MCP/Server/Request.pm

=head1 NAME

AnyEvent::MCP::Server::Request - one MCP request

=head1 DESCRIPTION

Each incoming request gets a Request object. The handler can reply
immediately, or keep the object and reply when asynchronous work finishes.
Returning from the handler does not complete the request; calling
C<reply>, C<result> or C<error> does.

There is one important consequence: do not reply after cancellation or after
another callback has already completed the request. Check C<finished> in
late asynchronous callbacks. A second reply is a programming error.

You normally receive this object as the first argument to a
L<AnyEvent::MCP::Server::Toolset> callback. See
L<AnyEvent::MCP::Server::Simple/TUTORIAL> for complete synchronous and
asynchronous examples rather than constructing requests yourself.

=head1 PUBLIC FIELDS

Request fields are accessed directly through the hash.

=over

=item $req->{server}

The server handling this request.

=item $req->{id}

The JSON-RPC request id, used to associate the response with the request.

=item $req->{method}

The JSON-RPC method name, such as C<tools/call>.

=item $req->{protocol_version}

The protocol revision used for this request. Modern requests supply it in
C<_meta>; legacy requests use the initialized peer or HTTP version.

=item $req->{peer}

The connection's peer hash reference, supplied by the transport or embedder.
It holds transport context and legacy state, rather than a user identity.
Modern client identity and capabilities come from this request's C<_meta>.

=item $req->{params}

The original decoded JSON-RPC parameters. For a tool call, this hash contains
C<name>, C<arguments> and any C<_meta> supplied by the client. These are the
protocol parameters, rather than just the tool arguments.

=item $req->{tool}

The tool name from C<< $req->{params}{name} >>. Present for tool calls.

=item $req->{args}

The tool argument hash reference from C<< $req->{params}{arguments} >>.
Present for tool calls. The tool callback also receives this same reference
as its second parameter, for convenience.

=item $req->{toolset}

The Toolset invoking the tool callback. Set by the Toolset when it dispatches
the call; absent for requests dispatched without a Toolset.

=item $req->{finished}

True after a reply or cancellation. Replying to a finished request is an
error. Notifications and progress after completion are ignored.

=item $req->{cancelled}

True if the request was cancelled. An asynchronous handler can check this
before attempting to reply.

=back

=head1 METHODS

=over

=item $grant = $req->require_permission ({ %request })

Synchronously checks a permission request using the server's C<permissions>
object. C<%request> has the fields described by
L<AnyEvent::MCP::Server::Permissions/check>. Returns the granted sandbox-grant
array reference; it can be reduced from the requested set.

A denial dies. A missing permission throws a special exception handled by
Server, which asks and retries the handler. Multiple checks are supported:
one-time grants belong to this tool invocation and survive permission retries.
They do not authorize later calls. Current rules are checked on every retry.

Complete all checks before side effects or asynchronous work starts.
The handler can run more than once. Do not catch the permission exception
as an ordinary tool error; let it reach Server's dispatch boundary.

=item $req->reply ($result)

Completes the request with the MCP result hash reference C<$result>. The
server adds the JSON-RPC envelope. Tools do not construct JSON-RPC errors.
Dies if the request has already finished.

Use this method for arbitrary MCP results, including structured errors,
large results and results requiring a particular content representation.

=item $req->error ($message)

Replies with C<isError> set to true and C<$message> as one text content item.
Use C<reply> for errors with structured content or other content types.

=item $req->result ($data)

Replies with the hash reference C<$data> as C<structuredContent>, and its
JSON encoding as one text content item for clients that consume only text.

This deliberately duplicates the data. Use C<reply> for large results or
when JSON text is unsuitable, including clients that encode text as JSON
again. Arrays and scalars must be wrapped in an object explicitly.

=item $req->notify ($method, $params)

Sends a notification associated with this request. C<$method> is the
notification method name and C<$params> its parameter hash reference.

A notification does not complete the request. Delivery is best effort:
notifications can be dropped if the transport does not implement delivery.
Calls after completion are ignored.

=item $req->progress ($progress, $total, $message)

Sends a progress notification if the client supplied a progress token in
C<< $req->{params}{_meta}{progressToken} >>. C<$progress> is the amount
completed; C<$total> and C<$message> can be omitted or undefined.

Uses C<notify>, with the same best-effort delivery. Calls after completion
are ignored.

=item $req->cancel ($reason)

Marks the request as cancelled and calls C<on_cancel>, allowing the handler
to stop work and release resources. C<$reason> is an optional explanation.

Cancellation completes the transport's request bookkeeping without sending
a JSON-RPC response.

=back

=head1 EVENTS

These callbacks are stored in the request hash like other MCP events.

=over

=item on_reply => $callback->($req, $result)

Called once when the request is completed with C<reply>. The server installs
C<$callback> to deliver the result.

=item on_notify => $callback->($req, $method, $params)

Called for each notification while the request is active. The server installs
C<$callback> to deliver notifications through the transport.

=item on_cancel => $callback->($req, $reason)

Called once when the request is cancelled. A handler can set C<$callback>
to cancel its asynchronous operation.

=back

=cut

package AnyEvent::MCP::Server::Request;

use common::sense;
use AnyEvent::MCP ();
use JSON::XS ();

our @ISA = qw(AnyEvent::MCP::Base);

sub require_permission {
   my ($self, $request) = @_;

   my $permissions = $self->{server}{permissions}
      or die "Server has no permission configuration\n";

   $permissions->require_permission ($self, $request)
}

sub reply {
   my ($self, $result) = @_;

   die "MCP request already finished\n"
      if $self->{finished};

   $self->{finished} = 1;

   my $reply = delete $self->{on_reply};
   delete @$self{qw(on_notify on_cancel _reply)};

   $reply->($self, $result) if $reply
}

sub error {
   my ($self, $message) = @_;

   $self->reply ({
      isError => JSON::XS::true,
      content => [{ type => "text", text => $message }],
   })
}

sub result {
   my ($self, $data) = @_;

   ref $data eq "HASH"
      or die "MCP structured result must be an object\n";

   $self->reply ({
      structuredContent => $data,
      content           => [{ type => "text", text => JSON::XS->new->encode ($data) }],
   })
}

sub notify {
   my ($self, $method, $params) = @_;

   return if $self->{finished};

   $self->event (notify => $method, $params)
}

sub progress {
   my ($self, $progress, $total, $message) = @_;

   return unless $self->{on_notify} && !$self->{finished};

   my $meta = $self->{params}{_meta}
      or return;

   return unless exists $meta->{progressToken};

   my $params = {
      progressToken => $meta->{progressToken},
      progress      => $progress,
   };

   $params->{total}   = $total   if defined $total;
   $params->{message} = $message if defined $message;

   $self->notify ("notifications/progress", $params)
}

sub cancel {
   my ($self, $reason) = @_;

   return if $self->{finished};
   $self->{finished} = $self->{cancelled} = 1;

   delete $self->{peer}{requests}{$self->{id}}
      if $self->{peer};

   my $cancel = delete $self->{on_cancel};
   my $reply = delete $self->{_reply};
   delete @$self{qw(on_reply on_notify)};

   $cancel->($self, $reason) if $cancel;
   $reply->(undef) if $reply
}

1
Revision:	1.6
Committed:	Wed Oct 21 17:28:16 2026 UTC (3 weeks, 2 days ago) by root
Branch:	MAIN
CVS Tags:	rel-0_81, rel-0_82, rel-0_71, rel-0_61, rel-0_65, rel-0_6, rel-0_7, rel-0_8, rel-0_62
Changes since 1.5:	+5 -0 lines
Log Message:	* empty log message *
#	User	Rev	Content
1	root	1.1	=head1 NAME
2
3			AnyEvent::MCP::Server::Request - one MCP request
4
5			=head1 DESCRIPTION
6
7	root	1.2	Each incoming request gets a Request object. The handler can reply
8			immediately, or keep the object and reply when asynchronous work finishes.
9			Returning from the handler does not complete the request; calling
10			C<reply>, C<result> or C<error> does.
11
12			There is one important consequence: do not reply after cancellation or after
13			another callback has already completed the request. Check C<finished> in
14			late asynchronous callbacks. A second reply is a programming error.
15	root	1.1
16	root	1.6	You normally receive this object as the first argument to a
17			L<AnyEvent::MCP::Server::Toolset> callback. See
18			L<AnyEvent::MCP::Server::Simple/TUTORIAL> for complete synchronous and
19			asynchronous examples rather than constructing requests yourself.
20
21	root	1.1	=head1 PUBLIC FIELDS
22
23			Request fields are accessed directly through the hash.
24
25	root	1.2	=over
26	root	1.1
27			=item $req->{server}
28
29			The server handling this request.
30
31			=item $req->{id}
32
33			The JSON-RPC request id, used to associate the response with the request.
34
35			=item $req->{method}
36
37			The JSON-RPC method name, such as C<tools/call>.
38
39			=item $req->{protocol_version}
40
41			The protocol revision used for this request. Modern requests supply it in
42			C<_meta>; legacy requests use the initialized peer or HTTP version.
43
44			=item $req->{peer}
45
46			The connection's peer hash reference, supplied by the transport or embedder.
47			It holds transport context and legacy state, rather than a user identity.
48			Modern client identity and capabilities come from this request's C<_meta>.
49
50			=item $req->{params}
51
52			The original decoded JSON-RPC parameters. For a tool call, this hash contains
53			C<name>, C<arguments> and any C<_meta> supplied by the client. These are the
54			protocol parameters, rather than just the tool arguments.
55
56			=item $req->{tool}
57
58			The tool name from C<< $req->{params}{name} >>. Present for tool calls.
59
60			=item $req->{args}
61
62			The tool argument hash reference from C<< $req->{params}{arguments} >>.
63			Present for tool calls. The tool callback also receives this same reference
64			as its second parameter, for convenience.
65
66			=item $req->{toolset}
67
68			The Toolset invoking the tool callback. Set by the Toolset when it dispatches
69			the call; absent for requests dispatched without a Toolset.
70
71			=item $req->{finished}
72
73			True after a reply or cancellation. Replying to a finished request is an
74			error. Notifications and progress after completion are ignored.
75
76			=item $req->{cancelled}
77
78			True if the request was cancelled. An asynchronous handler can check this
79			before attempting to reply.
80
81			=back
82
83			=head1 METHODS
84
85	root	1.4	=over
86
87			=item $grant = $req->require_permission ({ %request })
88	root	1.1
89			Synchronously checks a permission request using the server's C<permissions>
90			object. C<%request> has the fields described by
91	root	1.4	L<AnyEvent::MCP::Server::Permissions/check>. Returns the granted sandbox-grant
92	root	1.1	array reference; it can be reduced from the requested set.
93
94			A denial dies. A missing permission throws a special exception handled by
95			Server, which asks and retries the handler. Multiple checks are supported:
96			one-time grants belong to this tool invocation and survive permission retries.
97			They do not authorize later calls. Current rules are checked on every retry.
98
99			Complete all checks before side effects or asynchronous work starts.
100			The handler can run more than once. Do not catch the permission exception
101			as an ordinary tool error; let it reach Server's dispatch boundary.
102
103	root	1.4	=item $req->reply ($result)
104	root	1.1
105			Completes the request with the MCP result hash reference C<$result>. The
106			server adds the JSON-RPC envelope. Tools do not construct JSON-RPC errors.
107			Dies if the request has already finished.
108
109			Use this method for arbitrary MCP results, including structured errors,
110			large results and results requiring a particular content representation.
111
112	root	1.4	=item $req->error ($message)
113	root	1.1
114			Replies with C<isError> set to true and C<$message> as one text content item.
115			Use C<reply> for errors with structured content or other content types.
116
117	root	1.4	=item $req->result ($data)
118	root	1.1
119			Replies with the hash reference C<$data> as C<structuredContent>, and its
120			JSON encoding as one text content item for clients that consume only text.
121
122			This deliberately duplicates the data. Use C<reply> for large results or
123			when JSON text is unsuitable, including clients that encode text as JSON
124			again. Arrays and scalars must be wrapped in an object explicitly.
125
126	root	1.4	=item $req->notify ($method, $params)
127	root	1.1
128			Sends a notification associated with this request. C<$method> is the
129			notification method name and C<$params> its parameter hash reference.
130
131			A notification does not complete the request. Delivery is best effort:
132			notifications can be dropped if the transport does not implement delivery.
133			Calls after completion are ignored.
134
135	root	1.4	=item $req->progress ($progress, $total, $message)
136	root	1.1
137			Sends a progress notification if the client supplied a progress token in
138			C<< $req->{params}{_meta}{progressToken} >>. C<$progress> is the amount
139			completed; C<$total> and C<$message> can be omitted or undefined.
140
141			Uses C<notify>, with the same best-effort delivery. Calls after completion
142			are ignored.
143
144	root	1.4	=item $req->cancel ($reason)
145	root	1.1
146			Marks the request as cancelled and calls C<on_cancel>, allowing the handler
147			to stop work and release resources. C<$reason> is an optional explanation.
148
149	root	1.5	Cancellation completes the transport's request bookkeeping without sending
150			a JSON-RPC response.
151	root	1.1
152	root	1.4	=back
153
154	root	1.1	=head1 EVENTS
155
156			These callbacks are stored in the request hash like other MCP events.
157
158	root	1.4	=over
159
160			=item on_reply => $callback->($req, $result)
161	root	1.1
162			Called once when the request is completed with C<reply>. The server installs
163			C<$callback> to deliver the result.
164
165	root	1.4	=item on_notify => $callback->($req, $method, $params)
166	root	1.1
167			Called for each notification while the request is active. The server installs
168			C<$callback> to deliver notifications through the transport.
169
170	root	1.4	=item on_cancel => $callback->($req, $reason)
171	root	1.1
172			Called once when the request is cancelled. A handler can set C<$callback>
173			to cancel its asynchronous operation.
174
175	root	1.4	=back
176
177	root	1.1	=cut
178
179			package AnyEvent::MCP::Server::Request;
180
181			use common::sense;
182			use AnyEvent::MCP ();
183			use JSON::XS ();
184
185			our @ISA = qw(AnyEvent::MCP::Base);
186
187			sub require_permission {
188			my ($self, $request) = @_;
189
190			my $permissions = $self->{server}{permissions}
191			or die "Server has no permission configuration\n";
192
193			$permissions->require_permission ($self, $request)
194			}
195
196			sub reply {
197			my ($self, $result) = @_;
198
199			die "MCP request already finished\n"
200			if $self->{finished};
201
202			$self->{finished} = 1;
203
204			my $reply = delete $self->{on_reply};
205			delete @$self{qw(on_notify on_cancel _reply)};
206
207			$reply->($self, $result) if $reply
208			}
209
210			sub error {
211			my ($self, $message) = @_;
212
213			$self->reply ({
214			isError => JSON::XS::true,
215			content => [{ type => "text", text => $message }],
216			})
217			}
218
219			sub result {
220			my ($self, $data) = @_;
221
222	root	1.3	ref $data eq "HASH"
223			or die "MCP structured result must be an object\n";
224	root	1.1
225			$self->reply ({
226			structuredContent => $data,
227			content => [{ type => "text", text => JSON::XS->new->encode ($data) }],
228			})
229			}
230
231			sub notify {
232			my ($self, $method, $params) = @_;
233
234			return if $self->{finished};
235
236			$self->event (notify => $method, $params)
237			}
238
239			sub progress {
240			my ($self, $progress, $total, $message) = @_;
241
242			return unless $self->{on_notify} && !$self->{finished};
243
244			my $meta = $self->{params}{_meta}
245			or return;
246
247			return unless exists $meta->{progressToken};
248
249			my $params = {
250			progressToken => $meta->{progressToken},
251			progress => $progress,
252			};
253
254			$params->{total} = $total if defined $total;
255			$params->{message} = $message if defined $message;
256
257			$self->notify ("notifications/progress", $params)
258			}
259
260			sub cancel {
261			my ($self, $reason) = @_;
262
263			return if $self->{finished};
264			$self->{finished} = $self->{cancelled} = 1;
265
266			delete $self->{peer}{requests}{$self->{id}}
267			if $self->{peer};
268
269			my $cancel = delete $self->{on_cancel};
270	root	1.5	my $reply = delete $self->{_reply};
271			delete @$self{qw(on_reply on_notify)};
272	root	1.1
273	root	1.5	$cancel->($self, $reason) if $cancel;
274			$reply->(undef) if $reply
275	root	1.1	}
276
277			1