NAME

       Rinci::resmeta - Function/method result metadata

SPECIFICATION VERSION

        1.1

VERSION

       This document describes version 1.1.86 of Rinci::resmeta (from Perl distribution Rinci),
       released on 2017-12-09.

INTRODUCTION

       This document describes metadata for function/method result. This specification is part of
       Rinci. Please do a read up on it first, if you have not already done so.

SPECIFICATION

       There are currently several properties being used:

   Property: undo_data => ANY
       (DEPRECATED) Explained in "undo" feature section in Rinci::function.

   Property: perm_err => bool
       Indicate that error is permanent (instead of temporary/transient). This is to provide a
       feature like that found in SMTP/POP protocol, where 4xx codes indicate transient errors
       and 5xx permanent ones.

   Properties: func.* => ANY
       These properties allow function to return extra stuffs. Usually done to avoid breaking
       format of existing result (to maintain API compatibility). The attributes after "func." is
       up to the respective function. An example is the "get_args_from_argv()" function in the
       Perinci::Sub::GetArgs::Argv Perl module. The function returns $args but from v0.26 it also
       wants to give hints about whether or not there are missing arguments. It can do this via
       "func.missing_arg" result metadata.

   Properties: cmdline.*
       Interpreted by Perinci::CmdLine. See its documentation for more detail.

   Property: logs => ARRAY OF HASH
       Store log of events happening to this result, stored chronologically (older first). Each
       log should be a hash which should have at least the following keys: "time" (Unix
       timestamp), "type" (string).

       Normally, the first element of the log will contain information about who produced the
       result and where/when. It has the "type" key with the value of "create". It should be a
       hash with the following keys:

       •   package => STR

           Package (namespace) where this result is produced.

       •   file => STR

           File name where the result is created. Might be a relative or absolute path.

       •   line => INT

           Line number where the result is created.

       •   func => STR

           Function name where this result is produced.

       •   stack_trace => ARRAY

           Optional, a stack trace. In Perl this can be produced by using << [caller(1),
           caller(2), ...] >>.

   Property: prev => ARRAY
       Store "previous result". Result MUST be enveloped. Usually useful when tracing errors,
       especially in conjunction with "logs": when reporting error that results from a call to
       another function, the original result can be set here, to preserve information. See
       Perinci::Sub::Util's "err()" for a convenience function for this, and Perinci::CmdLine's
       way of displaying it.

       Example:

        sub f1 {
            ...
            if (error) { return [500, "Can't f1: blah"] }
            ...
        }

        sub f2 {
            ...
            my $res = f1(...);
            if ($res is error) { return [500, "Can't f2", undef, {prev=>$res}] }
            ...
        }

        sub f3 {
            ...
            my $res = f1(...);
            if ($res is error) { return [500, "Can't f3", undef, {prev=>$res}] }
        }

   Property: results => array
       When a function returns an error response (in particular status 207, but other statuses
       can also use this), it can put detailed errors here. For example, a function which
       processed 5 items wanted to report that 2 items were successfully processed but the rest 3
       failed:

        [207, "Multistatus", undef, {
             results => [
                 {status=>200, message=>"OK", item_id=>1},
                 {status=>403, message=>"Forbidden", item_id=>2},
                 {status=>404, message=>"Not found", item_id=>3},
                 {status=>500, message=>"Failed", item_id=>4},
                 {status=>200, message=>"OK", item_id=>5},
             ],
         }]

       Each result is a hash to be able to store "status", "message", as well as additional data
       like "item_id" or whatever the function wants.

       Another example, a function wants to give information on what arguments fail validation:

        [400, "Some arguments fail validation", undef, {
             results => [
                 {status=>400, arg=>"name", message=>"Missing"},
                 {status=>400, arg=>"location/street", message=>"Missing"},
                 {status=>400, arg=>"age", message=>"Must be numbers only"},
                 {status=>400, arg=>"password", is_warning=>1,
                  message=>"Should be longer than 4 characters"}, # warning only
             ],
        }]

Property: part_start => int

Property: len => int

Property: part_len => int

       The "len", "part_start" and "part_len" properties specifies the range of data when
       function sends partial result. Suppose your function is returning a partial content of a
       large file where total file size is 24500000 bytes and the returned content is from bytes
       10000000 to 15000000, then "len" is 24500000, "part_len" is 5000000, and "part_start" is
       10000000. When returning partial content, status will be 206.

Property: stream => bool

       If set to true, signify that result is an output stream. Usually in implementations the
       result will be a filehandle or an object with "getline" or "getitem" methods, where caller
       can then fetch data from it.

FAQ

HOMEPAGE

       Please visit the project's homepage at <https://metacpan.org/release/Rinci>.

SOURCE

       Source repository is at <https://github.com/perlancar/perl-Rinci>.

BUGS

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

       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

AUTHOR

       perlancar <perlancar@cpan.org>

COPYRIGHT AND LICENSE

       This software is copyright (c) 2017, 2016, 2015, 2014, 2013, 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.