summary of the first chapter "Introduction to Front-End Development"

• "The internet" = Interconnected Network

  a network is made up of at least two devices that connect and communicate via a wire or wireless connection.

• "Web Server"

  server is a computer that runs applications and services.

  web server stores and delivers the content for a website to clients that request it.

• "Web Page"

  a document that displays images, texts, videos and other content in the web browser.

• "Web Site"

  a collection of webpages that link together.

• "Web Browser"

  a software application that you use to browse The World Wide Web.

• "IP Address" = Internet Protocol Address

  every computer on a network is assigned an IP Address.

  when you send a data across a network, IP Packets are sent.

  IP Packets contain header, payload(data), destination & source IP address.

  • TCP (Transmission Control Protocol) : slow but correct
    ex. text, image

  • UDP (User Datagram Protocol) : fast but can be lost

    ex. voice calls, live video streaming

• "HTTP" = Hypertext Transfer Protocol

  a protocol used by web clients and web servers.

  core operational protocol of the world wide web.

  a request & response based protocol

  • "HTTPS"
    the secure version of HTTP

    before the content is sent, it is turned into a secret code.

• 

• Request

  • Method

    • GET: to retrieve information from the server (request)

    • POST: to send data to the server (submit)

    • PUT: updates whatever currently exists on the web server (replace)

    • DELETE: removes the resource (delete)

  • / (path): representation of where the resource is stored on the server.

    ex. example.com/images/image.jpg

  • version: versions of the HTTP protocol (1.1, 2.0 are the most used)

  • headers: contains additional information

• Response

  • HTTP Status Code

    

    • 1XX - Informational responses
      100 continue

    • 2XX - Successful responses
      200 OK

    • 3XX - Redirection responses
      301 Moved Permanently,
      302 Found

    • 4XX - Client error responses
      400 Bad Request: submitted bad data to the web server
      401 Unauthorized: user must log into an account before the request can be processed
      403 Forbidden: web server is refusing to process it (user doesn't have sufficient permissions)
      404 Not Found: the request was not found on the web server

    • 5XX - Server error responses
      500 Internal server error: the server failed to process the request