Perl JSON example

json_sample.pl

package main;

use strict;
use warnings;
use Time::HiRes qw(gettimeofday);
use Data::Dumper qw(Dumper);
use JSON qw (decode_json encode_json);


my $jsonStr='[
  {
    "id": "0.2",
    "name": "generic",
    "data": [
      {
        "dmsg": "-",
        "protocol_info": "x",
        "raw": "MS;P1=-2140;P2=309;P3=-4690;P4=-9695;D=2421232323232121232123232321212121212121212123212121232121;CP=2;SP=4;R=211;m1;",
        "state": "no info",
        "user": "unknown"
      }
    ]
  },
  {
    "id": "0",
    "name": "generic",
    "data": [
      {
        "dmsg": "-",
        "protocol_info": "x",
        "raw": "MS;P1=-7949;P2=492;P3=-1978;P4=-3970;D=21232423232424242423232323232324242423232323232424;CP=2;SP=1;R=245;O;",
        "state": "no info",
        "user": "unknown"
      }
    ]
  },
  {
    "id": "0",
    "name": "generic",
    "data": [
      {
        "dmsg": "-",
        "protocol_info": "x",
        "raw": "MS;P1=-7949;P2=492;P3=-1978;P4=-3970;D=21232423232424242423232323232324242423232323232424;CP=2;SP=1;R=245;O;",
        "state": "no info",
        "user": "unknown"
      },
      {
        "dmsg": "-",
        "protocol_info": "x",
        "raw": "MS;P1=-7949;P2=492;P3=-1978;P4=-3970;D=21232423232424242423232323232324242423232323232424;CP=2;SP=1;R=245;O;",
        "state": "no info",
        "user": "unknown"
      }
    ]
  }
]
';
my @decoded_json = @{decode_json($jsonStr)};
print "foreach version:\n";

foreach my $entry (@decoded_json)
{
	print "--------------------------\n";

	foreach (@{${$entry}{data}})
	{
		#print Dumper($_->{user})."\n";
		
		#my @data=@{$_};
		printf "%s(%s): from: %s\trmsg=%s -> dmsg=%s\n" , ${$entry}{name}, ${$entry}{id}, ${$_}{user},${$_}{raw},${$_}{dmsg};	
	}
}


print "\n\nfor loop with index version:\n";

for my $i (0 .. $#decoded_json)
{
	print "--------------------------\n";
	for my $j (0 .. $#{$decoded_json[$i]{data}})
	{
		#print Dumper($_->{user})."\n";
		#my @data=@{$_};
		
		printf "%s(%s): from: %s\trmsg=%s -> dmsg=%s\n" , $decoded_json[$i]{name}, $decoded_json[$i]{id}, $decoded_json[$i]{data}[$j]{user},$decoded_json[$i]{data}[$j]{raw},$decoded_json[$i]{data}[$j]{dmsg};	
	}
}

exit;
								

Will generate the following output:

foreach version
--------------------------
generic(0.2): from: unknown     rmsg=MS;P1=-2140;P2=309;P3=-4690;P4=-9695;D=2421232323232121232123232321212121212121212123212121232121;CP=2;SP=4;R=211;m1; -> dmsg=-
--------------------------
generic(0): from: unknown       rmsg=MS;P1=-7949;P2=492;P3=-1978;P4=-3970;D=21232423232424242423232323232324242423232323232424;CP=2;SP=1;R=245;O; -> dmsg=-
--------------------------
generic(0): from: unknown       rmsg=MS;P1=-7949;P2=492;P3=-1978;P4=-3970;D=21232423232424242423232323232324242423232323232424;CP=2;SP=1;R=245;O; -> dmsg=-
generic(0): from: unknown       rmsg=MS;P1=-7949;P2=492;P3=-1978;P4=-3970;D=21232423232424242423232323232324242423232323232424;CP=2;SP=1;R=245;O; -> dmsg=-


for loop with index version
--------------------------
generic(0.2): from: unknown     rmsg=MS;P1=-2140;P2=309;P3=-4690;P4=-9695;D=2421232323232121232123232321212121212121212123212121232121;CP=2;SP=4;R=211;m1; -> dmsg=-
--------------------------
generic(0): from: unknown       rmsg=MS;P1=-7949;P2=492;P3=-1978;P4=-3970;D=21232423232424242423232323232324242423232323232424;CP=2;SP=1;R=245;O; -> dmsg=-
--------------------------
generic(0): from: unknown       rmsg=MS;P1=-7949;P2=492;P3=-1978;P4=-3970;D=21232423232424242423232323232324242423232323232424;CP=2;SP=1;R=245;O; -> dmsg=-
generic(0): from: unknown       rmsg=MS;P1=-7949;P2=492;P3=-1978;P4=-3970;D=21232423232424242423232323232324242423232323232424;CP=2;SP=1;R=245;O; -> dmsg=-