The Wikipedia API can do a lot, but it’s not easy to get started.

With WikipediaKit, it’s easy to build apps that search and show Wikipedia content—without worrying about the raw API. Instead of exposing all options and endpoints, WikipediaKit provides comfortable access to the most interesting parts for building a reader app. WikipediaKit comes with opinions and an attitude—but that’s the point!

The WikipediaKit framework is written in Swift, has no third-party dependencies, and runs on macOS, iOS, watchOS, and tvOS.

If this doesn’t convince you to build a shiny new reader app for Wikipedia yourself, have a look at V for Wiki, the award-winning app that WikipediaKit was created for. The shipping version on the iOS App Store uses exactly the code that you can explore and download here.

WikipediaKit can be added to your Xcode project using the Swift Package Manager.

You can use Carthage to install and update WikipediaKit.

Drag and drop the WikipediaKit.xcodeproj to your app project and add the WikipediaKit embedded framework in your app project’s build settings.

The Wikipedia class connects your app to Wikipedia’s API. You can search, get articles, and list nearby places by querying a freshly created Wikipedia instance…

let wikipedia = Wikipedia()

…or by using the shared singleton instance:

let wikipedia = Wikipedia.shared

Before doing anything else, make sure to add your email address:

WikipediaNetworking.appAuthorEmailForAPI = "appauthor@example.com"

WikipediaKit will use this email address and your app’s bundle info to generate and send a User-Agent header. This will identify your app to Wikipedia’s servers with every API request, as required by the API guidelines.

The User-Agent header is printed to your Xcode console when you make the first API request. It’ll look similar to this:

User-Agent: ExampleApp/1.0 (com.example.ExampleApp; appauthor@example.com) WikipediaKit/1.0

Please double-check that the User-Agent header is correct before shipping your app.

The return type of all Wikipedia methods is a standard URLSessionTask:

let language = WikipediaLanguage("en")

let searchSessionTask = Wikipedia.shared.requestOptimizedSearchResults(language: language, term: "Soft rime") { (searchResults, error) in
    // This code will be called asynchronously
    // whenever the results have been downloaded.
    // …
}

A URLSessionTask can be cancelled like this:

searchSessionTask.cancel()

See the URLSessionTask documentation for further reading.

A WikipediaLanguage has a language code, a localized name, an autonym, and sometimes a variant (e.g. zh-hans for Simplified Chinese and zh-hant for Traditional Chinese).

// French language, localized name for German, no variant
let l = WikipediaLanguage(code: "fr",
                          localizedName: "Französisch", // FR in DE
                          autonym: "Français") // FR in FR

WikipediaKit comes with a list of Wikipedia languages and their autonyms. This lets you initialize a WikipediaLanguage by passing the language code. Please note that if you use this shorthand method, the localized names will be in English.

let language = WikipediaLanguage("fr")
// code: "fr", localizedName: "French", autonym: "Français"

Search Wikipedia—e.g. for the term “Soft rime” in English—like this:

let language = WikipediaLanguage("en")

let _ = Wikipedia.shared.requestOptimizedSearchResults(language: language, term: "Soft rime") { (searchResults, error) in

    guard error == nil else { return }
    guard let searchResults = searchResults else { return }

    for articlePreview in searchResults.items {
        print(articlePreview.displayTitle)
    }
}

The searchResults are a WikipediaSearchResults object.

To load more search results for a query, simply start another search for the same language: and term:, passing the previous WikipediaSearchResults object as the existingSearchResults: parameter.

The default batch size is 15, but can be changed by passing a different number in the maxCount parameter.

There are two supported search methods (WikipediaSearchMethod) to search for articles on Wikipedia. You can pass them to requestSearchResults(method:language:term:).

• .prefix searches the article titles only
• .fullText searches the complete articles

For better search results quality, use requestOptimizedSearchResults(language:term:), which doesn’t take a method: parameter (see the example above). This will use the .prefix search and then fall back to the .fullText search whenever there are few or no results for a search term.

You can adjust the minimum number of results—before the fallback .fullText search is triggered—with the minCount: parameter.

The desired maximum pixel width of the WikipediaArticlePreview’s image URL can be adjusted in the optional imageWidth: parameter.

Searches are cached automatically until the app quits (see section on caching below).

WikipediaArticlePreview objects represent search result items. They’re similar to full articles, but contain only an excerpt of the article text.

The displayTitle and displayText can be formatted via your WikipediaFormattingDelegate.

Update: Since WikipediaKit 3.0, this method uses the new Wikipedia REST API. The rewrite was a good opportunity to modernize WikipediaKit and return a Result<WikipediaArticle, WikipediaError> type.

Load the article about “Soft rime” in English like this:

let language = WikipediaLanguage("en")

let _ = Wikipedia.shared.requestArticle(language: language, title: "Soft rime") { result in
    switch result {
    case .success(let article):
      print(article.displayTitle)
      print(article.displayText)
    case .failure(let error):
      print(error)
    }
}

The displayTitle and displayText can be formatted via your WikipediaFormattingDelegate.

Wikipedia articles come with a table of contents, stored in a array of WikipediaTOCItem. The section titles can be formatted in your WikipediaFormattingDelegate.

To query other available languages for a given article, use the requestAvailableLanguages(for:) call on your Wikipediainstance, passing the existing article.

Articles are cached automatically until the app is restarted (see section on caching below).

This search mode returns geo-tagged articles around a specific location. Pass in a coordinate (latitude and longitude) around which to search:

let language = WikipediaLanguage("en")

let _ = Wikipedia.shared.requestNearbyResults(language: language, latitude: 52.4555592, longitude: 13.3175333) { (articlePreviews, resultsLanguage, error) in

    guard error == nil else { return }
    guard let articlePreviews = articlePreviews else { return }

    for a in articlePreviews {
        print(a.displayTitle)
        if let coordinate = a.coordinate {
            print(coordinate.latitude)
            print(coordinate.longitude)
        }
    }
}

The requestFeaturedArticles(language:date:) query gets a list of the most popular articles for a specific date from Wikipedia’s official analytics.

Please note: Versions of WikipediaKit before 3.0 used the raw data from an older Wikipedia API to implement this feature. The new (current) implementation uses the same new API as the official Wikipedia app, which seems to filter the articles, stripping out potentially offensive content.

let language = WikipediaLanguage("en")

let dayBeforeYesterday = Date(timeIntervalSinceNow: -60 * 60 * 48)

let _ = Wikipedia.shared.requestFeaturedArticles(language: language, date: dayBeforeYesterday) { result in
    switch result {
    case .success(let featuredCollection):
	    for a in featuredCollection.mostReadArticles {
	        print(a.displayTitle)
	    }
    case .failure(let error):
      print(error)
    }
}

To find out the URL for a given Wikipedia image at a specific size, use this call:

let language = WikipediaLanguage("en")

// You can pass multiple images here.
// Make sure to limit the number somehow
// because the API server will bail out
// if the query URL gets too long.

let urls = ["https://en.wikipedia.org/wiki/File:Raureif2.JPG"]

let _ = Wikipedia.shared.(language: language, urls: urls, width: 1000) { (imagesMetadata, error) in
    guard error == nil else { return }
    for metadata in imagesMetadata {
	    print(metadata.url) // URL for 1000px width version
	    print(metadata.description)
	    print(metadata.license)
	  }
}

Instead of the urls: parameter, you can specify image IDs; in this case the ids: parameter would be ["File:Raureif2.JPG"].

WikipediaKit comes with a few delegate protocols that help you track state, filter, and format.

WikipediaNetworking.sharedActivityIndicatorDelegate = MyActivityIndicatorDelegate.shared

Set a WikipediaNetworkingActivityDelegate to receive start() and stop() calls whenever a network operation starts and stops.

Wikipedia.sharedFormattingDelegate = MyFormattingDelegate.shared

The WikipediaArticle and WikipediaArticlePreview classes have a displayTitle and a displayText property.

You can parse and reformat article texts, titles, and the table of contents in your WikipediaFormattingDelegate before it’s being cached.

class MyFormattingDelegate: WikipediaTextFormattingDelegate {

    static let shared = MyFormattingDelegate()

    func format(context: WikipediaTextFormattingDelegateContext, rawText: String, title: String?, language: WikipediaLanguage, isHTML: Bool) -> String {
        // Do something to rawText before returning…
        return rawText
    }
}

Caching happens automatically (after processing and formatting) for search results and articles. WikipediaKit uses simple NSCache instances.

There’s also the automatic NSURLCache, controlled by the server’s cache headers. You can modify the cache duration headers to be included API response in Wikipedia.maxAgeInSeconds.

Request an array of random WikipediaArticlePreview objects like this:

Wikipedia.shared.requestRandomArticles(language: self.language, maxCount: 8, imageWidth: 640) {
    (articlePreviews, language, error) in

    guard let articlePreviews = articlePreviews else { return }

    for article in articlePreviews {
        print(article.displayTitle)
    }
}

WikipediaKit has this convenience function that gets one single random WikipediaArticlePreview at a time:

Wikipedia.shared.requestSingleRandomArticle(language: self.language, maxCount: 8, imageWidth: 640) {
    (article, language, error) in

    guard let article = article else { return }

    print(article.displayTitle)
}

If maxCount is larger than 1, the surplus results from the API query are buffered in a shared WikipediaRandomArticlesBuffer object and will be returned one-by-one with every subsequent call of requestSingleRandomArticle. A new network request is only triggered when there are no buffered random articles left or when the query language changes.

• Improve unit tests
• Pass request options in an array instead of function parameters

WikipediaKit was created by Frank Rausch (@frankrausch) for Raureif.

© 2017–22 Raureif GmbH / Frank Rausch

MIT License; please read the LICENSE file in this repository.

This project is not affiliated with the official Wikipedia projects or the Wikimedia Foundation.

Wikipedia® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization.