transport and a Wamp object

 WampTransport wt {"ws://demo.crossbar.io:8080"};
 Wamp wamp {wt};

Connecting

You are ready to connect:

wamp->connect([&]() {
// Your statements after connection go here
}

Publish

wamp->pub("yourtopic",arg1, arg2, arg3);

Subscribe

wamp->subscribe("com.example.topic", [](MPNode args, MPNode kwargs) {
    LOG("Received event: " << args);
}

Call remote procedure

wamp->call("com.example.add", MsgPackArr {20,3}, MsgPackMap{},
           [](URI err, MPNode args, MPNode kwargs) {
               (void) kwargs;
           if (!err.empty()) {
        LOG("Received result:" << args);
    }

});

Register procedure

int sum(int x, int y) {
    return x+y;
}

wamp->registerProcedure("com.mydevice.sum", sum, [](URI err) {
    if (!err.empty()) {
        LOG("REGISTRATION ERROR:" << err);
    }
    LOG("Registration OK");
});

Example

Start new project

• Create new directory

mkdir hellowamp
cd hellowamp

• Initialize yotta

yotta init
yotta target frdm-k64f-gcc

• Add dependency to wamped module to module.json

{
  "name": "hellowamp",
  "version": "0.0.0",
  "bin": "./source",
  "private": true,
  "author": "",
  "license": "Apache-2.0",
  "dependencies": {
  	"wamped" : "alvistar/wamped#",
  	"mbed-drivers" : "*",
  	"sockets" : "*"
  }
}

• (Optional) create config.json for logging

{
	"wamped":{
		"debug": {
			"transport" : false,
			"wamp" : true
		}
	}
}

• Create the main app file "sources/app.cpp"

#include <iostream>
#include "mbed-drivers/mbed.h"
#include "minar/minar.h"
#include "wamped/Wamp.h"
#include "wamped/WampTransportWS.h"
#include "wamped/logger.h"

WampTransportWS *wt;
Wamp *wamp;


DigitalOut cled {LED_BLUE,1};

static void blinky(void) {
    static DigitalOut led(LED1);
    led = !led;
}

void app_start(int, char**) {

    std::cout << "Hello world!\r\n";

    wt = new WampTransportWS {"ws://demo.crossbar.io:8080"};
    wamp = new Wamp (*wt);

    wamp->onClose = [&]() {
        NVIC_SystemReset();
    };

    wamp->connect([&]() {
        LOG("Session joined :" << wamp->sessionID);

        wamp->pub("com.freedom.welcome", "hello");

        wamp->subscribe("com.freedom.oncounter", [](MPNode args, MPNode kwargs) {
            LOG("Received event: " << args);
            blinky();
        });
    });
};

• We need to enable C++ 11 support: create file "sources/app.CMAKE"

set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++11 -Wno-literal-suffix")

As Mbed OS is in current beta there can be problems in building with some versions of Cmake.

Full Demo

Some demos are available in this repository.

First change the ip address and put the one of your host in file source/test.WampMBEDMain.cpp.

const std::string URL {"ws://192.168.20.192:8080/ws"};

To build it:

git clone https://github.com/alvistar/wamped.git
cd wamped
yotta target frdm-k64f-gcc
yotta build

Demos will be built in build/frdm-k64f-gcc/existing/source/test

To launch demo Crossbar router:

cd crossbar
pip install -r requirements.txt
crossbar start --loglevel trace

You can now connect from freedom board and launch web demo at localhost:8080.