问使用Delphi/Indy调用
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Stack Overflow用户

提问于 2014-05-09 12:53:52

回答 1查看 2K关注 0票数 2

我正在开发一个简单的应用程序来与Amazon“交谈”。因为这里有很多现有的代码，所以我需要在Delphi 2010中使用Indy 10 (10.5.5)组件完成这一任务，过去我已经成功地将这些组件与许多其他API集成在一起。然而，Amazon似乎对最小的细节非常敏感，以至于我所有的调用都被已经臭名昭著的"SignatureDoesNotMatch“错误消息所拒绝。

以下是我到目前为止所取得的成就：

1)我的应用程序将组装一个请求，用HMAC- the 256(使用OpenSSL库)签名，并将其发送到Amazon端点。

2)仅HMAC签名本身就是一个挑战，但现在它已经100%正确工作(根据生成的请求进行验证)。

但是，正如我前面所指出的，MWS服务器总是拒绝我的请求，同时也会出现SignatureDoesNotMatch错误，尽管它们确实是正确的。我认为唯一可能造成问题的是Indy处理POST请求的方式，特别是文本编码过程。

是否有人成功地将Delphi/Indy客户端连接到MWS？如果是，那么使用了什么样的TIdHTTP设置？我现在拥有的是：

procedure TAmazon.TestGetOrder(OrderID:String);

const AwsAccessKey = 'MyAccessKey';
      AwsSecretKey = 'MySecretKey';
      MerchantID = 'MyMerchantID';
      MarketplaceID = 'MyMarketplaceID';
      ApiVersion = '2013-09-01';
      CallUri = '/Orders/2013-09-01';

var HTTP:TIdHTTP;
    SSL:TIdSSLIOHandlerSocketOpenSSL;
    SS:TStringStream;
    Params:TStringList;
    S,Timestamp,QueryString,Key,Value:String;
    i:Integer;

begin
   HTTP:=TIdHTTP.Create(nil);
   SSL:=TIdSSLIOHandlerSocketOpenSSL.Create(nil);
   Params:=TStringList.Create;
   try
      Params.Delimiter:='&';
      Params.StrictDelimiter:=True;

      // HTTP Client Options
      HTTP.HTTPOptions:=HTTP.HTTPOptions+[hoKeepOrigProtocol]-[hoForceEncodeParams];
      HTTP.ConnectTimeout:=5000;
      HTTP.ReadTimeout:=20000;
      HTTP.ProtocolVersion:=pv1_1;
      HTTP.IOHandler:=SSL;
      HTTP.HandleRedirects:=True;
      HTTP.Request.Accept:='text/plain, */*';
      HTTP.Request.AcceptLanguage:='en-US';
      HTTP.Request.ContentType:='application/x-www-form-urlencoded';
      HTTP.Request.CharSet:='utf-8';
      HTTP.Request.UserAgent:='MyApp/1.0 (Language=Delphi)';
      HTTP.Request.CustomHeaders.AddValue('x-amazon-user-agent',HTTP.Request.UserAgent);

      // generate the timestamp per Amazon specs
      Timestamp:=TIso8601.UtcDateTimeToIso8601(TIso8601.ToUtc(Now));
      // we can change the timestamp to match a value from the Scratchpad as a way to validate the signature:
      //Timestamp:='2014-05-09T20:32:28Z';

      // add required parameters from API function GetOrder
      Params.Add('Action=GetOrder');
      Params.Add('SellerId='+MerchantID);
      Params.Add('AWSAccessKeyId='+AwsAccessKey);
      Params.Add('Timestamp='+Timestamp);
      Params.Add('Version='+ApiVersion);
      Params.Add('SignatureVersion=2');
      Params.Add('SignatureMethod=HmacSHA256');
      Params.Add('AmazonOrderId.Id.1='+OrderID);
      // generate the signature using the parameters above
      Params.Add('Signature='+GetSignature(Params.Text,CallUri));

      // after generating the signature, make sure all values are properly URL-Encoded
      for i:=0 to Params.Count-1 do begin
         Key:=Params.Names[i];
         Value:=ParamEnc(Params.ValueFromIndex[i]);
         QueryString:=QueryString+Key+'='+Value+'&';
      end;
      Delete(QueryString,Length(QueryString),1);

      // there are two ways to make the call...
      // #1: according to the documentation, all parameters are supposed to be in
      // the URL, and the body stream is supposed to be empty
      SS:=TStringStream.Create;
      try
         try
            Log('POST '+CallUri+'?'+QueryString);
            S:=HTTP.Post('https://mws.amazonservices.com'+CallUri+'?'+QueryString,SS);
         except
            on E1:EIdHTTPProtocolException do begin
               Log('RawHeaders='+#$D#$A+HTTP.Request.RawHeaders.Text);
               Log('Protocol Exception:'+#$D#$A+StringReplace(E1.ErrorMessage,#10,#$D#$A,[rfReplaceAll]));
            end;
            on E2:Exception do
               Log('Unknown Exception: '+E2.Message);
         end;
         Log('ResponseText='+S);
      finally
         SS.Free;
      end;

      // #2: both the Scratchpad and the CSharp client sample provided by Amazon
      // do things in a different way, though... they POST the parameters in the
      // body of the call, not in the query string
      SS:=TStringStream.Create(QueryString,TEncoding.UTF8);
      try
         try
            SS.Seek(0,0);
            Log('POST '+CallUri+' (parameters in body/stream)');
            S:=HTTP.Post('https://mws.amazonservices.com'+CallUri,SS);
         except
            on E1:EIdHTTPProtocolException do begin
               Log('RawHeaders='+#$D#$A+HTTP.Request.RawHeaders.Text);
               Log('Protocol Exception:'+#$D#$A+StringReplace(E1.ErrorMessage,#10,#$D#$A,[rfReplaceAll]));
            end;
            on E2:Exception do
               Log('Unknown Exception: '+E2.Message);
         end;
         Log('ResponseText='+S);
      finally
         SS.Free;
      end;
   finally
      Params.Free;
      SSL.Free;
      HTTP.Free;
   end;
end;