Url

URL

A Uniform Resource Locator (URL), colloquially termed a web address, is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it. URLs are used to retrieve web pages, image files, video files, and other types of digital content. They are a fundamental aspect of Internet navigation and functionality.

Overview

URLs provide a way for computers to retrieve information over the internet. They are a type of Uniform Resource Identifier (URI); although many people use the two terms interchangeably, a URL is actually a specific type of URI.

The URL contains information about the location of a web resource as well as the protocol used to access it. This typically includes a protocol (such as HTTP or HTTPS), a hostname, and a file or resource location.

Syntax

The syntax of a URL is defined by RFC 3986 and is typically in the following form:

protocol://hostname/path

The protocol indicates the method of access, the hostname specifies the location of the server hosting the resource, and the path specifies the specific resource to be accessed.

Components

A URL consists of several components, some of which are optional:

• Scheme: This is the protocol used to access the resource. Common schemes include http, https, ftp, and mailto.
• Authority: This includes the domain name or IP address of the server hosting the resource, as well as optional user information and port number.
• Path: This specifies the specific resource on the server. It often resembles a file path, but does not have to point to an actual file.
• Query: This is a string of parameters and values that are passed to a script on the server. It is preceded by a question mark.
• Fragment: This is an optional part of the URL that is preceded by a hash mark (#). It specifies a part or a position within the overall resource or document.

Encoding

URLs can only be sent over the Internet using the ASCII character-set. Since URLs often contain characters outside the ASCII set, the URL has to be converted into a valid ASCII format. URL encoding replaces unsafe ASCII characters with a "%" followed by two hexadecimal digits.

See also

• Uniform Resource Identifier
• Hypertext Transfer Protocol
• Domain name
• IP address