eh-api-client

Battle-proven HTTP client for communication between microservices.

Built for production service-to-service traffic: contextual authentication, correlation ID propagation, connection pooling, and automatic recovery from transient network failures.

Install

npm install eh-api-client

Quick start

const ClientFactory = require("eh-api-client");

const users = new ClientFactory("http://users-service/v1");
const client = users.getClient(42, "orders-service");

const user = await client.get(["/users/??", 42]);
await client.patch(["/users/??", 42], { active: true });

Every method supports both Promises and Node-style callbacks. Available methods are get, post, put, patch, delete, head, and exists.

Correlation IDs

Propagate x-request-id automatically across asynchronous call chains with AsyncLocalStorage:

const { AsyncLocalStorage } = require("async_hooks");
const ClientFactory = require("eh-api-client");

const requestContext = new AsyncLocalStorage();
ClientFactory.setAsyncLocalStorage(requestContext);

requestContext.run(new Map([["requestId", "req-123"]]), async () => {
  await client.get("/profile"); // sends x-request-id: req-123
});

Request, session, and device IDs can also be assigned directly with setRequestId, setSessionId, and setDeviceId.

Resilient by default

Transient network failures are retried automatically for GET requests. Retries are bounded and configurable:

users.setRetryOptions({
  maxAttempts: 5,
  retryDelay: 100
});

For safe-to-retry writes, set retryOnTransientError: true. Stream bodies are never retried.

Production features

• Shared keep-alive connection pool
• Internal, bearer-token, and secret-based authentication
• URL placeholders with safe value encoding
• Forked clients for nested API paths
• Request modifiers and configurable defaults
• Structured HTTP and network errors
• request-done and network-error lifecycle events
• TypeScript declarations included

See the test suite for focused examples of each feature.

License

ISC