Middleware

A collection of express/connect middleware.

Exports

• RequestId: Class for adding request ids.
• RequestLog: Class for logging requests.
• RequestLogOptions: [TypeScript] Configuration parameters for the RequestLog middleware.

RequestId

A class to uniquely id incoming requests. Use the inject middleware at the beginning of your stack.

import express from "express";
import { RequestId } from "@alexsasharegan/middleware";

const app = express();
// This middleware injects a request id in both the request/response objects.
// It does not set any headers.
app.use(RequestId.injectMiddleware);
// This sets the request id on the response header.
app.use(RequestId.setHeaderMiddleware);
// This is the default header name used. Customize it to use a different name.
RequestId.headerName = "X-Request-ID";

If you need to make use of the id for something like writing it in response headers, an extract method is available:

app.get("/", function(req, res) {
    // You can extract from either the request/response.
    let requestId = RequestId.extract(req);
    res.setHeader("X-Request-ID", requestId.toString());
    res.end();
});

RequestLog

A class to log requests. Call the middleware function to configure a middleware handler. Place is at the beginning of your stack.

import express from "express";
import { RequestId, RequestLog } from "@alexsasharegan/middleware";

const app = express();

// Set up the request id injector to enable request ids in the logs.
app.use(RequestId.injectMiddleware);
app.use(RequestId.setHeaderMiddleware);

// Make sure to place this after the request id middleware,
// but at the beginning of the middleware chain to get accurate timing.
app.use(
    RequestLog.middleware({
        withColors: true, // tty color output
        newLine: RequestLog.NewLine.LF, // Linux/Mac style new line.
        stream: process.stderr, // log to any stream
    })
);

$ curl -I localhost:3333

HTTP/1.1 200 OK
X-Powered-By: Express
X-Request-ID: alex-oryx/aMzi8qbV9t-000003
Content-Type: text/html; charset=utf-8
Content-Length: 210
ETag: W/"d2-GN0jX1nIvHaoCqXqmz8Mk80JF74"
Date: Sat, 02 Mar 2019 15:50:53 GMT
Connection: keep-alive