perl asn1 module encode SEQUENCE OF SEQUENCE - perl

Question

In the exmaple below, the asn1 definition has two tags schoolId and student. The tag student is SEQUENCE of SEQUENCE. I get the student info from a a file in JSON format such as:
{"school1": [{"name": "jason","id": 12345, "age": 14}, {"name": "karen","id": 12346, "age": 14},{"name": "mike","id": 12347, "age": 15}]}
{"school2": [{"name": "dave","id": 12645, "age": 16}, {"name": "angel","id": 12346, "age": 14},{"name": "susan","id": 12347, "age": 15}]}
So each school has a different number of students. My question is how to encode the student tag since it has unspecified number of students.
Thanks for your help!
use Convert::ASN1;
use Data::Dumper;
my %scope = qw(base 0 one 1 single 1 sub 2 subtree 2);
my %deref = qw(never 0 search 1 find 2 always 3);
my $search_pdu = Convert::ASN1->new;
$search_pdu->prepare(q(
SEQUENCE {
schoolId INTEGER,
student [0] SEQUENCE OF SEQUENCE {
name STRING,
id INTEGER,
age INTEGER
}
}
)) or die $search_pdu->error;
$buf = $search_pdu->encode(
schoolId => 1001,
student => [
{
name => "Jason Howard",
id => 310089,
age => 14
},
{
name => " Angel Disante",
id => 310456,
age => 15
}
]
);
$Data::Dumper::Indent = 1;
print Dumper( $search_pdu->decode($buf));
$h = unpack("H*",$buf);
print $h,"\n";
My question, For example, if school1 has 100 students, school2 has 300 students, ......., is there any way to use a for loop in the encode function to figure out the number of students programmatically?
$student_json = "{"school-1001": [{"name": "jason","id": 12345, "age": 14}, {"name": "karen","id": 12346, "age": 14},{"name": "mike","id": 12347, "age": 15}]}";
student => [
for my $hashref (#{$student_json}) {
{
name => $hashref->{'name'},
id => $hashref->{'id'},
age => $hashref->{'age'}
}
]
I tried many ways to use the for loop as shown above to encode programmatically, but it always failed.

Answer 1

My question, For example, if school1 has 100 students, school2 has 300 students, ......., is there any way to use a for loop in the encode function to figure out the number of students programmatically?
$student_json = "{"student": [{"name": "jason","id": 12345, "age": 14}, {"name": "karen","id": 12346, "age": 14},{"name": "mike","id": 12347, "age": 15}]}";
student => [
for my $hashref (#{$student_json}) {
{
name => $hashref->{'name'},
id => $hashref->{'id'},
age => $hashref->{'age'}
}
]

Answer 2

Given a JSON string with the school and student data, you can try:
use feature qw(say);
use strict;
use warnings;
use Convert::ASN1;
use Data::Dumper;
use JSON::XS;
my $json = <<'END';
{
"school1": [{"name": "jason","id": 12345, "age": 14}, {"name": "karen","id": 12346, "age": 14},{"name": "mike","id": 12347, "age": 15}],
"school2": [{"name": "dave","id": 12645, "age": 16}, {"name": "angel","id": 12346, "age": 14},{"name": "susan","id": 12347, "age": 15}]
}
END
my $hash = decode_json $json;
my $search_pdu = Convert::ASN1->new;
$search_pdu->prepare(q(
school SEQUENCE OF SEQUENCE {
schoolId INTEGER,
student SEQUENCE OF SEQUENCE {
name STRING,
id INTEGER,
age INTEGER
}
}
)) or die $search_pdu->error;
my #schools;
my $data = {school => \#schools};
my $school_id = 1001;
for my $school ( keys %$hash ) {
my #students;
my $item = { schoolId => $school_id, student => \#students };
for my $student (#{$hash->{$school}}) {
push #students, $student;
}
push #schools, $item;
$school_id++;
}
my $buf = $search_pdu->encode( $data );
$Data::Dumper::Indent = 1;
print Dumper( $search_pdu->decode($buf));
Output:
$VAR1 = {
'school' => [
{
'student' => [
{
'name' => 'jason',
'id' => 12345,
'age' => 14
},
{
'name' => 'karen',
'id' => 12346,
'age' => 14
},
{
'age' => 15,
'id' => 12347,
'name' => 'mike'
}
],
'schoolId' => 1001
},
{
'schoolId' => 1002,
'student' => [
{
'age' => 16,
'id' => 12645,
'name' => 'dave'
},
{
'name' => 'angel',
'age' => 14,
'id' => 12346
},
{
'name' => 'susan',
'age' => 15,
'id' => 12347
}
]
}
]
};