Files
FACULTATE-LICENTA/User/src/helpers/json_manager.ts
T

120 lines
4.0 KiB
TypeScript

import fs from 'fs';
import path from 'path';
export class JsonManager {
private readonly filePath: string;
private readonly lockFilePath: string;
constructor(filePath: string) {
const dir = path.dirname(filePath);
// Check if the directory exists, throw error if it doesn't
if (!fs.existsSync(dir)) {
throw new Error(`The directory does not exist: ${dir}`);
}
this.filePath = filePath;
this.lockFilePath = `${filePath}.lock`; // Define the lock file path
// If the file doesn't exist, create it
if (!fs.existsSync(filePath)) {
fs.writeFileSync(filePath, JSON.stringify({}, null, 2), 'utf8');
}
}
// Method to acquire a lock (create .lock file)
private async acquireLock(): Promise<void> {
while (fs.existsSync(this.lockFilePath)) {
// Wait until the lock file is released
await new Promise(resolve => setTimeout(resolve, 100)); // 100ms delay before retrying
}
// Create the lock file
fs.writeFileSync(this.lockFilePath, '');
}
// Method to release the lock (delete .lock file)
private releaseLock(): void {
if (fs.existsSync(this.lockFilePath)) {
fs.unlinkSync(this.lockFilePath);
}
}
// Read a value by key from the JSON file with a lock
public async readValue(key: string): Promise<any | null> {
await this.acquireLock(); // Acquire the lock
try {
if (!fs.existsSync(this.filePath)) return null;
const data = JSON.parse(fs.readFileSync(this.filePath, 'utf8'));
return data[key] !== undefined ? data[key] : null;
} catch (err: any) {
console.error(`Error reading from JSON file: ${err.message}`);
return null;
} finally {
this.releaseLock(); // Always release the lock after the operation
}
}
// Write a key-value pair to the JSON file with a lock
public async writeValue(key: string, value: any): Promise<boolean> {
await this.acquireLock(); // Acquire the lock
try {
let data: { [key: string]: any } = {};
if (fs.existsSync(this.filePath)) {
data = JSON.parse(fs.readFileSync(this.filePath, 'utf8'));
}
// Update the key with the new value
data[key] = value;
fs.writeFileSync(this.filePath, JSON.stringify(data, null, 2), 'utf8');
return true;
} catch (err: any) {
console.error(`Error writing to JSON file: ${err.message}`);
return false;
} finally {
this.releaseLock(); // Always release the lock after the operation
}
}
// Remove a key-value pair from the JSON file with a lock
public async removeValue(key: string): Promise<boolean> {
await this.acquireLock(); // Acquire the lock
try {
if (!fs.existsSync(this.filePath)) return false;
const data = JSON.parse(fs.readFileSync(this.filePath, 'utf8'));
if (data[key] !== undefined) {
delete data[key];
fs.writeFileSync(this.filePath, JSON.stringify(data, null, 2), 'utf8');
return true;
}
return false;
} catch (err: any) {
console.error(`Error removing key from JSON file: ${err.message}`);
return false;
} finally {
this.releaseLock(); // Always release the lock after the operation
}
}
// Reset the JSON file by clearing all data with a lock
public async resetFile(): Promise<boolean> {
await this.acquireLock(); // Acquire the lock
try {
fs.writeFileSync(this.filePath, JSON.stringify({}, null, 2), 'utf8');
return true;
} catch (err: any) {
console.error(`Error resetting JSON file: ${err.message}`);
return false;
} finally {
this.releaseLock(); // Always release the lock after the operation
}
}
}