/ 
Sah-Schemas-JSON-0.007
River stage three • 11 direct dependents • 156 total dependents
/ Sah::Schema::hash_from_json

NAME

Sah::Schema::hash_from_json - Hash, coerced from JSON string

VERSION

This document describes version 0.007 of Sah::Schema::hash_from_json (from Perl distribution Sah-Schemas-JSON), released on 2022-11-15.

SYNOPSIS

Sample data and validation results against this schema

""  # INVALID (Empty string is not a valid JSON)

1  # INVALID (Valid JSON but not a hash)

"[]"  # INVALID (Valid JSON but not a hash)

{}  # valid (Already a hash)

[]  # INVALID (Not a hash)

"foo"  # INVALID (Not a valid JSON literal)

"{}"  # valid, becomes {}

"{\"a\":1,\"b\":2}"  # valid, becomes {a=>1,b=>2}

"{\"a\":1,\"b\":2"  # INVALID (Missing closing curly bracket)

Using with Data::Sah

To check data against this schema (requires Data::Sah):

use Data::Sah qw(gen_validator);
my $validator = gen_validator("hash_from_json*");
say $validator->($data) ? "valid" : "INVALID!";

The above schema returns a boolean result (true if data is valid, false if otherwise). To return an error message string instead (empty string if data is valid, a non-empty error message otherwise):

my $validator = gen_validator("hash_from_json", {return_type=>'str_errmsg'});
my $errmsg = $validator->($data);

# a sample valid data
$data = {};
my $errmsg = $validator->($data); # => ""

# a sample invalid data
$data = [];
my $errmsg = $validator->($data); # => "Not of type hash"

Often a schema has coercion rule or default value, so after validation the validated value is different. To return the validated (set-as-default, coerced, prefiltered) value:

my $validator = gen_validator("hash_from_json", {return_type=>'str_errmsg+val'});
my $res = $validator->($data); # [$errmsg, $validated_val]

# a sample valid data
$data = {};
my $res = $validator->($data); # => ["",{}]

# a sample invalid data
$data = [];
my $res = $validator->($data); # => ["Not of type hash",[]]

Data::Sah can also create validator that returns a hash of detailed error message. Data::Sah can even create validator that targets other language, like JavaScript, from the same schema. Other things Data::Sah can do: show source code for validator, generate a validator code with debug comments and/or log statements, generate human text from schema. See its documentation for more details.

Using with Params::Sah

To validate function parameters against this schema (requires Params::Sah):

use Params::Sah qw(gen_validator);

sub myfunc {
    my @args = @_;
    state $validator = gen_validator("hash_from_json*");
    $validator->(\@args);
    ...
}

Using with Perinci::CmdLine::Lite

To specify schema in Rinci function metadata and use the metadata with Perinci::CmdLine (Perinci::CmdLine::Lite) to create a CLI:

# in lib/MyApp.pm
package
  MyApp;
our %SPEC;
$SPEC{myfunc} = {
    v => 1.1,
    summary => 'Routine to do blah ...',
    args => {
        arg1 => {
            summary => 'The blah blah argument',
            schema => ['hash_from_json*'],
        },
        ...
    },
};
sub myfunc {
    my %args = @_;
    ...
}
1;

# in myapp.pl
package
  main;
use Perinci::CmdLine::Any;
Perinci::CmdLine::Any->new(url=>'/MyApp/myfunc')->run;

# in command-line
% ./myapp.pl --help
myapp - Routine to do blah ...
...

% ./myapp.pl --version

% ./myapp.pl --arg1 ...

Using with Type::Tiny

To create a type constraint and type library from a schema:

package My::Types {
    use Type::Library -base;
    use Type::FromSah qw( sah2type );

    __PACKAGE__->add_type(
        sah2type('$sch_name*', name=>'HashFromJson')
    );
}

use My::Types qw(HashFromJson);
HashFromJson->assert_valid($data);

DESCRIPTION

You can use this schema if you want to accept a hash, but if user supplies a string e.g. in a command-line script as command-line argument or option, the string will be coerced into hash if the string contains a JSON-encoded object (hash). Data will not be valid if the string does not contain valid JSON.

Note that hash data is accepted, unlike the json_str::hash schema which only accepts hash in JSON-encoded string form.

HOMEPAGE

Please visit the project's homepage at https://metacpan.org/release/Sah-Schemas-JSON.

SOURCE

Source repository is at https://github.com/perlancar/perl-Sah-Schemas-JSON.

AUTHOR

perlancar <perlancar@cpan.org>

CONTRIBUTING

To contribute, you can send patches by email/via RT, or send pull requests on GitHub.

Most of the time, you don't need to build the distribution yourself. You can simply modify the code, then test via:

% prove -l

If you want to build the distribution (e.g. to try to install it locally on your system), you can install Dist::Zilla, Dist::Zilla::PluginBundle::Author::PERLANCAR, Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me.

COPYRIGHT AND LICENSE

This software is copyright (c) 2022, 2021 by perlancar <perlancar@cpan.org>.

This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.

BUGS

Please report any bugs or feature requests on the bugtracker website https://rt.cpan.org/Public/Dist/Display.html?Name=Sah-Schemas-JSON

When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.