How can I access data on the host web on a development app using JavaScript?

Question

'use strict';

ExecuteOrDelayUntilScriptLoaded(initializePage, "sp.js");

function initializePage() { var context, appContext, hostWeb, user, lists, listItemCollection, projectList;

// This code runs when the DOM is ready and creates a context object which is needed to use the SharePoint object model
$(document).ready(function () {

    // Get hostweb and appweb string values
    var appWebUrl = window.location.protocol + "//" + window.location.hostname + _spPageContextInfo.webServerRelativeUrl;
    var hostUrl = _spPageContextInfo.siteAbsoluteUrl;

    // Create and access objects 
    context = new SP.ClientContext(appWebUrl);

    // Host web data access
    appContext = new SP.AppContextSite(context, hostUrl);
    hostWeb = appContext.get_web();
    lists = hostWeb.get_lists();
    projectList = lists.getByTitle('Projects');

    // Generate a CamlQuery 
    var camlQuery = new SP.CamlQuery();
    camlQuery.set_viewXml(
        '<View><Query><Where><Geq><FieldRef Name=\'ID\'/>' +
        '<Value Type=\'Number\'>1</Value></Geq></Where></Query><RowLimit>10</RowLimit></View>'
        );

// Get the items using the query
    listItemCollection = projectList.getItems(camlQuery);

// Load the object to browser
    context.load(listItemCollection);
    context.executeQueryAsync(
        Function.createDelegate(this, listSuccess),
        Function.createDelegate(this, listFail)
    );
});

function listSuccess() {
alert('Success');
}

function listFail(sender, args) {
    alert('Request failed. ' + args.get_message() +
    '\n' + args.get_stackTrace());
}

}

The browser loads the object but the collection seems to be empty. When i test this code on the success handler

function listSuccess() {
alert(listItemCollection.get_itemCount());
}

This will return the expected number of items. But when I try this code

firstItem = listItemCollection.getById(1);

This will run the error handler callback Finally, when I iterate using the enumerator

alert(itemEnumerator.moveNext());

It will display a false meaning there are no items on the loaded collection. When I replace it with local app web list items and not host web list items, I can access them without any issues. One more thing, the program is located in App testing list for a development site so the url contains some random codes like https://{myhostname}-{randomcodehere}.sharepoint.com/sites/bm while the list items I am trying to access is located on the https://{myhostname}.sharepoint.com/sites/bm.

Answer 1

You should use var hostUrl = GetUrlKeyValue("SPHostUrl"); to get your host web url. _spPageContextInfo.siteAbsoluteUrl will give you the url of the app web not hostweb.

Answer 2

hi try using iteration in success also check for AppManifest.xml add a READ permission for list and Web

var listItemEnumerator = listItemCollection.getEnumerator();

while (listItemEnumerator.moveNext()) {
    var oListItem = listItemEnumerator.get_current();
    listItemInfo += '\nID: ' + oListItem.get_id() + 
        '\nTitle: ' + oListItem.get_item('Title') + 
        '\nBody: ' + oListItem.get_item('Body');
}