App issue with SharePoint 2013 Developer Site

Question

In SharePoint 2013 Developer Site:

I am installing an app to my site and it worked fine with default stuff. I added some custom .js file in this app which will set the master page of site coll and deployed again. I am able to open it once, but not able to set the master page. And from 2nd time onwards it always gives be below error:

**Sorry, there was a problem with FinanceConfigApp

For support, please contact the developer. Accessing referenced file https://microsoft-e25da8eeaa88f2.sharepoint.com/teams/NaveenDevSite/_catalogs/masterpage/seattle.master from https://microsoft-e25da8eeaa88f2.sharepoint.com/teams/NaveenDevSite/FinanceConfigApp/Pages/Default.aspx?SPHostUrl=https://microsoft.sharepoint.com/teams/NaveenDevSite&SPLanguage=en-US&SPClientTag=3&SPProductNumber=15.0.4454.1026&SPAppWebUrl=https://microsoft-e25da8eeaa88f2.sharepoint.com/teams/NaveenDevSite/FinanceConfigApp is not allowed because the reference is outside of the App Web.**

Any help would be highly appreciated!!!

I have tried: hardcoded the client context like below:

context = new SP.ClientContext('/teams/NaveenDevSite');
context = new SP.ClientContext('https://microsoft.sharepoint.com/teams/NaveenDevSite');
    context = new SP.ClientContext.get_current();

below is the complete code which works perfect in my page. but not in App:

$(document).ready(function () {
    jQuery('.cmdSet').click(function () {

        var scriptBase = _spPageContextInfo.webAbsoluteUrl + "/_layouts/15/";

        $.getScript(scriptBase + "sp.runtime.js", function () {

            $.getScript(scriptBase + "sp.js", function () {

                $.getScript(scriptBase + "sp.core.js", sharePointReady);

            });
        });

    });
});


var context;
var web;
var masterurl;
var site;
function sharePointReady() {
    context = new SP.ClientContext.get_current();
    web = context.get_web();


    context.load(web, 'ServerRelativeUrl');
    var splitBaseUrl = L_Menu_BaseUrl.split('/');
    var baseUrl = '/' + splitBaseUrl[1] + '/' + splitBaseUrl[2];
    web.set_customMasterUrl(baseUrl + '/_catalogs/masterpage/seattle.master');
    web.set_masterUrl(baseUrl + '/_catalogs/masterpage/seattle.master');
    web.update();

    context.executeQueryAsync(function () {
        masterurl = web.get_serverRelativeUrl() + "/_catalogs/masterpage/seattle.master";
        alert("Master Page is Set Successfully!!!");

    }, function (sender, args) {

        alert("Error: " + args.get_message());

    });
}

Answer 1

Try putting: context.load(web, 'ServerRelativeUrl');

after you perform web.update()

As per your error, you might have to read SPHostUrl from the parameters.

See this: http://sharepointquicksolutions.blogspot.com/2013/01/get-host-web-url-in-sharepoint-2013-apps.html