Jedimaster0 Jedimaster0 - 10 days ago 6
JSON Question

Parse any number of subkeys in a perl hash

I have a perl hash that is obtained from parsing JSON. The JSON could be anything a user defined API could generated. The goal is to obtain a date/time string and determine if that date/time is out of bounds according to a user defined threshold. The only issue I have is that perl seems a bit cumbersome when dealing with hash key/subkey iteration. How can I look through all the keys and determine if a key or subkey exists throughout the hash? I have read many threads throughout stackoverflow, but nothing that exactly meets my needs. I only started perl last week so I may be missing something... Let me know if that's the case.

Below is the "relevant" code/subs. For all code see: https://gitlab.com/Jedimaster0/check_http_freshness

use warnings;
use strict;
use LWP::UserAgent;
use Getopt::Std;
use JSON::Parse 'parse_json';
use JSON::Parse 'assert_valid_json';
use DateTime;
use DateTime::Format::Strptime;

# Verify the content-type of the response is JSON
eval {
assert_valid_json ($response->content);
};
if ( $@ ){
print "[ERROR] Response isn't valid JSON. Please verify source data. \n$@";
exit EXIT_UNKNOWN;
} else {
# Convert the JSON data into a perl hashrefs
$jsonDecoded = parse_json($response->content);
if ($verbose){print "[SUCCESS] JSON FOUND -> ", $response->content , "\n";}

if (defined $jsonDecoded->{$opts{K}}){
if ($verbose){print "[SUCCESS] JSON KEY FOUND -> ", $opts{K}, ": ", $jsonDecoded->{$opts{K}}, "\n";}
NAGIOS_STATUS(DATETIME_DIFFERENCE(DATETIME_LOOKUP($opts{F}, $jsonDecoded->{$opts{K}})));
} else {
print "[ERROR] Retreived JSON does not contain any data for the specified key: $opts{K}\n";
exit EXIT_UNKNOWN;
}
}




sub DATETIME_LOOKUP {
my $dateFormat = $_[0];
my $dateFromJSON = $_[1];

my $strp = DateTime::Format::Strptime->new(
pattern => $dateFormat,
time_zone => $opts{z},
on_error => sub { print "[ERROR] INVALID TIME FORMAT: $dateFormat OR TIME ZONE: $opts{z} \n$_[1] \n" ; HELP_MESSAGE(); exit EXIT_UNKNOWN; },
);

my $dt = $strp->parse_datetime($dateFromJSON);
if (defined $dt){
if ($verbose){print "[SUCCESS] Time formatted using -> $dateFormat\n", "[SUCCESS] JSON date converted -> $dt $opts{z}\n";}
return $dt;
} else {
print "[ERROR] DATE VARIABLE IS NOT DEFINED. Pattern or timezone incorrect."; exit EXIT_UNKNOWN
}
}




# Subtract JSON date/time from now and return delta
sub DATETIME_DIFFERENCE {
my $dateInitial = $_[0];
my $deltaDate;
# Convert to UTC for standardization of computations and it's just easier to read when everything matches.
$dateInitial->set_time_zone('UTC');

$deltaDate = $dateNowUTC->delta_ms($dateInitial);
if ($verbose){print "[SUCCESS] (NOW) $dateNowUTC UTC - (JSON DATE) $dateInitial ", $dateInitial->time_zone->short_name_for_datetime($dateInitial), " = ", $deltaDate->in_units($opts{u}), " $opts{u} \n";}

return $deltaDate->in_units($opts{u});
}


Sample Data

{
"localDate":"Wednesday 23rd November 2016 11:03:37 PM",
"utcDate":"Wednesday 23rd November 2016 11:03:37 PM",
"format":"l jS F Y h:i:s A",
"returnType":"json",
"timestamp":1479942217,
"timezone":"UTC",
"daylightSavingTime":false,
"url":"http:\/\/www.convert-unix-time.com?t=1479942217",
"subkey":{
"altTimestamp":1479942217,
"altSubkey":{
"thirdTimestamp":1479942217
}
}
}

Answer

You could try use Hash::Flatten. For example:

use Hash::Flatten qw(flatten);

my $json_decoded = parse_json($json_str);
my $flat = flatten( $json_decoded );
say "found" if grep /(?:^|\.)\Q$key\E(?:\.?|$)/, keys %$flat;
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