# .NET quickstart for customers

Follow the steps in this quickstart guide, and in about 10 minutes you have
a simple .NET C# console app that makes requests to the zero-touch enrollment
customer API.

## Prerequisites

To run this quickstart, you need:

- A Google account, that's a member of your zero-touch enrollment customer account. See [Customer
  accounts](https://developers.google.com/zero-touch/guides/customer/auth#customer_accounts).
- Visual Studio 2013 or later.
- Access to the internet and a web browser.

## Step 1: Turn on the zero-touch enrollment API

1. Use [this
   wizard](https://console.developers.google.com/start/api?id=androiddeviceprovisioning.googleapis.com) to create or select a project in the Google Developers Console and automatically turn on the API. Click **Continue** , then **Go to credentials**.
2. Click **Cancel** on the Create credentials.
3. At the top of the page, select the **OAuth consent screen** tab. Select an **Email address** , enter a **Product name** if not already set, and click the **Save** button.
4. Select the **Credentials** tab, click the **Create credentials** button and select **OAuth client ID**.
5. Select the application type **Other** , enter the name "Quickstart", and click the **Create** button.
6. Click **OK** to dismiss the *OAuth client* panel.
7. Click **Download JSON**.
8. Move the file to your working directory and rename it `client_secret.json`.

## Step 2: Prepare the project

1. Create a new .NET Core C# *Console Application* project in Visual Studio.
2. Open the Package Manager, select the package source **nuget.org** , and add the following packages:
   - `Google.Apis.AndroidProvisioningPartner.v1`
   - `Google.Apis.Auth`

To learn more, read the Microsoft document [Install and use a
package](https://docs.microsoft.com/en-us/nuget/quickstart/use-a-package).

## Step 3: Set up the sample

1. Drag `client_secret.json` (downloaded in Step 1) into your Visual Studio Solution Explorer.
2. Select `client_secret.json`, and then go to the Properties window and set **Copy to output directory** field to *Always copy*.
3. Replace the contents of `Program.cs` with the following code:

```c#
using Google.Apis.AndroidProvisioningPartner.v1;
using Google.Apis.AndroidProvisioningPartner.v1.Data;
using Google.Apis.Auth.OAuth2;
using Google.Apis.Services;
using Google.Apis.Util.Store;
using System;
using System.Collections.Generic;
using System.IO;
using System.Threading;

namespace ZeroTouchCustomerQuickstart
{
    class Program
    {
        // A single scope is used for the zero-touch enrollment customer API.
        static readonly string[] Scopes =
            { "https://www.googleapis.com/auth/androidworkzerotouchemm" };
        static string ApplicationName = "Zero-touch Enrollment .NET Quickstart";

        static void Main(string[] args)
        {
            UserCredential credential;

            // Ask the user to authorize the request using their Google Account
            // in their browser.
            using (var stream =
                new FileStream("client_secret.json", FileMode.Open, FileAccess.Read))
            {
                string credPath = System.Environment.GetFolderPath(
                    System.Environment.SpecialFolder.Personal);
                credPath = Path.Combine(credPath, ".credentials/zero-touch.quickstart.json");

                credential = GoogleWebAuthorizationBroker.AuthorizeAsync(
                    GoogleClientSecrets.FromStream(stream).Secrets,
                    Scopes,
                    "user",
                    CancellationToken.None,
                    new FileDataStore(credPath, true)).Result;
                Console.WriteLine("Credential file saved to: " + credPath);
            }

            // Create a zero-touch enrollment API service endpoint.
            var service = new AndroidProvisioningPartnerService(new BaseClientService.Initializer
            {
                HttpClientInitializer = credential,
                ApplicationName = ApplicationName
            });

            // Get the customer's account. Because a customer might have more
            // than one, limit the results to the first account found.
            CustomersResource.ListRequest accountRequest = service.Customers.List();
            accountRequest.PageSize = 1;
            CustomerListCustomersResponse accountResponse = accountRequest.Execute();
            if (accountResponse.Customers.Count == 0)
            {
                // No accounts found for the user. Confirm the Google Account
                // that authorizes the request can access the zero-touch portal.
                Console.WriteLine("No zero-touch enrollment account found.");
                Environment.Exit(-1);
            }
            Company customer = accountResponse.Customers[0];
            var customerAccount = String.Format("customers/{0}", customer.CompanyId);


            // Send an API request to list all the DPCs available.
            CustomersResource.DpcsResource.ListRequest request = service.Customers.Dpcs.
                List(customerAccount);
            CustomerListDpcsResponse response = request.Execute();

            // Print out the details of each DPC.
            IList<Dpc> dpcs = response.Dpcs;
            foreach (Dpc dpcApp in dpcs)
            {
                Console.WriteLine("Name:{0}  APK:{1}",
                                  dpcApp.DpcName,
                                  dpcApp.PackageName);
            }

        }
    }
}
```

## Step 4: Run the sample

To build and run the sample, click **Start** in the Visual Studio toolbar.

The first time you run the app, you need to authorize access:

1. The app tries to open a new tab in your default browser. If this fails, copy the URL from the console and open it in your browser. If you're not already logged into your Google Account, you're prompted to log in. If you're logged into multiple Google accounts, the page prompts you to select an account for the authorization.
2. Click **Accept**.
3. Close the browser tab---the app continues running.

## Notes

- Because Google API client library stores authorization data on the file system, subsequent launches don't prompt you for authorization.
- To reset the app's authorization data, delete the `~/.credentials/zero-touch.quickstart.json` file and run the app again.
- The authorization flow in this quickstart is ideal for a command-line app. To learn how to add authorization to a web app, see [Using OAuth 2.0, Web applications (ASP.NET MVC)](https://developers.google.com/api-client-library/dotnet/guide/aaa_oauth#web-applications-aspnet-mvc).

## Troubleshooting

Here are some common things you'll want to check.
[Tell us what went wrong]() with the quickstart and we'll work to fix it.

- Check that you're authorizing API calls with the same Google Account that's a member of your zero-touch enrollment customer account. Try signing in to the zero-touch enrollment [portal](https://enterprise.google.com/android/zero-touch/resellers) using the same Google Account to test your access.
- Confirm that the account has accepted the latest Terms of Service in the [portal](https://enterprise.google.com/android/zero-touch/resellers). See [Customer accounts](https://developers.google.com/zero-touch/guides/customer/auth#customer_accounts).

## Learn more

- [Google Developers Console help documentation](https://developers.google.com/console/help/new)
- [Google API Client Library for .NET
  documentation](https://developers.google.com/api-client-library/dotnet)