From: Matt S Trout <mst@shadowcat.co.uk>
Date: Sun, 22 Nov 2009 08:07:00 +0000 (-0500)
Subject: subdispatch
X-Git-Tag: v0.003~46
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=795c4698606dcaac5f660d9c759cda2474038eae;hp=da8429c93d5e013a72456da945681cb2a84aaf80;p=catagits%2FWeb-Simple.git

subdispatch
---

diff --git a/examples/dispatchex/dispatchex.cgi b/examples/dispatchex/dispatchex.cgi
new file mode 100644
index 0000000..9c357a5
--- /dev/null
+++ b/examples/dispatchex/dispatchex.cgi
@@ -0,0 +1,29 @@
+use Web::Simple 'DispatchEx';
+
+package DispatchEx;
+
+dispatch [
+  filter_response {
+    [ 200, [ 'Content-type' => 'text/plain' ], $_[1] ];
+  },
+  subdispatch sub (.html) {
+    [
+      filter_response { [ @{$_[1]}, '.html' ] },
+      sub (/foo) { [ '/foo' ] },
+    ]
+  },
+  subdispatch sub (/domain/*/...) {
+    return unless (my $domain_id = $_[1]) =~ /^\d+$/;
+    [
+      sub (/) {
+        [ "Domain ${domain_id}" ]
+      },
+      sub (/user/*) {
+        return unless (my $user_id = $_[1]) =~ /^\d+$/;
+        [ "Domain ${domain_id} user ${user_id}" ]
+      }
+    ]
+  }
+];
+
+DispatchEx->run_if_script;
diff --git a/lib/Web/Simple.pm b/lib/Web/Simple.pm
index 5307bbb..f4b28f0 100644
--- a/lib/Web/Simple.pm
+++ b/lib/Web/Simple.pm
@@ -36,6 +36,9 @@ sub _export_into {
     *{"${app_package}::redispatch_to"} = sub {
       $app_package->_construct_redispatch($_[0]);
     };
+    *{"${app_package}::subdispatch"} = sub ($) {
+      $app_package->_construct_subdispatch($_[0]);
+    };
     *{"${app_package}::default_config"} = sub {
       $app_package->_setup_default_config(@_);
     };
@@ -149,6 +152,8 @@ It also exports the following subroutines:
 
   redispatch_to '/somewhere';
 
+  subdispatch sub (...) { ... }
+
 and creates a $self global variable in your application package, so you can
 use $self in dispatch subs without violating strict (Web::Simple::Application
 arranges for dispatch subroutines to have the correct $self in scope when
@@ -251,6 +256,26 @@ Thus if you receive a POST to '/some/url' and return a redipstch to
 '/other/url', the dispatch behaviour will be exactly as if the same POST
 request had been made to '/other/url' instead.
 
+=head2 subdispatch
+
+  subdispatch sub (/user/*/) {
+    my $u = $self->user($_[1]);
+    [
+      sub (GET) { $u },
+      sub (DELETE) { $u->delete },
+    ]
+  }
+
+The subdispatch subroutine is designed for use in dispatcher construction.
+
+It creates a dispatcher which, if it matches, treats its return value not
+as a final value but an arrayref of dispatch specifications such as could
+be passed to the dispatch subroutine itself. These are turned into a dispatcher
+which is then invoked. Any changes the match makes to the request are in
+scope for this inner dispatcher only - so if the initial match is a
+destructive one like .html the full path will be restored if the
+subdispatch fails.
+
 =head1 DISPATCH STRATEGY
 
 =head2 Description of the dispatcher object
diff --git a/lib/Web/Simple/Application.pm b/lib/Web/Simple/Application.pm
index 2a5831b..e11eef7 100644
--- a/lib/Web/Simple/Application.pm
+++ b/lib/Web/Simple/Application.pm
@@ -25,7 +25,7 @@ use warnings FATAL => 'all';
 
   sub dispatch {
     my ($self, $env, @args) = @_;
-    my $next = $self->next;
+    my $next = $self->_has_match ? $self->next : undef;
     if (my ($env_delta, @match) = $self->_match_against($env)) {
       if (my ($result) = $self->_execute_with(@args, @match)) {
         if ($self->_is_dispatcher($result)) {
@@ -36,9 +36,18 @@ use warnings FATAL => 'all';
         }
       }
     }
+    return () unless $next;
     return $next->dispatch($env, @args);
   }
 
+  sub call {
+    @_ > 1
+      ? $_[0]->{call} = $_[1]
+      : shift->{call}
+  }
+
+  sub _has_match { $_[0]->{match} }
+
   sub _match_against {
      return ({}, $_[1]) unless $_[0]->{match};
      $_[0]->{match}->($_[1]);
@@ -81,7 +90,9 @@ sub _construct_response_filter {
   $_[0]->_build_dispatcher({
     call => sub {
       my ($d, $self, $env) = (shift, shift, shift);
-      $self->_run_with_self($code, $d->next->dispatch($env, $self, @_));
+      my @next = $d->next->dispatch($env, $self, @_);
+      return unless @next;
+      $self->_run_with_self($code, @next);
     },
   });
 }
@@ -112,36 +123,75 @@ sub _cannot_call_twice {
 }
 
 sub _setup_dispatcher {
-  my ($class, $dispatch_subs) = @_;
+  my ($class, $dispatch_specs) = @_;
   {
     no strict 'refs';
     if (${"${class}::_dispatcher"}{CODE}) {
       $class->_cannot_call_twice('_setup_dispatcher', 'dispatch');
     }
   }
+  my $chain = $class->_build_dispatch_chain(
+    [ @$dispatch_specs, $class->_build_final_dispatcher ]
+  );
+  {
+    no strict 'refs';
+    *{"${class}::_dispatcher"} = sub { $chain };
+  }
+}
+
+sub _construct_subdispatch {
+  my ($class, $dispatch_spec) = @_;
+  my $disp = $class->_build_dispatcher_from_spec($dispatch_spec);
+  my $call = $disp->call;
+  $disp->call(sub {
+    my @res = $call->(@_);
+    return unless @res;
+    my $chain = $class->_build_dispatch_chain(@res);
+    return $class->_build_dispatcher({
+      call => sub {
+        my ($d, $self, $env) = (shift, shift, shift);
+        return $chain->dispatch($env, $self, @_);
+      }
+    });
+  });
+  return $class->_build_dispatcher({
+    call => sub {
+      my ($d, $self, $env) = (shift, shift, shift);
+      my @sub = $disp->dispatch($env, $self, @_);
+      return @sub if @sub;
+      return unless (my $next = $d->next);
+      return $next->dispatch($env, $self, @_);
+    },
+  });
+}
+
+sub _build_dispatcher_from_spec {
+  my ($class, $spec) = @_;
+  return $spec unless ref($spec) eq 'CODE';
+  my $proto = prototype $spec;
   my $parser = $class->_build_dispatch_parser;
+  my $matcher = (
+    defined($proto)
+      ? $parser->parse_dispatch_specification($proto)
+      : undef
+  );
+  return $class->_build_dispatcher({
+    match => $matcher,
+    call => sub { shift;
+      shift->_run_with_self($spec, @_)
+    },
+  });
+}
+
+sub _build_dispatch_chain {
+  my ($class, $dispatch_specs) = @_;
   my ($root, $last);
-  foreach my $dispatch_sub (@$dispatch_subs) {
-    my $proto = prototype $dispatch_sub;
-    my $matcher = (
-      defined($proto)
-        ? $parser->parse_dispatch_specification($proto)
-        : undef
-    );
-    my $new = $class->_build_dispatcher({
-      match => $matcher,
-      call => sub { shift;
-        shift->_run_with_self($dispatch_sub, @_)
-      },
-    });
+  foreach my $dispatch_spec (@$dispatch_specs) {
+    my $new = $class->_build_dispatcher_from_spec($dispatch_spec);
     $root ||= $new;
     $last = $last ? $last->next($new) : $new;
   }
-  $last->next($class->_build_final_dispatcher);
-  {
-    no strict 'refs';
-    *{"${class}::_dispatcher"} = sub { $root };
-  }
+  return $root;
 }
 
 sub _build_dispatcher {