Per chi inizia con gli Sharepoint add-ins

Un po' di codice già pronto da utilizzare in tutti gli addins Sharepoint-hosted che debbano accedere all'host web.

// Function to retrieve a query string value.
// For production purposes you may want to use
//  a library to handle the query string.
function getQueryStringParameter(paramToRetrieve) {
    var params =
        document.URL.split("?")[1].split("&");
    var strParams = "";
    for (var i = 0; i < params.length; i = i + 1) {
        var singleParam = params[i].split("=");
        if (singleParam[0] == paramToRetrieve)
            return singleParam[1];
    }
}
var clientContext = SP.ClientContext.get_current();
var hostweburl = decodeURIComponent(getQueryStringParameter("SPHostUrl"));
var appweburl = decodeURIComponent(getQueryStringParameter("SPAppWebUrl"));

$.getScript("../_layouts/15/SP.RequestExecutor.js", initializePart);
function initializePart() {
    var factory = new SP.ProxyWebRequestExecutorFactory(appweburl);
    clientContext.set_webRequestExecutorFactory(factory);
    var appContextSite = new SP.AppContextSite(clientContext, hostweburl);
    workWeb = appContextSite.get_web();
    clientContext.load(workWeb);
    clientContext.executeQueryAsync(ongetWebSuccess, ongetWebFail);
}