NAME
Data::Clean::JSON - Clean data so it is safe to output to JSON
VERSION
This document describes version 0.32 of Data::Clean::JSON (from Perl distribution Data-Clean-JSON), released on 2016-03-30.
SYNOPSIS
use Data::Clean::JSON;
my $cleanser = Data::Clean::JSON->get_cleanser;
my $data = { code=>sub {}, re=>qr/abc/i };
my $cleaned;
# modifies data in-place
$cleaned = $cleanser->clean_in_place($data);
# ditto, but deep clone first, return
$cleaned = $cleanser->clone_and_clean($data);
# now output it
use JSON;
print encode_json($cleaned); # prints '{"code":"CODE","re":"(?^i:abc)"}'DESCRIPTION
This class cleans data from anything that might be problematic when encoding to JSON. This includes coderefs, globs, and so on.
Data that has been cleaned will probably not be convertible back to the original, due to information loss (for example, coderefs converted to string "CODE").
The design goals are good performance, good defaults, and just enough flexibility. The original use-case is for returning JSON response in HTTP API service.
This module is significantly faster than modules like Data::Rmap or Data::Visitor::Callback because with something like Data::Rmap you repeatedly invoke callback for each data item. This module, on the other hand, generates a cleanser code using eval(), using native Perl for() loops.
If LOG_CLEANSER_CODE environment is set to true, the generated cleanser code will be logged using Log::Any at trace level. You can see it, e.g. using Log::Any::App:
% LOG=1 LOG_CLEANSER_CODE=1 TRACE=1 perl -MLog::Any::App -MData::Clean::JSON \
-e'$c=Data::Clean::JSON->new; ...'METHODS
CLASS->get_cleanser => $obj
Return a singleton instance, with default options. Use new() if you want to customize options.
CLASS->new(%opts) => $obj
Create a new instance. For list of known options, see Data::Clean::Base. Data::Clean::JSON sets some defaults.
DateTime => [call_method => 'epoch']
Regexp => ['stringify']
SCALAR => ['deref_scalar']
-ref => ['replace_with_ref']
-circular => ['clone']
-obj => ['unbless']$obj->clean_in_place($data) => $cleaned
Clean $data. Modify data in-place.
$obj->clone_and_clean($data) => $cleaned
Clean $data. Clone $data first.
FAQ
Why clone/modify? Why not directly output JSON?
So that the data can be used for other stuffs, like outputting to YAML, etc.
Why is it slow?
If you use new() instead of get_cleanser(), make sure that you do not construct the Data::Clean::JSON object repeatedly, as the constructor generates the cleanser code first using eval(). A short benchmark (run on my slow Atom netbook):
% bench -MData::Clean::JSON -b'$c=Data::Clean::JSON->new' \
'Data::Clean::JSON->new->clone_and_clean([1..100])' \
'$c->clone_and_clean([1..100])'
Benchmarking sub { Data::Clean::JSON->new->clean_in_place([1..100]) }, sub { $c->clean_in_place([1..100]) } ...
a: 302 calls (291.3/s), 1.037s (3.433ms/call)
b: 7043 calls (4996/s), 1.410s (0.200ms/call)
Fastest is b (17.15x a)Second, you can turn off some checks if you are sure you will not be getting bad data. For example, if you know that your input will not contain circular references, you can turn off circular detection:
$cleanser = Data::Clean::JSON->new(-circular => 0);Benchmark:
$ perl -MData::Clean::JSON -MBench -E '
$data = [[1],[2],[3],[4],[5]];
bench {
circ => sub { state $c = Data::Clean::JSON->new; $c->clone_and_clean($data) },
nocirc => sub { state $c = Data::Clean::JSON->new(-circular=>0); $c->clone_and_clean($data) }
}, -1'
circ: 9456 calls (9425/s), 1.003s (0.106ms/call)
nocirc: 13161 calls (12885/s), 1.021s (0.0776ms/call)
Fastest is nocirc (1.367x circ)The less number of checks you do, the faster the cleansing process will be.
Why am I getting 'Not a CODE reference at lib/Data/Clean/Base.pm line xxx'?
[2013-08-07 ] This error message is from Data::Clone::clone() when it is cloning an object. If you are cleaning objects, instead of using clone_and_clean(), try using clean_in_place(). Or, clone your data first using something else like Sereal.
ENVIRONMENT
LOG_CLEANSER_CODE
HOMEPAGE
Please visit the project's homepage at https://metacpan.org/release/Data-Clean-JSON.
SOURCE
Source repository is at https://github.com/sharyanto/perl-Data-Clean-JSON.
BUGS
Please report any bugs or feature requests on the bugtracker website https://rt.cpan.org/Public/Dist/Display.html?Name=Data-Clean-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.
SEE ALSO
Data::Abridge is similar in goal, which is to let Perl data structures (which might contain stuffs unsupported in JSON) be encodeable to JSON. But unlike Data::Clean::JSON, it has some (currently) non-configurable rules, like changing a coderef with a hash {CODE=>'\&main::__ANON__'} or a scalar ref with {SCALAR=>'value'} and so on. Note that the abridging process is similarly unidirectional (you cannot convert back the original Perl data structure).
AUTHOR
perlancar <perlancar@cpan.org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2016 by 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.