如何使用AnyEvent :: HTTP获取页面的一部分？

Question

有必要只读取部分页面（n字节）并关闭连接，如何在AnyEvent :: HTTP上执行此操作？

Answer 1

on_body随着块到达而被重复调用。从on_body返回错误将终止下载。

sub my_http_request { 
    my $cb = pop; 
    my ($method, $url, %args) = @_; 

    croak("Unsupported: on_body")   if $args{on_body}; 
    croak("Unsupported: want_body_handle") if $args{want_body_handle}; 

    my $max_to_read = delete($args{max_to_read}); 

    my $data; 
    return http_request(
     $method => $url, 
     %args, 
     on_body => sub { 
     #my ($chunk, $headers) = @_; 
     $data .= $_[0]; 
     return !defined($max_to_read) || length($data) < $max_to_read; 
     }, 
     sub { 
     my (undef, $headers) = @_; 
     $cb->($data, $headers); 
     }, 
    ); 
} 

---

使用my_http_request就像http_request，除了它接受一个可选的参数max_to_read。

例如，

my $cb = AnyEvent->condvar(); 
my_http_request(
    GET => 'http://...', 
    ... 
    max_to_read => ..., 
    $cb, 
); 

my ($data, $headers) = $cb->recv(); 

例如，

my $done = AnyEvent->condvar(); 
my_http_request(
    GET => 'http://...', 
    ... 
    max_to_read => ..., 
    sub { 
     my ($data, $headers) = @_; 
     ... 
     $done->send(); 
    }, 
); 

$done->recv();