localStorage in OSX webview not persisting on page reload - Office365 Addin

Question

I have a problem with localStorage in a webview on OSX (El Capitan + Yosemite).

I'm making an Office365 app, which on mac uses a webview . It all works fine on Windows and even Safari on a Mac - it's just the Mac webview that's proving troublesome. It's on a hosted domain, so this isn't the problem.

As you can see from my test code below, I am saving the info to localStorage, then setting a variable with the value. This means it must have saved to localStorage at some point, but if I refresh the page, the data is lost. Note: Not all data in my app is lost, just some bits.

I'm not getting a QUOTA_EXCEEDED_ERR on save.

Here is my test code that fails on refresh.

$scope.initTest = function () {

    $scope.errorsRecorded += "************** Initialize **************";

    var notNested = localStorage.getItem('lclNotNested');
    if (!notNested) {
        $scope.errorsRecorded += "*_*__NOT NESTED NOT SAVED";
        $scope.notNested = "NOTSET";
    } else {
        $scope.errorsRecorded += "*_*__NOT NESTED ___ val=" + notNested + ';';
        $scope.notNested = JSON.parse(notNested);
    }
};
$scope.initTest();


// Button press event

$scope.setSingle = function () {
    // Set the value to localStorage, then get it back for the UI
    // so we know the value was set.
    try {
        localStorage.setItem('lclNotNested', JSON.stringify(Date.now()));
    } catch (e) {
        $scope.errorsRecorded = $scope.errorsRecorded + '.....<br/>\r\n ' + e;
    }

    $scope.notNested = JSON.parse(localStorage.getItem('lclNotNested'));
};

Here are some screenshots of the values setting correctly and then failing to load.

I've spent hours trying to figure it out and can't find a way to debug it. I don't have access to the underlying webview code, it's just a web app on top of what Microsoft provides.

Does anyone know what is going on, or how I might be able to debug it please (eg view a localStorage file for a webview on a mac)?

Answer 1

Debated deleting the question, but this is bound to catch someone else out...

After a whole load of head scratching and creating this jsfiddle to try in the app, it seems that Office 365 apps don't currently persist localStorage as expected in a webview on OSX.

My confusion over the partial persistence was that some information was being saved to the document. Other (less important) information was being saved to localStorage only and so was not persisting.

The answer in my case was - if you want persistence over page reload or save and reopen for an Office 365 app - save to the document. Don't rely on localStorage for anything.

Code for jsfiddle:

<script>


        function deletMany() {

            var getManyNumber = parseInt(document.getElementById('setManyNumber').value);

            for (var i = 0; i < getManyNumber; i++) {
                try {
                    localStorage.removeItem('many' + i);
                } catch (e) {                   
                }
            }

            getMany();
        }

        function getMany() {
            var outputText = '';

            var getManyNumber = parseInt(document.getElementById('setManyNumber').value);


            for (var i = 0; i < getManyNumber; i++) {
                try {
                    var ot = localStorage.getItem('many' + i);

                    outputText += (ot) ? ot + '_' : i + " - no set <br/>";
                } catch (e) {
                    outputText += '|||' + i + '-' + e;
                }
            }

            var elm = document.getElementById('results');
            elm.innerHTML = outputText;
        }

        function setMany() {

            var getManyNumber = parseInt(document.getElementById('setManyNumber').value);

            for (var i = 0; i < getManyNumber; i++) {
                localStorage.setItem('many' + i, "MANY" + i);
            }
        }


        //---------

        function deleteFewWithLots() {

            var getLotsNumber = parseInt(document.getElementById('setLotsNumber').value);

            for (var i = 0; i < getLotsNumber; i++) {
                try {
                    localStorage.removeItem('few' + i);
                } catch (e) {

                }
            }

            getFewWithLots();

        }

        function getFewWithLots() {
            var outputText = '';

            var getLotsNumber = parseInt(document.getElementById('setLotsNumber').value);

            for (var i = 0; i < getLotsNumber; i++) {
                try {
                    var ot = localStorage.getItem('few' + i);

                    outputText += (ot) ? i + ':' + ot + '_' : i + " - no set <br/> \r\n___";
                } catch (e) {
                    outputText += '|||' + i + '-' + e;
                }
            }

            var elm = document.getElementById('results');
            elm.innerHTML = outputText;
        }

        function setFewWithLots() {

            var getLotsNumber = parseInt(document.getElementById('setLotsNumber').value);

            for (var i = 0; i < getLotsNumber; i++) {
                localStorage.setItem('few' + i, "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum. Section 1.10.32 of de Finibus Bonorum et Malorum, written by Cicero in 45 BC. Sed ut perspiciatis unde omnis iste natus error sit voluptatem accusantium doloremque laudantium, totam rem aperiam, eaque ipsa quae ab illo inventore veritatis et quasi architecto beatae vitae dicta sunt explicabo. Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit, sed quia non numquam eius modi tempora incidunt ut labore et dolore magnam aliquam quaerat voluptatem. Ut enim ad minima veniam, quis nostrum exercitationem ullam corporis suscipit laboriosam, nisi ut aliquid ex ea commodi consequatur? Quis autem vel eum iure reprehenderit qui in ea voluptate velit esse quam nihil molestiae consequatur, vel illum qui dolorem eum fugiat quo voluptas nulla pariatur? 1914 translation by H. Rackham. But I must explain to you how all this mistaken idea of denouncing pleasure and praising pain was born and I will give you a complete account of the system, and expound the actual teachings of the great explorer of the truth, the master-builder of human happiness. No one rejects, dislikes, or avoids pleasure itself, because it is pleasure, but because those who do not know how to pursue pleasure rationally encounter consequences that are extremely painful. Nor again is there anyone who loves or pursues or desires to obtain pain of itself, because it is pain, but because occasionally circumstances occur in which toil and pain can procure him some great pleasure. To take a trivial example, which of us ever undertakes laborious physical exercise, except to obtain some advantage from it? But who has any right to find fault with a man who chooses to enjoy a pleasure that has no annoying consequences, or one who avoids a pain that produces no resultant pleasure?" + i + '______________________________________________________________________ __________________________________________ ____________________________');
            }
        }


    </script>


<body>

    <hr />
    <button onclick="deletMany()">Delete Many</button>  
    <button onclick="getMany()">Get Many</button>
    <input id="setManyNumber" type="number" value="1" style="width:75px;" />
    <button onclick="setMany()">Set Many</button>
    <button onclick="deleteFewWithLots()">Delete Few Items With Lots</button>
    <button onclick="getFewWithLots()">Get Few Items With Lots</button>
    <input id="setLotsNumber" type="number" value="1" style="width:75px;" />
    <button onclick="setFewWithLots()">Set Few Items With Lots</button>
    <hr />
    <div style="background-color:aqua; word-break:break-all; width:500px;margin-left:100px; position: absolute; z-index: 10000;">
        <div id="results"></div>
    </div>

</body>