POC: use DFCom lib with NodeJS base on node-ffi

Usage:

get dependencies from npm

npm install

compile libDFcom

sudo apt-get install g++
cd /usr/src
curl -o Datafox_SDK_Linux_04.03.10.zip https://www.datafox.de/downloads-evo-line-28.de.html?file=files/Datafox_Devices/Downloads_Geraete_Zubehoer/001_MasterIV-Software/Datafox_SDK_Linux_04.03.10.zip
unzip Datafox_SDK_Linux_04.03.10.zip
cd Release_DatafoxLibraryIVSource/DatafoxLibraryIV
make all

place libDFCom.so in library path

export LD_LIBRARY_PATH=/usr/src/Release_DatafoxLibraryIVSource/DatafoxLibraryIV/bin

run the example ;-)

nodejs index.js

in case of error: could not locate the bindings file

sudo npm install -g node-gyp
$ cd node_modules/ffi
$ node-gyp rebuild 

Pitfalls

location of DFCom.ini

NOTE: you need to run node as root so DFCom.ini can be created next to the node binary. In my case:

/usr/bin/DFCom.ini

Rethink

node-ffi is known to be slow. Moreover each function needs to be defined manually in the mappings. It might be worth checking node-gyp with swig.

As the libDFCom function signatures reveal the c++ pointer background, it might be an idea not to use the lib but directly communicate via socket OR to wrap the whole API to have js friendly methods.