SQL with Prisma under Electron - sqlite

Question

My Main goal is to create an Electron App (Windows) that locally stores data in an SQLite Database. And because of type safety I choose to use the Prisma framework instead of other SQLite Frameworks.
I took this Electron Sample Project and now try to include Prisma. Depending on what I try different problems do arrise.
1. PrismaClient is unable to be run in the Browser
I executed npx prisma generate and then try to execute this function via a button:
import { PrismaClient } from '#prisma/client';
onSqlTestAction(): void {
const prisma = new PrismaClient();
const newTestObject = prisma.testTable.create(
{
data: {
value: "TestValue"
}
}
);
}
When executing this in Electron I get this:
core.js:6456 ERROR Error: PrismaClient is unable to be run in the browser.
In case this error is unexpected for you, please report it in https://github.com/prisma/prisma/issues
at new PrismaClient (index-browser.js:93)
at HomeComponent.onSqlTestAction (home.component.ts:19)
at HomeComponent_Template_button_click_7_listener (template.html:7)
at executeListenerWithErrorHandling (core.js:15281)
at wrapListenerIn_markDirtyAndPreventDefault (core.js:15319)
at HTMLButtonElement.<anonymous> (platform-browser.js:568)
at ZoneDelegate.invokeTask (zone.js:406)
at Object.onInvokeTask (core.js:28666)
at ZoneDelegate.invokeTask (zone.js:405)
at Zone.runTask (zone.js:178)
It somehow seems logical that Prisma cannot run in a browser. But I actually build a native app - with Electron that embeds a Browser. It seems to be a loophole.
2. BREAKING CHANGE: webpack < 5 used to include polyfills
So i found this Question: How to use Prisma with Electron
Seemed to be exactly what I looked for. But the error message is different (Debian binaries were not found).
The solution provided is to generate the prisma artifacts into the src folder instead of node_modules - and this leads to 19 polyfills errors. One for example:
./src/database/generated/index.js:20:11-26 - Error: Module not found: Error: Can't resolve 'path' in '[PATH_TO_MY_PROJECT]\src\database\generated'
BREAKING CHANGE: webpack < 5 used to include polyfills for node.js core modules by default.
This is no longer the case. Verify if you need this module and configure a polyfill for it.
If you want to include a polyfill, you need to:
- add a fallback 'resolve.fallback: { "path": require.resolve("path-browserify") }'
- install 'path-browserify'
If you don't want to include a polyfill, you can use an empty module like this:
resolve.fallback: { "path": false }
And this repeats with 18 other modules. Since the error message to begin with was different I also doubt that this is the way to go.

Answer 1

I finally figured this out. What I needed to understand was, that all Electron apps consist of 2 parts: The Frontend Webapp (running in embedded Chromium) and a Node backend server. Those 2 parts are called IPC Main and IPC Renderer and they can communicate with each other. And since Prisma can only run on the main process which is the backend I had to send my SQL actions to the Electron backend and execute them there.
My minimal example
In the frontend (I use Angular)
// This refers to the node_modules folder of the Electron Backend, the folder where the main.ts file is located.
// I just use this import so that I can use the prisma generated classes for type safety.
import { TestTable } from '../../../app/node_modules/.prisma/client';
// Button action
onSqlTestAction(): void {
this.electronService.ipcRenderer.invoke("prisma-channel", 'Test input').then((value) => {
const testObject: TestTable = JSON.parse(value);
console.log(testObject);
});
The sample project I used already had this service to provide the IPC Renderer:
#Injectable({
providedIn: 'root'
})
export class ElectronService {
ipcRenderer: typeof ipcRenderer;
webFrame: typeof webFrame;
remote: typeof remote;
childProcess: typeof childProcess;
fs: typeof fs;
get isElectron(): boolean {
return !!(window && window.process && window.process.type);
}
constructor() {
// Conditional imports
if (this.isElectron) {
this.ipcRenderer = window.require('electron').ipcRenderer;
this.webFrame = window.require('electron').webFrame;
this.childProcess = window.require('child_process');
this.fs = window.require('fs');
// If you want to use a NodeJS 3rd party deps in Renderer process (like #electron/remote),
// it must be declared in dependencies of both package.json (in root and app folders)
// If you want to use remote object in renderer process, please set enableRemoteModule to true in main.ts
this.remote = window.require('#electron/remote');
}
}
And then in the Electron backend I first added "#prisma/client": "^3.0.1" to the package.json (for the Electron backend not the frontend). Then I added to the main.ts this function to handle the requests from the renderer:
// main.ts
ipcMain.handle("prisma-channel", async (event, args) => {
const prisma = new PrismaClient();
await prisma.testTable.create(
{
data: {
value: args
}
}
);
const readValue = await prisma.testTable.findMany();
return JSON.stringify(readValue);
})
This way of simply adding the IPC Main handler in the main.ts file of course is a big code smell but usefull as minimal example. I think I will move on with the achitecture concept presented in this article.