download file via perl IO module

dl_via_IO.pl

#!/usr/bin/perl

use strict;
use warnings;
use IO::Socket::INET;
use IO::Socket::SSL;

my $proxy_host = 'proxy.boss.com';
my $proxy_port = 3128;
my $dest_host  = 'github.com';
my $dest_port  = 443;
my $path       = '/AUTHOR/REPOSITORY/archive/refs/heads/master.zip';
my $filename   = '/tmp/master.zip';

sub read_chunked_response {
    my ($sock) = @_;
    my $body = '';

    while (1) {
        # Читаем размер текущего чанка (шестнадцатеричное число + \r\n)
        my $size_line = '';
        while (<$sock>) {
            $size_line .= $_;
            last if /\r\n$/;
        }
        chomp($size_line);
        $size_line =~ s/\r$//;

        # Преобразуем размер из hex в десятичное
        my $chunk_size = hex($size_line);

        # Если размер 0 — конец потока
        last if $chunk_size == 0;

        # Читаем ровно $chunk_size байт данных
        my $data = '';
        my $bytes_read = 0;
        while ($bytes_read < $chunk_size) {
            my $chunk;
            my $ret = sysread($sock, $chunk, $chunk_size - $bytes_read);
            die "Read error" unless defined $ret;
            last unless $ret;
            $data .= $chunk;
            $bytes_read += $ret;
        }

        # Добавляем прочитанные данные к телу ответа
        $body .= $data;

        # Пропускаем \r\n после данных чанка
        <$sock>;  # читаем и игнорируем \r\n
    }

    return $body;
}

sub download_with_redirects {
    my ($host, $port, $path, $redirect_count) = @_;
    $redirect_count ||= 0;
    if ($redirect_count > 5) {
        die "Too many redirects\n";
    }

    # Подключаемся к прокси
    my $sock = IO::Socket::INET->new(
        PeerAddr => $proxy_host,
        PeerPort => $proxy_port,
        Proto    => 'tcp'
    ) or die "Cannot connect to proxy: $!";

    print $sock "CONNECT $host:$port HTTP/1.1\r\n";
    print $sock "Host: $host\r\n";
    print $sock "\r\n";

    my $connect_resp = '';
    while (<$sock>) {
        $connect_resp .= $_;
        last if /^\s*$/;
    }
    unless ($connect_resp =~ /^HTTP\/1\.\d\s+200/) {
        close $sock;
        die "Proxy CONNECT failed: $connect_resp";
    }

    # Устанавливаем SSL
    my $ssl_sock = IO::Socket::SSL->start_SSL(
        $sock,
        SSL_startHandshake => 1,
        PeerHost           => $host
    ) or die "SSL handshake failed: $SSL_ERROR";

    # Отправляем запрос
    print $ssl_sock "GET $path HTTP/1.1\r\n";
    print $ssl_sock "Host: $host\r\n";
    print $ssl_sock "User-Agent: Perl\r\n";
    print $ssl_sock "Connection: close\r\n";
    print $ssl_sock "\r\n";

    # Читаем заголовки
    my $headers = '';
    while (<$ssl_sock>) {
        $headers .= $_;
        last if /^\s*$/;
    }

    # Проверяем статус
    unless ($headers =~ /^HTTP\/1\.\d\s+200\s+OK/i) {
        if ($headers =~ /^HTTP\/1\.\d\s+(\d+)/) {
            my $status = $1;
            if ($status == 301 || $status == 302) {
                # Обработка редиректов
                if ($headers =~ /^Location:\s*(.*?)\r?$/im) {
                    my $new_url = $1;
                    if ($new_url =~ m!^https?://([^/]+)(.*)$!) {
                        my $new_host = $1;
                        my $new_path = $2 || '/';
                        return download_with_redirects($new_host, 443, $new_path, $redirect_count + 1);
                    } else {
                        die "Invalid redirect URL: $new_url\n";
                    }
                } else {
                    die "Redirect without Location header\n";
                }
            } else {
                die "HTTP error: $status\n";
            }
        } else {
            die "Invalid response from server\n";
        }
    }

    # Проверяем, используется ли chunked encoding
    my $is_chunked = $headers =~ /Transfer-Encoding:\s*chunked/i;

    my $body;
    if ($is_chunked) {
        $body = read_chunked_response($ssl_sock);
    } else {
        # Обычный режим: читаем до закрытия соединения
        $body = '';
        my $chunk;
        while (sysread($ssl_sock, $chunk, 8192)) {
            $body .= $chunk;
        }
    }

    close $ssl_sock;
    return $body;
}

# Запускаем загрузку
my $content = download_with_redirects($dest_host, $dest_port, $path);

# Сохраняем файл
open(my $fh, '>', $filename) or die "Can't open file: $!\n";
binmode $fh;
print $fh $content;
close $fh;

print "File saved as $filename (size: " . length($content) . " bytes)\n";