Crypto Price & Market Analysis MCP Server

import { COINCAP_API_V2_BASE, COINCAP_API_V3_BASE, CACHE_TTL } from '../config/index.js'; import type { AssetsResponse, CacheEntry, HistoricalData, MarketsResponse } from '../types/index.js'; const cache = new Map<string, CacheEntry<any>>(); // Expose cache clear function for testing export function clearCache(): void { cache.clear(); } function getCachedData<T>(key: string): T | null { const entry = cache.get(key); if (!entry) return null; const now = Date.now(); if (now - entry.timestamp > CACHE_TTL) { cache.delete(key); return null; } return entry.data; } function setCacheData<T>(key: string, data: T): void { cache.set(key, { data, timestamp: Date.now() }); } /** * Makes a request to the CoinCap API with fallback logic: * 1. If API key is provided, tries v3 API first * 2. If v3 fails or no API key is provided, falls back to v2 * 3. If both fail, throws an error */ async function makeCoinCapRequest<T>(endpoint: string): Promise<T> { // Check cache first const cacheKey = endpoint; const cachedData = getCachedData<T>(cacheKey); if (cachedData) { return cachedData; } const apiKey = process.env.COINCAP_API_KEY; let error: Error | null = null; // Try v3 API if API key is provided if (apiKey) { try { const v3Response = await fetch(`${COINCAP_API_V3_BASE}${endpoint}`, { headers: { 'Authorization': `Bearer ${apiKey}` } }); if (v3Response.ok) { const data = await v3Response.json() as T; setCacheData(cacheKey, data); return data; } else { error = new Error(`V3 API error: ${v3Response.status} - ${v3Response.statusText}`); console.warn("V3 API request failed, falling back to V2:", error.message); } } catch (e) { error = e instanceof Error ? e : new Error(String(e)); console.warn("V3 API request failed, falling back to V2:", error.message); } } // Fall back to v2 API try { const headers: HeadersInit = {}; if (apiKey) { headers['Authorization'] = `Bearer ${apiKey}`; } const v2Response = await fetch(`${COINCAP_API_V2_BASE}${endpoint}`, { headers }); if (v2Response.ok) { const data = await v2Response.json() as T; setCacheData(cacheKey, data); return data; } else { throw new Error(`V2 API error: ${v2Response.status} - ${v2Response.statusText}`); } } catch (e) { const v2Error = e instanceof Error ? e : new Error(String(e)); console.error("V2 API request failed:", v2Error.message); // If we have both errors, combine them for better debugging if (error) { throw new Error(`API requests failed. V3: ${error.message}, V2: ${v2Error.message}`); } else { throw v2Error; } } } export async function getAssets(): Promise<AssetsResponse | null> { try { return await makeCoinCapRequest<AssetsResponse>('/assets'); } catch (error) { console.error("Failed to get assets:", error); return null; } } export async function getMarkets(assetId: string): Promise<MarketsResponse | null> { try { return await makeCoinCapRequest<MarketsResponse>(`/assets/${assetId}/markets`); } catch (error) { console.error(`Failed to get markets for asset ${assetId}:`, error); return null; } } export async function getHistoricalData( assetId: string, interval: string, start: number, end: number ): Promise<HistoricalData | null> { try { return await makeCoinCapRequest<HistoricalData>( `/assets/${assetId}/history?interval=${interval}&start=${start}&end=${end}` ); } catch (error) { console.error(`Failed to get historical data for asset ${assetId}:`, error); return null; } }