API:Cross-site requests
 | This page is part of the MediaWiki Action API documentation. |
If an external site needs to make an API call against a MediaWiki site, it must use CORS (preferred) or JSONP (older, less secure).
CORS usage
If a user script or gadget is used to make an API call against a site within the same wiki family, it must use a MediaWiki module that uses CORS under the hood: mediawiki.ForeignApi.
This is the way to go for instance, if a script on the English Wikipedia needs to check image information on Commons.
The MediaWiki API requires that the origin be supplied as a query string parameter. If the CORS request is authenticated, its value must be the site from which the request originates, which is matched against the Origin header required by the CORS protocol.
Note that this parameter must be included in any pre-flight request, and so should be included in the query string portion of the request URI even for POST requests.
When the origin parameter is supplied and the request does not return a successful CORS response, MediaWiki≥1.30 will return a MediaWiki-CORS-Rejection header with a brief reason for the failure, e.g. in case of mismatched origin or unsupported headers in a Access-Control-Request-Headers request header.
Unauthenticated CORS Requests
Unauthenticated CORS requests may be made from any origin by setting the origin request parameter to *.
In this case MediaWiki will include the Access-Control-Allow-Credentials: false header in the response and will process the request as if logged out.
Example
GET request
Sample code
var apiEndpoint = "https://commons.wikimedia.org/w/api.php";
var params = "action=query&list=allimages&ailimit=3&format=json";
/**
* Send the request to get the images
*/
fetch(apiEndpoint + "?" + params + "&origin=*")
.then(function(response){return response.json();})
.then(function(response) {
var allimages = response.query.allimages; // Process the output to get the image names
Object.keys(allimages).forEach(function(key) {
console.log(allimages[key].name);
});
});
Response
!!!!!_Mdina_Fortifications,_Ditch,_Bridge_and_Main_Gate.jpg
!!!!_Mdina_buildings_!!!!.jpg
!!!!_Palazzo_Dorell_ancillary_building.jpg
Authenticated CORS Requests
To make an authenticated CORS request, the remote wiki's $wgCrossSiteAJAXdomains setting must be set to allow the origin site.
If the CORS origin check passes, MediaWiki will include the Access-Control-Allow-Credentials: true header in the response, so authentication cookies may be sent.
Manual:CORS contains more instructions and examples on how to handle CORS requests in JavaScript.
JSONP usage
The API's format=json accepts a callback parameter, whose value is a JavaScript function which the JSON result will be wrapped in.
This may be used to call the API on a remote site by dynamically adding <script> tags to the document.
Example
GET request
Sample code
var apiEndpoint = "https://en.wikipedia.org/w/api.php";
var params = "action=query&list=random&rnlimit=3&format=json";
/**
* The function to wrap the result
*/
window.my_callback = function (response) {
var pages = response.query.random; // Process the output to get the titles
Object.keys(pages).forEach(function(key) {
console.log(pages[key].title);
});
};
var scriptTag = document.createElement("script"); // Dynamically create a "script" tag
scriptTag.src = apiEndpoint + "?" + params + "&callback=my_callback"; // Point to the query string
document.body.appendChild(scriptTag); // Add the script tag to the document
Response
Kache Aye Shoi
Talk:Sarbka, Wągrowiec County
Category:Nakhon Ratchasima Province