NAME
    File::Append::Undoable - Append string to a file, with undo support

VERSION
    This document describes version 0.05 of File::Append::Undoable (from
    Perl distribution File-Append-Undoable), released on 2017-07-10.

FUNCTIONS
  append
    Usage:

     append(%args) -> [status, msg, result, meta]

    Append string to a file, with undo support.

    On do, will trash file, copy it to original location (with the same
    permission and ownership as the original) and append the string to the
    end of file. On undo will trash the new file and untrash the original.

    Some notes:

    *   Chown will not be done if we are not running as root.

    *   Symlink is currently not permitted.

    *   Since transaction requires the function to be idempotent, in the
        "check_state" phase the function will check if the string has been
        appended. It will refuse to append the same string twice.

    *   Take care not to use string that are too large, as the string, being
        a function parameter, is entered into the transaction table.

    Fixed state: file exists and string has been appended to end of file.

    Fixable state: file exists and string has not been appended to end of
    file.

    Unfixable state: file does not exist or path is not a regular file
    (directory and symlink included).

    This function is not exported.

    This function is idempotent (repeated invocations with same arguments
    has the same effect as single invocation). This function supports
    transactions.

    Arguments ('*' denotes required arguments):

    *   path* => *str*

        The file to append.

    *   string* => *any*

        The string to append to file.

    Special arguments:

    *   -tx_action => *str*

        For more information on transaction, see Rinci::Transaction.

    *   -tx_action_id => *str*

        For more information on transaction, see Rinci::Transaction.

    *   -tx_recovery => *str*

        For more information on transaction, see Rinci::Transaction.

    *   -tx_rollback => *str*

        For more information on transaction, see Rinci::Transaction.

    *   -tx_v => *str*

        For more information on transaction, see Rinci::Transaction.

    Returns an enveloped result (an array).

    First element (status) is an integer containing HTTP status code (200
    means OK, 4xx caller error, 5xx function error). Second element (msg) is
    a string containing error message, or 'OK' if status is 200. Third
    element (result) is optional, the actual result. Fourth element (meta)
    is called result metadata and is optional, a hash that contains extra
    information.

    Return value: (any)

HOMEPAGE
    Please visit the project's homepage at
    <https://metacpan.org/release/File-Append-Undoable>.

SOURCE
    Source repository is at
    <https://github.com/perlancar/perl-File-Append-Undoable>.

BUGS
    Please report any bugs or feature requests on the bugtracker website
    <https://rt.cpan.org/Public/Dist/Display.html?Name=File-Append-Undoable>

    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
    Rinci::Transaction

AUTHOR
    perlancar <perlancar@cpan.org>

COPYRIGHT AND LICENSE
    This software is copyright (c) 2017, 2015, 2014, 2012 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.