perl - www::curl - 如何上传(发布)大文件

Question

我使用 WWW::Curl 上传文件:

use WWW::Curl::Easy 4.14;
use WWW::Curl::Form;

my $url = 'http://example.com/backups/?sid=12313qwed323';
my $params = {
    name => 'upload',
    action => 'keep',
    backup1 => [ '/tmp/backup1.zip' ],   # 1st file for upload
};

my $form = WWW::Curl::Form->new();
foreach my $k (keys %{$params}) {
    if (ref $params->{$k}) {
        $form->formaddfile(@{$params->{$k}}[0], $k, 'multipart/form-data');
    } else {
        $form->formadd($k, $params->{$k});
    }
}

my $curl = WWW::Curl::Easy->new() or die $!; 
$curl->setopt(CURLOPT_HTTPPOST, $form);
$curl->setopt(CURLOPT_URL, $url);

my $body;   
$curl->setopt(CURLOPT_WRITEDATA, \$body);
my $retcode = $curl->perform();
my $response_code = $curl->getinfo(CURLINFO_HTTP_CODE); 

这里没什么特别的，这段代码运行良好。

我想上传大文件，我不想预加载内存中的所有内容。至少那是我听说 libcurl 正在做的事情。

CURLOPT_READFUNCTION 接受返回部分内容的回调。这意味着我不能使用 WWW::Curl::Form 来设置 POST 参数，但我必须通过这个回调返回整个内容。是对的吗？

我认为代码可能如下所示:

use WWW::Curl::Easy 4.14;

my $url = 'http://example.com/backups/?sid=12313qwed323'
my $params = {
    name => 'upload',
    action => 'keep',
    backup1 => [ '/tmp/backup1.zip' ],   # 1st file for upload
};

my $fields;
foreach my $k (keys %{$params}) {
    $fields .= "$k=".(ref $params->{$k} ? '@'.@{$params->{$k}}[0] : uri_escape_utf8($params->{$k}))."&";
}
chop($fields);

my $curl = WWW::Curl::Easy->new() or die $!;
$curl->setopt(CURLOPT_POST, 1);
$curl->setopt(CURLOPT_POSTFIELDS, $fields); # is it needed with READFUNCTION??
$curl->setopt(CURLOPT_URL, $url);

my @header = ('Content-type: multipart/form-data', 'Transfer-Encoding: chunked');
$curl->setopt(CURLOPT_HTTPHEADER, \@header);

#$curl->setopt(CURLOPT_INFILESIZE, $size);
$curl->setopt(CURLOPT_READFUNCTION, sub {

    # which data to return here?
    # $params (without file) + file content?

    return 0;
});

CURLOPT_READFUNCTION 回调必须返回哪些数据？ $params + 文件内容？采用哪种格式？

我真的必须自己创建数据(由 CURLOPT_READFUNCTION 返回)还是有一种简单的方法可以以正确的格式创建数据？

谢谢

Answer 1

测试 16formpost.t是相关的。如您所见，它已完全禁用。这个事实和我对回调函数的各种返回值的徒劳实验让我相信 CURLOPT_READFUNCTION已知功能在 Perl 绑定(bind)中被破坏。

I have to return the whole content through this callback. Is that right?

不，您可以分段提供请求正文，适用于分 block 编码。根据 CURLOPT_INFILESIZE 中设置的限制，回调必然会被调用多次。 .

Which data does CURLOPT_READFUNCTION callback have to return?

HTTP 请求正文。由于您进行文件上传，这意味着 Content-Type multipart/form-data .以下是使用 HTTP::Message 的示例。 CURLOPT_HTTPPOST是另一种构造这种格式的方法。

use HTTP::Request::Common qw(POST);
use WWW::Curl::Easy 4.14;

my $curl = WWW::Curl::Easy->new or die $!;
$curl->setopt(CURLOPT_POST, 1);
$curl->setopt(CURLOPT_URL, 'http://localhost:5000');
$curl->setopt(CURLOPT_HTTPHEADER, [
    'Content-type: multipart/form-data', 'Transfer-Encoding: chunked'
]);
$curl->setopt(CURLOPT_READFUNCTION, sub {
    return POST(undef, Content_Type => 'multipart/form-data', Content => [
        name    => 'upload',
        action  => 'keep',
        backup1 => [ '/tmp/backup1.zip' ],   # 1st file for upload
    ])->content;
});
my $r = $curl->perform;