MM2 can get POST API?

[hikano765]

I am developing a module of MM.
By the way, I want to control one of these modules by an external client, and I want to do that control method by REST API method.
For example, if an external client sends a POST API to MM2, the corresponding message is displayed on the MM2 screen.
I don’t know because I haven’t read the MM2 code in detail, but as far as I’ve checked, the server also automatically turns on when running MM2, so I want to process REST API communication on that server as well, but which file should I modify and put a phrase related to REST API communication in order that?

server.js?
server_function.js?

Examples of API codes that I want to put in are these.
The API code is an API that stores the message as a txt file when a message is transmitted in a POST method.

app.post('/api/saveMessage', (req, res) => {
    const message = req.body.message;

    if (!message) {
        res.status(400).send('Message not provided.');
        return;
    }

    fs.unlink(`appid.txt`, (err) => {
        fs.appendFile(`appid.txt`, message + '\n', (err) => {
            if (err) {
                console.error('Error saving message:', err);
                res.status(500).send('Error saving message');
            } else {
                res.send('The message was saved successfully..');
            }
        });
    });
});

[sdetweil]

@hikano765 you use express lib to set up a server.

you can look at the node_helper in my mmm-config module, as I provide an API.

https://github.com/sdetweil/MMM-Config

I redirect , but u can do whatever

  // add express routes to allow invoking the form
  extraRoutes: function () {
    this.expressApp.get("/modules/MMM-Config/review", (req, res) => {
      // redirect to config form
      res.redirect(
        //this.config.url +
        "/modules/" + this.name + "/config.html?port=" + socket_io_port
      );
    });
  },

[MMRIZE]

@hikano765
use this.expressApp in node_helper.js
Of course, you can use your own express or fastify whatever by importing that node module.