nslookup for IP & replace the result FQDN with IP - bash

Question

Requirement
I have a txt file in which last column have URLs.
Some of the URL entries have IPs instead of FQDN.
So, for entries with IPs (e.g. url=https://174.37.243.85:443*), I need to do reverse nslookup for IP and replace the result (FQDN) with IP.
Text File Input
httpMethod=SSL-SNI destinationIPAddress=174.37.243.85 url=https://174.37.243.85:443*
httpMethod=SSL-SNI destinationIPAddress=183.3.226.92 url=https://pingtas.qq.com:443/*
httpMethod=SSL-SNI destinationIPAddress=184.173.136.86 url=https://v.whatsapp.net:443/*
Expected Output
httpMethod=SSL-SNI destinationIPAddress=174.37.243.85 url=https://55.f3.25ae.ip4.static.sl-reverse.com:443/*
httpMethod=SSL-SNI destinationIPAddress=183.3.226.92 url=https://pingtas.qq.com:443/*
httpMethod=SSL-SNI destinationIPAddress=184.173.136.86 url=https://v.whatsapp.net:443/*

Answer 1

Here's a quick and dirty attempt in pure Awk.
awk '$3 ~ /^url=https?:\/\/[0-9.]*([:\/?*].*)?$/ {
# Parse out the hostname part
split($3, n, /[\/:?\*]+/);
cmd = "dig +short -x " n[2]
cmd | getline reverse;
sub(/\.$/, "", reverse);
close(cmd)
# Figure out the tail after the hostname part
match($3, /^url=https:?\/\/[0-9.]*/); # update index
$3 = n[1] "://" reverse substr($3, RSTART+RLENGTH) } 1' file
If you don't have dig, you might need to resort to nslookup or host instead; but the only one of these which portably offers properly machine-readable output is dig so you might want to install it for that feature alone.

Answer 2

Solution 1st: Within single awk after discussion on comments adding this now:
awk '
{
if(match($0,/\/[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+/)){
val_match=substr($0,RSTART+1,RLENGTH-1);
system("nslookup " val_match " > temp")};
val=$0;
while(getline < "temp"){
if($0 ~ /name/){
num=split($0, array," ");
sub(/\./,"",array[num]);
sub(val_match,array[num],val);
print val}}
}
NF
' Input_file
Solution 2nd: It is my initial solution with awk and shell.
Following simple script may help you on same:
cat script.ksh
CHECK_IP () {
fdqn=$(echo "$1" | awk '{if(match($0,/\/[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+/)){system("nslookup " substr($0,RSTART+1,RLENGTH-1))}}')
actual_fdqn=$(echo "$fqdn" | awk '/name/{sub(/\./,""$NF);print $NF}')
echo "$actual_fdqn"
}
while read line
do
val=$(CHECK_IP "$line")
if [[ -n "$val" ]]
then
echo "$line" | awk -v var="$val" '{if(match($0,/\/[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+/)){ip_val=substr($0,RSTART+1,RLENGTH-1);sub(ip_val,var)}} 1'
else
echo "$line"
fi
done < "Input_file"