从AWS-API网关发布到Lambda [英] Posting from AWS-API Gateway to Lambda

问题描述

我有一个简单的C#Aws Lambda函数，该函数可以通过Lambda控制台测试成功进行测试，但是如果从API网关(我是从Lambda触发选项生成的)中调用的，则失败并显示502(错误网关)使用邮递员.(此初始功能具有开放访问权限(无安全性))

I have a simple C# Aws Lambda function which succeeds to a test from the Lambda console test but fails with a 502 (Bad Gateway) if called from the API Gateway (which i generated from the Lambda trigger option) and also if I use postman.(this initial function has open access (no security))

// request header
    Content-Type: application/json

//  request body
    {
        "userid":22,
        "files":["File1","File2","File3","File4"]
    }

我在日志中得到的错误是:

The error I get in the logs is:

Wed Feb 08 14:14:54 UTC 2017 : Endpoint response body before transformations: {
  "errorType": "NullReferenceException",
  "errorMessage": "Object reference not set to an instance of an object.",
  "stackTrace": [
    "at blahblahmynamespace.Function.FunctionHandler(ZipRequest input, ILambdaContext context)",
    "at lambda_method(Closure , Stream , Stream , ContextInfo )"
  ]
}

似乎发布的对象没有传递给lambda输入参数.

It seems like the posted object is not being passed to the lambda input argument.

下面的代码

// Lambda function
     public LambdaResponse FunctionHandler(ZipRequest input, ILambdaContext context)
        {
            try
            {
                var logger = context.Logger;
                var headers = new Dictionary<string, string>();

                if (input == null || input.files.Count == 0)
                {
                    logger.LogLine($"input was null");
                    headers.Add("testheader", "ohdear");
                    return new LambdaResponse { body = "fail", headers = headers, statusCode = HttpStatusCode.BadRequest };
                }
                else
                {
                    logger.LogLine($"recieved request from user{input?.userid}");
                    logger.LogLine($"recieved {input?.files?.Count} items to zip");
                    headers.Add("testheader", "yeah");
                    return new LambdaResponse { body = "hurrah", headers = headers, statusCode = HttpStatusCode.OK };
                }
            }
            catch (Exception ex)
            {
                throw ex;
            }
        }

//Lambda响应/ZipRequest类

//Lambda response/ZipRequest class

public class LambdaResponse
{

    public HttpStatusCode statusCode { get; set; }
    public Dictionary<string, string> headers { get; set; }
    public string body { get; set; }
}
public class ZipRequest
{
    public int userid { get; set; }
    public IList<string> files { get; set; }
}

推荐答案

在API Gateway中使用Lambda代理集成时，FunctionHandler的第一个参数不是POST的主体，而是另一个API Gateway创建的对象，我们称之为LambdaRequest.尝试对示例代码进行这些更改.添加:

When using Lambda Proxy Integration in API Gateway, the first parameter to your FunctionHandler is not the body of your POST, but is another API Gateway-created object, which let's call LambdaRequest. Try these changes to your sample code. Add:

public class LambdaRequest
{
   public string body { get; set; }
}

将处理程序原型更改为:

Change your handler prototype to:

public LambdaResponse FunctionHandler(LambdaRequest req, ILambdaContext context)

并在FunctionHandler内添加:

ZipRequest input = JsonConvert.DeserializeObject<ZipRequest>(req.Body);

完整的LambdaRequest对象记录在

The full LambdaRequest object is documented under Input Format of a Lambda Function for Proxy Integration in the AWS docs, and contains HTTP headers, the HTTP method, the query string, the body, and a few other things.

这篇关于从AWS-API网关发布到Lambda的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！