NAME

Module::Generic::Exception - Generic Module Exception Class

SYNOPSIS

    my $ex = Module::Generic::Exception->new({
        code => 404,
        type => $error_type,
        file => '/home/joe/some/lib/My/Module.pm',
        lang => 'en_GB',
        # or alternatively
        # locale => 'en_GB',
        line => 120,
        message => 'Invalid property provided',
        package => 'My::Module',
        subroutine => 'customer_info',
        # Some optional discretionary metadata hash reference
        cause =>
            {
            object => $some_object,
            payload => $raw_data,
            },
    });

or, providing a list of string that will be concatenated:

    my $ex = Module::Generic::Exception->new( "Some error", "has occurred:", $details );

or, re-using an exception object:

    my $ex = Module::Generic::Exception->new( $other_exception_object );

    print( "Error stack trace: ", $ex->stack_trace, "\n" );
    # or
    $object->customer_orders || die( "Error in file ", $object->error->file, " at line ", $object->error->line, "\n" );
    # or simply:
    $object->customer_orders || die( "Error: ", $object->error, "\n" );
    $ex->cause->payload;

VERSION

    v1.3.1

DESCRIPTION

This is a simple and straightforward exception class you can use or inherit from. The error object can be stringified or compared.

When stringified, it provides the error message along with precise information about where the error occurred and a stack trace.

Module::Generic::Exception objects are created by "error" in Module::Generic method.

METHODS

new

It takes either an Module::Generic::Exception object or an hash reference of properties, or a list of arguments that will be concatanated to form the error message. The list of arguments can contain code reference such as reference to sub routines, who will be called and their returned value added to the error message string. For example :

    my $ex = Module::Generic::Exception->new( "Invalid property. Value recieved are: ", sub{ Dumper( $hash ) } );

    # or

    my $ex = Module::Generic::Exception->new( $other_exception_object_for_reuse );
    # This will the I<object> property

    # or

    my #ex = Module::Generic::Exception->new({
        message => "Invalid property.",
        code => 404,
        type => 'customer',
    })

Possible properties that can be specified are :

• cause

  An optional and arbitrary hash reference of metadata that serve to provide more context on the error.

• code

  An error code

• file

  The location where the error occurred. This is populated using the "filename" in Devel::StackTrace

• lang

  An iso 639 language code that represents the language the error message is in.

  You can use locale alternatively. See the "lang" method below for more information.

• line

  The line number in the file where the error occurred.This is populated using the "line" in Devel::StackTrace

• locale

  An iso 639 language code that represents the language the error message is in.

  You can use lang alternatively. See the "lang" method below for more information.

• message

  The error message. It can be provided as a list of arguments that will be concatenated, or as the message property in an hash reference, or copied from another exception object passed as the sole argument.

• object

  When this is set, such as when another Module::Generic::Exception object is provided as unique argument, then the properties message, code, type, retry_after are copied from it in the new exception object.

• package

  The package name where the error occurred. This is populated using the "package" in Devel::StackTrace

• retry_after

  An optional value to indicate in seconds how long to wait to retry.

• skip_frames

  This is used as a parameter to Devel::StackTrace upon instantiation to instruct how many it should skip to start creating the stack trace.

• subroutine

  The name of the sub routine from which this was called. This is populated using the "subroutine" in Devel::StackTrace

• type

  An optional error type

It returns the exception object.

as_string

This returns a string representation of the Exception such as :

    Invalid property within package My::Module at line 120 in file /home/john/lib/My/Module.pm
        # then some strack trace here

caught

    use Nice::Try;
    try
    {
        # An error made with Module::Generic::Exception
        die( $object->error );
    }
    catch( $e )
    {
        # If this error is one of ours
        if( Module::Generic::Exception->caught( $e ) )
        {
            # Do something about it
        }
    }

But Nice::Try let's you do this:

    try
    {
        die( $object->error );
    }
    catch( Module::Generic::Exception $e )
    {
        # Do something about it
    }

cause

    my $ex = Module::Generic::Exception->new({
        code => 401,
        message => 'Not authorised',
        cause => {
            id => 1234,
        },
    });
    say $ex->cause->id; # 1234

Sets or gets an hash reference of metadata that serve to provide more context on the error.

This returns an hash object.

code

Set or get the error code. It returns the current value.

file

Set or get the file path where the error originated. It returns the current value.

lang

Set or get the language iso 639 code representing the language the error message is in.

If the error message is a string object that has a locale or lang object, it will be used to set this lang value.

This is the case if you use the module Text::PO::Gettext to implement GNU PO localisation framework. For example:

    use Text::PO::Gettext;
    my $po = Text::PO::Gettext->new || die( Text::PO::Gettext->error, "\n" );
    my $po = Text::PO::Gettext->new({
        category => 'LC_MESSAGES',
        debug    => 3,
        domain   => "com.example.api",
        locale   => 'ja-JP',
        path     => "/home/joe/locale",
        use_json => 1,
    }) || die( Text::PO::Gettext->error, "\n" );

    my $message = $po->gettext( "Something wrong happened." );

Then, $message would be a Text::PO::String

See "gettext" in Text::PO::Gettext for more information.

line

Set or get the line where the error originated. It returns the current value.

locale

This is an alias for "lang"

message

Set or get the error message. It returns the current value.

It takes a string, or a list of strings which will be concatenated.

For example :

    $ex->messsage( "I found some error:", $some_data );

package

Set or get the class/package name where the error originated. It returns the current value.

PROPAGATE

This method is called by perl when you call "die" in perlfunc with no parameters and $@ is set to a Module::Generic::Exception object.

This returns a new exception object that perl will use to replace the value in $@

rethrow

This rethrow (i.e. "die" in perlfunc) the original error. It must be called with the exception object or else it will return undef.

This is ok :

    $ex->rethrow;

But this is not :

    Module::Generic::Exception->rethrow;

retry_after

Set or get the number of seconds to way before to retry whatever cause the error. It returns the current value.

subroutine

Set or get the subroutine where the error originated. It returns the current value.

throw

Provided with a message string, this will create a new Module::Generic::Exception object and call "die" in perlfunc with it.

TO_JSON

Special method called by JSON to transform this object into a string suitable to be added in a json data.

trace

Set or get the Devel::StackTrace object used to provide a full stack trace of the error. It returns the current value.

type

Set or get the error type. It returns the current value.

SERIALISATION

Serialisation by CBOR, Sereal and Storable::Improved (or the legacy Storable) is supported by this package. To that effect, the following subroutines are implemented: FREEZE, THAW, STORABLE_freeze and STORABLE_thaw

AUTHOR

Jacques Deguest <jack@deguest.jp>

COPYRIGHT & LICENSE

Copyright (c) 2000-2020 DEGUEST Pte. Ltd.

You can use, copy, modify and redistribute this package and associated files under the same terms as Perl itself.

cpanm Module::Generic

perl -MCPAN -e shell
install Module::Generic