A problem of executing bin file generated by C

Developing Nodes
1

We recently attempt to use tuya cloud in Node-red, and we have found out that tuya's SDK is base on C--tuya SDK.
After following the instructions, we do compliled and got the executable bin file "subdevice_basic_demo". It dose work in command line like this, and links to the tuya cloud well.

croot@PN6400:~# cd /home/tuya/tuya-iot-core-sdk-main/build/bin
root@PN6400:/home/tuya/tuya-iot-core-sdk-main/build/bin# ./subdevice_basic_demo

But when we call the bin file in js file like this:

var fs = require("fs");
var exec = require('child_process').exec;

module.exports = function(RED) {
    function PN6400_tuyaInit(config) {
					RED.nodes.createNode(this,config);
					var node = this;
					this.key = RED.nodes.getNode(config.key);

					node.on('input', function(msg) {
						//run ('export PATH="/home/tuya/tuya-iot-core-sdk-main/build/bin/:$PATH"') ahead of time 
						exec('subdevice_basic_demo'+' ',function(error,stdout,stderr){
							if(error) {
								console.info('stderr : '+stderr);
							}
						});
					});
    }
    RED.nodes.registerType("PN6400_tuyaInit",PN6400_tuyaInit);
}

Then nothing happened, aka the executable file "subdevice_basic_demo" never executed.
So anyone can help us?

2

Is the problem that it is not calling your code or that the code does not work when called like that? You can check by adding some logging to your C code so that it, for example, logs what is happening to file.

3

The code does not work when called.
And I have added some logging codes in the C file, but still nothing happended.

FYI
If I replace the bin file with a simple python file instead, the python file works.

exec('#a python file instead #'+' ',function(error,stdout,stderr){
							if(error) {
								console.info('stderr : '+stderr);
							}
						});

So the problem should not be the JS calling part itself.

4

If it does work outside of Node-RED from the command line, then you proabably either need the full path to the command when you call it - or the environment that you are running Node-RED is not the same as the user you are using to run from command line.

5
  1. Try using ./subdevice_basic_demo
  2. Is the executable available in the cwd? Node-red current working directory will NOT be /home/tuya/tuya-iot-core-sdk-main/build/bin (i.e. try using full path) and check the account running node-red can access and execute the binary)

Ps. Instead of calling exec, you might want to investigate adding c bindings to call the program/functions directly: How to call C/C++ code from Node.js | by Konstantin Tarkus | Medium

6

Why not use one of the existing Node.js wrappers for Tuya?

tuya - npm search (npmjs.com)

7

Thanks for your advice.
The problem is solved.
As I put the bin file under the path of /usr/bin, like this:

1675057218487
16750572184871306×322 38.6 KB

Then the JS code can call the bin file.
PS: In both cmdline and Node-RED mode, the logged user is root.

8

Thanks.Right, the path is the key point.

9

Surely this is a bright idea.
I have planned to create some different functions from the existing libraries.

10

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