Question 18773 in Amazon Web Sevices Question posted in
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.net core How to get AWS lambda mock tool to parse json array – Amazon Web Sevices

I am converting several .NET Core 6 web services to AWS Lambda functions. I have completed eight so far with no issues, except for this one. I am trying to test it from Visual Studio using the mock lambda tool. This is my mock json request:

{
  "body": "{"PolicyNumbers":[{"Number":"WCU9799P"},{"Number":"B1V48603"}],"RenewalEffectiveDate":"09/28/2016","State":""}",
  "resource": "/{proxy+}",
  "path": "api/GetClaimsCount",
  "httpMethod": "POST",
  "headers": {
    "Accept": "application/json",
    "Accept-Encoding": "gzip, deflate, sdch",
    "Accept-Language": "en-US,en;q=0.8"
    }
}

Before the debugger hits the first line of my function handler, I get a long error that begins with:

System.Exception: Error deserializing the input JSON to type String
at Amazon.Lambda.TestTool.Runtime.LambdaExecutor.BuildParameters(ExecutionRequest request, ILambdaContext context) in …

And here is the beginning of my function handler. I use this same code on the other lambdas and it works fine. I think this has something to do with the array part of this json. If I am right, then how do I format my request to accept json arrays?

 public Task<APIGatewayHttpApiV2ProxyResponse> FunctionHandler(string input, ILambdaContext context)
    {
        string? message = "";
        string inputString = (input != null) ? JsonSerializer.Serialize(input) : 
string.Empty;
        _log.Debug("Request:" + inputString);
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2

Answers


  1. Chosen as BEST ANSWER
    0

    I found the issue. I need to change the first parameter in the Function Handler to "ApiGatewayRequest.Root input" since the request is coming through the API Gateway:

     public Task<APIGatewayHttpApiV2ProxyResponse> FunctionHandler(ApiGatewayRequest.Root input, ILambdaContext context)
    {
        string? message = "";
        string inputString = (input != null) ? JsonSerializer.Serialize(input) : 
    string.Empty;
    _log.Debug("Request:" + inputString);

  2. 0

    It appears there is a closing brace missing

    {
  "body": "{"PolicyNumbers":[{"Number":"WCU9799P"},{"Number":"B1V48603"}],"RenewalEffectiveDate":"09/28/2016","State":""}",
  "resource": "/{proxy+}",
  "path": "api/GetClaimsCount",
  "httpMethod": "POST",
  "headers": {
    "Accept": "application/json",
    "Accept-Encoding": "gzip, deflate, sdch",
    "Accept-Language": "en-US,en;q=0.8"

    …. does this next brace close "headers" or the entire object"?

    }

    Try adding a final } at the end and see if that helps.

    Also tools like https://jsonformatter.curiousconcept.com/ could be quite handy in this situation to see if the JSON is valid.

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