Fate of List Definitions in VS App for SharePoint Project

Question

I cannot seem to find any information on the behaviour of lists added to a VS "App for SharePoint" project.

The process of adding a custom list is quite similar to what you would do in SP Designer.

When adding a List to your project, there is even the option to Show/Hide that particular list in the "Quick Launch".

However, when I deploy my simple app to the SP server and access it, the list I defined in the project is nowhere to be found (or so it seems).

I therefore wonder what the expected behaviour is for this or how one should go about to deploy a custom app that makes use of one or more custom lists.

EDIT

This question seems related to this one (if not completely the same) so I was a bit to quick to duplicate it here. Nonetheless, as I now understand, lists added to a VS App project will only be available in the "App Web".

So that makes me wonder, what If I want to use my app to add information to a SP website such that it will also be available/persisted outside the App itself?

Taking the common example of a TODO list App for Sharepoint and instead of using a pre-existing "Tasks" list, I add my own version to my App project.

How can I make that custom list accessible outside my app, or is that never a good idea?

What happens if I make updates to my app and re-deploy it? Will all my data be lost?

Answer 1

Here are a few points of considerations

1. Apps are virtually a subsite complete with their site-settings and site-contents.
2. Data stored in a list in the appweb is not persistant over multiple deployments.
3. The hostweb and the appweb are virtually considered different domains.

---

what If I want to use my app to add information to a SP website such that it will also be available/persisted outside the App itself?

If you want to store persistant data, consider storing it in the host web -

You need to use SP.RequestExecutor.js to achive this. The typical structure of a function is something like the following.

    var url = appwebUrl +    
    "/_api/SP.AppContextSite(@target)/web/lists/getbytitle('"+listName+
    "')/items?$select=Title,ID&@target='" + hostUrl + "'";


    var scriptbase = hostUrl + "/_layouts/15/";
    $.getScript(scriptbase + "SP.RequestExecutor.js", function () {

        var url =  appwebUrl +
                  "/_api/SP.AppContextSite(@target)/web/lists/getbytitle('" + listName + "')/items?$select=Title,ID&@target='" + hostUrl + "'";


        var executor = new SP.RequestExecutor(appwebUrl);
        executor.executeAsync(
        {
            url:     url,
            method:  "POST",
            headers: { "Accept": "application/json; odata=verbose", "content-type": "application/json; odata=verbose"},
            success: function () {alert('success')},
            error:   function(){alert("error");
        }

How can I make that custom list accessible outside my app, or is that never a good idea?

AFAIK, there is no reason to do that, as you can always push updates to host web. In case you wanna display the app data in the hostweb consider implementing a Client Web Part

What happens if I make updates to my app and re-deploy it? Will all my data be lost?

All the data inside the appweb i.e. your app level lists and libraries, will be lost.