growwapi/dist/utils/fileCache.js

NodeJS SDK for Groww trading APIs

import fs from 'fs';
import fsPromises from 'fs/promises';
import path from 'path';
import os from 'os';
import crypto from 'crypto';
import { FILECACHE_TTL } from '../config';
const CACHE_FOLDER = 'csv-cache';
const memoryCache = {};
function getCacheFilePath(url) {
    const hash = crypto.createHash('md5').update(url).digest('hex');
    const cacheDir = path.join(os.tmpdir(), CACHE_FOLDER);
    return path.join(cacheDir, `${hash}.csv`);
}
async function ensureCacheDir(filePath) {
    const dir = path.dirname(filePath);
    await fsPromises.mkdir(dir, { recursive: true });
}
async function isCacheValid(filePath, ttl) {
    try {
        const stat = await fsPromises.stat(filePath);
        const age = Date.now() - new Date(stat.mtime).getTime();
        return age < ttl;
    }
    catch {
        return false;
    }
}
async function deleteFileIfExists(filePath) {
    try {
        await fsPromises.unlink(filePath);
    }
    catch {
        return;
    }
}
async function downloadCSVToFile(url, filePath) {
    const response = await fetch(url);
    if (!response.ok || !response.body) {
        throw new Error(`Failed to fetch CSV: ${response.status} ${response.statusText}`);
    }
    const writer = fs.createWriteStream(filePath);
    const reader = response.body.getReader();
    return new Promise((resolve, reject) => {
        writer.on('finish', resolve);
        writer.on('error', reject);
        (async () => {
            try {
                while (true) {
                    const { done, value } = await reader.read();
                    if (done)
                        break;
                    writer.write(Buffer.from(value));
                }
                writer.end();
            }
            catch (error) {
                writer.destroy();
                reject(error);
            }
        })();
    });
}
export async function fetchCSV(url, ttl = FILECACHE_TTL) {
    const cacheFile = getCacheFilePath(url);
    await ensureCacheDir(cacheFile);
    const validCache = await isCacheValid(cacheFile, ttl);
    if (validCache) {
        if (memoryCache[cacheFile]) {
            return { fileContent: memoryCache[cacheFile] };
        }
        else {
            const fileContent = await fsPromises.readFile(cacheFile, 'utf-8');
            memoryCache[cacheFile] = fileContent;
            return { fileContent };
        }
    }
    await deleteFileIfExists(cacheFile);
    await downloadCSVToFile(url, cacheFile);
    const fileContent = await fsPromises.readFile(cacheFile, 'utf-8');
    memoryCache[cacheFile] = fileContent;
    return { fileContent };
}