Access Host Web list inside SharePoint hosted app

Question

I have SharePoint hosted app Now I need to get host web list data inside my hosted app. Is it possible to get data from host web? Suggest some help

Answer 1

Yes. It is possible.

The sample code given below will read data from Blog list from host web and display data in your app.

<script type="text/javascript">
        // Set the style of the client web part page to be consistent with the host web.
        (function () {
            'use strict';
            var hostUrl = '';
            if (document.URL.indexOf('?') != -1) {
                var params = document.URL.split('?')[1].split('&');
                for (var i = 0; i < params.length; i++) {
                    var p = decodeURIComponent(params[i]);
                    if (/^SPHostUrl=/i.test(p)) {
                        hostUrl = p.split('=')[1];
                        document.write('<link rel="stylesheet" href="' + hostUrl + '/_layouts/15/defaultcss.ashx" />');
                        break;
                    }
                }
            }
            if (hostUrl == '') {
                document.write('<link rel="stylesheet" href="/_layouts/15/1033/styles/themable/corev15.css" />');
            }
        })();
    </script>


    <script type="text/javascript">
        var hostweburl;
        var appweburl;
        // Load the required SharePoint libraries
        $(document).ready(function () {
            //Get the URI decoded URLs.
            hostweburl =
                decodeURIComponent(
                    getQueryStringParameter("SPHostUrl")
            );
            appweburl =
                decodeURIComponent(
                    getQueryStringParameter("SPAppWebUrl")
            );
            // resources are in URLs in the form:
            // web_url/_layouts/15/resource
            var scriptbase = hostweburl + "/_layouts/15/";
            // Load the js files and continue to the successHandler
            $.getScript(scriptbase + "SP.RequestExecutor.js", execCrossDomainRequest);
        });
        // Function to prepare and issue the request to get
        //  SharePoint data
        function execCrossDomainRequest() {
            // executor: The RequestExecutor object
            // Initialize the RequestExecutor with the app web URL.
            var executor = new SP.RequestExecutor(appweburl);
            // Issue the call against the app web.
            // To get the title using REST we can hit the endpoint:
            //      appweburl/_api/web/lists/getbytitle('listname')/items
            // The response formats the data in the JSON format.
            // The functions successHandler and errorHandler attend the
            //      sucess and error events respectively.
            executor.executeAsync(
                {
                    url: appweburl + "/_api/SP.AppContextSite(@target)/web/lists/getbytitle('Posts')/items?@target='" + hostweburl + "/blog'&$top=1",
                    method: "GET",
                    headers: { "Accept": "application/json; odata=verbose" },
                    success: successHandler,
                    error: errorHandler
                }
            );
        }
        // Function to handle the success event.
        // Prints the data to the page.
        function successHandler(data) {
            var jsonObject = JSON.parse(data.body);
            var blogsHTML = "";
            var results = jsonObject.d.results;
            for (var i = 0; i < results.length; i++) {
                blogsHTML = blogsHTML + "<div><a href=\"" + hostweburl + "/blog/Lists/Posts/Post.aspx?ID=" + results[i].ID + "\" target=\"_blank\">" + results[i].Title + "</a></div><br>";
            }
            $('#internal').append(blogsHTML);
        }
        // Function to handle the error event.
        // Prints the error message to the page.
        function errorHandler(data, errorCode, errorMessage) {
            document.getElementById("internal").innerText =
                "Could not complete cross-domain call: " + errorMessage;
        }
        // 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];
            }
        }
    </script>

You can find detail description about the code SharePoint Hosted App to access list data in your Host Web

Also there is another good blog on this Access SharePoint 2013 data from add-ins using the cross-domain library

Also Get Host Web List data in SharePoint-Hosted App

I have already implemented this code so I am confident about this code.