如果我理解正确,PSGI应用程序将作为下一个：
>从浏览器获得请求
>请求通过顺序中的某些中间件“起泡”,因为它们是在构建器中定义的
>请求来到我的应用程序
>我的应用程序产生一些回应
>这通过一些中间件再次响应泡沫
>最后将响应发送到浏览器
当请求登陆我的$app时,我可以轻松地调试打印所有标题(例如cookie).
问题是：
如何通过许多中间件向我的应用程序发出请求,同时响应通过中间件再次出现时,如何调试打印标题的实际状态.
所以,有一个(简单的)app.psgi,就像下一个：
use strict;
use warnings;
use Plack::Builder;
my $app = sub { ... };
builder {
# <- debug-print the first request headers
# and the last respond headers here
enable "Debug";
# <- debug-print the actual state of request/respond headers here
enable "mid2";
# <- and here
enable "mid3";
# <- and here
$app; # <- and finally here - this is of course EASY
}
它可能不像是那样容易,
print STDERR Dumper $dont_know_what->request->headers(); #HTTP::Headers ??? print STDERR Dumper $dont_know_what->respond->headers();
所以加一个赏金:);)
解决方法
中间件
package ShowMeTheHeaders;
use parent "Plack::Middleware";
use Plack::Request;
use Plack::Response
require Text::Wrap;
my $_call_back = sub {
my $response = Plack::Response->new(@{+shift});
print "* Response Headers:\n",Text::Wrap::wrap("\t","\t",$response->headers->as_string);
return; # Explicit return suggested by docs.
};
sub call {
my $self = shift;
my $request = Plack::Request->new(shift);
print "* Request Headers:\n",$request->headers->as_string);
my $response = $self->app->($request);
Plack::Util::response_cb($response,$_call_back);
}
1;
您可以在没有客观化的情况下执行此操作(Plack::Request和Plack::Response),但是您必须处理标题字段的原始属性和键,而不是完全更愉快的> as_string.另见Plack::Middleware的“响应回调”部分.
演示psgi
use warnings;
use strict;
use Plack::Builder;
my $app = sub {
[ 200,[ "Content-Type" => "text/plain" ],[ "O HAI,PLAK!" ]
];
};
builder {
enable "+ShowMeTheHeaders";
mount "/" => $app;
};