.NET MAUI中如何处理API返回的ProblemDetails响应

背景 #

我基于微软的.NET MAUI参考应用开发项目，其中的RequestProvider服务提供了与API交互的PutAsync方法，但该方法仅能返回泛型TResult类型。当API返回验证或其他错误时，会返回ProblemDetails格式的响应，我已经定义了ProblemDetailsWithErrors类来接收这类错误信息，现在需要修改PutAsync方法，使其能在出错时返回错误信息，成功时返回目标对象。

现有PutAsync方法代码 #

public async Task<TResult> PutAsync<TResult>(string uri, TResult data, string token = "", string header = "")
{
    HttpClient httpClient = GetOrCreateHttpClient(token);

    if (!string.IsNullOrEmpty(header))
    {
        RequestProvider.AddHeaderParameter(httpClient, header);
    }

    var content = new StringContent(JsonSerializer.Serialize(data));
    content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
    HttpResponseMessage response = await httpClient.PutAsync(uri, content).ConfigureAwait(false);

    await RequestProvider.HandleResponse(response).ConfigureAwait(false);
    TResult result = await response.Content.ReadFromJsonAsync<TResult>();

    return result;
}

修改方案一：返回包含结果和错误的包装类 #

1. 定义通用响应包装类 #

创建泛型类同时承载成功结果与错误信息：

public class ApiResponse<TResult>
{
    public TResult SuccessResult { get; set; }
    public ProblemDetailsWithErrors ErrorResult { get; set; }
    public bool IsSuccess => ErrorResult == null;
}

2. 修改PutAsync方法 #

调整返回类型为ApiResponse<TResult>，根据响应结果序列化对应对象：

public async Task<ApiResponse<TResult>> PutAsync<TResult>(string uri, TResult data, string token = "", string header = "")
{
    HttpClient httpClient = GetOrCreateHttpClient(token);

    if (!string.IsNullOrEmpty(header))
    {
        RequestProvider.AddHeaderParameter(httpClient, header);
    }

    var content = new StringContent(JsonSerializer.Serialize(data));
    content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
    HttpResponseMessage response = await httpClient.PutAsync(uri, content).ConfigureAwait(false);

    try
    {
        await RequestProvider.HandleResponse(response).ConfigureAwait(false);
        var successResult = await response.Content.ReadFromJsonAsync<TResult>();
        return new ApiResponse<TResult> { SuccessResult = successResult };
    }
    catch (Exception)
    {
        var errorResult = await response.Content.ReadFromJsonAsync<ProblemDetailsWithErrors>();
        return new ApiResponse<TResult> { ErrorResult = errorResult };
    }
}

3. 调用修改后的方法 #

通过IsSuccess区分场景，分别处理结果：

var apiResponse = await _requestProvider.PutAsync(uri, profile, authToken);
if (apiResponse.IsSuccess)
{
    var updatedProfile = apiResponse.SuccessResult;
    // 执行成功逻辑
}
else
{
    var errorDetails = apiResponse.ErrorResult;
    // 弹出错误提示，如显示errorDetails.Detail或errorDetails.Title
}

修改方案二：使用Try模式（返回布尔值+输出参数） #

如果不想新增包装类，可采用Try模式：

public async Task<bool> TryPutAsync<TResult>(string uri, TResult data, out TResult successResult, out ProblemDetailsWithErrors errorResult, string token = "", string header = "")
{
    successResult = default;
    errorResult = default;
    HttpClient httpClient = GetOrCreateHttpClient(token);

    if (!string.IsNullOrEmpty(header))
    {
        RequestProvider.AddHeaderParameter(httpClient, header);
    }

    var content = new StringContent(JsonSerializer.Serialize(data));
    content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
    HttpResponseMessage response = await httpClient.PutAsync(uri, content).ConfigureAwait(false);

    try
    {
        await RequestProvider.HandleResponse(response).ConfigureAwait(false);
        successResult = await response.Content.ReadFromJsonAsync<TResult>();
        return true;
    }
    catch (Exception)
    {
        errorResult = await response.Content.ReadFromJsonAsync<ProblemDetailsWithErrors>();
        return false;
    }
}

调用方式：

bool isSuccess = await _requestProvider.TryPutAsync(uri, profile, out var updatedProfile, out var errorDetails, authToken);
if (isSuccess)
{
    // 处理成功逻辑
}
else
{
    // 处理错误提示
}

注意事项 #

• 原RequestProvider.HandleResponse方法通常会在响应状态码非2xx时抛出异常，因此通过捕获异常来序列化错误响应；如果该方法返回布尔值而非抛出异常，可直接用条件判断替代try-catch。
• 确保ProblemDetailsWithErrors的属性名与API返回的ProblemDetails JSON字段完全匹配，避免序列化失败。

内容的提问来源于stack exchange，提问作者BryanCass