URL

URL
(Uniform Resource Locator) - a standardized format for addressing
resources, standardized form of writing addresses on the Internet.

Each URL is unique and shows the location of the network.
Initially, the creator of URL Tim Berners-Lee wanted to use the
identifier to determine separate files in local area networks, and later
in the global Internet. Currently URL has its own standard (RFC 1738) and used for the determination of any files and nodes in the network.





URL format
URLs that are the traditional form of writing: <protocol> :/ /
<contenttype> strony="">. <username> Domeny="">
<port> / <path URL> / For example: http://www.example . com:
8080/somepath.php / </ port> </ name> </ type> </
protocol>

<protocol> <contenttype> strony=""> <username> domeny=""> <port>

Protocol - Specifies the type of data transfer: http - plain text,
https - the message text over an encrypted connection, FTP - file
transfer protocol, mailto - e-mail address.

Page type - specifies for which browser page is adapted.
According initially accepted standards all URLs beginning with the
letters WWW, allowing to identify the site as a resource available on
the Web with the help of a regular browser (for mobile phones was
subsequently adopted abbreviation wap - Wireless Application Protocol).
Now this principle is used much less frequently, and if, before the
page name is not shown the type, it is assumed that this is the site for
a regular browser. If the site is suitable for viewing on a mobile device, or have it both ways - wap and web extensions are shown.

Domain name - a unique resource address symbols expressed in the network.

Port - port number to access. Any web application has its own data exchange protocols, which are connected to specific ports. Http protocol works with TCP ports 80 or 8080. If the server to which the request is sent, there are just web pages, the default port does not show up. If the server has access can be obtained, for example, ftp, it should still show the port number.

URL Path - indicates the exact position of the home page. Recording Form URL in the URL initially could only use the basic Latin alphabet, numbers and some punctuation marks. Now, with transcoding capabilities, the URL may consist of symbols of many different alphabets, Arabic, Chinese, Cyrillic, etc.

Internet services needed to simplify working with URL
Among the disadvantages include URL lack of clarity, length, and lack
of flexibility, the parties may change or disappear, and the URL will
continue to lead to a non-existent page. Therefore, the resulting Web services, providing the opportunity to simplify the URL:

PURL (called Persistent Uniform Resource Locator - permanent tenant URL). PURL provides specific databases to protect URL. When the output link is changed, this information reaches the database and the necessary changes are introduced. In this way, the external service address remain unchanged.
This is the preferred method for pages with dynamic content that can
often change and change their position: search systems to index page
with the URL PURL and even if you change the output path, file or page
can be found on the server, and the page will not lose position search
results.

Short URL - generic name for Web services, which can significantly
shorten the length of the URL, which is possible by creating aliases
(synonyms) for the final URL of a short domain name.

Friendly URL (friendly URL) - URL is easy and convenient for the user's
address, which greatly facilitates the use of it, not only by the
Internet, but also by the search engine robots.
Getting friendly URLów is possible thanks to so-called process of
rewriting pages (called rewriting), which is usually configured in.
Htaccess file. Many CMS that offer this service, such as Joomla! for each site is assigned a number corresponding to the number in the database.