参阅：https://www.cnblogs.com/ClaireWu/p/12487028.html
function xxx.UploadFile(const sAccessToken, sFile, sFileType: string):string;
var IdHttp: TIdHTTP; MutPartForm: TIdMultiPartFormDataStream; Ms: TStringStream; sTmp: string; LStream: TIdReadFileExclusiveStream; SSLIO: TIdSSLIOHandlerSocketOpenSSL;begin Result := ‘‘; try Ms := TStringStream.Create(‘‘, TEncoding.UTF8); IdHttp := TIdHttp.Create(nil); IdHttp.ReadTimeout := 30000; MutPartForm := TIdMultiPartFormDataStream.Create; LStream := TIdReadFileExclusiveStream.Create(sFile); SSLIO := TIdSSLIOHandlerSocketOpenSSL.Create(nil); try IdHttp.AllowCookies := True; IdHttp.HandleRedirects := True; //允许重定向 SSLIO.SSLOptions.Method:=sslvTLSv1; SSLIO.SSLOptions.Mode := sslmClient; IdHttp.IOHandler := SSLIO; // Http1.1 IdHttp.HTTPOptions := IdHttp.HTTPOptions + [hoKeepOrigProtocol]; IdHttp.ProtocolVersion := pv1_1; MutPartForm.AddObject(‘media‘, ‘application/octet-stream‘, LStream, ExtractFileName(sFile)); sTmp := Format(‘http://qyapi.weixin.qq.com/cgi-bin/media/upload?access_token=%s&type=%s‘,[sAccessToken, sFileType]); IdHttp.Post(sTmp, MutPartForm, Ms); Result := Ms.DataString; finally LStream.Free; Ms.Free; IdHttp.Free; MutPartForm.Free; SSLIO.Free; end; except on E: Exception do Result := E.Message; end;end;idhttp+tidmultpartfromdatastream
原文：https://www.cnblogs.com/suhq/p/13175147.html