原始答案有效，但它不是为 ASP.NET Web 应用程序执行此操作的最佳方法。有关处理 ASP.NET Web 应用程序流的更好方法，请参阅下面的更新。
原答案
所以，我想通了。问题在于 Google 将 Web 应用程序视为基于 JavaScript 的 Web 应用程序，而不是具有服务器端处理功能的 Web 应用程序。因此，您不能在 Google Developer Console 中为基于服务器的 Web 应用程序创建 Web 应用程序 OAuth 客户端 ID。
解决方法是在Google Developer Console中创建OAuth Client ID时选择Other类型。这将使 Google 将其视为已安装的应用程序而不是 JavaScript 应用程序，因此不需要重定向 URI 来处理回调。
这有点令人困惑，因为 Google 的 .NET 文档告诉您创建 Web App OAuth 客户端 ID。
2018 年 2 月 16 日更新了更好的答案：
我想提供对此答案的更新。虽然，我上面所说的有效，但这并不是为 ASP.NET 解决方案实现 OAuth 工作流的最佳方式。有一种更好的方法可以实际使用适当的 OAuth 2.0 流程。 Google 的文档在这方面很糟糕（尤其是对于 .NET），所以我将在这里提供一个简单的实现示例。该示例使用 ASP.NET 核心，但它很容易适应完整的 .NET 框架:)
注意：Google 确实有一个 Google.Apis.Auth.MVC 包来帮助简化此 OAuth 2.0 流程，但不幸的是，它与特定的 MVC 实现耦合，不适用于 ASP.NET Core或 Web API。所以，我不会使用它。我将给出的示例适用于所有 ASP.NET 应用程序。相同的代码流可用于您启用的任何 Google API，因为它取决于您请求的范围。
另外，我假设您已在 Google 开发者仪表板中设置了您的应用程序。也就是说，您已经创建了一个应用程序，启用了必要的 YouTube API，创建了一个 Web 应用程序客户端，并正确设置了您允许的重定向 url。
流程将像这样工作：
- 用户点击按钮（例如添加 YouTube）
- View调用Controller上的方法获取授权URL
- 在控制器方法中，我们要求 Google 根据我们的客户端凭据（在 Google Developer Dashboard 中创建的凭据）向我们提供授权 URL，并向 Google 提供我们应用程序的重定向 URL（此重定向 URL 必须在您的您的 Google 应用程序接受的重定向 URL 列表）
- Google 将授权 URL 返还给我们
- 我们将用户重定向到该授权 URL
- 用户授予我们的应用程序访问权限
- Google 使用我们根据请求提供给 Google 的重定向 URL 向我们的应用程序返回一个特殊的访问代码
- 我们使用该访问代码为用户获取 Oauth 令牌
- 我们为用户保存 Oauth 令牌
您需要以下 NuGet 包
- Google.Apis
- Google.Apis.Auth
- Google.Apis.Core
- Google.apis.YouTube.v3
模型
public class ExampleModel
{
public bool UserHasYoutubeToken { get; set; }
}
控制者
public class ExampleController : Controller
{
// I'm assuming you have some sort of service that can read users from and update users to your database
private IUserService userService;
public ExampleController(IUserService userService)
{
this.userService = userService;
}
public async Task<IActionResult> Index()
{
var userId = // Get your user's ID however you get it
// I'm assuming you have some way of knowing if a user has an access token for YouTube or not
var userHasToken = this.userService.UserHasYoutubeToken(userId);
var model = new ExampleModel { UserHasYoutubeToken = userHasToken }
return View(model);
}
// This is a method we'll use to obtain the authorization code flow
private AuthorizationCodeFlow GetGoogleAuthorizationCodeFlow(params string[] scopes)
{
var clientIdPath = @"C:\Path\To\My\client_id.json";
using (var fileStream = new FileStream(clientIdPath, FileMode.Open, FileAccess.Read))
{
var clientSecrets = GoogleClientSecrets.Load(stream).Secrets;
var initializer = new GoogleAuthorizationCodeFlow.Initializer { ClientSecrets = clientSecrets, Scopes = scopes };
var googleAuthorizationCodeFlow = new GoogleAuthorizationCodeFlow(initializer);
return googleAuthorizationCodeFlow;
}
}
// This is a route that your View will call (we'll call it using JQuery)
[HttpPost]
public async Task<string> GetAuthorizationUrl()
{
// First, we need to build a redirect url that Google will use to redirect back to the application after the user grants access
var protocol = Request.IsHttps ? "https" : "http";
var redirectUrl = $"{protocol}://{Request.Host}/{Url.Action(nameof(this.GetYoutubeAuthenticationToken)).TrimStart('/')}";
// Next, let's define the scopes we'll be accessing. We are requesting YouTubeForceSsl so we can manage a user's YouTube account.
var scopes = new[] { YouTubeService.Scope.YoutubeForceSsl };
// Now, let's grab the AuthorizationCodeFlow that will generate a unique authorization URL to redirect our user to
var googleAuthorizationCodeFlow = this.GetGoogleAuthorizationCodeFlow(scopes);
var codeRequestUrl = googleAuthorizationCodeFlow.CreateAuthorizationCodeRequest(redirectUrl);
codeRequestUrl.ResponseType = "code";
// Build the url
var authorizationUrl = codeRequestUrl.Build();
// Give it back to our caller for the redirect
return authorizationUrl;
}
public async Task<IActionResult> GetYoutubeAuthenticationToken([FromQuery] string code)
{
if(string.IsNullOrEmpty(code))
{
/*
This means the user canceled and did not grant us access. In this case, there will be a query parameter
on the request URL called 'error' that will have the error message. You can handle this case however.
Here, we'll just not do anything, but you should write code to handle this case however your application
needs to.
*/
}
// The userId is the ID of the user as it relates to YOUR application (NOT their Youtube Id).
// This is the User ID that you assigned them whenever they signed up or however you uniquely identify people using your application
var userId = // Get your user's ID however you do (whether it's on a claim or you have it stored in session or somewhere else)
// We need to build the same redirect url again. Google uses this for validaiton I think...? Not sure what it's used for
// at this stage, I just know we need it :)
var protocol = Request.IsHttps ? "https" : "http";
var redirectUrl = $"{protocol}://{Request.Host}/{Url.Action(nameof(this.GetYoutubeAuthenticationToken)).TrimStart('/')}";
// Now, let's ask Youtube for our OAuth token that will let us do awesome things for the user
var scopes = new[] { YouTubeService.Scope.YoutubeForceSsl };
var googleAuthorizationCodeFlow = this.GetYoutubeAuthorizationCodeFlow(scopes);
var token = await googleAuthorizationCodeFlow.ExchangeCodeForTokenAsync(userId, code, redirectUrl, CancellationToken.None);
// Now, you need to store this token in rlation to your user. So, however you save your user data, just make sure you
// save the token for your user. This is the token you'll use to build up the UserCredentials needed to act on behalf
// of the user.
var tokenJson = JsonConvert.SerializeObject(token);
await this.userService.SaveUserToken(userId, tokenJson);
// Now that we've got access to the user's YouTube account, let's get back
// to our application :)
return RedirectToAction(nameof(this.Index));
}
}
观点
@using YourApplication.Controllers
@model YourApplication.Models.ExampleModel
<div>
@if(Model.UserHasYoutubeToken)
{
<p>YAY! We have access to your YouTube account!</p>
}
else
{
<button id="addYoutube">Add YouTube</button>
}
</div>
<script>
$(document).ready(function () {
var addYoutubeUrl = '@Url.Action(nameof(ExampleController.GetAuthorizationUrl))';
// When the user clicks the 'Add YouTube' button, we'll call the server
// to get the Authorization URL Google built for us, then redirect the
// user to it.
$('#addYoutube').click(function () {
$.post(addYoutubeUrl, function (result) {
if (result) {
window.location.href = result;
}
});
});
});
</script>