Loop through an array ignores \n - json

Question

#edit
Below is the JSON getting saved as $content
[
{
"date_created": 1234,
"fingerprint_hash": null,
"address": "xx:xx:xx:xx:xx:xx",
"name": null,
"manufacturer": "xxx",
"date_updated": 1234,
"active": true,
"date_last_active": 1234,
"mac_group_info": {
"name": null,
"id": 0,
"remarks": null
},
"id": 1234,
"remarks": null,
"arp_mapping_info": [
{
"ip_info": {
"date_changed": 1234,
"date_last_kerberos_login": null,
"dns_name": "xxxx",
"id": 6,
"remarks": null,
"date_created": 1234,
"kerberos_user_name": null,
"ip_group_info": {
"remarks": null,
"id": 0,
"name": null
},
"address": "x.x.x.x"
},
"interface_info": [
{
"link": "on",
"name": "x",
"discovery_info": null,
"speed": 1234,
"host_info": {
"backup_sensor_id": 0,
"type": "xxxx",
"radius_coa_flags": null,
"moment": 1,
"name": null,
"host_group_info": {
"name": null,
"id": 0,
"remarks": null
},
"interface_mib": "D",
"uplink_count": 1,
"sensor_info": {
"id": 1,
"os_version": "xxxx",
"architecture": "xxxx",
"remarks": null,
"last_contact": "xxxx",
"queue": 0,
"address": "x.x.xx",
"status": "active",
"os_name": "linux",
"name": "xxxx",
"version": "x.x.x-x"
},
"mode": "xx",
"address": "x.x.x.x",
"radius_secret": null,
"arp_mib": "2",
"cam_count": 1,
"discovery2_mib": "C",
"discovery1_mib": "3",
"radius_coa_port": null,
"radius_requests_count": 0,
"vlan_count": 1,
"access_to_port": 1,
"vlan_mib": "C",
"interval": 1,
"snmp_traps_community": null,
"engine_mode": "dynamic",
"manufacturer": "ciscoSystems",
"engine_id": null,
"snmp_traps_version": "1",
"mib_options": null,
"remarks": null,
"snmp_write_version": "2c",
"snmp_write_community": "private",
"access_to_cam": 1,
"status": "ok",
"access_to_cto": 1,
"access_to_interface": 1,
"snmp_read_version": "1",
"snmp_read_community": "public",
"id": 1,
"cam_mib": "C",
"arp_count": 1,
"access_to_arp": 1,
"port_count": 1,
"main_sensor_id": 1
},
"status": "on",
"index": 1,
"protocols": [
"ARP",
"NDP"
],
"id": 1,
"remarks": null,
"sniffer_mode": null
}
],
"host_id": 1
}
],
"cam_mapping_info": []
}
]
Thats my code:
foreach ($content){
$content =~ s/\[/\[\n\t/g;
$content =~ s/{/{\n\t/g;
$content =~ s/\]/\n\]/g;
$content =~ s/}/}\n/g;
$content =~ s/,/\n\t/g;
print $content;
}
Todo: get the same output as the JSON above but with a perl skript runing it withouth any modules, normaly we use postman for it. As I asked my "couch" for help he only said: just learn to programm. Yeah...
The output I get with my regex is almost the solution. It just stops tabing after the first tab, doent repeat it on another opening bracket.

Answer 1

$line eq "{" || "[" is interpreted as
(($line eq '{') or '[')
(as Deparse would show you). Use
$line eq '{' || $line eq '['
Moreover, $data is a scalar variable, i.e. it contains a single value. Iterating over it makes just a single step.
Normally, you'd iterate over an array:
foreach my $line (#lines)
or maybe an array reference:
foreach my $line (#$data)
or whatever else
foreach my $line ($line1, $line2, #rest_of_lines)
# or
foreach my $line (split /\n/, $message)

Answer 2

Using the YAML module, you can get a quick human readable format. I'm sure there are other and/or better ways to format your text, but this is one example. The benefit here is that you can transform a JSON data structure (using JSON::PP, a core Perl module that comes pre-installed) into a Perl data structure and then into a YAML structure that you can print easily. I did this with a few lines of code and a few modules, using some sample JSON data.
use strict;
use warnings;
use JSON::PP;
use YAML;
my $text = do { local $/; <DATA> };
my $json = decode_json($text);
print Dump $json;
__DATA__
{
"ITEM":[
{
"-itemID": "1000000" ,
"-itemName": "DisneyJuniorLA" ,
"-thumbUrl": "" ,
"-packageID": "1" ,
"-itemPrice": "0" ,
"-isLock": "true"
},
{
"-itemID": "1000001" ,
"-itemName": "31 minutos" ,
"-thumbUrl": "" ,
"-packageID": "1" ,
"-itemPrice": "0" ,
"-isLock": "true"
},
{
"-itemID": "1000002" ,
"-itemName": "Plaza SÚsamo" ,
"-thumbUrl": "" ,
"-packageID": "1" ,
"-itemPrice": "0" ,
"-isLock": "true"
}
]
}
Output:
---
ITEM:
- -isLock: true
-itemID: 1000000
-itemName: DisneyJuniorLA
-itemPrice: 0
-packageID: 1
-thumbUrl: ''
- -isLock: true
-itemID: 1000001
-itemName: 31 minutos
-itemPrice: 0
-packageID: 1
-thumbUrl: ''
- -isLock: true
-itemID: 1000002
-itemName: Plaza S┌samo
-itemPrice: 0
-packageID: 1
-thumbUrl: ''
EDIT: With the new json data, I get this output:
- active: !!perl/scalar:JSON::PP::Boolean 1
address: xx:xx:xx:xx:xx:xx
arp_mapping_info:
- host_id: 1
interface_info:
- discovery_info: ~
host_info:
access_to_arp: 1
access_to_cam: 1
access_to_cto: 1
access_to_interface: 1
access_to_port: 1
address: x.x.x.x
arp_count: 1
arp_mib: 2
backup_sensor_id: 0
cam_count: 1
cam_mib: C
discovery1_mib: 3
discovery2_mib: C
engine_id: ~
engine_mode: dynamic
host_group_info:
id: 0
name: ~
remarks: ~
id: 1
interface_mib: D
interval: 1
main_sensor_id: 1
manufacturer: ciscoSystems
mib_options: ~
mode: xx
moment: 1
name: ~
port_count: 1
radius_coa_flags: ~
radius_coa_port: ~
radius_requests_count: 0
radius_secret: ~
remarks: ~
sensor_info:
address: x.x.xx
architecture: xxxx
id: 1
last_contact: xxxx
name: xxxx
os_name: linux
os_version: xxxx
queue: 0
remarks: ~
status: active
version: x.x.x-x
snmp_read_community: public
snmp_read_version: 1
snmp_traps_community: ~
snmp_traps_version: 1
snmp_write_community: private
snmp_write_version: 2c
status: ok
type: xxxx
uplink_count: 1
vlan_count: 1
vlan_mib: C
id: 1
index: 1
link: on
name: x
protocols:
- ARP
- NDP
remarks: ~
sniffer_mode: ~
speed: 1234
status: on
ip_info:
address: x.x.x.x
date_changed: 1234
date_created: 1234
date_last_kerberos_login: ~
dns_name: xxxx
id: 6
ip_group_info:
id: 0
name: ~
remarks: ~
kerberos_user_name: ~
remarks: ~
cam_mapping_info: []
date_created: 1234
date_last_active: 1234
date_updated: 1234
fingerprint_hash: ~
id: 1234
mac_group_info:
id: 0
name: ~
remarks: ~
manufacturer: xxx
name: ~
remarks: ~

Answer 3

Asked a coworker for help and he has just writen it in 5 minutes without big thinking...
use strict;
use warnings;
my $content = #JSON#
my #arr = split //, $content;
my $length = scalar #arr;
my $tabcounter = 0;
for (my $i=0; $i < $length; $i++) {
print $arr[$i];
if ( $arr[$i] eq '[' || $arr[$i] eq ']' || $arr[$i] eq '{' || $arr[$i] eq '}' || $arr[$i] eq ',') {
print "\n";
if ( $arr[$i] eq '[' || $arr[$i] eq '{' ) {
$tabcounter++;
}
if ( $arr[$i] eq '}' || $arr[$i] eq ']' ) {
$tabcounter--;
}
for (my $j=0; $j < $tabcounter; $j++) {
print "\t";
}
}
}
So if anyone has to read and print out of a JSON file without any modules, here is the solution.