HTTP: Hyper Text Transfer Protocol

  • Protocol for transfer of resources
    • Resources:
      • Files
      • Result of :
        • Database query
        • Program execution
        • Automatic translation of a document
  • Specified in two incompatible versions:
    • HTTPv1.0 → RFC 1945
    • HTTPv1.1 → RFC 2616
  • Client-Server Model
  • Operates with simple “transactions”
    • Request – Response
      • Client requests objects → generates “requests”
        • Messages in ASCII format (understandable for humans
      • Server transfers objects → generates “responses”
        • ASCII messages MIME type (RFC 822)
    • Stateless and Connectionless protocol
      • Server does not store information on clients or transactions
      • Simplifies Servers design  High performance web servers, capable of handling many TCP connections
  • Uses TCP as transport layer protocol:
    • Client initiates a TCP connection (creates socket) to server, port 80
    • Server accepts TCP connection from client (connection socket is created in server)
    • HTTP messages (application-layer protocol messages) exchanged between browser (HTTP client) and Web server (HTTP server)
    • TCP connection closed
  • HTTP response status codes
    • 200 OK
      • request succeeded, requested object later in this msg
    • 301 Moved Permanently
      • requested object moved, new location specified later in this msg (Location:)
    • 400 Bad Request
      • request msg not understood by server
    • 404 Not Found
      • requested document not found on this server
    • 505 HTTP Version Not Supported
Picture showing a screenshot of a web browser with the 404 HTTP code
UHI logo

All efforts have been made to ensure materials created by the EDU comply with current accessibility guidelines (JISC: Support for learners with disabilities).

If further assistance is required with accessibility matters please contact the student support section in your academic partner UHI: Accessing learner support.

We welcome any comments on how to improve this unit. Please feel free to pass these on at any time.

If you have any difficulty viewing this resource please contact EDU (edu@uhi.ac.uk) with:

  • the name of the resource;
  • a description of the problem (please give as much detail as possible);
  • the section of the resource where the problem occurred;
  • your internet browser (you can check your browser version at: http://detectmybrowser.com/).

UHI provides links to external sources of information and may refer to specific Web sites, products, processes or services within this resource. Such references are examples and are not endorsements and whilst every effort is taken to ensure the accuracy of information provided UHI is not responsible for any of the content or guidance. You are advised to exercise caution.

Audio

Video

Reading

Download

Information

External link

Activity

Print

Question

Asterisk

Discussion

Collaboration

Reflection/journal/log

History

Pause for thought

Download a copy of this resource in PDF format.

You can also print individual pages by printing directly from the browser.

×