Frank Nnabugo’s Post

In a nutshell - TCP Handshake Simplified When a client and server talk to each other, they often use TCP (Transmission Control Protocol). TCP connection between client and server starts with a process called TCP Handshake. It occurs in 3 steps, sometimes referred as 3-way handshake. The handshake is for both client and server to confirm that when they send a message through, the opposite party can receive. SYN ( Synchronise ) Client sends a message to the server and requires proof from the server it has received. SYN ACK ( Synchronise Acknowledge) The server receives the message from the client and sends two messages back to the client: 1. Acknowledging it is able to receive the message from client 2. Requesting proof from the client it has received this message from the server ACK (Acknowledge) Client sends back a message to the server acknowledging that it is able to receive the message from the server

HTTP status codes are used by a server to respond to a client’s request. They are typically returned in the format of 3-digit codes. The first digit represents the class of response, while the second two digits represent the specific response.

HTTP status codes are used by a server to respond to a client’s request. They are typically returned in the format of 3-digit codes. The first digit represents the class of response, while the second two digits represent the specific response.

If you observe below code, we are importing http module by using require directive and created the server to listen a request and response on port number 4200.

18 Important HTTP Status Codes You Must Know 🔥 - 200 OK: Request succeeded - 201 Created: Resource created - 202 Accepted: Accepted request - 204 No Content: Accepted request - 301 Moved Permanently: Accepted request - 302 Found: Temporarily moved - 304 Not Modified: Not modified - 400 Bad Request: Bad request error - 401 Unauthorized: Needs authentication - 403 Forbidden: Access Forbidden - 404 Not Found: Resource Not Found - 405 Not Allowed: Method not allowed - 408 Request Timeout: Request timed out - 500 Internal Server Error: Server error - 501 Not Implemented: Not implemented - 502 Bad Gateway: Bad gateway error - 503 Service Unavailable: Service unavailable - 504 Gateway Timeout: Gateway Timeout

18 Common HTTP Status Codes You Must Know - 200 OK: Request succeeded - 201 Created: Resource created - 202 Accepted: Accepted request - 204 No Content: Accepted request - 301 Moved Permanently: Accepted request - 302 Found: Temporarily moved - 304 Not Modified: Not modified - 400 Bad Request: Bad request error - 401 Unauthorized: Needs authentication - 403 Forbidden: Access Forbidden - 404 Not Found: Resource Not Found - 405 Not Allowed: Method not allowed - 408 Request Timeout: Request timed out - 500 Internal Server Error: Server error - 501 Not Implemented: Not implemented - 502 Bad Gateway: Bad gateway error - 503 Service Unavailable: Service unavailable - 504 Gateway Timeout: Gateway Timeout

18 Common HTTP Status Codes You Must Know - 200 OK: Request succeeded - 201 Created: Resource created - 202 Accepted: Accepted request - 204 No Content: Accepted request - 301 Moved Permanently: Accepted request - 302 Found: Temporarily moved - 304 Not Modified: Not modified - 400 Bad Request: Bad request error - 401 Unauthorized: Needs authentication - 403 Forbidden: Access Forbidden - 404 Not Found: Resource Not Found - 405 Not Allowed: Method not allowed - 408 Request Timeout: Request timed out - 500 Internal Server Error: Server error - 501 Not Implemented: Not implemented - 502 Bad Gateway: Bad gateway error - 503 Service Unavailable: Service unavailable - 504 Gateway Timeout: Gateway Timeout

In http2, client and server has to establish TCP connection only once, which generally takes 50ms to 250ms(maybe more) depending upon how far the server is geographically located from the client. In http1, every request has to establish a new TCP connection. http2 can be a savior in polling since client doesn't need to establish new TCP connection periodically, quite interesting!

The Internet Assigned Numbers Authority (IANA) maintains the official registry of HTTP status codes. All HTTP response status codes are separated into five classes or categories. The first digit of the status code defines the class of response, while the last two digits do not have any classifying or categorization role. There are five classes defined by the standard: 👉1xx informational response – the request was received, continuing process 👉2xx successful – the request was successfully received, understood, and accepted 👉3xx redirection – further action needs to be taken in order to complete the request 👉4xx client error – the request contains bad syntax or cannot be fulfilled 👉5xx server error – the server failed to fulfil an apparently valid request

An HTTP status code is a three-digit number a server generates in response to a browser’s request. The Complete List of HTTP Status Codes.