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package Perinci::Examples::FileStream;

use 5.010;
use strict;
use warnings;

use Fcntl qw(:DEFAULT);

our $AUTHORITY = 'cpan:PERLANCAR'; # AUTHORITY
our $DATE = '2024-07-17'; # DATE
our $DIST = 'Perinci-Examples'; # DIST
our $VERSION = '0.825'; # VERSION

our %SPEC;

$SPEC{':package'} = {
    v => 1.1,
    summary => 'Examples for reading/writing files (using streaming result)',
    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
<pm:Perinci::Examples> is exposed to the network by accident.

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

_
};

$SPEC{read_file} = {
    v => 1.1,
    args => {
        path => {schema=>'str*', req=>1, pos=>0},
    },
    result => {schema=>'buf*', stream=>1},
    description => <<'_',

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 <pm: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
<pod:Riap::HTTP> (version 1.2) and <pm:Perinci::Access::HTTP::Client>. Streams
are translated into HTTP chunks.

_
};
sub read_file {
    my %args = @_; my $arg_err; { no warnings ('void');if (exists($args{'path'})) { ((defined($args{'path'})) ? 1 : (($arg_err //= "Required but not specified"),0)) && ((!ref($args{'path'})) ? 1 : (($arg_err //= "Not of type text"),0)); if ($arg_err)...

    my $path = $args{path};
    (-f $path) or return [404, "No such file '$path'"];

    open my($fh), "<", $path or return [500, "Can't open '$path': $!"];

    [200, "OK", sub { scalar <$fh> }, {stream=>1}];
}

$SPEC{write_file} = {
    v => 1.1,
    description => <<'_',

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 <pm: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,
<pod: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 <pm: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.

_
    args => {
        path => {schema=>'str*', req=>1, pos=>0},
        content => {schema=>'buf*', req=>1, pos=>1, stream=>1,
                    cmdline_src=>'stdin_or_files',
                },
    },
};
sub write_file {
    my %args = @_; my $arg_err; { no warnings ('void');if (exists($args{'content'})) { ((defined($args{'content'})) ? 1 : (($arg_err //= "Required but not specified"),0)) && ((!ref($args{'content'})) ? 1 : (($arg_err //= "Not of type buffer"),0)); if...

    my $path = $args{path};

    open my($fh), ">", $path
        or return [500, "Can't open '$path' for writing: $!"];
    my $content = $args{content};
    my $written = 0;
    if (ref($content)) {
        local $_;
        while (defined($_ = $content->())) {
            print $fh $_; $written += length($_);
        }
    } else {
        print $fh $content;
        $written += length($content);
    }

    [200, "Wrote $written byte(s)"];
}

$SPEC{append_file} = {
    v => 1.1,
    description => <<'_',

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

_
    args => {
        path => {schema=>'str*', req=>1, pos=>0},
        content => {schema=>'buf*', req=>1, pos=>1, stream=>1,
                    cmdline_src=>'stdin_or_files'},
    },
};
sub append_file {
    my %args = @_; my $arg_err; { no warnings ('void');if (exists($args{'content'})) { ((defined($args{'content'})) ? 1 : (($arg_err //= "Required but not specified"),0)) && ((!ref($args{'content'})) ? 1 : (($arg_err //= "Not of type buffer"),0)); if...

    my $path = $args{path};

    open my($fh), ">>", $path
        or return [500, "Can't open '$path' for writing: $!"];
    my $content = $args{content};
    my $written = 0;
    if (ref($content)) {
        local $_;
        while (defined($_ = $content->())) {
            print $fh $_; $written += length($_);
        }
    } else {
        print $fh $content;
        $written += length($content);
    }

    [200, "Appended $written byte(s)"];
}

1;
# ABSTRACT: Examples for reading/writing files (using streaming result)

__END__

=pod

=encoding UTF-8

=head1 NAME

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

=head1 VERSION

This document describes version 0.825 of Perinci::Examples::FileStream (from Perl distribution Perinci-Examples), released on 2024-07-17.

=head1 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
L<Perinci::Examples> is exposed to the network by accident.

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

=head1 FUNCTIONS


=head2 append_file

Usage:

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

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

This function is not exported.

Arguments ('*' denotes required arguments):

=over 4

=item * B<content>* => I<buf>

(No description)

=item * B<path>* => I<str>

(No description)


=back

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)



=head2 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 L<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
L<Riap::HTTP> (version 1.2) and L<Perinci::Access::HTTP::Client>. Streams
are translated into HTTP chunks.

This function is not exported.

Arguments ('*' denotes required arguments):

=over 4

=item * B<path>* => I<str>

(No description)


=back

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)



=head2 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 C<stream> property set to true (C<< stream =E<gt> 1 >>). In this example, the
C<content> argument is set to streaming.

If you run the function through L<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,
L<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 L<Perinci::Access::HTTP::Client> does not yet support this.

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

Note: This function overwrites existing file.

This function is not exported.

Arguments ('*' denotes required arguments):

=over 4

=item * B<content>* => I<buf>

(No description)

=item * B<path>* => I<str>

(No description)


=back

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)

=head1 HOMEPAGE

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

=head1 SOURCE

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

=head1 AUTHOR

perlancar <perlancar@cpan.org>

=head1 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 L<Dist::Zilla>,
L<Dist::Zilla::PluginBundle::Author::PERLANCAR>,