Question

I’m developing a Windows 8 application using HTML5. The application requires some user data to create a new event. The event has a title, description, date and time. I want to store this data in a text file in JSON format after the user has filled the form so that it can be visible the next time user opens the application.

I can find different methods of writing JSON objects to text file but I can’t find anything related to appending data at the end of the text file. Basically, I have one events.txt from which I read and display data and I want to append events to the same .txt after user adds an event.

My events.txt looks like this

[
        {
        "key": "event1",
        "title": "title1", 
        "description": "description1",
        "date": "<sample date>",
        "time": "<sample time>",
        "backgroundImage": "../images/logo.png"
        }
]

I’m reading the events from this file using the following code

WinJS.xhr({ url: "../data/events.txt" }).then(function (xhr) {
        var events = JSON.parse(xhr.responseText);

        events.forEach(function (feed) {
            event.push({
                group: feed,
                key: feed.key,
                title: feed.title,
                description: feed.description,
                date: feed.date,
                time: feed.time,
                backgroundImage: feed.backgroundImage
            });
        });
    });

Any kind of help will be greatly appreciated as I’m running tight on a deadline here.

Thanks.

Answer 1

Are you looking for this File Access sample for Consumer Preview?

If I understood your question correctly, I think here are some important API that you want to use.

// Create a file
var eventFile;
Windows.Storage.KnownFolders.documentsLibrary.createFileAsync("event.txt", Windows.Storage.CreationCollisionOption.openIfExists).done(function (file) {
        eventFile = file;
    });

// Write Text to a file
Windows.Storage.FileIO.writeTextAsync(eventFile, JSON.stringify(yourJSONObject));

// Append Text to a file
Windows.Storage.FileIO.appendTextAsync(eventFile, JSON.stringify(yourJSONObject));

More reference to FileIO API:
http://msdn.microsoft.com/en-us/library/windows/apps/hh701440.aspx

In addition, why don’t you consider using local storage or indexedDB to store your event info?