API:Query

The action=query module allows you to get most of the data stored in a wiki, including tokens for editing.

The query module has many submodules (called query modules), each with a different function. There are three types of query modules:
 * Meta information about the wiki and the logged-in user
 * Properties of pages, including page revisions and content
 * Lists of pages that match certain criteria

Multiple modules should be used together to get what you need in one request, e.g.  is a call to six modules in one request.

Unlike meta and list modules, all property modules work on a set of pages provided with either titles, pageids, revids, or generator parameters. Use the first three if you know page's title/page id/revision id. Do not ask for one page at a time - this is very inefficient, and consumes lots of extra resources and bandwidth. You should combine multiple titles or ids with a "|" symbol: titles=PageA|PageB|PageC.

Use generator if you want to get data about pages that are result of another api call. For example, if you want to get data about pages in a certain category (list=categorymembers), and then call api with pageids set to all the returned results, you should combine two calls into one by setting generator=categorymembers</tt> instead of the list parameter.

Lastly, you should always request the new "continue" syntax to iterate over results. To use it, always pass an empty continue=</tt> parameter, and check if the result contains a continue</tt> section. If it does, merge returned values with the original request and call the api again. Repeat until there is no more continue</tt> section.

Sample query
Before we get into the nitty-gritty, here's a useful sample query that simply gets the wiki markup (content) of a page:

api.php?action=query&prop=revisions&rvprop=content&format=xml&titles=Main%20Page

This means fetch (action=query) the content (rvprop=content) of the most recent revision of Main Page (titles=Main%20Page) in XML format (format=xml).

Alternatively, you can use action=raw</tt> as a parameter to index.php to get the content of a page: index.php?title=Main%20Page&action=raw

Specifying pages
You can specify pages in the following ways:
 * By name using the  parameter, e.g.
 * By page ID using the  parameter, e.g.
 * By revision ID using the  parameter, e.g.
 * Most query modules will convert revision ID to the corresponding page ID. Only prop=revisions actually uses the revision ID itself.
 * Using a generator

Specifying titles through the query string (either through  or  ) is limited to 50 titles per query (or 500 for those with the   right, usually bots and sysops).

Title normalization
Title normalization converts page titles to their canonical form. This means capitalizing the first character, replacing underscores with spaces, and changing namespace to the localized form defined for that wiki. Title normalization is done automatically, regardless of which query modules are used. However, any trailing line breaks in page titles (\n) will cause odd behavior and they should be stripped out first.

Missing and invalid titles
Titles that don't exist or are invalid still appear in the  section, but they have the   or   attribute set. In output formats that support numeric array keys (such as JSON and PHP serialized), missing and invalid titles will have unique, negative page IDs. Query modules will just ignore missing or invalid titles, as they can't do anything useful with them. The titles in the Special: and Media: namespaces cannot be queried. If any such titles are found in the  parameter or passed to a module by a generator, a warning will be issued.

Resolving redirects
Redirects can be resolved automatically, so that the target of a redirect is returned instead of the given title. The example below isn't really useful because it doesn't use any query modules, but shows how the  parameter works. Both normalization and redirection may take place. In case of double redirects, all redirects will be resolved, and in case of a circular redirect, there might not be a page in the 'pages' section (see also below). Redirect resolution cannot be used in combination with the  parameter or with a generator generating revids; doing that will produce a warning and will not resolve redirects for the specified revids.

Limits
See here for more information on limits.

Continuing queries

 * See legacy continue for the  information

Very often you will not get all the data you want in one request. If there is more data, the result will have a  element. Appending contained values to your original request will get the next portion of the data. Due to legacy reasons, until we introduce API 2.0, you should always include a  parameter to let the servers know you support this feature.

You can now add  and   to the original request (the new value for   would replace the initial empty string) to get the next set of results. If there is no more results, there will not be a  element.

Here is the recommended way to iterate over query results (uses python requests lib). Note that clients should not be manipulating or depending on any specifics of the values returned inside the  element, as they may change.

Getting a list of page IDs
With the  parameter, you'll get a list of all page IDs listed in the   element. This is particularly useful for formats like JSON in which the pages array has numeric indexes.

Exporting pages
You can export pages through the API with the  parameter. If the  parameter is set, an XML dump of all pages in the   element will be added to the result. The  parameter only gives a result when used with specified titles (Generator, titles</tt>, pageids</tt> or revid</tt>). Note that the XML dump will be wrapped in the requested format; if that format is XML, characters like &lt; and &gt; will be encoded as entities (&amp;lt; and &amp;gt;) If the  parameter is also set, only the XML dump (not wrapped in an API result) will be returned.

See also: Importing pages

Generators
With generators, you can use the output of a list instead of the  parameter. The output of the list must be a list of pages, whose titles are automatically used instead of the,   or   parameter. Other query modules will treat generated pages as if they were given in a parameter. Only one generator is allowed. Some prop modules can also be used as a generator.

Parameters passed to a generator must be prefixed with a. For instance, when using, use   instead of.

It should also be noted that generators only pass page titles to the 'real' query, and do not output any information themselves. Setting parameters like  will therefore have no effect.

Generators and redirects
Here, we use prop=links as a generator. This query will get all the links from all the pages that are linked from Title. For this example, assume that Title has links to TitleA and TitleB. TitleB is a redirect to TitleC. TitleA links to TitleA1, TitleA2, TitleA3; and TitleC links to TitleC1 and TitleC2. Redirect are solved because the  parameter is set.

The query will execute the following steps:
 * 1) Resolve redirects for titles in the   parameter
 * 2) For all the titles in the   parameter, get the list of pages they link to
 * 3) Resolve redirects in that list
 * 4) Run the prop=links query on that list of titles

More generator examples

 * Show info about 4 pages starting at the letter "T"
 * http://en.wikipedia.org/w/api.php?action=query&generator=allpages&gaplimit=4&gapfrom=T&prop=info


 * Show content of first 2 non-redirect pages beginning at "Re"
 * http://en.wikipedia.org/w/api.php?action=query&generator=allpages&gaplimit=2&gapfilterredir=nonredirects&gapfrom=Re&prop=revisions&rvprop=content

Possible warnings

 * No support for special pages has been implemented
 * Thrown if a title in the Special: or Media: namespace is given
 * Redirect resolution cannot be used together with the revids= parameter. Any redirects the revids= point to have not been resolved.
 * Note that this can also be caused by a generator that generates revids