Provided by: librinci-perl_1.1.102-1_all 
NAME
Rinci::resmeta - Function/method result metadata
SPECIFICATION VERSION
1.1
VERSION
This document describes version 1.1.102 of Rinci::resmeta (from Perl distribution Rinci),
released on 2022-04-22.
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:
cmdline.*
Interpreted by Perinci::CmdLine. See its documentation for more detail.
content_type
Value: str* (MIME content type)
Can be used to describe the MIME content type of result. Example enveloped result (in
Perl):
[200, "OK", "...", {content_type => "image/jpeg"}]
See also "Properties: func_content_type.*".
Note: borrowed from HTTP.
func.*
Value: any.
These properties allow function to return extra results. 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. Some other examples (in Perl):
# result from check_user()
[200, "OK", 1, # 1 means valie
{
"func.detail" => { # detailed check result
last_login => '2021-01-21T01:55:40Z',
password_secure => 1,
quota_exceeded => 0,
},
}]
func_content_type.*
Value: str* (MIME content type)
Can be used to describe the MIME content type of each extra result. Example (in Perl):
func.attachment => '...',
func_content_type.attachment => 'image/jpeg',
See also "Property: content_type".
len
Value: 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.
location
Value: str* (URL)
Can be used to specify that the content is elsewhere. Used in combination with 301 or 302
result status. Example (in Perl):
# result from a function that generates a chart
[301, "Moved", undef, {content_type => "image/jpeg", location=>"file:/tmp/asd9uxzw.png"}]
Note: borrowed from HTTP.
logs
Value: array[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
Package (namespace) where this result is produced.
• file
File name where the result is created. Might be a relative or absolute path.
• line
Line number where the result is created.
• func
Function name where this result is produced.
• stack_trace
Optional, a stack trace. In Perl this can be produced by using << [caller(1),
caller(2), ...] >>.
part_len
Value: int*
See "Property: len"
part_start
Value: int*
See "Property: len".
perm_err
Value: 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.
prev
Value: any
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}] }
}
results
Value: 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
],
}]
schema
Value: sah::schema
Describe result's schema. Has lower precedence than schema from function metadata's result
property.
stream
Value: 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.
caption
Value: str*
Optional.
undo_data
Value: any
(DEPRECATED) Explained in "undo" feature section in Rinci::function.
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>.
SEE ALSO
Rinci
AUTHOR
perlancar <perlancar@cpan.org>
CONTRIBUTING
To contribute, you can send patches by email/via RT, or send pull requests on GitHub.
Most of the time, you don't need to build the distribution yourself. You can simply modify
the code, then test via:
% prove -l
If you want to build the distribution (e.g. to try to install it locally on your system),
you can install Dist::Zilla, Dist::Zilla::PluginBundle::Author::PERLANCAR, and sometimes
one or two other Dist::Zilla plugin and/or Pod::Weaver::Plugin. Any additional steps
required beyond that are considered a bug and can be reported to me.
COPYRIGHT AND LICENSE
This software is copyright (c) 2022, 2021, 2020, 2019, 2018, 2017, 2016, 2015, 2014, 2013,
2012 by perlancar <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.
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.