What is the App_Data folder used for in Visual Studio?

When creating a new ASP.NET application in Visual Studio, a couple of files and folders are created automatically. One of those folders is called App_Data.

Also when publishing a website by selecting the menu option Build->Publish a checkbox is available Include files from the App_Data folder.

Am I right assuming that the files put in this file and its sub-folders are not going to be accessible through the web? For example, would it be safe to put in that folder resources that I only intend to be used by the application code?

What is the real intended use of the App_Data folder?

EDIT:

Thank you for all the answers. From the answers received so far I am interested mostly in two points mentioned:

1. App_Data is essentially a storage point for file-based data store
2. It should not be viewable by the web and is a place for the web app to store and read data from

Would someone be able specify how the "not viewable by the web" is ensured? Can I rely on that fact when performing standard deployment, or do I need to check some IIS settings on the server as well.

In the situation when I have a set of pdf files that I want to be accessible only from the application. Would App_Data folder be the right place to use, or should I create a separate folder and manually set IIS to ensure that it is not accessible by Web?

App_Data is essentially a storage point for file-based data stores (as opposed to a SQL server database store for example). Some simple sites make use of it for content stored as XML for example, typically where hosting charges for a DB are expensive.

in IIS, highlight the machine, double-click "Request Filtering", open the "Hidden Segments" tab. "App_Data" is listed there as a restricted folder. Yes i know this thread is really old, but this is still applicable.

The intended use of App_data is to store application data for the web process to acess. It should not be viewable by the web and is a place for the web app to store and read data from.

It's a place to put an embedded database, such as Sql Server Express, Access, or SQLite.

The App_Data folder is a folder, which your asp.net worker process has files sytem rights too, but isn't published through the web server.

For example we use it to update a local CSV of a contact us form. If the preferred method of emails fails or any querying of the data source is required, the App_Data files are there.

It's not ideal, but it it's a good fall-back.

From the documentation about ASP.NET Web Project Folder Structure in MSDN:

> You can keep your Web project's files in any folder structure that is > convenient for your application. To make it easier to work with your > application, ASP.NET reserves certain file and folder names that you > can use for specific types of content. > > App_Data contains application data files including .mdf database files, XML files, and other data store files. The App_Data folder is > used by ASP.NET to store an application's local database, such as the > database for maintaining membership and role information. For more information, see http://msdn.microsoft.com/en-us/library/yh26yfzy(v=vs.100).aspx">Introduction to Membership and http://msdn.microsoft.com/en-us/library/5k850zwb(v=vs.100).aspx">Understanding Role Management.

The main intention is for keeping your application's database file(s) in.

And no this will not be accessable from the web by default.

We use it as a temporary storage area for uploaded csv files. Once uploaded, an ajax method processes and deletes the file.

The intended use for App_Data is to store database related file. Usually SQL Server Express .mdf files.