在 Plack::Builder 中挂载“主机”

Question

Plack::Builder 和 this answer 的概要说：

# in .psgi
use Plack::Builder;

my $app = sub { ... };

builder {
    mount "/foo" => builder {
        enable "Foo";
        $app;
    };

    mount "/bar" => $app2;
    mount "http://example.com/" => builder { $app3 };
};

我尝试了以下方法：

use Plack::Builder;
my $app1 = sub { return [200, ['Content-Type' => 'text/plain'], [ "Hello 1"] ]; };
my $app2 = sub { return [200, ['Content-Type' => 'text/plain'], [ "Hello 2"] ]; };
my $app3 = sub { return [200, ['Content-Type' => 'text/plain'], [ "Hello 3"] ]; };

builder {
        mount "/a1" => builder { $app1 };
        mount "http://myhost.com" => builder{ $app2 };
        mount "/" => builder{ $app3 };
}

但是当尝试使用plackup 运行它时，得到：

加载 /tmp/app.psgi 时出错：路径需要以 / 开头 /home/cw/.anyenv/envs/pleenv/versions/5.20.3/lib/perl5/site_perl/5.20.3/Plack/Builder.pm 第 108 行。

怎么了？

Answer 1

我没有在文档中明确提到这一点，但是除了主机名之外，您还必须包含一个路径组件，例如http://myhost.com/foo。改变

mount "http://myhost.com" => builder{ $app2 };

到

mount "http://myhost.com/" => builder{ $app2 };

（即主机myhost.com上的/）

相关代码在Plack::App::URLMap中（mount只是调用了Plack::App::URLMap的map方法）：

if ($location =~ m!^https?://(.*?)(/.*)!) {
    $host     = $1;
    $location = $2;
}