refactor: implement McpResource and McpPrompt traits to handle MCP endpoints generically

server/src/router.rs

@@ -15,15 +15,124 @@ pub trait McpTool: Send + Sync {
     async fn execute(&self, args: Value, state: Arc<MemoryState>) -> Result<String, String>;
 }
 
+
+#[async_trait]
+pub trait McpResource: Send + Sync {
+    fn uri(&self) -> &'static str;
+    fn name(&self) -> &'static str;
+    fn description(&self) -> Option<&'static str> { None }
+    fn mime_type(&self) -> Option<&'static str> { Some("application/json") }
+    async fn read(&self, state: Arc<MemoryState>) -> Result<String, String>;
+}
+
+#[async_trait]
+pub trait McpPrompt: Send + Sync {
+    fn name(&self) -> &'static str;
+    fn description(&self) -> Option<&'static str> { None }
+    fn arguments(&self) -> serde_json::Value { serde_json::json!([]) }
+    async fn get(&self, args: Value, state: Arc<MemoryState>) -> Result<serde_json::Value, String>;
+}
+
 pub struct MemoryHandler {
     pub state: Arc<MemoryState>,
     pub tools: std::collections::HashMap<String, Box<dyn McpTool>>,
+    pub resources: std::collections::HashMap<String, Box<dyn McpResource>>,
+    pub prompts: std::collections::HashMap<String, Box<dyn McpPrompt>>,
 }
 
 impl MemoryHandler {
     pub fn new(state: Arc<MemoryState>) -> Self {
-        let mut tools: std::collections::HashMap<String, Box<dyn McpTool>> =
+        let mut tools: std::collections::HashMap<String, Box<dyn McpTool>> = std::collections::HashMap::new();
-            std::collections::HashMap::new();
+        let mut resources: std::collections::HashMap<String, Box<dyn McpResource>> = std::collections::HashMap::new();
+        let mut prompts: std::collections::HashMap<String, Box<dyn McpPrompt>> = std::collections::HashMap::new();
+
+        macro_rules! register_resource {
+            ($handler:ident) => {
+                let h = $handler;
+                resources.insert(h.uri().to_string(), Box::new(h));
+            };
+        }
+
+        macro_rules! register_prompt {
+            ($handler:ident) => {
+                let h = $handler;
+                prompts.insert(h.name().to_string(), Box::new(h));
+            };
+        }
+
+        struct GraphEntitiesResource;
+        #[async_trait]
+        impl McpResource for GraphEntitiesResource {
+            fn uri(&self) -> &'static str { "memory://graph/entities" }
+            fn name(&self) -> &'static str { "Graph Entities" }
+            fn description(&self) -> Option<&'static str> { Some("All nodes and entities currently stored in the knowledge graph") }
+            async fn read(&self, state: Arc<MemoryState>) -> Result<String, String> {
+                let state_clone = Arc::clone(&state);
+                tokio::task::spawn_blocking(move || {
+                    let graph = state_clone.graph.cache.read().unwrap();
+                    let data: Vec<_> = graph.entities.values().collect();
+                    Ok(serde_json::to_string_pretty(&data).unwrap_or_default())
+                }).await.unwrap()
+            }
+        }
+
+        struct GraphRelationsResource;
+        #[async_trait]
+        impl McpResource for GraphRelationsResource {
+            fn uri(&self) -> &'static str { "memory://graph/relations" }
+            fn name(&self) -> &'static str { "Graph Relations" }
+            fn description(&self) -> Option<&'static str> { Some("All relationships between entities currently stored in the knowledge graph") }
+            async fn read(&self, state: Arc<MemoryState>) -> Result<String, String> {
+                let state_clone = Arc::clone(&state);
+                tokio::task::spawn_blocking(move || {
+                    let graph = state_clone.graph.cache.read().unwrap();
+                    let data = &graph.relations;
+                    Ok(serde_json::to_string_pretty(&data).unwrap_or_default())
+                }).await.unwrap()
+            }
+        }
+
+        struct TasksActiveResource;
+        #[async_trait]
+        impl McpResource for TasksActiveResource {
+            fn uri(&self) -> &'static str { "memory://tasks/active" }
+            fn name(&self) -> &'static str { "Active Tasks" }
+            fn description(&self) -> Option<&'static str> { Some("List of currently active tasks") }
+            async fn read(&self, state: Arc<MemoryState>) -> Result<String, String> {
+                let state_clone = Arc::clone(&state);
+                tokio::task::spawn_blocking(move || {
+                    let tasks = state_clone.tasks.cache.read().unwrap();
+                    let data: Vec<_> = tasks.iter().filter(|t| t.status != "completed" && t.status != "done").collect();
+                    Ok(serde_json::to_string_pretty(&data).unwrap_or_default())
+                }).await.unwrap()
+            }
+        }
+
+        struct AnalyzeTechDebtPrompt;
+        #[async_trait]
+        impl McpPrompt for AnalyzeTechDebtPrompt {
+            fn name(&self) -> &'static str { "analyze_tech_debt" }
+            fn description(&self) -> Option<&'static str> { Some("Analyze the project's current technical debt") }
+            async fn get(&self, _args: Value, _state: Arc<MemoryState>) -> Result<serde_json::Value, String> {
+                Ok(serde_json::json!({
+                    "messages": [
+                        {
+                            "role": "user",
+                            "content": {
+                                "type": "text",
+                                "text": "Please read the current technical debt from the knowledge graph (or use the list_tech_debt tool) and provide a prioritization plan for addressing it."
+                            }
+                        }
+                    ]
+                }))
+            }
+        }
+
+        register_resource!(GraphEntitiesResource);
+        register_resource!(GraphRelationsResource);
+        register_resource!(TasksActiveResource);
+        
+        register_prompt!(AnalyzeTechDebtPrompt);
 
         macro_rules! register {
             ($module:ident::$handler:ident) => {
@@ -102,7 +211,7 @@ impl MemoryHandler {
         register!(workspaces::GetPrChecklistHandler);
         register!(workspaces::ClearPrChecklistHandler);
 
-        Self { state, tools }
+        Self { state, tools, resources, prompts }
     }
 
     pub async fn handle_request(&self, req: serde_json::Value) -> Option<serde_json::Value> {
@@ -165,30 +274,24 @@ impl MemoryHandler {
                 ))
             }
             "resources/list" => {
-                let payload = serde_json::json!({
+                let resources: Vec<_> = self.resources.values().map(|r| {
-                    "resources": [
+                    let mut obj = serde_json::json!({
-                        {
+                        "uri": r.uri(),
-                            "uri": "memory://graph/entities",
+                        "name": r.name(),
-                            "name": "Graph Entities",
-                            "mimeType": "application/json",
-                            "description": "All nodes and entities currently stored in the knowledge graph"
-                        },
-                        {
-                            "uri": "memory://graph/relations",
-                            "name": "Graph Relations",
-                            "mimeType": "application/json",
-                            "description": "All edge relationships between entities in the knowledge graph"
-                        },
-                        {
-                            "uri": "memory://tasks/active",
-                            "name": "Active Tasks",
-                            "mimeType": "application/json",
-                            "description": "All currently active or uncompleted tracking tasks"
-                        }
-                    ]
                     });
+                    if let Some(desc) = r.description() {
+                        obj["description"] = serde_json::json!(desc);
+                    }
+                    if let Some(mime) = r.mime_type() {
+                        obj["mimeType"] = serde_json::json!(mime);
+                    }
+                    obj
+                }).collect();
+                
+                let payload = serde_json::json!({ "resources": resources });
                 Some(crate::mcp::success(id, payload))
             }
+            
             "resources/templates/list" => {
                 let payload = serde_json::json!({
                     "resourceTemplates": []
@@ -197,83 +300,58 @@ impl MemoryHandler {
             }
             "resources/read" => {
                 let params = req.get("params").unwrap_or(&serde_json::Value::Null);
-                let uri = params
+                let uri = params.get("uri").and_then(|u| u.as_str()).unwrap_or("");
-                    .get("uri")
-                    .and_then(|u| u.as_str())
-                    .unwrap_or("")
-                    .to_string();
-
-                let state_clone = Arc::clone(&self.state);
-                let uri_clone = uri.clone();
-                let text = match tokio::task::spawn_blocking(move || match uri_clone.as_str() {
-                    "memory://graph/entities" => {
-                        let graph = state_clone.graph.cache.read().unwrap();
-                        let data: Vec<_> = graph.entities.values().collect();
-                        Some(serde_json::to_string_pretty(&data).unwrap_or_default())
-                    }
-                    "memory://graph/relations" => {
-                        let graph = state_clone.graph.cache.read().unwrap();
-                        let data = &graph.relations;
-                        Some(serde_json::to_string_pretty(&data).unwrap_or_default())
-                    }
-                    "memory://tasks/active" => {
-                        let tasks = state_clone.tasks.cache.read().unwrap();
-                        let data: Vec<_> = tasks
-                            .iter()
-                            .filter(|t| t.status != "completed" && t.status != "done")
-                            .collect();
-                        Some(serde_json::to_string_pretty(&data).unwrap_or_default())
-                    }
-                    _ => None,
-                })
-                .await
-                {
-                    Ok(Some(text)) => text,
-                    _ => return Some(crate::mcp::error(id, -32602, "Resource not found")),
-                };
                 
+                if let Some(resource) = self.resources.get(uri) {
+                    match resource.read(Arc::clone(&self.state)).await {
+                        Ok(text) => {
                             let payload = serde_json::json!({
                                 "contents": [{
                                     "uri": uri,
-                        "mimeType": "application/json",
+                                    "mimeType": resource.mime_type().unwrap_or("application/json"),
                                     "text": text
                                 }]
                             });
                             Some(crate::mcp::success(id, payload))
                         }
-            "prompts/list" => {
+                        Err(e) => Some(crate::mcp::error(id, -32603, &e))
-                let payload = serde_json::json!({
-                    "prompts": [
-                        {
-                            "name": "analyze_tech_debt",
-                            "description": "Analyze the project's current technical debt",
-                            "arguments": []
                     }
-                    ]
+                } else {
+                    Some(crate::mcp::error(id, -32602, "Resource not found"))
+                }
+            }
+            
+            "prompts/list" => {
+                let prompts: Vec<_> = self.prompts.values().map(|p| {
+                    let mut obj = serde_json::json!({
+                        "name": p.name(),
+                        "arguments": p.arguments(),
                     });
+                    if let Some(desc) = p.description() {
+                        obj["description"] = serde_json::json!(desc);
+                    }
+                    obj
+                }).collect();
+                
+                let payload = serde_json::json!({ "prompts": prompts });
                 Some(crate::mcp::success(id, payload))
             }
+            
             "prompts/get" => {
                 let params = req.get("params").unwrap_or(&serde_json::Value::Null);
                 let name = params.get("name").and_then(|n| n.as_str()).unwrap_or("");
+                let args = params.get("arguments").cloned().unwrap_or_else(|| serde_json::json!({}));
                 
-                if name == "analyze_tech_debt" {
+                if let Some(prompt) = self.prompts.get(name) {
-                    let payload = serde_json::json!({
+                    match prompt.get(args, Arc::clone(&self.state)).await {
-                        "messages": [
+                        Ok(messages) => Some(crate::mcp::success(id, messages)),
-                            {
+                        Err(e) => Some(crate::mcp::error(id, -32603, &e))
-                                "role": "user",
-                                "content": {
-                                    "type": "text",
-                                    "text": "Please read the current technical debt from the knowledge graph (or use the list_tech_debt tool) and provide a prioritization plan for addressing it."
                     }
-                            }
-                        ]
-                    });
-                    Some(crate::mcp::success(id, payload))
                 } else {
                     Some(crate::mcp::error(id, -32602, "Prompt not found"))
                 }
             }
+            
             "tools/call" => {
                 let params = req.get("params").unwrap_or(&serde_json::Value::Null);
                 let name = params.get("name").and_then(|n| n.as_str()).unwrap_or("");