TYPO3

TYPO3 is a Web Content management system (CMS) written in the programming language PHP. It is able to run on a variety of web servers, such as Apache, Nginx, or Internet Information Services (IIS), and on many operating systems, including Linux, Microsoft Windows, FreeBSD, macOS, and OS/2. It is free and open-source software released under the GNU General Public License version 2.

TYPO3 is similar to other content management systems such as, Drupal, Joomla! and WordPress. It is used more widely in Europe than in other regions, with larger market share in German-speaking countries, the Netherlands and France.

TYPO3 is credited to be highly flexible, as code and content are run separately. It can be extended by new functions without writing any program code. TYPO3 supports publishing content in multiple languages due to its built-in localization system. Due to its features like editorial workplace and workflow, advanced frontend editing, scalability and maturity, TYPO3 makers classify it as an enterprise level content management system.

History and usage
TYPO3 was initially authored by the Dane Kasper Skårhøj in 1997. It is now developed by over 300 contributors under the lead of Benjamin Mack (Core team leader).

Calculations from the TYPO3 Association show that it is currently used in more than 500,000 installations. The number of installations detected by the public website "CMS Crawler" was around 384,000 in February 2017.

Features
TYPO3 provides a base set of interfaces, functions and modules. Most functionality exceeding the base set can be implemented via the use of extensions. More than 5000 extensions are currently available for TYPO3 for download under the GNU General Public License from a repository called the TYPO3 Extension Repository, or TER.

TYPO3 is able to run on most HTTP servers such as Apache, Nginx or IIS on top of Linux, Microsoft Windows or macOS. It uses PHP 7.2 or newer and any relational database supported by the TYPO3 DBAL including MySQL/MariaDB, PostgreSQL, and SQLite. Some 3rd-party extensions – not using the database API – support MySQL as the only database engine. The system can be run on any web server with at least 256 MB RAM and a CPU appropriate for that RAM. The backend can be displayed in any modern browser with JavaScript. There is no browser restriction for displaying user-oriented content generated by TYPO3.

Building basic proficiency in TYPO3 takes between a few weeks up to some months. For an author or editor who administers and operates a TYPO3 based website, this requirement can range from a few minutes to a few hours. A developer setting up a website with TYPO3 would need to work intensively with the meta-language Typoscript.

System architecture
Conceptually, TYPO3 consists of two parts: the frontend, visible to visitors, and the administrative backend. The frontend displays the web content. The backend is responsible for administration and managing content. The core functions of TYPO3 include user privileges and user roles, timed display control of content (show/hide content elements), a search function for static and dynamic content, search-engine friendly URLs, an automatic sitemap, multi-language capability for frontend and backend, and more.

Like most modern CMS's, TYPO3 follows the policy of separation of content and layout: The website content is stored in a relational database, while the page templates are stored on the file system. Therefore, both can be managed and updated separately.

TYPO3 defines various basic types of content data. Standard content elements are described as text, text with media, images, (plain) HTML, video etc. Various added types of content elements can be handled using extensions.

The fundamental content unit is a "page". Pages represent a URL in the frontend and are organized hierarchically in the backends' page tree. Standard pages serve as "containers" for one or multiple content elements. There are several added special page types, including:
 * shortcuts (they show content from another page)
 * mount points (that insert a part of the page tree at the mount point)
 * external URLs
 * system folders (to handle complex data such as registered users)

Internally, TYPO3 is managed by various PHP arrays. They contain all the information necessary to generate HTML code from the content stored in the database. This is achieved by a unique configuration language called Typoscript.

Design elements
Designing and developing with TYPO3 is commonly based on the following elements, among others:


 * Page tree
 * Representation of all pages of a site, their structure and properties.


 * Constants
 * System-wide configuration parameters


 * Template
 * Since TYPO3 6, the system runs on the templating engine Fluid. Fluid combines HTML markup with conditions and control structures. It can be extended by custom view helpers written in PHP.


 * Until version 4.3, an HTML skeleton was used, with markers (e.g.,  ) and range markers, called subparts (e.g.,  ); that were replaced by various content elements or served as a sub template. This template system can still be found in older extensions or installations.


 * Typoscript
 * Typoscript is a purely declarative configuration language. In Typoscript, configuration values are defined, which are parsed into a system-wide PHP array. Typoscript is object-based and organized in a tree-like structure.


 * Extensions
 * Added plug-ins to enable more functions. See Extensions.


 * PHP
 * TYPO3 CMS is written in PHP. Thus, most features can be modified or extended by experienced users. For example, the XCLASS mechanism allows classes and methods to be overwritten and extended.

Extensions
Extensions are the cornerstone in the internal architecture of TYPO3. A feature that was introduced with version 3.5 in 2003 is the Extension Manager, a control center managing all TYPO3 extensions. The division between the TYPO3 core and the extensions is an important concept which determined the development of TYPO3 in the past years. Extensions are designed in a way so they can supplement the core seamlessly. This means that a TYPO3 system will appear as a unit while actually being composed of the core application and a set of extensions providing various features.



They can be downloaded from the online repository (TER) directly from the backend, and are installed and updated with a few clicks. Every extension is identified by a unique extension key (for example, tt news). Also, developers can share new or modified extensions by uploading them to the repository.

Generally, extensions are written in PHP. The full command set of PHP 5.3 can be used (regarded the system requirements of the specific TYPO3 version), but TYPO3 also provides several library classes for better efficiency: Best known and most used is the Pibase library class. With introduction of TYPO3 4.3 in 2009, Pibase has been replaced (or extended) by the Extbase library, which is a modern, model–view–controller (MVC) based development framework. To ensure backward compatibility, both libraries can be used in the same TYPO3 installation. Extbase is a backport of some features of FLOW3, renamed Neos Flow, a general web application framework.

Notable projects
As it classifies as an enterprise CMS, many global companies and organizations base their web or intranet sites on TYPO3. The majority are based in German-speaking countries, such as the state of Saxony-Anhalt, the German Green Party, the University of Lucerne (Switzerland), the University of Vienna (Austria) and the Technical University of Berlin. International organizations running one or more TYPO3 sites are: Airbus, Konica-Minolta, Leica Microsystems, Air France, Greenpeace, and Meda (Sweden).

Neos
A completely rewritten version (code-named "Phoenix") was originally planned as TYPO3 version 5.0. While working on this new release and analyzing the 10-year history and complexity of TYPO3 v4, the TYPO3 community decided to branch out version 5 as a completely separate product, one that wouldn't replace version 4 in the near future and as such needed to have its own name. Published as FLOW3, now renamed Neos Flow, it along with various other packages then served as the basis for the start of development of project Phoenix.

In September 2012, the TYPO3 developers decided on the name for the new product, "TYPO3 Neos". With TYPO3 Neos 1.0 alpha1, a public test version was released in late 2012. In May 2015 the TYPO3 Association and the Neos team decided to go separate ways, with TYPO3 CMS remaining the only CMS product endorsed by the Association and the Neos team publishing Neos as a stand-alone CMS without any connection to the TYPO3 world.

In January 2017, Neos 3.0 has been published, along with a new version of Flow framework and a name change of its configuration language from TypoScript2 to Fusion.