node.js-addon

So I am writing a node.js module in C++ which processes data from a camera. I want to invoke a callback function in my app.js file whenever new data is available. What I have at the moment Right now I have in my node javascript file ( app.js ) the following code. Every second it calls a function in my C++-Module and returns the number of frames that have been processed so far: setInterval(function () { var counter = MyCPPModule.NumberOfFrames(); console.log(counter); }, 1000); In my C++ file I have the following functions. 1.) I have a function to get the number of frames - the function that

I am trying to implement a C++ extension to be integrated with node.js. This extension will internally invoke some blocking calls, so it needs to provide a non-blocking interface to the node.js world. As specified in https://nodejs.org/api/addons.html , there are two ways to implement non-blocking callbacks: a) By using a simple callback to a JavaScript function. So my extension would have to spawn a thread and return immediately, and let that thread call the blocking code and then invoke the JavaScript callback upon return. This seems relatively simple to implement. b) By using the libuv

I have two subclasses of Nan::ObjectWrap class Zyre: public Nan::ObjectWrap {...} class ZyreEvent: public Nan::ObjectWrap {...} How can I return a ZyreEvent javascript object from a method in Zyre ? I have the following method, in which I create a ZyreEvent : NAN_METHOD (Zyre::_recv) { Zyre *node = Nan::ObjectWrap::Unwrap <Zyre> (info.Holder ()); ZyreEvent *zyre_event = new ZyreEvent (node->self); info.GetReturnValue().Set(zyre_event->Wrap(info.This())); } But I can't Wrap the zyre_event because Wrap is a protected member. If I understand correctly, you want to return from (subclass of) Nan:

I'm working on native Node.js addon and following nan docs I included nan into binding.gyp like: "include_dirs" : [ "<!(node -e \"require('nan')\")" ] Also nan is in npm dependencies. But when I install the package inside the another node module node-gyp is failed with error > nnb@1.0.2 install /Users/Shopgate/sandbox/stress/node_modules/nnb > node-gyp rebuild module.js:338 throw err; ^ Error: Cannot find module 'nan' at Function.Module._resolveFilename (module.js:336:15) at Function.Module._load (module.js:278:25) at Module.require (module.js:365:17) at require (module.js:384:17) at [eval]:1

I've got some existing C++ code that does numerical processing within a stand-alone C++ application. I now want to use that code within a new node.js application. Researching how to access C++ code from node.js, two options come up: Write a node.js extension Use node-ffi node-ffi seems like a good option to access existing libraries , but am I right thinking if I use node-ffi I would have to write a C wrapper to make my C++ accessible? (This was the only way I could get a simple test case to work on Windows with Visual Studio). For my case where my source code is already in C++, not C, what

I'd like to make use of the V8 Float32Array data structure. How can I initialise it? I'd also be interested in direct memory access to the data. How could that be done? Updated The best way now is to use the helper Nan::TypedArrayContents . assert(args[i]->IsFloat32Array()); Local<Float32Array> myarr = args[i].As<Float32Array>(); Nan::TypedArrayContents<float> dest(myarr); // Now use dest, e.g. (*dest)[0] There's a good example of this in node-canvas . Original Answer, which shows why the helper is useful The v8 API is changing rapidly right now so this depends on your version of node/io.js.

I'm writing a Node plugin and I'm having problems trying to call a V8 function object from a C++ worker thread. My plugin basically starts a C++ std::thread and enters a wait loop using WaitForSingleOject(), this is triggered by a different C++ app (An X-Plane plugin) writing to a bit of shared memory. I'm trying to get my Node plugin to wake up when the Windows shared event is signaled then call a JavaScript function that I've registered from the node app, which will in turn pass the data which originated in X-Plane back to Node and the web world. I've managed to work out how to register a