..  include:: /Includes.rst.txt
..  _introduction:

============
Introduction
============

..  _what-does-it-do:

What does it do?
================

The Indexed Search Engine provides two major elements to TYPO3:

#.  **Indexing:** An indexing engine which indexes TYPO3 pages on-the-fly
    as they are rendered by TYPO3's frontend. Indexing a page means that
    all words from the page (or specifically defined areas on the page)
    are registered, counted, weighted and finally inserted into a database
    table of words. Then another table will be filled with relation
    records between the word table and the page. This is the basic idea.

#.  **Searching:** A plugin you can insert on your website which allows
    website users to search for information on your website. By searching
    the plugin first looks in the word-table if the word exist and if it
    does all pages which has a relation to that word will be considered
    for the search result display. The search results are ordered based on
    factors like where on the page the word was found or the frequency of
    the word on the page.

This is an example of how the search interface on a website looks:

..  figure:: ../Images/FrontendSearchResults.png
    :alt: Frontend search results

    Search results in the frontend


..  _features-of-the-indexer:

Features of the indexer
=======================

The indexing engine has several features:

-   HTML data priority: 1) <title>-data 2) <meta-keywords>, 3) <meta-
    description>, 4) <body>

-   Indexing external files: Text formats like html and txt and doc, pdf
    by external programs (catdoc / pdftotext)

-   Wordcounting and frequency used to rate results

-   Exact or partial search

-   Searching freely for sentences (non-indexed).

-   NOT case-sensitive in any ways though.


..  _features-of-the-search-frontend-the-plugin:

Features of the search frontend (the plugin)
============================================

The search interface has several options for advanced searching. Any
of those can be disabled and/or preset with default values:

-   Searching whole word, part of word, sentence

-   Logical AND and OR search including syntactical recognition of AND, OR
    and NOT as logical keywords. Furthermore sentences encapsulated in
    quotes will be recognized.

-   Searching can be targeted at specific media, for instance searching
    only indexed PDF files, HTML-files, Word-files, TYPO3-pages or
    everything

-   The engine is language-sensitive based on the multiple-language
    feature of the TYPO3 CMS frontend.

-   Searching can be performed in specific sections of the website.

-   Results can be sorted descending or ascending and ordered by word
    frequency, weight, location relative to page top, page modification
    date, page title, etc.

-   The display of search results can be intelligently divided into
    sections based on the internal page hierarchy. Thus results are
    primarily grouped by relation, then by hit-relevance.

This shows the full range of default options for "advanced search":

..  figure:: ../Images/AdvancedSearchOptions.png
    :alt: Advanced search options

    All possible advanced search options


..  warning::

    The search frontend plugin is optimized for features, *not* speed.
    Especially it will be slow on a website with many pages in the page
    tree because it traverses the whole tree each time to build a list of
    accessible pages. However you can circumvent this by modifications to
    the search plugin so it does not check page access based on the id-
    list. But then you loose that feature of course. Can't have both.

    In any case; The indexing of pages and searching the indexed
    information are two different processes and therefore you can easily
    use another frontend plugin for making searches in the same data for
    whatever reason you might have for discarding the default search
    plugin.
