Intro
This time, I will try outputting logs, loading external settings files.
- [TypeScript] Try Electron
- [Electron][TypeScript][PDF.js] Create images from PDF
- [PDF-LIB][Electron][TypeScript] Edit PDF
Environments
- Node.js ver.16.1.0
- TypeScript ver.4.2.4
- Electron ver.12.0.2
- electron-log ver.4.3.5
- electron-store ver.8.0.0
Outputting logs
For outputting logs on Electron applications, I choosed "electron-log".
From Electron side
I can output logs like below.
main.ts
...
import * as log from 'electron-log';
...
log.debug('hello');
function createWindow (filePath: string): BrowserWindow {
log.error('create window');
...
}
Result
Console
08:09:23.097 > hello
08:09:23.160 > create window
main.log
[2021-05-16 08:09:23.097] [debug] hello
[2021-05-16 08:09:23.160] [error] create window
By default, the log files are saved in "C:/Users/example/AppData/Roaming/{ApplicationName}/logs".
And they are divided in "main.log" and "renderer.log".
So if I call "log.debug('hello')" from "preload.ts", the logs are written in "renderer.log".
Change saving directory and file names
I can change the saving directory and the file names.
log.debug('before');
log.transports.file.resolvePath = () => 'C:/Users/example/OneDrive/Documents/sample.log';
log.debug('after');
Of cource, before changing the path, the logs are saved at default path.
And "log.transports.file.resolvePath" is only affected in the same file.
So if I execute "log.transports.file.resolvePath" only in "main.ts", the logs of "preload.ts" are saved in "C:/Users/example/AppData/Roaming/{ApplicationName}/logs/renderer.log".
Client side
"electron-log" only can be used in Node.js applications.
So I can't use it in client side.
So I add outputting log functions in the contextBridge.
global.d.ts
declare global {
interface Window {
myapi: Sandbox
};
}
export interface Sandbox {
greet: (message: string) => void,
saveFile: (name: string, data: Uint8Array) => void,
logDebug: (callFrom: string, message: string) => void,
logError: (callFrom: string, message: string) => void,
};
preload.ts
import { ipcRenderer, contextBridge } from 'electron';
import * as log from 'electron-log';
window.addEventListener('DOMContentLoaded', () => {
log.warn('Loaded');
});
contextBridge.exposeInMainWorld('myapi', {
greet: async (data: any) => await ipcRenderer.invoke('greet', data),
saveFile: async (name: string, data: Uint8Array) => await ipcRenderer.invoke('saveFile', name, data),
logDebug: (callFrom: string, message: string) => log.debug(`[${callFrom}] ${message}`),
logError: (callFrom: string, message: string) => log.error(`[${callFrom}] ${message}`)
}
);
main.page.ts
...
export async function load(filePath: string) {
window.myapi.logDebug('main', 'call from client');
...
}
Result
[2021-05-16 08:59:06.969] [warn] Loaded
[2021-05-16 08:59:06.978] [debug] [main] call from client
Loading external settings files
When I searched how to load config files in Electron applications, I found "electron-store".
I can save user settings in "config.json".
main.ts
...
import ElectronStore from 'electron-store';
const settings = new ElectronStore();
settings.set({
filePath: 'example'
});
...
The file is saved at "C:/Users/example/AppData/Roaming/{ApplicationName}".
config.json
{
"filePath": "example"
}
But in this time, I want to load external settings file like "appsettings.json" in ASP.NET Core.
So I just load JSON file by fs.
settingsLoader.ts
import * as fs from 'fs';
import { AppSettings } from "print.type";
export async function load(): Promise<AppSettings> {
const fileData = await fs.promises.readFile('./appsettings.json', {
encoding: 'utf-8'
});
return JSON.parse(fileData);
}
appsettings.json
{
"filePath": "sample.pdf"
}
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