Re: about request route

On 07.08.2017 13:18, 风河 wrote:
> Hi,
>
> for this like request:
> curlhttp://dns-api.org/AAAA/dns-api.org
>
> in Dancer we could write:
>
> get '/:type/:domain/?' => sub {
>
>      my $rtype  = params->{ 'type' };
>      my $domain = params->{ 'domain' };
>
>
> But in a MP handler, how could we get the similiar result, treating request path as
> GET/POST arguments?
>

Well, fundamentally you could not treat the request path, transparently, as a GET/POST 
argument. That is precisely the kind of thing which a framework such as Dancer allows you 
to do : "abstracting" the fundamental difference which exists at the HTTP level (and the 
Apache httpd level) between a request path and e.g. the parameters in a query string, and 
make them "kind of look the same" to an application, using some elegant syntax.

In a mod_perl handler, you would do this :

my $r = shift; # Request object
my $uri = $r->uri; # gets "/AAAA/dns-api.org"
my ($nothing,$type,$domain) = split('/',$uri);

# or, if you insist on treating the HTTP request path parts as "arguments" :
my @args = split('/',$uri);
@args = grep(!~#/#,@args);
my $params = {
	'type' => $args[0],
	'domain' => $args[1],
	};
# (I'm sure there is a more elegant way to do this)

mod_perl is not a framework. It gives you access from perl to the Apache internals, as 
they are deep down, but it does not "abstract" anything. For Apache "/AAAA/dns-api.org" is 
a request URI, it is not "GET/POST arguments". If this URI does not contain a "?", then 
the whole URI is a path. If it does contain a "?", then the part before the "?" is a path, 
and the part after it is a query-string, which may or may not contain key/value pairs 
which could be "parameters". Those are the underlying "apache objects", when apache has 
parsed the request.
mod_perl gives you access to these URI, path, and query-string objects of apache, but it 
does not "abstract" them further.

Dancer (and other frameworks) are different : their users want some way by which they can 
treat path components as "arguments" ? so let's provide them with some way of doing this, 
elegantly if possible. But behind the scenes, they do exactly as above. It's just that as 
a user, you don't see that.