What is HTTP Full Form?

Hypertext Transfer Protocol (HTTP) is an application layer protocol for transmitting hypermedia documents, such as HTML. It was designed for communication between web browsers and web servers, but it can also be used for other purposes.

When you enter a URL in your browser, this initiates an HTTP request to fetch and transmit resources like HTML documents, images, videos, etc. from a web server. The server then responds with an HTTP response message, containing the requested content or an error message.

HTTP allows for secure communication over a computer network and defines how messages are formatted and transmitted between the client and the server. It determines how web browsers should respond to different commands, codes and file requests.

Key Takeaway: HTTP (Hypertext Transfer Protocol) is a protocol for fetching resources such as HTML documents over a network. It defines how messages are formatted and transmitted between clients and servers.

What is HTTP Full Form?

What Does HTTP Stand For?

  • HTTP stands for Hypertext Transfer Protocol.
  • It is the foundation of the World Wide Web and defines how data is exchanged on the web.
  • HTTP works on a request-response model between a client (web browser) and a server.

Meta Description: HTTP or Hypertext Transfer Protocol is the underlying protocol of the World Wide Web that defines how messages are exchanged between clients and servers.

How Does HTTP Work?

HTTP works in a client-server model:

  • A web browser or client sends an HTTP request message to a web server for a resource like an HTML page, image, etc.
  • The server handles the request and sends back an HTTP response message.
  • The response contains a status line indicating if the request succeeded or failed, along with the requested content if successful.

The HTTP request message contains:

  • A request line indicating the HTTP method, URL and protocol version.
  • Request headers containing metadata for the request.
  • An optional request body with data.

The HTTP response message contains:

  • A status line with the protocol version, success/error code and status message.
  • Response headers with metadata about the response.
  • An optional response body containing the requested resource.

Key Takeaway: HTTP establishes a connection between a client (web browser) and a server to exchange resources. It sends requests from the client to the server and delivers responses from the server back to the client.

HTTP Request Methods

HTTP defines a set of request methods that indicate the desired action to be performed on a resource.

The main HTTP request methods are:

  • GET – Requests a resource from the server. This only retrieves data and should have no other effect.
  • POST – Submits data to the server. This is often used when submitting forms or uploading files.
  • PUT – Uploads a resource to replace the target resource. This is like uploading a file to edit a document.
  • PATCH – Performs a partial update of a resource. This only updates specific fields rather than replacing the entire resource.
  • DELETE – Deletes the specified resource. This removes a file or document from the server.

There are also other more niche HTTP methods like OPTIONS, HEAD, TRACE, etc. Servers can support different subsets of HTTP request methods.

Key Takeaway: HTTP has common request methods like GET, POST, PUT, PATCH and DELETE that indicates the action to perform on the resource.

HTTP Response Status Codes

After receiving an HTTP request, a server sends back an HTTP response message. The first part of the response is a status line containing the status code and reason message.

Some common HTTP status code classifications are:

  • 1xx Informational – Request received and the process is continuing.
  • 2xx Success – The request succeeded. The most common is 200 OK.
  • 3xx Redirection – Further action needs to be taken to complete the request. Common codes are 301 Moved Permanently, 302 Found and 304 Not Modified.
  • 4xx Client Error – The error is caused by the client. Common codes are 400 Bad Request, 401 Unauthorized, 403 Forbidden and 404 Not Found.
  • 5xx Server Error – The server failed to fulfill the request. Common error codes are 500 Internal Server Error, 502 Bad Gateway and 503 Service Unavailable.

The status codes provide information about what happened to the request and how the client should proceed.

Key Takeaway: HTTP response status codes indicate if the request succeeded, failed or needs further action. Codes are categorized as 1xx informational, 2xx success, 3xx redirection, 4xx client error and 5xx server error.

HTTP Headers

HTTP headers provide additional information about the request or response message in text format. Headers consist of a case-insensitive name followed by a colon and value.

Some common request and response headers are:

  • User-Agent: Browser or client information
  • Content-Type: Format and encoding of the message body
  • Content-Length: Length of the message body
  • Cache-Control: Caching policies for the response
  • Set-Cookie: Sets a cookie value to be stored by the client

Headers can also be used for security, compression, authentication, proxies and more. Custom application-specific headers can also be created.

Multiple headers can be sent in a single request or response. The blank line after the last header indicates the end of headers and the start of the body.

Key Takeaway: HTTP headers provide additional context and metadata for requests and responses like browser details, cookies, caching and more.

HTTP Version History

There have been two major versions of HTTP:

HTTP/0.9

  • Released in 1991
  • Only allowed GET requests with no headers
  • Did not have HTTP status codes
  • Very simple and limited protocol

HTTP/1.0

  • Released in 1996 as RFC 1945
  • Introduced HTTP headers and status codes
  • Added POST and HEAD methods
  • HTTP/1.0 connections were not persistent by default

HTTP/1.1

  • Released in 1997 as RFC 2068
  • Better connection handling with persistent connections
  • Support for chunked transfer encoding and pipelining
  • More caching and proxy support
  • Host and connection header support
  • Added PUT, DELETE and other methods

HTTP/1.1 has been refined over the years but retains much of the original functionality. It is the version most commonly used today.

HTTP/2 was released in 2015 and introduced major improvements like multiplexing, header compression and server push.

Key Takeaway: HTTP/0.9 was a very basic protocol, HTTP/1.0 introduced headers and status codes, while HTTP/1.1 improved performance and HTTP/2 added advanced features.

HTTP and HTTPS

HTTP (Hypertext Transfer Protocol) is used for communication between clients and servers.

By itself, HTTP is an unsecured protocol that transfers data in plaintext. This means that any data sent over HTTP can potentially be intercepted and read by third parties.

HTTPS (Hypertext Transfer Protocol Secure) adds a layer of encryption on top of HTTP:

  • HTTPS websites use SSL/TLS certificates to encrypt the data exchange between servers and clients. This protects against eavesdropping and man-in-the-middle attacks.
  • The protocol uses port 443 instead of HTTP’s port 80.
  • HTTPS connections are indicated by the https:// in the URL instead of http://. Modern browsers also display a lock icon.
  • HTTPS ensures the integrity and confidentiality of data between the user’s browser and website.

Any website that handles private user data, passwords, financial information or other sensitive information should use HTTPS.

Key Takeaway: HTTP is unsecured while HTTPS adds SSL/TLS encryption to secure HTTP data and prevent snooping of communication. HTTPS should be used by websites handling sensitive user information.

HTTP/2 New Features

HTTP/2 was a major revision of HTTP released in 2015. It includes the following new features:

  • Multiplexing – Multiple HTTP requests can be sent over a single TCP connection, interleaved and prioritized. This removes the head-of-line blocking problem in HTTP/1.
  • Header Compression – Common HTTP headers are compressed using HPACK for faster transfers.
  • Server Push – Servers can send resources to clients before they request for them.
  • Stream Prioritization – Clients can specify priority order for HTTP requests to improve page load times.
  • Request/Response Multiplexing – Requests and responses can be transferred asynchronously and interleaved.

Key Takeaway: HTTP/2 provides major performance benefits through multiplexing, header compression and server push while retaining the semantics of HTTP/1.1.

HTTP vs HTTPS – Key Differences

Here are some key differences between HTTP and HTTPS:

HTTP HTTPS
Uses port 80 by default Uses port 443 by default
Unsecured protocol, no encryption Secured and encrypted with SSL/TLS
Transfers data as plaintext Encrypts and protects data transfer
Uses http:// in URL Uses https:// in URL
Not protected against man-in-the-middle attacks Secure against MITM attacks
No verification of website identity Verifies website identity with certificates

Key Takeaways:

  • HTTP has no encryption while HTTPS uses TLS/SSL to encrypt all communication.
  • HTTPS verifies the website identity while HTTP does not.
  • HTTPS provides a secure, tamper-proof connection while HTTP is vulnerable to attackers.

Why HTTPS and Security Matter

There are several important reasons why website security matters and HTTPS should be used:

  • Privacy – Encryption protects user data like credentials, personal info and browsing activity from network snooping.
  • Data Integrity – HTTPS prevents tampering or manipulation of data during transfer. This is crucial for sensitive information.
  • Trust and Identity – The TLS certificates used in HTTPS verifies the identity of the website and company. This prevents impersonation.
  • Compliance – HTTPS may be required to meet regulatory compliance in industries like healthcare and banking.
  • Search Rankings – Google and other search engines give higher rankings to HTTPS sites compared to HTTP sites.
  • User Perception – Users feel safer and are more willing to share data on HTTPS sites since their information is secure.

Key Takeaway: HTTPS is a minimum requirement for security, privacy, trust and compliance for modern websites, especially those handling sensitive user data.

Transitioning a Site to HTTPS

Transitioning an existing website from HTTP to HTTPS involves:

  • Obtaining an SSL/TLS certificate from a trusted Certificate Authority like Let’s Encrypt.
  • Installing the certificate on your web server and properly configuring it for HTTPS.
  • Force redirecting all HTTP traffic to HTTPS by returning a 301 status code.
  • Updating all internal links to use relative or HTTPS URLs instead of HTTP.
  • Changing embed codes, canonical tags, sitemaps etc. to HTTPS.
  • Moving to secure cookies flagged with Secure attribute.
  • Informing users, such as through a notice on the site.

With HTTPS properly set up, users will enjoy a secure, encrypted browsing experience when visiting your website.

Key Takeaway: Transitioning sites from HTTP to HTTPS requires obtaining and installing SSL/TLS certificates, redirecting HTTP to HTTPS, using secure cookies and updating links.

Conclusion

HTTP is the fundamental protocol that defines communication between web clients and servers. Understanding its request-response model, core methods like GET and POST, status codes and headers provides a basis for how the web works.

Upgrading sites from HTTP to secure HTTPS connections is vital for performance, privacy, trust and compliance. Features like multiplexing and compression make HTTP/2 a major upgrade. As the web advances, HTTP will continue adapting to meet evolving needs around speed, security and capability.

Key Takeaway: HTTP is a crucially important protocol powering communication on the web. Advances like HTTPS and HTTP/2 aim to keep it fast, secure and capable of meeting new demands.

Frequently Asked Questions

1. What does HTTP stand for?

HTTP stands for Hypertext Transfer Protocol. It is the underlying protocol used by the World Wide Web to define how messages are formatted and transmitted between web browsers and servers.

2. Is HTTP secure?

No, HTTP has no encryption and is not secure. Sensitive data sent over HTTP can be intercepted by third parties. HTTPS is the secure version of HTTP.

3. What is the difference between HTTP and HTTPS?

HTTP is unsecured while HTTPS uses SSL/TLS encryption to secure data transfer and authenticate the website’s identity. HTTPS sites use https:// in the URL.

4. What is HTTP/2?

HTTP/2 is a major revision of HTTP released in 2015 that includes performance enhancements like multiplexing, header compression and server push. It retains the core HTTP/1.1 semantics.

5. What is the HTTP status code for Not Found?

The 404 (Not Found) status code indicates the resource requested by the client cannot be found or does not exist on the server.

6. What is a 301 redirect?

A 301 redirect indicates a resource has permanently moved to a new location. It tells clients and search engines to update to the new URL for future requests.

7. What are the most common HTTP response codes?

200 OK, 301 Moved Permanently, 400 Bad Request, 401 Unauthorized, 403 Forbidden, 404 Not Found and 500 Internal Server Error.

8. When should I use POST vs GET requests?

Use GET to retrieve data from a server. Use POST to send data to be processed or stored by a server, such as submitting a form.

9. What are some common HTTP request header fields?

Common request headers include User-Agent, Content-Type, Accept, Cookie and Cache-Control among others.

10. How can I check if a site uses HTTP or HTTPS?

HTTP sites use http:// in the URL while HTTPS sites use https://. Most browsers also display a lock icon for HTTPS sites.

11. Is HTTP/2 supported by all major browsers?

Yes, HTTP/2 has wide browser support including Chrome, Firefox, Safari, Opera, Edge and IE. Older browsers can use HTTP/2 via protocol upgrade.

12. Does HTTP/2 replace HTTP/1.1?

No, HTTP/2 augments rather than replaces HTTP/1.1. Many underlying concepts remain the same, allowing easy adoption.

13. How do I debug HTTP requests and responses?

Developer tools in browsers like Chrome or Firefox allow you to inspect the HTTP traffic including headers, status codes and timings.

14. What are the components of an HTTP request?

An HTTP request consists of a request line, headers, blank line and optional body. The request line indicates the HTTP method, URL and version.

15. When should I force a site redirect from HTTP to HTTPS?

You should always redirect HTTP to HTTPS to ensure connections are secure, prevent mixed content errors and get SEO benefits.

16. What are some benefits of HTTP persistent connections?

They improve performance by reusing TCP connections for multiple requests. They remove connection establishment overheads and reduce latency.

17. How can I compress HTTP responses?

Response compression reduces file sizes by compressing HTML, CSS, JS and other text-based assets before sending. Gzip and Brotli are commonly used.

18. How do I enable HTTP caching for my web app?

Using headers like Cache-Control, Etag and Expires properly configures caching policies to improve performance. This allows browsers to cache and reuse resources locally.

19. What are the steps to set up HTTPS on a server?

Obtain an SSL certificate, install it on the server, redirect HTTP to HTTPS, use secure cookies, update links to HTTPS and test the site for any issues.

20. What are some debugging tips for HTTP issues?

Inspect network requests in browser tools, check server access and error logs, use command line tools like cURL, test with different clients and connections and validate resource URLs.

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