Electron - problem creating file, error "EROFS: read-only file system"

Question

Well, I'm working on a certain app that would improve work in the company. For this I would need to create, save and read a file without a dialog box.

I created this code with the help of documentation and the Internet:

const electron = require('electron');
let fs = require('fs'), app = electron.remote;
let localData, fileName = "appdata.json";

function loadAppData() {
    fs.readFile(fileName, (err, data) => {
        if (err) {
            console.log("There was a problem reading the data!");
            // console.log(err);
        } else {
            console.log("Data loaded!");

            localData = JSON.parse(data);
            console.log(localData);
        }
    });
}

function saveAppData(content) {
    content = JSON.stringify(content);

    fs.writeFile(fileName, content, (err) => {
        if (err) {
            console.log("There was a problem saving data!");
            // console.log(err);
        } else {
            console.log("Data saved correctly!");
            loadAppData();
        }
    });
}

function initappData() {
    if (fs.existsSync(fileName)) {
        console.log("File detected, loading");
        loadAppData();

    } else {
        let defData = {
            "patients": [],
            "actions": [],
            "visits": []
        };
        console.log("No file! I create! Saving! Loading!");
        saveAppData(defData);
    }
}
initappData();

And I have a problem because if the script works on the local version, after the application build on MacOS (using electron-builder) the error appears in the console: "There was a problem writing data!". After displaying the error content appears: Error: EROFS: read-only file system, open 'appdata.json'.

I checked permissions, I checked in other locations - still the same :( I was looking for a solution on the net but unfortunately nothing solved the problem.

Has anyone encountered such a problem?

Answer 1

After the build. The resource will be packaged inside asar file But this is just read-only. You can't modify the file inside of asar.

If I were you. I'm going to store the appData.json at Application Support. And I think this is the popular configure for application.

You can get the Application Data path by using this.

function getAppDataPath() {
  switch (process.platform) {
    case "darwin": {
      return path.join(process.env.["HOME"], "Library", "Application Support", "Your app name");
    }
    case "win32": {
      return path.join(process.env.APPDATA, "Your app name");
    }
    case "linux": {
      return path.join(process.env.["HOME"], ".Your app name");
    }
    default: {
      console.log("Unsupported platform!");
      process.exit(1);
    }
  }
}


function saveAppData(content) {
    const appDatatDirPath = getAppDataPath();
    
    // Create appDataDir if not exist
    if (!fs.existsSync(appDatatDirPath)) {
        fs.mkdirSync(appDatatDirPath);
    }

    const appDataFilePath = path.join(appDatatDirPath, 'appData.json');
    content = JSON.stringify(content);

    fs.writeFile(appDataFilePath, content, (err) => {
        if (err) {
            console.log("There was a problem saving data!");
            // console.log(err);
        } else {
            console.log("Data saved correctly!");
            loadAppData();
        }
    });
}