Nodejs Talking To C Executable 1

Date:: 21 Sep 2019

What is the idea?

My boss prefers to implement webserver in C by himself, but I think people have already spent tons of time making the state of art nodejs, it doesn’t make sense not to use it. And since I am not a engineer but a physicist, I don’t want to spend too much time on the already-solved-for-decades engineering problem. So I will just use Nodejs without thinking
However we will still use C to do the basic memory mapping, as it is already done.
So the problem now is to make Nodejs talk to C executable, turns out to be very easy

Install Nodejs and Clion

I recommend using Clion for C part, if you are a student, you can get free license with a edu email address
For Nodejs on Ubuntu

curl -sL https://deb.nodesource.com/setup_10.x | sudo -E bash -
sudo apt install nodejs
node -v

For Nodejs on Angstrom Linux and ARMv7
- First download from here
- Then read this

C Part

#include <stdio.h>

int main(int argumentCount, char ** arg) {
    //if you ran your program like this:
    //    ./program hello world
    // Then:
    //    argumentCount = 3
    //    argv[0] = "./program"
    //    argv[1] = "hello"
    //    argv[2] = "world"
    printf("argv[0] =  %s\n",arg[0]);
    printf("argv[1] =  %s\n",arg[1]);
    printf("argv[2] =  %s\n",arg[2]);
    return 0;
}

In Clion, go to Build -> Build Project, then the executable file will be in folder cmake-build-debug, copy this file to same directory as your Nodejs code (below)

Nodejs Part

make a file named app.js, and put the following in it:

const { execFile } = require('child_process');
const child = execFile('./hello', ["hello","world"], (error, stdout, stderr) => {
  if (error) {
    throw error;
  }
  console.log("stdout:");
  console.log(stdout);
});

then command: node app.js