idHttp - IPv6 - IPVersion-ProtocolSwitch on Redirect (HandleRedirects=true)

[tobfel]

First reqest is done via IPv6, but when the server response with 301, the RedirectUrl ist not called with the same IP-Protocol-Version.
Can be fixed via:

if Request.IPVersion=Id_IPv6 then
    begin
    with TIdURI.Create(LLocation) do
         begin
         URI := LLocation;
         IPVersion := Id_IPv6;
         LLocation := URI;
         Free;
         end;
    end;

in

function TIdHTTPProtocol.ProcessResponse(AIgnoreReplies: array of Int16): TIdHTTPWhatsNext;
...
after:
LLocation := Response.Location;
LMethod := Request.Method;

[rlebeau]

TIdURI is already being used to process the Request.URL inside of TIdCustomHTTP.PrepareRequest(), which is called just after LLocation is assigned to Request.URL. So, rather than modifying LLocation itself, it would probably work/make more sense to instead have PrepareRequest() preserve the existing IPVersion when processing ARequest.URL, eg:

procedure TIdCustomHTTP.PrepareRequest(ARequest: TIdHTTPRequest);
var
  LURI: TIdURI;
  ...
begin
  LURI := TIdURI.Create(ARequest.URL);

  try
    // Add this...?
    LURI.IPVersion := ARequest.IPVersion;
    // or maybe this?
    if ARequest.IPVersion = Id_IPv6 then begin
      LURI.IPVersion := Id_IPv6;
    end;

    ...
  finally
    FreeAndNil(LURI);  // Free URI Object
  end;
end;