rmcp/model/
meta.rs

1use std::ops::{Deref, DerefMut};
2
3use serde::{Deserialize, Serialize};
4use serde_json::Value;
5
6use super::{
7    ClientNotification, ClientRequest, CustomNotification, CustomRequest, Extensions, JsonObject,
8    JsonRpcMessage, NumberOrString, ProgressToken, ServerNotification, ServerRequest,
9};
10
11pub trait GetMeta {
12    fn get_meta_mut(&mut self) -> &mut Meta;
13    fn get_meta(&self) -> &Meta;
14}
15
16pub trait GetExtensions {
17    fn extensions(&self) -> &Extensions;
18    fn extensions_mut(&mut self) -> &mut Extensions;
19}
20
21/// Trait for request params that contain the `_meta` field.
22///
23/// Per the MCP 2025-11-25 spec, all request params should have an optional `_meta`
24/// field that can contain a `progressToken` for tracking long-running operations.
25pub trait RequestParamsMeta {
26    /// Get a reference to the meta field
27    fn meta(&self) -> Option<&Meta>;
28    /// Get a mutable reference to the meta field
29    fn meta_mut(&mut self) -> &mut Option<Meta>;
30    /// Set the meta field
31    fn set_meta(&mut self, meta: Meta) {
32        *self.meta_mut() = Some(meta);
33    }
34    /// Get the progress token from meta, if present
35    fn progress_token(&self) -> Option<ProgressToken> {
36        self.meta().and_then(|m| m.get_progress_token())
37    }
38    /// Set a progress token in meta
39    fn set_progress_token(&mut self, token: ProgressToken) {
40        match self.meta_mut() {
41            Some(meta) => meta.set_progress_token(token),
42            none => {
43                let mut meta = Meta::new();
44                meta.set_progress_token(token);
45                *none = Some(meta);
46            }
47        }
48    }
49}
50
51/// Trait for task-augmented request params that contain both `_meta` and `task` fields.
52///
53/// Per the MCP 2025-11-25 spec, certain requests (like `tools/call` and `sampling/createMessage`)
54/// can include a `task` field to signal that the caller wants task-augmented execution.
55pub trait TaskAugmentedRequestParamsMeta: RequestParamsMeta {
56    /// Get a reference to the task field
57    fn task(&self) -> Option<&JsonObject>;
58    /// Get a mutable reference to the task field
59    fn task_mut(&mut self) -> &mut Option<JsonObject>;
60    /// Set the task field
61    fn set_task(&mut self, task: JsonObject) {
62        *self.task_mut() = Some(task);
63    }
64}
65
66impl GetExtensions for CustomNotification {
67    fn extensions(&self) -> &Extensions {
68        &self.extensions
69    }
70    fn extensions_mut(&mut self) -> &mut Extensions {
71        &mut self.extensions
72    }
73}
74
75impl GetMeta for CustomNotification {
76    fn get_meta_mut(&mut self) -> &mut Meta {
77        self.extensions_mut().get_or_insert_default()
78    }
79    fn get_meta(&self) -> &Meta {
80        self.extensions()
81            .get::<Meta>()
82            .unwrap_or(Meta::static_empty())
83    }
84}
85
86impl GetExtensions for CustomRequest {
87    fn extensions(&self) -> &Extensions {
88        &self.extensions
89    }
90    fn extensions_mut(&mut self) -> &mut Extensions {
91        &mut self.extensions
92    }
93}
94
95impl GetMeta for CustomRequest {
96    fn get_meta_mut(&mut self) -> &mut Meta {
97        self.extensions_mut().get_or_insert_default()
98    }
99    fn get_meta(&self) -> &Meta {
100        self.extensions()
101            .get::<Meta>()
102            .unwrap_or(Meta::static_empty())
103    }
104}
105
106macro_rules! variant_extension {
107    (
108        $Enum: ident {
109            $($variant: ident)*
110        }
111    ) => {
112        impl GetExtensions for $Enum {
113            fn extensions(&self) -> &Extensions {
114                match self {
115                    $(
116                        $Enum::$variant(v) => &v.extensions,
117                    )*
118                }
119            }
120            fn extensions_mut(&mut self) -> &mut Extensions {
121                match self {
122                    $(
123                        $Enum::$variant(v) => &mut v.extensions,
124                    )*
125                }
126            }
127        }
128        impl GetMeta for $Enum {
129            fn get_meta_mut(&mut self) -> &mut Meta {
130                self.extensions_mut().get_or_insert_default()
131            }
132            fn get_meta(&self) -> &Meta {
133                self.extensions().get::<Meta>().unwrap_or(Meta::static_empty())
134            }
135        }
136    };
137}
138
139variant_extension! {
140    ClientRequest {
141        PingRequest
142        InitializeRequest
143        CompleteRequest
144        SetLevelRequest
145        GetPromptRequest
146        ListPromptsRequest
147        ListResourcesRequest
148        ListResourceTemplatesRequest
149        ReadResourceRequest
150        SubscribeRequest
151        UnsubscribeRequest
152        CallToolRequest
153        ListToolsRequest
154        CustomRequest
155        GetTaskInfoRequest
156        ListTasksRequest
157        GetTaskResultRequest
158        CancelTaskRequest
159    }
160}
161
162variant_extension! {
163    ServerRequest {
164        PingRequest
165        CreateMessageRequest
166        ListRootsRequest
167        CreateElicitationRequest
168        CustomRequest
169    }
170}
171
172variant_extension! {
173    ClientNotification {
174        CancelledNotification
175        ProgressNotification
176        InitializedNotification
177        RootsListChangedNotification
178        CustomNotification
179    }
180}
181
182variant_extension! {
183    ServerNotification {
184        CancelledNotification
185        ProgressNotification
186        LoggingMessageNotification
187        ResourceUpdatedNotification
188        ResourceListChangedNotification
189        ToolListChangedNotification
190        PromptListChangedNotification
191        ElicitationCompletionNotification
192        CustomNotification
193    }
194}
195#[derive(Debug, Serialize, Deserialize, Clone, Default, PartialEq)]
196#[cfg_attr(feature = "schemars", derive(schemars::JsonSchema))]
197#[serde(transparent)]
198pub struct Meta(pub JsonObject);
199const PROGRESS_TOKEN_FIELD: &str = "progressToken";
200impl Meta {
201    pub fn new() -> Self {
202        Self(JsonObject::new())
203    }
204
205    /// Create a new Meta with a progress token set
206    pub fn with_progress_token(token: ProgressToken) -> Self {
207        let mut meta = Self::new();
208        meta.set_progress_token(token);
209        meta
210    }
211
212    pub(crate) fn static_empty() -> &'static Self {
213        static EMPTY: std::sync::OnceLock<Meta> = std::sync::OnceLock::new();
214        EMPTY.get_or_init(Default::default)
215    }
216
217    pub fn get_progress_token(&self) -> Option<ProgressToken> {
218        self.0.get(PROGRESS_TOKEN_FIELD).and_then(|v| match v {
219            Value::String(s) => Some(ProgressToken(NumberOrString::String(s.to_string().into()))),
220            Value::Number(n) => {
221                if let Some(i) = n.as_i64() {
222                    Some(ProgressToken(NumberOrString::Number(i)))
223                } else if let Some(u) = n.as_u64() {
224                    if u <= i64::MAX as u64 {
225                        Some(ProgressToken(NumberOrString::Number(u as i64)))
226                    } else {
227                        None
228                    }
229                } else {
230                    None
231                }
232            }
233            _ => None,
234        })
235    }
236
237    pub fn set_progress_token(&mut self, token: ProgressToken) {
238        match token.0 {
239            NumberOrString::String(ref s) => self.0.insert(
240                PROGRESS_TOKEN_FIELD.to_string(),
241                Value::String(s.to_string()),
242            ),
243            NumberOrString::Number(n) => self
244                .0
245                .insert(PROGRESS_TOKEN_FIELD.to_string(), Value::Number(n.into())),
246        };
247    }
248
249    pub fn extend(&mut self, other: Meta) {
250        for (k, v) in other.0.into_iter() {
251            self.0.insert(k, v);
252        }
253    }
254}
255
256impl Deref for Meta {
257    type Target = JsonObject;
258
259    fn deref(&self) -> &Self::Target {
260        &self.0
261    }
262}
263
264impl DerefMut for Meta {
265    fn deref_mut(&mut self) -> &mut Self::Target {
266        &mut self.0
267    }
268}
269
270impl<Req, Resp, Noti> JsonRpcMessage<Req, Resp, Noti>
271where
272    Req: GetExtensions,
273    Noti: GetExtensions,
274{
275    pub fn insert_extension<T: Clone + Send + Sync + 'static>(&mut self, value: T) {
276        match self {
277            JsonRpcMessage::Request(json_rpc_request) => {
278                json_rpc_request.request.extensions_mut().insert(value);
279            }
280            JsonRpcMessage::Notification(json_rpc_notification) => {
281                json_rpc_notification
282                    .notification
283                    .extensions_mut()
284                    .insert(value);
285            }
286            _ => {}
287        }
288    }
289}
rmcp/model/meta.rs

rmcp/model/
meta.rs
