ASP.NET Core API部署AWS后客户端PATCH请求返回405错误

问题背景 #

部署在AWS Fargate的Amazon ECS上的ASP.NET Core Web API，通过Postman测试PATCH请求可正常运行，但客户端实现相同请求后返回StatusCode: 405, ReasonPhrase: 'Method Not Allowed'，响应头显示允许的方法仅为GET、PUT。

客户端代码 #

public async Task<ActionResult> Patch(int companyId, string description)
{
    JsonPatchDocument<CompanyInfo> patchDoc = new JsonPatchDocument<CompanyInfo>();
    patchDoc.Replace(e => e.Description, description);

    var jsonSerializeObject = JsonConvert.SerializeObject(patchDoc);
    Debug.WriteLine(jsonSerializeObject);

    var method = new HttpMethod("PATCH");
    var request = new HttpRequestMessage(method, "api/CompanyInfo/" + companyId)
    {
        Content = new StringContent(jsonSerializeObject, Encoding.Unicode, "application/json")
    };

    response = await _httpClient.SendAsync(request);
    Debug.WriteLine(response);

    return RedirectToAction(nameof(Index));
}

响应信息 #

StatusCode: 405, ReasonPhrase: 'Method Not Allowed', Version: 1.1, Content: System.Net.Http.HttpConnectionResponseContent, Headers:
{
  Date: Sat, 26 Nov 2022 06:06:08 GMT
  Connection: keep-alive
  Server: Kestrel
  Content-Length: 0
  Allow: GET, PUT
}

Postman验证可用的JSON Patch文档 #

[
    {
        "value":"some text value",
        "path":"/Description",
        "op":"replace"
    }
]

API代码 #

[HttpPatch]
public async Task<ActionResult> PartiallyUpdateCompanyInfo(int companyId, JsonPatchDocument<CompanyInfoForPatchDto> patchDocument)
{
    var companyEntity = await _moviePlanetRepository.GetCompanyById(companyId, false);
    if (companyEntity == null)
    {
        return NotFound();
    }

    var companyToPatch = _mapper.Map<CompanyInfoForPatchDto>(companyEntity);

    patchDocument.ApplyTo(companyToPatch, ModelState);

    if (!ModelState.IsValid)
    {
        return BadRequest(ModelState);
    }

    if (!TryValidateModel(companyToPatch))
    {
        return BadRequest(ModelState);
    }

    _mapper.Map(companyToPatch, companyEntity);
    await _moviePlanetRepository.Save();

    return NoContent();
}

原因分析 #

• 路由未明确匹配：API的[HttpPatch]未指定具体路由模板，若控制器路由前缀为api/CompanyInfo，方法需显式绑定{companyId}参数才能匹配客户端请求的api/CompanyInfo/{companyId}路径。
• DTO类型不匹配：客户端使用JsonPatchDocument<CompanyInfo>生成请求内容，而API接收的是JsonPatchDocument<CompanyInfoForPatchDto>，序列化后的字段结构可能存在差异，导致请求无法命中目标方法。
• 请求编码不一致：客户端使用Encoding.Unicode（UTF-16）发送请求，Postman默认使用UTF-8，部分服务器配置对编码敏感，可能导致请求解析失败，触发405错误。

解决方法 #

1. 修正API路由配置 #

确保控制器有正确的路由前缀，且HttpPatch方法明确指定路由参数：

[Route("api/[controller]")]
[ApiController]
public class CompanyInfoController : ControllerBase
{
    [HttpPatch("{companyId}")] // 绑定companyId参数到路由
    public async Task<ActionResult> PartiallyUpdateCompanyInfo(int companyId, JsonPatchDocument<CompanyInfoForPatchDto> patchDocument)
    {
        // 原有业务逻辑
    }
}

2. 统一DTO类型 #

客户端使用与API一致的CompanyInfoForPatchDto创建JsonPatchDocument，避免类型差异：

// 客户端代码修改
JsonPatchDocument<CompanyInfoForPatchDto> patchDoc = new JsonPatchDocument<CompanyInfoForPatchDto>();
patchDoc.Replace(e => e.Description, description);

3. 调整请求编码为UTF-8 #

将客户端请求编码改为UTF-8，与Postman保持一致：

Content = new StringContent(jsonSerializeObject, Encoding.UTF8, "application/json")

4. 验证请求URL正确性 #

确认客户端请求URL与Postman完全一致，检查是否存在拼写错误、前缀缺失等问题。

内容的提问来源于stack exchange，提问作者khaira777