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Perinci-Examples-0.824
River stage three • 19 direct dependents • 522 total dependents
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/ Perinci::Examples::FileStream

NAME

Perinci::Examples::FileStream - Examples for reading/writing files (using streaming result)

VERSION

This document describes version 0.824 of Perinci::Examples::FileStream (from Perl distribution Perinci-Examples), released on 2023-07-09.

DESCRIPTION

The functions in this package demonstrate byte streaming of input and output.

The functions are separated into this module because these functions read/write files on the filesystem and might potentially be dangerous if Perinci::Examples is exposed to the network by accident.

See also Perinci::Examples::FilePartial which uses partial technique instead of streaming.

FUNCTIONS

append_file

Usage:

 append_file(%args) -> [$status_code, $reason, $payload, \%result_meta]

This is like write_file() except that it appends instead of overwrites existing file.

This function is not exported.

Arguments ('*' denotes required arguments):

  • content* => buf

    (No description)

  • path* => str

    (No description)

Returns an enveloped result (an array).

First element ($status_code) is an integer containing HTTP-like status code (200 means OK, 4xx caller error, 5xx function error). Second element ($reason) is a string containing error message, or something like "OK" if status is 200. Third element ($payload) is the actual result, but usually not present when enveloped result is an error response ($status_code is not 2xx). Fourth element (%result_meta) is called result metadata and is optional, a hash that contains extra information, much like how HTTP response headers provide additional metadata.

Return value: (any)

read_file

Usage:

 read_file(%args) -> [$status_code, $reason, $payload, \%result_meta]

This function demonstrate output streaming of bytes.

To do output streaming, on the function side, you just return a coderef which can be called by caller (e.g. CLI framework Perinci::CmdLine) to read data from. Code must return data or undef to signify exhaustion.

This works over remote (HTTP) too, because output streaming is supported by Riap::HTTP (version 1.2) and Perinci::Access::HTTP::Client. Streams are translated into HTTP chunks.

This function is not exported.

Arguments ('*' denotes required arguments):

  • path* => str

    (No description)

Returns an enveloped result (an array).

First element ($status_code) is an integer containing HTTP-like status code (200 means OK, 4xx caller error, 5xx function error). Second element ($reason) is a string containing error message, or something like "OK" if status is 200. Third element ($payload) is the actual result, but usually not present when enveloped result is an error response ($status_code is not 2xx). Fourth element (%result_meta) is called result metadata and is optional, a hash that contains extra information, much like how HTTP response headers provide additional metadata.

Return value: (buf)

write_file

Usage:

 write_file(%args) -> [$status_code, $reason, $payload, \%result_meta]

This function demonstrates input streaming of bytes.

To do input streaming, on the function side, you just specify one your args with the stream property set to true (stream => 1). In this example, the content argument is set to streaming.

If you run the function through Perinci::CmdLine, you'll get a coderef instead of the actual value. You can then repeatedly call the code to read data. This currently works for local functions only. As of this writing, Riap::HTTP protocol does not support input streaming. It supports partial input though (see the documentation on how this works) and theoretically streaming can be emulated by client library using partial input. However, client like Perinci::Access::HTTP::Client does not yet support this.

Note that the argument's schema is still buf*, not code*.

Note: This function overwrites existing file.

This function is not exported.

Arguments ('*' denotes required arguments):

  • content* => buf

    (No description)

  • path* => str

    (No description)

Returns an enveloped result (an array).

First element ($status_code) is an integer containing HTTP-like status code (200 means OK, 4xx caller error, 5xx function error). Second element ($reason) is a string containing error message, or something like "OK" if status is 200. Third element ($payload) is the actual result, but usually not present when enveloped result is an error response ($status_code is not 2xx). Fourth element (%result_meta) is called result metadata and is optional, a hash that contains extra information, much like how HTTP response headers provide additional metadata.

Return value: (any)

HOMEPAGE

Please visit the project's homepage at https://metacpan.org/release/Perinci-Examples.

SOURCE

Source repository is at https://github.com/perlancar/perl-Perinci-Examples.

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, Pod::Weaver::PluginBundle::Author::PERLANCAR, and sometimes one or two other Dist::Zilla- and/or Pod::Weaver plugins. Any additional steps required beyond that are considered a bug and can be reported to me.

COPYRIGHT AND LICENSE

This software is copyright (c) 2023, 2022, 2020, 2019, 2018, 2017, 2016, 2015, 2014, 2013, 2012, 2011 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=Perinci-Examples

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.