Extension:DynamicPageList (third-party)/de-formal

The DynamicPageList (third-party) extension is a reporting tool for MediaWiki, listing category members and intersections with various formats and details. For full documentation, see the full original manual or manual (German Manual Hilfe:DynamicPageList).

In its most basic form, DPL displays a list of pages in one or more categories. Selections may also be based on factors such as author, namespace, date, name pattern, usage of templates or references to other articles. Output takes a variety of forms, some of which incorporate elements of selected articles.

This extension is invoked with the parser function  or parser tag. A Wikimedia-compatible implementation of certain features can be invoked with.

DPL can result in computationally-expensive database queries. For best performance, use the optional parameters allowcachedresults and/or dplcache where possible.

Configuration
DPL configuration settings and their default values, from the manual:

These are all public static variables.

The global variable is also respected by DPL. It will prevent the contents of the listed namespaces from appearing in DPL's output.

Functional richness
DynamicPageList has many features; some are expensive, or dangerous in the wrong hands. It is important to choose an appropriate level of functionality for your wiki.


 * - equivalent to Wikimedia's DPL
 * - adds additional formatting parameters
 * - adds performance equivalent features for templates and pagelinks
 * - allows more-expensive page inclusion features and regular expression queries; expect to use the dplcache parameter
 * - permits exotic and potentially dangerous batch update and delete operations; not recommended for public websites

Extended DPL functionality
DPL is invoked by using the parser function, or the parser extension tag .


 *  See: Manual - General Usage and Invocation Syntax and Manual - DPL parameters

Backwards-compatible functionality
Functionality compatible with Wikimedia's DPL extension can be invoked with.
 * See: 

Overview
Assume you have written some articles about countries. Typically these articles will have three things in common:


 * They will belong to a common category
 * They will have a similar chapter structure, i.e. they will contain paragraphs named 'Religion' or 'History'
 * They will use a template which is used to present highly structured short data items ('Capital', 'Inhabitants', ..) in a nice way (e.g. as a wikitable)

DPL generates reports on articles
Let us assume that there is an article on Islam. You want to give some information about the spreading of this religion over various countries. But you do not want to create redundancy by repeating information that was already given in the articles on the countries.

In our scenario the natural approach with DPL would be to generate a list of 'countries' (=category) where Islam plays a role (i.e. restrict your selection to articles of category 'Country' which contain a link to 'Islam'). Typically you would want to include part of the text chapter on 'Religion' from each of the relevant countries. You might also want to give the number of inhabitants for each country. The output should be shown as an alphabetically ordered table. It would be nice if the user could easily sort the table by inhabitants or some other criteria.

With DPL you can ..


 * generate a list of all those articles (or a random sample)
 * show metadata of the articles (popularity, date of last update, ..)
 * show one or more chapters of the articles ('transclude' content)
 * show parameter values which are passed to the common template
 * order articles appropriately
 * present the result in a sortable table (e.g.)
 * use multi column output

Which steps are necessary?
Find the articles you want to list:


 * select by a logical combination (AND,OR,NOT) of categories
 * specify a range for the number of categories the article must be assigned to
 * select by a logical combination (AND,OR,NOT) of namespaces
 * define a pattern which must match the article's name
 * name a page to which the article must or must not link
 * name a template which the article must or must not use
 * name a text pattern which must occur within external links from a page
 * exclude or include redirections
 * restrict your search to stable pages or quality pages ("flagged revisions")
 * use other criteria for selection like author, date of last change etc.
 * define regular expressions to match the contents of pages you want to include

Order the result list of articles according to


 * name
 * date of last change
 * popularity
 * user who changed them last
 * size
 * restrict the output to the first n articles or to a random sample
 * use descending or ascending sequence

Define attributes you want to see


 * article name
 * article namespace
 * article size
 * date of last change
 * date of last access
 * user who changed them last

Define contents you want to show


 * whole article
 * contents of certain chapters (identified by headings)
 * text portions (defined by special marker tags in the article)
 * values of template calls
 * substitute the original template by a different one and show the output of that template

Define the output format


 * specify headline and footer for your report
 * use ordered list, unordered list
 * use tables, sorted tables (using javascript)
 * format table fields individually by applying templates to their content
 * use category style listing
 * create "tag clouds" by varying output text size depending on popularity of pages
 * multi column output
 * truncate title or contents to a certain maximum length
 * add a link to the article or to one or more of its chapters

DPL generates reports on categories
Apart from producing a list of pages which match certain criteria, DPL can also create a list of categories a selected set of pages belongs to. This can be useful to get an idea of the semantic scope of a group of pages (which can be defined by some arbitrary criteria). One of the more useful applications would be question like: "To which categories do the pages belong which contain a reference to the current page?"

DPL can be used for bulk editing
Sometimes you want to perform a similar editing task on many articles (like adding a template at the beginning of the text). DPL has a feature which allows you to update other articles based on regular expressions. This feature is experimental and can be disabled in the DPL config file.

DPL interacts with other extensions
There is a special mechanism which allows you to call your own extension inside the result loop of a DPL query. This opens doors for assembling new 'applications' without having to program on php level. For example you can create menu trees for Extension:Treeview, you can create dependency graphs or timebars with Extension:Wgraph, you can generate nice bar graphs or pie charts using DPL together with Ploticus, you can call 'gallery' or whatever you want...

DPL is a platform for building other applications
The power of DPL makes it possible to create applications on wiki template level which would normally require PHP programming. One example of this is a light-weight "semantic wiki" approach. See the DPL demo page for details.

DPL and performance
With a few lines of DPL code it is possible to create huge output and CPU load (think of a DPL query which tries to include the contents of all articles in your mediawiki ;-)). Normally this is not a problem because users who write DPL queries have some level of expertise. If you are afraid, however, you can restrict the execution of DPL queries to protected articles.

Apart from that the general performance of DPL on medium-size wikis is quite acceptable (see the performance tests on the dpldemo website). Use of allowcachedresults and/or dplcache where possible can improve performance.



Related extensions

 * – An overview and comparison.
 * turns links and data in wiki pages into queryable information
 * deletes pages based on DynamicPageList; also useful for testing different DPL settings without actually deleting the pages