在 C# 中，使用贷款模式、TryAsync 和 RestClient.ExecuteAsync()，如何让系统等待第二次标注的结果？

Question

我目前正在重构一个使用 RestSharp 的 RestClient 调用 Personio 的微服务，以便使用最新版本的 RestSharp (v107)，以及使用 ExecuteAsync 而不是 Execute。

我有以下方法：

    [SuppressMessage("Style", "IDE0053:Use expression body for lambda expressions", Justification = "lambda leave Match ambiguous.")]
    public TryAsync<T> WithAuthorization<T>(Func<Token, Task<T>> doSomething, CancellationToken cancellationToken) =>
        TryAsync(async () =>
        {
            T? result = default;
            Exception? resultException = null;
            TryAsync<Token> authorizationAttempt = TryAuthorize(cancellationToken);
            _ = await apply(token => doSomething(token), authorizationAttempt)
                .Match(
                    Succ: async dataTask =>
                    {
                        result = await dataTask;
                    },
                    Fail: exception =>
                    {
                        resultException = exception;
                    }
                )
                .ConfigureAwait(false);

            // FIXME:  Does not wait!!!!

            return result
                ?? ((resultException == null)
                    ? throw new PersonioRequestException("Could not get data from Personio: Reason unknown.")
                    : throw new PersonioRequestException($"Could not get data from Personio: {resultException.Message}", resultException)
                );
        });

如上面的代码所示，该方法在返回结果之前不会等待，或者碰巧抛出原因未知的异常。

使用调试器，我已经能够确定authorizationAttempt 获得了一个值并调用了doSomething()，但是在等待响应时，抛出了错误。

使用上述方法，为doSomething()提供函数的代码是这样的：

public TryAsync<RequestResponse<T>> TryGet<T>(RequestOptions options, CancellationToken cancellationToken) =>
        _authorizationClient.WithAuthorization<RequestResponse<T>>(
            async token =>
                {
                    UriBuilder urlBuilder = new(_personioConfig.BaseUrl.AppendPathSegment(options.Endpoint))
                    {
                        // This is used to add parameters which are used for filtering and may be unique for the record type, such as "updated_from".
                        Query = options.QueryParameters.ToString()
                    };

                    RestRequest request = new(urlBuilder.Uri, Method.Get);
                    request.Timeout = -1;
                    if (options.Pagination.IsActive)
                    {
                        request = request.AddQueryParameters(options.Pagination);
                    }

                    request = request
                        .AddHeader("Accept", "application/json")
                        .AddHeader("Authorization", $"Bearer {token.Value}");

                    return await GetRecords<T>(request, cancellationToken);
                },
                cancellationToken
            );

    private async Task<RequestResponse<T>> GetRecords<T>(RestRequest request, CancellationToken cancellationToken)
    {
        RestResponse<RequestResponse<T>> requestResponse = await _restClient.ExecuteAsync<RequestResponse<T>>(request, cancellationToken);

        // FIXME: The next line is never executed.

        RequestResponse<T>? dataResponse = JsonConvert.DeserializeObject<RequestResponse<T>>(requestResponse?.Content ?? "");
        return (requestResponse?.IsSuccessful ?? false)
            ? (dataResponse != null && dataResponse.WasSuccessful)
                ? dataResponse
                : throw new PersonioRequestException("Connected to Personio, but could not get records.")
            : throw (
                (requestResponse?.ErrorException != null)
                    ? new("Could not get records from Personio.", requestResponse.ErrorException)
                    : new($"Could not get records from Personio. {dataResponse?.Error?.Message ?? UnknownProblem}."));
    }

如上面的代码所示，方法 GetRecords() 被调用，但在 ExecuteAsync() 有任何结果之前，result（回到上面的第一个方法）未填充，系统会抛出一个错误。

代码的早期形式，带有早期版本的 RestSharp(v106) 和同步执行工作正常。当时的TryGet是这样的：

    public TryAsync<RequestResponse<T>> TryGet<T>(RequestOptions options) =>
        _authorizationClient.WithAuthorization<RequestResponse<T>>(token =>
        {
            UriBuilder urlBuilder = new(_personioConfig.BaseUrl.AppendPathSegment(options.Endpoint))
            {
                // This is used to add parameters which are used for filtering and may be unique for the record type, such as "updated_from".
                Query = options.QueryParameters.ToString()
            };
            _restClient.BaseUrl = urlBuilder.Uri;
            _restClient.Timeout = -1;

            IRestRequest request = new RestRequest(Method.GET);
            if (options.Pagination.IsActive)
            {
                request = request.AddQueryParameters(options.Pagination);
            }

            request = request
                .AddHeader("Accept", "application/json")
                .AddHeader("Authorization", $"Bearer {token.Value}");

            return Task.FromResult(GetRecords<T>(request));
        });

    private RequestResponse<T> GetRecords<T>(IRestRequest request)
    {
        IRestResponse<RequestResponse<T>> requestResponse = _restClient.Execute<RequestResponse<T>>(request);
        RequestResponse<T>? dataResponse = JsonConvert.DeserializeObject<RequestResponse<T>>(requestResponse.Content);
        return requestResponse.IsSuccessful
            ? (dataResponse != null && dataResponse.WasSuccessful)
                ? dataResponse
                : throw new PersonioRequestException("Connected to Personio, but could not get records.")
            : throw (
                (requestResponse.ErrorException != null)
                    ? new("Could not get records from Personio.", requestResponse.ErrorException)
                    : new($"Could not get records from Personio. {dataResponse?.Error?.Message ?? UnknownProblem}."));
    }

我做错了什么或错过了什么？ 如何使用 RestSharp 107.x 和 ExecuteAsync() 完成这项工作？

Answer 1

感谢@AlexeyZimarev，我能够让 TryGet() 方法正常工作。

现在看起来像：

    public TryAsync<RequestResponse<T>> TryGet<T>(RequestOptions options, CancellationToken cancellationToken) =>
        TryAsync(async () =>
        {
            _restClient.Authenticator = _authorizationClient;
            Uri uri = new UriBuilder(_personioConfig.BaseUrl.AppendPathSegment(options.Endpoint)).Uri;
            RestRequest request = new RestRequest(uri, Method.Get)
               .AddQueryParameters(options.QueryParameters);

            if (options.Pagination.IsActive)
            {
                request = request.AddQueryParameters(options.Pagination);
            }

            request.Timeout = -1;
            return await GetRecords<T>(request, cancellationToken);
        });

_restClient.Authenticator = _authorizationClient; 行在这里不是很安全，因为它被分配在注入而不是 RestClient 上，将来可能会在其他地方使用，但我通过使客户端瞬态而不是单例来“解决”这个问题.

我还从 PersonioAuthorizationClient 中删除了所有 TryAsync，因为无论 AuthenticatorBase 正在做什么，它似乎都不能很好地发挥作用。