LoadRunner - Date Handling (1 of 3) - lr_save_datetime

If you are using LoadRunner, you've probably encountered date and time values in your scripts. These values should be evaluated and dealt with.

 Where Do Date/Time Values Come From?

• Entered during recording.
• Returned by the server.
• Generated by the client.

Let's look at each one and determine how to handle the data.

 Entered During Recording

• Why did I pick this date?
• Is the date always the same?
• Is there a calculation involved?  For example: today + 7 days, today - 1 hour?

If it's always the same, leave it hard-coded or create a parameter file to store the value.  If it's a calculation, use the lr_save_datetime function to generate the required date information.   From the ‘HP LoadRunner Online Function Reference’:

 lr_save_datetime

Assigns the current date and time to a parameter.

void lr_save_datetime (const char *format, int offset, const char *name);

• format – The format of the retrieved data/time information.
• offset – Offset from the current date and time, using the constants: DATE_NOW, TIME_NOW, ONE_DAY, ONE_HOUR, ONE_MIN.  For example, TIME_NOW + ONE_HOUR.
• name – The name of the parameter to store the date/time information.

The supported format codes can be found at: ‘HP LoadRunner Online Function Reference > Utility Functions: C Language (LR) > Datetime Format Codes’

Examples

lr_save_datetime ("%m/%d/%Y", DATE_NOW, "pDate1");
lr_output_message ("Today's Date is %s", lr_eval_string ("{pDate1}"));

lr_save_datetime ("%B %d, %Y", DATE_NOW+ONE_DAY, "pDate2");
lr_output_message ("Tomorrow’s Date is %s", lr_eval_string ("{pDate2}"));

lr_save_datetime("%a-%b-%d-%Y %H:%M:%S", DATE_NOW-(ONE_DAY*4)-(ONE_MIN*30), "pDate3");
lr_output_message ("Date/Time 4 days and 30 minutes ago is %s", lr_eval_string ("{pDate3}"));

lr_save_datetime ("%d", DATE_NOW, "pDate4");
lr_save_datetime ("%m/01/%Y", DATE_NOW-(ONE_DAY*(atoi(lr_eval_string ("{pDate4}"))+1)), "pDate5");
lr_output_message ("First Day of Previous Month is %s", lr_eval_string ("{pDate5}"));

// Find the last day of next month
// Not efficient, but a different use of lr_save_datetime
// Keep adding days until month changes 2 times, then back off 1 day

int iDays = 1, iMonthCurrent, iMonthChanged = 0, iMonth, bDone = 0;

lr_save_datetime ("%m", DATE_NOW, "pDate6");
iMonthCurrent = atoi (lr_eval_string ("{pDate6}"));

while (bDone == 0)
{
    lr_save_datetime ("%m", DATE_NOW+(ONE_DAY*(iDays)), "pDate7");
    iMonth = atoi (lr_eval_string ("{pDate7}"));
    if (iMonth != iMonthCurrent)
    {
        bMonthChanged++;
        iMonthCurrent = iMonth;
    }

    if (bMonthChanged == 2)
    {
        bDone = 1;
    }
    else
    {
        iDays++;
    }
}

lr_save_datetime ("%m/%d/%Y", DATE_NOW+(ONE_DAY*(iDays-1)), "pDate8");
lr_output_message ("Last Day of Next Month is %s", lr_eval_string ("{pDate8}"));

 Returned By Server

• Correlate the value into a parameter and use this new parameter.

Script snippet

web_reg_save_param ("dServerDate", "LB=currentdate=", "RB=;", "ORD=1", LAST);
web_url(...);

web_submit_data(...
    ITEMDATA,
    "Name=_someKey", "Value={dServerDate}", ENDITEM,
    LAST);

 Generated By The Client

• Determine the calculation and use lr_save_datetime.

 Common Question And Answer

In most situations, lr_save_datetime will handle the date requirements(if the date in question is relative to the current date/time of your system).

Recently on a LoadRunner forum on Google Groups someone asked how to change the date returned by the server (https://groups.google.com/forum/#!topic/lr-loadrunner/zzG_431yPO4).  As suggested, the simplest solution would be to use lr_save_datetime with the given format and DATE_NOW+ONE_MIN.  These answers assume the desired date was related to the current date/time and makes lr_save_datetime an easy solution to implement. 

lr_save_datetime solution

lr_save_datetime ("%d-%b-%Y %H:%M:%S", DATE_NOW, "pCurrentDate");
lr_save_datetime ("%d-%b-%Y %H:%M:%S", DATE_NOW+ONE_MIN, "pNewDate");
lr_output_message ("Current Date is %s", lr_eval_string ("{pCurrentDate}"));
lr_output_message ("Current Date plus one minute is %s", lr_eval_string ("{pNewDate}"));

 Tougher Questions And Answers

What if the date could be any date?  Given the date format, how would you safely add/subtract date/time elements? 

• 21-Aug-2012 07:33:00, add 1 minute
• 31-Dec-2011 23:59:59, add 1 minute
• 24-Feb-2009 12:34:56, add 50 hours
• 01-Sep-2012 09:00:00, subtract 100 days

You can not just parse the data and increment a number.  Depending on the date/time given, any additions/subtractions could result in date/time rollovers.  What about leap years?  Like the example above, an inefficient looping structure could work, but there must be an easier way.

Part 2 – Solution using C date/time functions

Part 3 – Solution using Powershell

Comments

[JonyGreen]

I'm not a developer, i always use the free online timestamp generator(http://www.online-code.net/unix-timestamp.html) to create the unix timestamp.