Okay, this should do it:
function get_wiki_info() {
var ss = SpreadsheetApp.getActiveSpreadsheet();
var language = ss.getRangeByName('WikiLanguage').getValue();
var url = 'https://en.wikipedia.org/w/api.php?format=json&action=query&prop=extracts&exintro&explaintext&redirects=1&titles=' + language;
var response = UrlFetchApp.fetch(url);
var json = response.getContentText();
var data = JSON.parse(json);
var page_id = Object.keys(data.query.pages);
var extract = data.query.pages[page_id].extract;
ss.getRangeByName('WikiExtract').setValue(extract);
}
It uses two Named Ranges:
-
WikiLanguage
: a single cell range where you store the language string -
WikiExtract
: a single cell range where the extract will be written to