C# SP-API giving error of signature for getReportDocument but it works fine for other methods

Question

I am using C# Amazon SP-API library, I have converted C# wrapper classes using swagger codegen and all working fine with Pricing and also some of function in Reports API.

But when I tried to call getReportDocument, it gives error of AWS Signature does not match.

https://github.com/amzn/selling-partner-api-docs/blob/main/references/reports-api/reports_2020-09-04.md#getreportdocument

Answer 1

If you can confirm that the problem occurs only when calling single items by id like GetOrder, GetReport and you are using Amazon.SellingPartnerAPIAA.csproj provided by amazon for signing, it is most likely that AWSSigV4Signer.CreateCanonicalRequest Method signs the url with the segment placeholder not the id itself.

e.g. "/reports/2021-06-30/documents/{reportDocumentId}" instead of "/reports/2021-06-30/documents/0356cf79-b8b0-4226-b4b9-0ee058ea5760" One possible solution is resolving the url "by hand" before calling ExtractCanonicalURIParameters

foreach(var par in restRequest.Parameters)
{
   if(restRequest.Resource.Contains($"{{{par.Name}}}"))
   {
        restRequest.Resource = restRequest.Resource.Replace($"{{{par.Name}}}", par.Value.ToString());
   }
}

//CanonicalURI
canonicalizedRequest.AppendFormat("{0}\n", AwsSignerHelper.ExtractCanonicalURIParameters(restRequest.Resource));