An efficient, cross-platform interface to the Helium platform.

#include <helium.h>

// create a new connection
helium_connection_t *conn = helium_alloc();

// associate it with a proxy (if you don't have direct ipv6 connectivity) and callback function pointer
helium_open(conn, NULL, my_callback_function);

// you can also use block syntax if you have built libhelium with block support
helium_open_b(conn, NULL, ^(const helium_connection_t *conn, uint64_t mac, char *msg, size_t n) {
	printf("Received the string '%s' from MAC address %lX", msg, mac);
});

// subscribe to events from a given MAC address
helium_subscribe(conn, 0x0000112233440001, "magic_helium_token");

// send data to a device at a given mac address
helium_send(conn, 0x0000112233440001, "magic_helium_token", "Main screen turn on", strlen("Main screen turn on"));

// unsubscribe from a device if you don't want to see any more events from it
helium_unsubscribe(conn, 0x0000112233440001);

libhelium depends on libuv (>= 0.11.29) for cross-platform network functionality and OpenSSL (>= 1.0.1) for required cipher suites. Optional unit test infrastructure is provided by cunit.

You can download a prepackaged OS X installer for both libhelium and libuv here. This requires you have installed openssl from homebrew in the standard keg-only path.

Should you wish to compile from source, you'll need cmake, libuv and openssl (please note that the OpenSSL included with Darwin will not work). Assuming you have Homebrew installed:

brew install cmake
brew install openssl
brew install libuv

You'll need libuv. Install it from git or with your favorite package manager. You'll need clang and libblocksruntime if you want to build with C blocks support on.

You can install the prerequisite packages (other than cmake and libuv) with:

apt-get update && apt-get install -y autoconf automake build-essential \
clang doxygen git libblocksruntime-dev libcunit1-dev libssl-dev libtool \
wget

3.0 or higher is required, if your package manager doesn't have cmake 3, then build from source:

wget http://www.cmake.org/files/v3.0/cmake-3.0.2.tar.gz
tar -zxf cmake-3.0.2.tar.gz
cd cmake-3.0.2/
./bootstrap && make && make install

To build from source:

git clone https://github.com/libuv/libuv
cd libuv
sh autogen.sh
./configure
make
make install

libhelium will use cunit if you call make test and cunit is available. On Debian it is simple as

apt-get install libcunit1-dev

Then run make test after the cmake and make builds.

git clone git@github.com:helium/libhelium ; cd libhelium
mkdir build ; cd build
cmake ..
make && sudo make install

If you want to build the documentation, you'll need Doxygen. Run make doc to build it; the output will be placed in an html/ folder.

The shell executable listens on stdin for lines of the form <MAC> <token> <message>. Sending the single character 's' tests the subscription features.

For example (using a ipv4->ipv6 proxy at r01.foo.example.io):

./shell -p r01.foo.example.io
...
00212effffffffff 34dcxtSTIsyLFZ6Tffffff== s

will subscribe you to messages from device 00212effffffffff that is being proxied through r01.

libhelium is copyright (c) Helium Systems, Inc. and distributed to the public under the terms of the MIT license.