Hypertext Transfer Protocol (HTTP)

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Hypertext Transfer Protocol (HTTP) is a group of guidelines that authorise users of the World Wide Web to exchange information found on web pages. When accessing any web page, inputting http:// in front of the address informs the browser to communicate over HTTP.

Nowadays, HTTP is no longer required to be entered at the beginning of a URL, since it is the default course of communication. But it is still used in browsers in order to differentiate between HTTP and other protocols, like FTP.

For transmitting different kinds of files on the World Wide Web—like video, sound, graphic images, and text—HTTP is used as the default set of rules. As soon as a web browser is accessed, the user is automatically using HTTP. HTTP stays running even while the TCP/IP suite of protocols are running concurrently.

HTTP makes way for files to contain references to other files, selected for additional transfer requirements. The HTTP daemon is present in all web server machines for this purpose. An HTTP daemon waits for HTTP requests to come in, and works on them as they arrive. Your web browser is an HTTP client, transmitting requests to server machines. The browser creates an HTTP request and sends it to the Internet Protocol address (IP address), which is placed in the URL after a file request is submitted by a user. The file request can be submitted either through opening a web file or by following a hypertext link. As the request arrives, the HTTP daemon accepts it, and then sends back the requested file or files.

HTTP as a Stateless Protocol

Since each command is done autonomously, HTTP is referred to as a stateless protocol. There is no information available on the commands that were executed prior to it. It is difficult to implement web sites that respond logically, either to user input or to entry, because of this same statelessness. This limitation of HTTP is currently being compensated by a number of new technologies, such as cookies, Java, JavaScript, and ActiveX.

HTTP Information

  • Ted Nelson first coined the term HTTP.
  • HTTP connections use port 80 as the standard port.
  • The first version of the HTTP, introduced in 1991, was HTTP/0.9.
  • HTTP/1.0 was introduced in 1996, and is specified in RFC 1945.
  • HTTP/1.1 was officially released in January 1997, and is specified in RFC 2616. This is the latest version of HTTP 1.1.

HTTPS

Hypertext Transfer Protocol Secure (HTTPS) is a procedure which utilises HTTP on a connection which is itself encrypted by transport-layer security. HTTPS is used to secure sent data from prying eyes who have no right to look at it. It is the automatic protocol for managing financial connections on the web, and is furthermore capable of protecting website’s users from constraints set by a government or an ISP.

In order to send information, HTTPS uses port 443.

HTTPS is defined in RFC 2616, and was first used in HTTP/1.1.

HTTP Status Codes

1xx – 2xx 3xx – 4xx 5xx
100 (Continue)
101 (Switch protocols)
102 (Processing)
200 (Success)
201 (Fulfilled)
202 (Accepted)
204 (No content)
205 (Reset content)
206 (Partial content)
207 (Multi-Status)
301 (Moved permanently)
302 (Moved temporarily)
304 (Loaded Cached copy)
307 (Internal redirect)
400 (Bad request)
401 (Authorization required)
402 (Payment required)
403 (Forbidden)
404 (Not found)
405 (Method not allowed)
406 (Not acceptable)
407 (Proxy authentication required)
408 (Request timeout)
409 (Conflict)
410 (Gone)
411 (Length required)
412 (Precondition failed)
413 (Request entity too large)
414 (Request URI too large)
415 (Unsupported media type)
416 (Request range not satisfiable)
417 (Expectations failed)
422 (Unprocessable entity)
423 (Locked)
424 (Failed dependency
500 (Internal server error)
501 (Not Implemented)
502 (Bad gateway)
503 (Service unavailable)
504 (Gateway timeout)
505 (HTTP version not supported)
506 (Variant also negotiates)
507 (Insufficient storage)
510 (Not extended)