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Check null value in xml

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# 8  
Old 03-04-2013
Hi Bipin,

Thanks for the reply.

I am pulling my xml from logs. First I want to check whether my xml is empty or not. If it is not empty then I have to check the tag value of timestamp1. If that is empty then I have to insert current timestamp.

Could you please explain me the code.
# 9  
Old 03-04-2013
Sure, here is the explanation of code:
Code:
awk -F'[<>]' '                                                  # Set < > as field separators.
BEGIN {                                                         # BEGIN block.
                cmd = "date +%Y%m%d%H%M%S"                      # Define cmd = "date +%Y%m%d%H%M%S"
} /<timestamp1>/ {                                              # Search for pattern: <timestamp1>
        if ( $3 == "" )                                         # If pattern found check if 3rd field is NULL (3rd field is tag value)
        {
                cmd | getline dt                                # Run cmd and read output in variable: dt
                close(cmd)                                      # Close cmd
                $0 = "<timestamp1>" dt "</timestamp1>"          # Set current record = <timestamp1> dt (current timestamp) </timestamp1>
        }
} 1 ' xml                                                       # 1 == true, so print current record.

I hope this helps.
This User Gave Thanks to Yoda For This Post:
Neethu
# 10  
Old 03-05-2013
Above is working well if timestamp1 is the only tag in one line, and if there's no gap (space) between the two tags. For a bit more generic case, try
Code:
awk ' BEGIN {"date +%Y%m%d%H%M%S"|getline TS}
     {sub(/<timestamp1><\/timestamp1>/, "<timestamp1>"TS"<\/timestamp1>")}
     1
    ' FS="<|>" file

This User Gave Thanks to RudiC For This Post:
Neethu
# 11  
Old 03-05-2013
Thanks Bipin and RudiC... Both codes worked as expected.

Thanks a lot Bipin for explaining me the code.

Code:
awk '/<submit>/,/<\/submit>/' log.out > xml

This will pull the entire xml tag from log.out. From this I it will check the empty value for timestamp1. But I want to pull the entire xml from /<submit>/,/<\/submit>/ only if the tag value of timestamp1 is empty. Could you please help me
# 12  
Old 03-05-2013
The easiest way would be to scrap the result file if condition is not met:
Code:
awk     ' BEGIN {"date +%Y%m%d%H%M%S"|getline TS; n=1}
         /<timestamp1>/ {n=sub(/<timestamp1> *<\/timestamp1>/, "<timestamp1>"TS"<\/timestamp1>")}
         n
         !n {exit 1}
        ' FS="<|>" file && echo good || echo bad

If bad, scrap result file.
# 13  
Old 03-05-2013
Hi RudiC,

The above code is pulling the xml file from /<submit> till <timestamp1> even if the timestamp1 is not empty.

I want to pull the entire xml if the tag value of timestamp1 is empty.

Is it possible to add the condition to the below line so that it will pull the entire xml tag only if the tag value of timestamp1 is empty.

Code:
awk '/<submit>/,/<\/submit>/' log.out > xml

Last edited by Neethu; 03-05-2013 at 08:36 AM..
# 14  
Old 03-06-2013
Not sure if I got all requirements correctly, but you could give this a shot:
Code:
awk     ' BEGIN         {"date +%Y%m%d%H%M%S"|getline TS; n=1}          # prepare TS variable for timestamp
         /<submit>/,                                                    # discard e.th. outside "submit" tags
         /<\/submit>/   {if ($0 ~ /<timestamp1>/)                       # if "timestamp1" tag found within "submit" tags
                           {n = sub(/<timestamp1> *<\/timestamp1>/,     # replace zero+ spaces (= empty tag value)
                                    "<timestamp1>"TS"<\/timestamp1>")}  # with TS contents; n = 0 if not empty
                         if (!n) {exit 1}                               # if n = 0, i.e. non-empty tag value, quit with error
                         print           
                        }
        '  file > resultfile || rm resultfile                           # if error, i.e. non-empty tag value, remove output
$ cat resultfile 
<submit>
<ID>16</ID>
<Reference/>
<timestamp1>20130306225424<\/timestamp1>
....
.....
</submit>

If resultfile survives, it will have the before empty tag filled with actual timestamp. Resultfile will not survive timestamps with data in them.
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