ASP.NET Core 6中调用GraphQL API查询运单返回BadRequest求助

问题描述 #

在ASP.NET Core 6中调用GraphQL API获取运单详情时，提交运单ID（如101010）后收到BadRequest错误。期望获取的运单字段包括id、code、customerDue、timeFrom、timeTo、latitude、longitude、collected、paidToCustomer。以下是相关代码，请求协助排查解决。

控制器代码 #

public IActionResult shipment()
{
    return View();
}

[HttpPost]
public async Task<IActionResult> shipment(int shipmentId)
{
    try
    {
        var query = @"            query {
                shipment(id: " + shipmentId + @") {
                    id
                    code
                    customerDue
                    timeFrom
                    timeTo
                    latitude
                    longitude
                    collected
                    paidToCustomer
                }
            }
        ";

        var request = new HttpRequestMessage(HttpMethod.Post, "http://accuratess.holol-aldiar.com.sa:8000/graphql");
        request.Content = new StringContent(query, System.Text.Encoding.UTF8, "application/json");

        var response = await _httpClient.SendAsync(request);

        if (response.IsSuccessStatusCode)
        {
            var result = await response.Content.ReadAsStringAsync();
            var shipmentResponse = JsonConvert.DeserializeObject<Shipment>(result);

            return View(shipmentResponse);
        }
        else
        {
            throw new Exception("Failed to retrieve shipment details. Status code: " + response.StatusCode);
        }
    }
    catch (Exception ex)
    {
        // Handle the exception
        return StatusCode(500, ex.Message);
    }

    return View("shipment");
}

Shipment模型类代码 #

public class Shipment
{
    public int Id { get; set; }
    public string Code { get; set; }
    public DateTime CustomerDue { get; set; }
    public DateTime TimeFrom { get; set; }
    public DateTime TimeTo { get; set; }
    public double Latitude { get; set; }
    public double Longitude { get; set; }
    public bool Collected { get; set; }
    public decimal PaidToCustomer { get; set; }
}

视图代码 #

@model apiGraphQl.Models.Shipment

<form method="post" asp-action="shipment">
    <label for="shipmentId">Enter Shipment ID:</label>
    <input type="text" asp-for="Id" id="shipmentId" value="@Model" />

    <button type="submit">Get Shipment Details</button>
</form>

可能的错误原因及解决方法 #

• GraphQL请求格式错误
  GraphQL的POST请求要求内容是包含query字段的JSON对象，而非纯查询字符串。当前代码直接发送查询字符串，不符合API要求。修改请求内容构造逻辑：

  var query = @"query {
      shipment(id: " + shipmentId + @") {
          id
          code
          customerDue
          timeFrom
          timeTo
          latitude
          longitude
          collected
          paidToCustomer
      }
  }";
  var requestBody = new { query = query };
  var jsonContent = JsonConvert.SerializeObject(requestBody);
  request.Content = new StringContent(jsonContent, System.Text.Encoding.UTF8, "application/json");
  

• 运单ID参数类型不匹配
  如果GraphQL API要求id参数为字符串类型，需给shipmentId添加引号：

  var query = @"query {
      shipment(id: """ + shipmentId + @""") {
          id
          code
          customerDue
          timeFrom
          timeTo
          latitude
          longitude
          collected
          paidToCustomer
      }
  }";
  

• 视图模型绑定问题
  视图中value="@Model"会输出整个Shipment对象的ToString结果，导致提交的ID格式错误。同时初始GET请求未传入模型，会导致Model为null，修改如下：

  <input type="text" asp-for="Id" id="shipmentId" value="@(Model?.Id ?? 0)" />
  

  并更新GET方法：

  public IActionResult shipment()
  {
      return View(new Shipment());
  }
  

• JSON反序列化结构不匹配
  GraphQL返回结果通常包含data嵌套字段，需创建对应包装类适配：

  public class ShipmentResponse
  {
      public ShipmentData Data { get; set; }
  }
  
  public class ShipmentData
  {
      public Shipment Shipment { get; set; }
  }
  

  然后修改反序列化代码：

  var shipmentResponse = JsonConvert.DeserializeObject<ShipmentResponse>(result);
  return View(shipmentResponse.Data.Shipment);
  

内容的提问来源于stack exchange，提问作者عالم ديم