LoadRunner中如何验证下载的文件大小、统计下载时间、度量下载速度？

LoadRunner中的web_get_in_property函数可用于返回上一个HTTP请求的相关信息，包括HTTP请求返回码、下载大小、下载时间等：
The web_get_int_property function returns specific information about the previous HTTP request.
The meaning of the return value depends on the HttpInfoType argument. HttpInfoType can be any of the following options. The first constant in each pair (HTTP_*) is for C, the second (object.HTTP_*) is for object oriented languages.
HTTP_INFO_RETURN_CODE or object.HTTP_INFO_RETURN_CODE
The return code in HTTP response header.
HTTP_INFO_DOWNLOAD_SIZE or object.HTTP_INFO_DOWNLOAD_SIZE
The size (in bytes) of the last download, including the header, body, and communications overhead (for example, NTLM negotiation).
HTTP_INFO_DOWNLOAD_TIME or object.HTTP_INFO_DOWNLOAD_TIME
The time in (milliseconds) of the last download.
HTTP_INFO_TOTAL_REQUEST_STAT or object.HTTP_INFO_TOTAL_REQUEST_STAT
Returns the accumulated size of all headers and bodies since the first time web_get_int_property was issued with HTTP_INFO_TOTAL_REQUEST_STAT.
HTTP_INFO_TOTAL_RESPONSE_STAT or object.HTTP_INFO_TOTAL_RESPONSE_STAT
Returns the accumulated size, including header and body, of all responses since the first time web_get_int_property was issued with HTTP_INFO_TOTAL_RESPONSE_STAT
 
下面脚本发送HTTP请求下载一个PNG图片，然后用web_get_int_property取得这次请求相关的信息：
 
Action()
{
 
       int returnCode;
    float fFileDownloadSize, fFileDownloadTime, fFileDownloadRate;
 
    web_url("Image1",
                     "URL=http://localhost/welcome.png",
                     "Resource=1",
                     LAST);
 
       returnCode = web_get_int_property(HTTP_INFO_RETURN_CODE);     
       fFileDownloadSize = (web_get_int_property(HTTP_INFO_DOWNLOAD_SIZE)/1024.); //in kilobytes
       fFileDownloadTime = (web_get_int_property(HTTP_INFO_DOWNLOAD_TIME)/1000.); //in seconds
       fFileDownloadRate = fFileDownloadSize/fFileDownloadTime; //in KB/s
 
       lr_output_message("Return Code = %d",returnCode);
       lr_output_message("Size of download was %.0f kilobytes; Time of download was %.3f seconds", fFileDownloadSize, fFileDownloadTime);
       lr_output_message("Rate of download was %.2f KB/sec", fFileDownloadRate);
 
       return 0;
}
 
 
参考：http://www.loadrunnertnt.com/how-tos/how-to-verify-file-downloaded/