rxdb/src/plugins/backup/file-util.ts

A local-first realtime NoSQL Database for JavaScript applications - https://rxdb.info/

import * as fs from 'node:fs';
import * as path from 'node:path';
import type {
    BackupMetaFileContent,
    BackupOptions,
    RxDatabase
} from '../../types/index.d.ts';
import { blobToString, now } from '../../plugins/utils/index.ts';

/**
 * ensure that the given folder exists
 */
export function ensureFolderExists(folderPath: string): void {
    if (!fs.existsSync(folderPath)) {
        fs.mkdirSync(folderPath, { recursive: true });
    }
}

/**
 * deletes and recreates the folder
 */
export function clearFolder(folderPath: string): void {
    deleteFolder(folderPath);
    ensureFolderExists(folderPath);
}

export function deleteFolder(folderPath: string): void {
    // only remove if exists to not raise warning
    if (fs.existsSync(folderPath)) {
        fs.rmdirSync(folderPath, { recursive: true });
    }
}

export function prepareFolders(
    database: RxDatabase,
    options: BackupOptions
) {
    ensureFolderExists(options.directory);

    const metaLoc = metaFileLocation(options);

    if (!fs.existsSync(metaLoc)) {
        const currentTime = now();
        const metaData: BackupMetaFileContent = {
            createdAt: currentTime,
            updatedAt: currentTime,
            collectionStates: {}
        };
        fs.writeFileSync(metaLoc, JSON.stringify(metaData), 'utf-8');
    }

    Object.keys(database.collections).forEach(collectionName => {
        ensureFolderExists(
            path.join(
                options.directory,
                collectionName
            )
        );
    });
}

export async function writeToFile(
    location: string,
    data: string | Blob
): Promise<void> {
    if (typeof data !== 'string') {
        data = await blobToString(data);
    }
    return new Promise(function (res, rej) {
        fs.writeFile(
            location,
            data as string,
            'utf-8',
            (err) => {
                if (err) {
                    rej(err);
                } else {
                    res();
                }
            }
        );
    });
}

export function writeJsonToFile(
    location: string,
    data: any
): Promise<void> {
    return writeToFile(
        location,
        JSON.stringify(data)
    );
}

export function metaFileLocation(options: BackupOptions): string {
    return path.join(
        options.directory,
        'backup_meta.json'
    );
}

export function getMeta(options: BackupOptions): Promise<BackupMetaFileContent> {
    const loc = metaFileLocation(options);
    return new Promise((res, rej) => {
        fs.readFile(loc, 'utf-8', (err, data) => {
            if (err) {
                rej(err);
            } else {
                const metaContent = JSON.parse(data);
                res(metaContent);
            }
        });
    });
}

export function setMeta(
    options: BackupOptions,
    meta: BackupMetaFileContent
): Promise<void> {
    const loc = metaFileLocation(options);
    return writeJsonToFile(loc, meta);
}

export function documentFolder(
    options: BackupOptions,
    docId: string
): string {
    return path.join(
        options.directory,
        docId
    );
}