Medicaid MCP Server

/** * CSV Data Cache Manager for Medicaid MCP Server * * Handles in-memory caching with TTL for large CSV datasets * Implements download, parse, and cache with automatic expiration */ const axios = require('axios'); class CacheManager { constructor() { this.memory = {}; this.ttls = {}; this.metadata = {}; } /** * Get data from cache or fetch via provided function * @param {string} key - Cache key * @param {Function} fetchFn - Async function to fetch data if not cached * @param {number} ttl - Time to live in milliseconds (default: 1 hour) * @returns {Promise<any>} Cached or freshly fetched data */ async get(key, fetchFn, ttl = 3600000) { // Check if cached and not expired if (this.memory[key] && Date.now() < this.ttls[key]) { console.log(`[Cache HIT] ${key} (${this.metadata[key].records} records)`); return this.memory[key]; } // Cache miss or expired - fetch new data console.log(`[Cache MISS] ${key} - fetching...`); const startTime = Date.now(); const data = await fetchFn(); const elapsed = Date.now() - startTime; this.memory[key] = data; this.ttls[key] = Date.now() + ttl; this.metadata[key] = { records: Array.isArray(data) ? data.length : 0, fetchedAt: new Date().toISOString(), fetchDuration: elapsed }; console.log(`[Cache SET] ${key} (${this.metadata[key].records} records, ${elapsed}ms)`); return data; } /** * Invalidate specific cache entry * @param {string} key - Cache key to invalidate */ invalidate(key) { if (this.memory[key]) { delete this.memory[key]; delete this.ttls[key]; delete this.metadata[key]; console.log(`[Cache INVALIDATE] ${key}`); } } /** * Clear all cache entries */ clear() { this.memory = {}; this.ttls = {}; this.metadata = {}; console.log('[Cache CLEAR] All entries cleared'); } /** * Get cache statistics * @returns {Object} Cache stats */ getStats() { const entries = Object.keys(this.memory); return { entries: entries.length, totalRecords: entries.reduce((sum, key) => sum + (this.metadata[key]?.records || 0), 0), details: entries.map(key => ({ key, records: this.metadata[key]?.records, fetchedAt: this.metadata[key]?.fetchedAt, expiresAt: new Date(this.ttls[key]).toISOString(), isExpired: Date.now() >= this.ttls[key] })) }; } /** * Download CSV file from URL with progress tracking * @param {string} url - CSV download URL * @param {string} datasetName - Dataset name for logging * @returns {Promise<string>} CSV content as string */ async downloadCSV(url, datasetName = 'dataset') { try { const response = await axios.get(url, { timeout: 300000, // 5 minutes maxContentLength: 500 * 1024 * 1024, // 500MB max (Phase 3 datasets are huge) onDownloadProgress: (progressEvent) => { if (progressEvent.total) { const percent = Math.round((progressEvent.loaded * 100) / progressEvent.total); const mb = (progressEvent.loaded / 1024 / 1024).toFixed(2); if (percent % 10 === 0) { // Log every 10% console.log(`[Download] ${datasetName}: ${percent}% (${mb} MB)`); } } } }); const sizeInMB = (Buffer.byteLength(response.data) / (1024 * 1024)).toFixed(2); console.log(`[Download COMPLETE] ${datasetName}: ${sizeInMB} MB`); return response.data; } catch (error) { console.error(`[Download ERROR] ${datasetName}:`, error.message); throw new Error(`Failed to download ${datasetName}: ${error.message}`); } } /** * Parse CSV string to array of objects * @param {string} csvData - CSV content * @returns {Array<Object>} Parsed records */ parseCSV(csvData) { const lines = csvData.split('\n').filter(line => line.trim()); if (lines.length === 0) { return []; } // Parse header const header = lines[0].split(',').map(h => h.trim().replace(/"/g, '')); // Parse data rows const records = []; for (let i = 1; i < lines.length; i++) { const line = lines[i]; if (!line.trim()) continue; // Simple CSV parsing (handles quoted fields) const values = this._parseCSVLine(line); if (values.length !== header.length) { // Skip malformed rows continue; } const record = {}; header.forEach((col, idx) => { record[col] = values[idx]?.trim().replace(/"/g, '') || ''; }); records.push(record); } return records; } /** * Parse single CSV line (handles quoted fields with commas) * @private */ _parseCSVLine(line) { const values = []; let current = ''; let inQuotes = false; for (let i = 0; i < line.length; i++) { const char = line[i]; if (char === '"') { inQuotes = !inQuotes; } else if (char === ',' && !inQuotes) { values.push(current); current = ''; } else { current += char; } } values.push(current); // Add last value return values; } /** * Download and parse CSV in one operation * @param {string} url - CSV download URL * @param {string} datasetName - Dataset name for logging * @returns {Promise<Array<Object>>} Parsed records */ async downloadAndParseCSV(url, datasetName) { const csvData = await this.downloadCSV(url, datasetName); const records = this.parseCSV(csvData); console.log(`[Parse COMPLETE] ${datasetName}: ${records.length} records`); return records; } } // Singleton instance const cacheManager = new CacheManager(); module.exports = { CacheManager, cache: cacheManager };