錯誤：使用 Microsoft WebService.dll 使用 Delphi7 規范化 XML

Question

我正在使用 Delphi7 修改一個舊項目以添加使用證書和簽名。 在做了一些搜索后，我找到了 XML Canonicalization Functions但我無法使用這些函數中的任何一個：

• WsStartReaderCanonicalization / WsEndReaderCanonicalization
• WsStartWriterCanonicalization / WsEndWriterCanonicalization

這些功能包含在Microsoft WebServices.dll中，我在Github上找到了它的標題翻譯，但我仍然沒有運氣。 這是我測試的代碼：

 {$APPTYPE CONSOLE} program XmlBufferExample; //This example shows some use of the xml buffer APIs. //Original C++ code from Microsoft: //https://msdn.microsoft.com/en-us/library/windows/desktop/dd819131(v=vs.85).aspx uses Windows, Sysutils, Classes, webservices in 'webservices.pas'; Procedure PrintError(errorCode:HRESULT; error:PWS_ERROR); var hr:HRESULT; errorCount,i:ULONG; str:WS_STRING; s:string; begin writeln(Format('Failure: errorCode=0x8%.x',[errorCode])); if (errorCode=E_INVALIDARG) or (errorCode=WS_E_INVALID_OPERATION) then begin // Correct use of the APIs should never generate these errors writeln('The error was due to an invalid use of an API. This is likely due to a bug in the program.'); exit; end; hr:=NOERROR; if (error<>nil) then begin hr:=WsGetErrorProperty(error, WS_ERROR_PROPERTY_STRING_COUNT, @errorCount, sizeof(errorCount)); if (hr=NOERROR) and (errorCount>0) then for i:=0 to errorCount-1 do begin hr:=WsGetErrorString(error, i, @str); if (hr=NOERROR) then begin s:=copy(str.chars,1,str.length); writeln(s); end else errorCount:=i; //exit for end; end; if (hr<>NOERROR) then writeln(Format('Could not get error string (errorCode=0x8%.x)',[hr])); end; var MyCallbackStatus: Cardinal; Found: BOOL; Mybuffer:PWS_XML_BUFFER = nil; const HeapSize = 24 * 1024; //24 kb function MyCallback(callbackState: pointer; buffer: PWS_BYTES; count: ULONG; asyncContext: PWS_ASYNC_CONTEXT; error: PWS_ERROR):HRESULT; stdcall; var S: AnsiString; begin //debuging start Writeln('Inside MyCallback:'); Writeln('MyCallbackStatus:', IntToStr(MyCallbackStatus)); if Assigned(error) then PrintError(0, error); //debuging end if Assigned(buffer) then SetString(S, PAnsiChar(buffer.bytes), buffer.length); Writeln(s); end; var hr:HRESULT; error:PWS_ERROR; heap:PWS_HEAP; buffer:PWS_XML_BUFFER; writer:PWS_XML_WRITER; reader:PWS_XML_READER; newXml:pointer; newXmlLength:ULONG; xml:ansistring; ExitCode:integer; Stream: TMemoryStream; begin error:=nil; heap:=nil; buffer:=nil; writer:=nil; reader:=nil; newXml:=nil; newXmlLength:=0; // Create an error object for storing rich error information hr:= WsCreateError(nil, 0, @error); if (hr=NOERROR) then begin // Create a heap to store deserialized data hr:= WsCreateHeap(2048, //maxSize 512, //trimSize nil, 0, @heap, error); end; if hr=NOERROR then begin // Create an XML writer hr:= WsCreateWriter(nil, 0, @writer, error); end; if hr=NOERROR then begin // Create an XML reader hr:= WsCreateReader(nil, 0, @reader, error); end; // Some xml to read and write xml:='<a><b>1</b><c>2</c></a>'; if hr=NOERROR then begin hr:=WsReadXmlBufferFromBytes(reader, nil, nil, 0, PAnsiChar(xml), //@xml[1], length(xml), heap, @buffer, error); end; if hr=NOERROR then begin hr:=WsWriteXmlBufferToBytes(writer, buffer, nil, nil, 0, heap, @newXml, @newXmlLength, error); end; if hr=NOERROR then begin writeln('new xml:'); writeln(copy(PAnsiChar(newXml),1,newXmlLength)); writeln; ExitCode:=0; end; //---------------------------------------- //My test start //---------------------------------------- if hr=NOERROR then begin if Assigned(reader) then begin WsFreeReader(reader); reader:= nil; end; hr:= WsCreateReader(nil, 0, @reader, error); if Assigned(heap) then begin WsFreeHeap(heap); heap:= nil; end; hr:= WsCreateHeap(3 * HeapSize, 512, nil, 0, @heap, error); if hr=NOERROR then begin //load xml file Stream:= TMemoryStream.Create(); try Stream.LoadFromFile('Z:\zatca-einvoicing-sdk\test\100030.xml'); SetString(xml, PChar(Stream.Memory), Stream.Size); Writeln; Writeln('-------------------------------'); Writeln('XML File size is ' + IntToStr(Stream.Size) + ' Bytes'); finally Stream.Free(); end; hr:=WsReadXmlBufferFromBytes(reader, nil, nil, 0, PAnsiChar(xml), length(xml), heap, @buffer, error); end; (* according to https://learn.microsoft.com/en-us/windows/win32/api/webservices/nf-webservices-wsstartreadercanonicalization The usage pattern for canonicalization is: 1) Move the Reader to the element where canonicalization begins. 2) Call WsStartReaderCanonicalization. 3) Move the Reader forward to the end position. 4) Call WsEndReaderCanonicalization. *) // Step1: Move the Reader to the element where canonicalization begins. [this gives an error] if hr=NOERROR then hr:= WsMoveReader(reader, WS_MOVE_TO_PARENT_ELEMENT, @Found, error); // Step2: Call WsStartReaderCanonicalization. MyCallbackStatus:= 0; if hr=NOERROR then hr:=WsStartReaderCanonicalization(reader, MyCallback, @MyCallbackStatus, nil, 0, error); // Step3: Move the Reader forward to the end position. [this gives an error] if hr=NOERROR then hr:= WsMoveReader(reader, WS_MOVE_TO_EOF, @Found, error); // Step4: Call WsEndReaderCanonicalization [this will call MyCallback] if hr=NOERROR then hr:= WsEndReaderCanonicalization(reader, error); end; //---------------------------------------- //My test End //---------------------------------------- if hr <> NOERROR then begin PrintError(hr,error); ExitCode:=-1; end; if writer<>nil then WsFreeWriter(writer); if reader<>nil then WsFreeReader(reader); if heap<>nil then WsFreeHeap(heap); if error<>nil then WsFreeError(error); Readln; halt(exitcode); end.

正如您在代碼中看到的，function WsMoveReader() 給出了一個錯誤。 當我刪除對 WsMoveReader() 的調用時，代碼完成且沒有錯誤，但是當調用 MyCallback 時，緩沖區參數為 nil。 任何幫助將不勝感激。

Answer 1

經過多次嘗試，我終於找到了問題的答案。 這個解決方案有點原始，但它執行所需的 function。這是我的代碼。

下面是一個虛擬的 function 但沒有它代碼就不會運行。 我嘗試使用nil代替它但失敗了。

uses
  Windows, Sysutils, Classes, webservices, wcrypt2, ncrypt;

//   A user-defined callback used by the WS_XML_WRITER to write a buffer to some destination.
function MyCallback(callbackState : pointer; buffer : PWS_BYTES; count : ULONG;
                     asyncContext : PWS_ASYNC_CONTEXT; error : PWS_ERROR):HRESULT; stdcall;
begin
  Result := 0;
end; 

規范的 function。

function CanonicalXML(xml : string; Exclusive:Boolean=True; WithComment:Boolean=True) : string;
const
  HeapSize = 128 * 1024;  //128 KB for test
  Exclusives : array[Boolean, Boolean] of Integer = (
    (WS_INCLUSIVE_XML_CANONICALIZATION_ALGORITHM, WS_INCLUSIVE_WITH_COMMENTS_XML_CANONICALIZATION_ALGORITHM),
    (WS_EXCLUSIVE_XML_CANONICALIZATION_ALGORITHM, WS_EXCLUSIVE_WITH_COMMENTS_XML_CANONICALIZATION_ALGORITHM)
  );
  
var
  hr:HRESULT;
  heap:PWS_HEAP;
  buffer:PWS_XML_BUFFER;
  writer:PWS_XML_WRITER;
  reader:PWS_XML_READER;
  newXml:pointer;
  newXmlLength :ULONG;
  MyCallbackStatus : Cardinal;
  CanProp : WS_XML_CANONICALIZATION_PROPERTY;
  PtrCanProp : PWS_XML_CANONICALIZATION_PROPERTY;
  Algorithm : ULONG;
begin
  buffer := nil;
  writer := nil;
  reader := nil;
  
  //Setup algorithm used in canonicalization. 
  Algorithm := Exclusives[Exclusive, WithComment];
  CanProp.id := WS_XML_CANONICALIZATION_PROPERTY_ALGORITHM ;
  CanProp.value := @Algorithm;
  CanProp.valueSize := SizeOf(Algorithm);
  PtrCanProp := @CanProp;   
   
  hr := WsCreateReader(nil, 0, @reader, nil);     // Create an XML reader

  if hr=NOERROR then
    hr := WsCreateWriter(nil, 0, @writer, nil);   // Create an XML writer

  if (hr=NOERROR) then
    hr := WsCreateHeap(HeapSize, 512, nil, 0, @heap, nil); // Create a heap to store data

  if hr=NOERROR then    //read data into buffer
    hr:=WsReadXmlBufferFromBytes(reader, nil, nil, 0, PAnsiChar(xml), length(xml), heap, @buffer, nil);

  if hr=NOERROR then
    hr:=WsWriteXmlBufferToBytes(writer, buffer, nil, nil, 0, heap, @newXml, @newXmlLength, nil);

  if hr=NOERROR then
    hr := WsStartWriterCanonicalization(writer, MyCallback, @MyCallbackStatus, PtrCanProp, 1, nil);
  if hr=NOERROR then
    hr := WsEndWriterCanonicalization(writer, nil);

  if hr=NOERROR then
    SetString(Result, PAnsiChar(newXml), newXmlLength);

  //Free created objects
  if Assigned(writer) then WsFreeWriter(writer);
  if Assigned(reader) then WsFreeReader(reader);
  if Assigned(heap) then WsFreeHeap(heap);
end;

筆記：
在某些情況下，這個 function 會在實際結果前后返回“#10”，因此必須將結果修改為：

SetString(Result, PAnsiChar(newXml), newXmlLength);
Result := Trim(Result);