NAME

Data::Roundtrip - convert between Perl data structures, YAML and JSON with unicode support (I believe ...)

VERSION

Version 0.06

SYNOPSIS

This module contains a collection of utilities for converting between JSON, YAML, Perl variable and a Perl variable's string representation (aka dump). Hopefully, all unicode content will be handled correctly between the conversions and optionally escaped or un-escaped. Also JSON can be presented in a pretty format or in a condensed, machine-readable format (not spaces, indendation or line breaks).

use Data::Roundtrip qw/:all/;

$jsonstr = '{"Songname": "Απόκληρος της κοινωνίας",'
           .'"Artist": "Καζαντζίδης Στέλιος/Βίρβος Κώστας"}'
;
$yamlstr = json2yaml($jsonstr);
print $yamlstr;
# NOTE: long strings have been broken into multilines
# and/or truncated (replaced with ...)
#---
#Artist: Καζαντζίδης Στέλιος/Βίρβος Κώστας
#Songname: Απόκληρος της κοινωνίας

$yamlstr = json2yaml($jsonstr, {'escape-unicode'=>1});
print $yamlstr;
#---
#Artist: \u039a\u03b1\u03b6\u03b1 ...
#Songname: \u0391\u03c0\u03cc\u03ba ...

$backtojson = yaml2json($yamlstr);
# $backtojson is a string representation
# of following JSON structure:
# {"Artist":"Καζαντζίδης Στέλιος/Βίρβος Κώστας",
#  "Songname":"Απόκληρος της κοινωνίας"}

# This is useful when sending JSON via
# a POST request and it needs unicode escaped:
$backtojson = yaml2json($yamlstr, {'escape-unicode'=>1});
# $backtojson is a string representation
# of following JSON structure:
# but this time with unicode escaped
# (pod content truncated for readbility)
# {"Artist":"\u039a\u03b1\u03b6 ...",
#  "Songname":"\u0391\u03c0\u03cc ..."}
# this is the usual Data::Dumper dump:
print json2dump($jsonstr);
#$VAR1 = {
#  'Songname' => "\x{391}\x{3c0}\x{3cc} ...",
#  'Artist' => "\x{39a}\x{3b1}\x{3b6} ...",
#};

# and this is a more human-readable version:
print json2dump($jsonstr, {'dont-bloody-escape-unicode'=>1});
# $VAR1 = {
#   "Artist" => "Καζαντζίδης Στέλιος/Βίρβος Κώστας",
#   "Songname" => "Απόκληρος της κοινωνίας"
# };

# pass some parameters to Data::Dumper
# like: be terse (no $VAR1):
print json2dump($jsonstr,
  {'dont-bloody-escape-unicode'=>0, 'terse'=>1}
 #{'dont-bloody-escape-unicode'=>0, 'terse'=>1, 'indent'=>0}
);
# {
#  "Artist" => "Καζαντζίδης Στέλιος/Βίρβος Κώστας",
#  "Songname" => "Απόκληρος της κοινωνίας"
# }

# this is how to reformat a JSON string to
# have its unicode content escaped:
my $json_with_unicode_escaped =
      json2json($jsonstr, {'escape-unicode'=>1});

# For some of the above functions there exist command-line scripts:
perl2json.pl -i "perl-data-structure.pl" -o "output.json" --pretty
json2json.pl -i "with-unicode.json" -o "unicode-escaped.json" --escape-unicode
# etc.

EXPORT

By default no symbols are exported. However, the following export tags are available (:all will export all of them):

:json : perl2json(), json2perl(), json2dump(), json2yaml(), json2json()
:yaml : perl2yaml(), yaml2perl(), yaml2dump(), yaml2yaml(), yaml2json()
:dump : perl2dump(), dump2perl(), dump2json(), dump2yaml()
:io : read_from_file(), write_to_file(), read_from_filehandle(), write_to_filehandle(),
:all : everything above

SUBROUTINES

`perl2json`

my $ret = perl2json($perlvar, $optional_paramshashref)

Arguments:

$perlvar
$optional_paramshashref

Return value:

$ret

Given an input $perlvar (which can be a simple scalar or a nested data structure, but not an object), it will return the equivalent JSON string. In $optional_paramshashref one can specify whether to escape unicode with 'escape-unicode' => 1 and/or prettify the returned result with 'pretty' => 1. The output can be fed back to Data::Roundtrip's json2perl() for getting the Perl variable back.

Returns the JSON string on success or undef on failure.

`json2perl`

Arguments:

$jsonstring

Return value:

$ret

Given an input $jsonstring as a string, it will return the equivalent Perl data structure using JSON::decode_json(Encode::encode_utf8($jsonstring)).

Returns the Perl data structure on success or undef on failure.

`perl2yaml`

my $ret = perl2yaml($perlvar, $optional_paramshashref)

Arguments:

$perlvar
$optional_paramshashref

Return value:

$ret

Given an input $perlvar (which can be a simple scalar or a nested data structure, but not an object), it will return the equivalent YAML string. In $optional_paramshashref one can specify whether to escape unicode with 'escape-unicode' => 1. Prettify is not supported yet. The output can fed to Data::Roundtrip's yaml2perl() for getting the Perl variable back.

Returns the YAML string on success or undef on failure.

`yaml2perl`

my $ret = yaml2perl($yamlstring);

Arguments:

$yamlstring

Return value:

$ret

Given an input $yamlstring as a string, it will return the equivalent Perl data structure using YAML::Load($yamlstring)

Returns the Perl data structure on success or undef on failure.

`perl2dump`

my $ret = perl2dump($perlvar, $optional_paramshashref)

Arguments:

$perlvar
$optional_paramshashref

Return value:

$ret

Given an input $perlvar (which can be a simple scalar or a nested data structure, but not an object), it will return the equivalent string (via Data::Dumper). In $optional_paramshashref one can specify whether to escape unicode with 'dont-bloody-escape-unicode' => 0, (or 'escape-unicode' => 1). The DEFAULT behaviour is to NOT ESCAPE unicode.

Additionally, use terse output with 'terse' => 1 and remove all the incessant indentation with 'indent' => 1 which unfortunately goes to the other extreme of producing a space-less output, not fit for human consumption. The output can fed to Data::Roundtrip's dump2perl() for getting the Perl variable back.

It returns the string representation of the input perl variable on success or undef on failure.

The output can be fed back to Data::Roundtrip's dump2perl().

CAVEAT: when not escaping unicode (which is the default behaviour), each call to this sub will override Data::Dumper's qquote() sub (with a call to Sub::Override' new()), call Data::Dumper's Dumper() and save its output to a temporary variable, restore qquote() sub (with a call to Sub::Override's restore() and return the contents. This exercise is done every time this perl2dump() is called. It can be expensive. The alternative is to redefine qquote() once, when the module is loaded.

Note that there are two other alternatives to this sub, Data::Roundtrip's perl2dump_filtered() which uses Data::Dump filters to control unicode escaping but lacks in aesthetics and functionality and handling all the cases Dump and Dumper do quite well.

There is also perl2dump_homebrew() which uses the same dump-recursively engine as Data::Roundtrip's perl2dump_filtered() but does not involve Data::Dump at all.

`perl2dump_filtered`

my $ret = perl2dump_filtered($perlvar, $optional_paramshashref)

Arguments:

$perlvar
$optional_paramshashref

Return value:

$ret

It does the same job as Data::Roundtrip's perl2dump() which is to stringify a perl variable. And takes the same options.

It returns the string representation of the input perl variable on success or undef on failure.

It uses Data::Dump::Filtered to add a filter to Data::Dump.

`perl2dump_homebrew`

my $ret = perl2dump_homebrew($perlvar, $optional_paramshashref)

Arguments:

$perlvar
$optional_paramshashref

Return value:

$ret

It does the same job as Data::Roundtrip's perl2dump() which is to stringify a perl variable. And takes the same options.

It returns the string representation of the input perl variable on success or undef on failure.

The output can be fed back to Data::Roundtrip's dump2perl().

It uses its own basic dumper. Which is recursive. So, beware of extremely deep nested data structures. Deep not long! But it probably is as efficient as it can be but definetely lacks in aesthetics and functionality compared to Dump and Dumper.

`dump_perl_var_recursively`

my $ret = dump_perl_var_recursively($perl_var)

Arguments:

$perl_var, a Perl variable like a scalar or an arbitrarily nested data structure. For the latter, it requires references, e.g. hash-ref or arrayref.

Return value:

$ret, the stringified version of the input Perl variable.

This sub will take a Perl var (as a scalar or an arbitrarily nested data structure) and emulate a very very basic Dump/Dumper but with enforced rendering unicode (for keys or values or array items), and not escaping unicode - this is not an option, it returns a string representation of the input perl var

There are 2 obvious limitations:

1. indentation is very basic,
1. it supports only scalars, hashes and arrays, (which will dive into them no problem) This sub can be used in conjuction with DataDumpFilterino() to create a Data::Dump filter like,
```
Data::Dump::Filtered::add_dump_filter( \& DataDumpFilterino );
```
or dumpf($perl_var, & DataDumpFilterino);

the input is a Perl variable as a reference, so no %inp but $inp={} and $inp=[].

This function is recursive. Beware of extremely deep nested data structures. Deep not long! But it probably is as efficient as it can be but definetely lacks in aesthetics and functionality compared to Dump and Dumper.

The output is a, possibly multiline, string. Which it can then be fed back to Data::Roundtrip's dump2perl().

`dump2perl`

my $ret = dump2perl($dumpstring)

Arguments:

$dumpstring, this comes from the output of Data::Dump, Data::Dumper or our own Data::Roundtrip's perl2dump(), Data::Roundtrip's perl2dump_filtered(), Data::Roundtrip's perl2dump_homebrew(). Escaped, or unescaped.

Return value:

$ret, the Perl data structure on success or undef on failure.

`json2perl`

my $ret = json2perl($jsonstring)

Arguments:

$jsonstring

Return value:

$ret

Given an input $jsonstring as a string, it will return the equivalent Perl data structure using JSON::decode_json(Encode::encode_utf8($jsonstring)).

Returns the Perl data structure on success or undef on failure.

In $optional_paramshashref one can specify whether to escape unicode with 'escape-unicode' => 1 and/or prettify the returned result with 'pretty' => 1.

Returns the yaml string on success or undef on failure.

`json2yaml`

my $ret = json2yaml($jsonstring, $optional_paramshashref)

Arguments:

$jsonstring
$optional_paramshashref

Return value:

$ret

Given an input JSON string $jsonstring, it will return the equivalent YAML string YAML by first converting JSON to a Perl variable and then converting that variable to YAML using Data::Roundtrip's perl2yaml(). All the parameters supported by Data::Roundtrip's perl2yaml() are accepted.

Returns the YAML string on success or undef on failure.

`yaml2json`

my $ret = yaml2json($yamlstring, $optional_paramshashref)

Arguments:

$yamlstring
$optional_paramshashref

Return value:

$ret

Given an input YAML string $yamlstring, it will return the equivalent YAML string YAML by first converting YAML to a Perl variable and then converting that variable to JSON using Data::Roundtrip's perl2json(). All the parameters supported by Data::Roundtrip's perl2json() are accepted.

Returns the JSON string on success or undef on failure.

`json2json` `yaml2yaml`

Transform a json or yaml string via pretty printing or via escaping unicode or via un-escaping unicode. Parameters like above will be accepted.

`json2dump` `dump2json` `yaml2dump` `dump2yaml`

similar functionality as their counterparts described above.

`read_from_file`

my $contents = read_from_file($filename)

Arguments:

$filename : the input filename.

Return value:

$contents

Given a filename, it opens it using :encoding(UTF-8), slurps its contents and closes it. It's a convenience sub which could have also been private. If you want to retain the filehandle, use Data::Roundtrip's read_from_filehandle().

Returns the file contents on success or undef on failure.

`read_from_filehandle`

my $contents = read_from_filehandle($filehandle)

Arguments:

$filehandle : the handle to an already opened file.

Return value:

$contents : the file contents slurped.

It slurps all content from the specified input file handle. Upon return the file handle is still open. Returns the file contents on success or undef on failure.

`write_to_file`

write_to_file($filename, $contents) or die

Arguments:

$filename : the output filename.
$contents : any string to write it to file.

Return value:

1 on success, 0 on failure

Given a filename, it opens it using :encoding(UTF-8), writes all specified content and closes the file. It's a convenience sub which could have also been private. If you want to retain the filehandle, use Data::Roundtrip's write_to_filehandle().

Returns 1 on success or 0 on failure.

`write_to_filehandle`

write_to_filehandle($filehandle, $contents) or die

Arguments:

$filehandle : the handle to an already opened file (for writing).

Return value:

1 on success or 0 on failure.

It writes content to the specified file handle. Upon return the file handle is still open.

Returns 1 on success or 0 on failure.

SCRIPTS

A few scripts have been put together and offer the functionality of this module to the command line. They are part of this distribution and can be found in the script directory.

These are: json2json.pl, json2yaml.pl, yaml2json.pl, json2perl.pl, perl2json.pl, yaml2perl.pl

AUTHOR

Andreas Hadjiprocopis, <bliako at cpan.org> / <andreashad2 at gmail.com>

BUGS

Please report any bugs or feature requests to bug-data-roundtrip at rt.cpan.org, or through the web interface at https://rt.cpan.org/NoAuth/ReportBug.html?Queue=Data-Roundtrip. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc Data::Roundtrip

You can also look for information at:

RT: CPAN's request tracker (report bugs here)

https://rt.cpan.org/NoAuth/Bugs.html?Dist=Data-Roundtrip
AnnoCPAN: Annotated CPAN documentation

http://annocpan.org/dist/Data-Roundtrip
CPAN Ratings

https://cpanratings.perl.org/d/Data-Roundtrip
Search CPAN

https://metacpan.org/release/Data-Roundtrip

ACKNOWLEDGEMENTS

Several Monks at PerlMonks.org (in no particular order):

haukex
Corion (the _qquote_redefinition_by_Corion() which harnesses Data::Dumper's incessant unicode escaping)
kcott (The EXPORT section among other suggestions)
jwkrahn
leszekdubiel
marto
and an anonymous monk

DEDICATIONS

Almaz!

LICENSE AND COPYRIGHT

This is free software, licensed under:

The Artistic License 2.0 (GPL Compatible)

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NAME

VERSION

SYNOPSIS

EXPORT

SUBROUTINES

perl2json

json2perl

perl2yaml

yaml2perl

perl2dump

perl2dump_filtered

perl2dump_homebrew

dump_perl_var_recursively

dump2perl

json2perl

json2yaml

yaml2json

json2json yaml2yaml

json2dump dump2json yaml2dump dump2yaml

read_from_file

read_from_filehandle

write_to_file

write_to_filehandle

SCRIPTS

AUTHOR

BUGS

SEE ALSO

SUPPORT

ACKNOWLEDGEMENTS

DEDICATIONS

LICENSE AND COPYRIGHT

Keyboard Shortcuts

`perl2json`

`json2perl`

`perl2yaml`

`yaml2perl`

`perl2dump`

`perl2dump_filtered`

`perl2dump_homebrew`

`dump_perl_var_recursively`

`dump2perl`

`json2perl`

`json2yaml`

`yaml2json`

`json2json` `yaml2yaml`

`json2dump` `dump2json` `yaml2dump` `dump2yaml`

`read_from_file`

`read_from_filehandle`

`write_to_file`

`write_to_filehandle`