Explore the http time of each HTTP request in Node.js

Node.js is an open source, cross-platform runtime environment for server-side JavaScript programming. It handles in an efficient event-driven manner and therefore performs well when handling large numbers of concurrent connections.

In Node.js, we can use the http module to create server-side applications. This module allows us to listen to HTTP requests and provide a convenient interface to respond to client requests.

In this article, we will explore the http time of individual HTTP requests in Node.js. These times include DNS lookup time, TCP connection time, request and response time, and connection closing time.

DNS lookup time

DNS lookup time is a measurement of the time required for the translation from a domain name to an IP address. In Node.js, DNS resolution is relatively slow, so we must plan ahead and know the IP address of the URL we want to request.

TCP Connection Time

Once we know the IP address of the requested URL, we need to establish a TCP connection. This process includes a three-way handshake, that is, sending a SYN request, receiving a SYN response and sending an ACK request, and receiving an ACK response. During these three steps, the round trip time will become part of the TCP connection time.

Request and response time

When the TCP connection is established, we can send an HTTP request to the server. This process involves sending a request and waiting for a response. While waiting for the server to respond, we need to consider factors such as network latency and server load.

Once we receive the HTTP response from the server, we also need to read the response into a buffer. This process also takes time, depending on the size of the response.

Close connection time

After we complete all HTTP request and response interactions, we need to close the TCP connection. This process includes sending a FIN signal, waiting for the server to send an ACK signal, and receiving an ACK signal. Like TCP connection time, closing a TCP connection also needs to take into account round-trip time.

Summary

In Node.js, the http time of each HTTP request is mainly composed of DNS lookup time, TCP connection time, request and response time, and connection closing time. To maximize performance, we need to minimize the impact of these times.

For example, we can use application-level caching to reduce DNS lookup times, or use HTTP/2 to avoid the cost of TCP connections and closing connections. We can also use Node.js's stream processing and asynchronous programming to maximize concurrent processing and reduce waiting times.

To sum up, understanding the http time of each HTTP request in Node.js can help us better optimize our server-side applications.

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