feat: V1.0 (#734)

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crates/mcp-core/src/protocol.rs

@@ -0,0 +1,238 @@
+/// The protocol messages exchanged between client and server
+use crate::{
+    content::Content,
+    prompt::{Prompt, PromptMessage},
+    resource::Resource,
+    resource::ResourceContents,
+    tool::Tool,
+};
+use serde::{Deserialize, Serialize};
+use serde_json::Value;
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct JsonRpcRequest {
+    pub jsonrpc: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub id: Option<u64>,
+    pub method: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub params: Option<Value>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct JsonRpcResponse {
+    pub jsonrpc: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub id: Option<u64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub result: Option<Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub error: Option<ErrorData>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct JsonRpcNotification {
+    pub jsonrpc: String,
+    pub method: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub params: Option<Value>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct JsonRpcError {
+    pub jsonrpc: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub id: Option<u64>,
+    pub error: ErrorData,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+#[serde(untagged, try_from = "JsonRpcRaw")]
+pub enum JsonRpcMessage {
+    Request(JsonRpcRequest),
+    Response(JsonRpcResponse),
+    Notification(JsonRpcNotification),
+    Error(JsonRpcError),
+    Nil, // used to respond to notifications
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+struct JsonRpcRaw {
+    jsonrpc: String,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    id: Option<u64>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    method: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    params: Option<Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    result: Option<Value>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    error: Option<ErrorData>,
+}
+
+impl TryFrom<JsonRpcRaw> for JsonRpcMessage {
+    type Error = String;
+
+    fn try_from(raw: JsonRpcRaw) -> Result<Self, <Self as TryFrom<JsonRpcRaw>>::Error> {
+        // If it has an error field, it's an error response
+        if raw.error.is_some() {
+            return Ok(JsonRpcMessage::Error(JsonRpcError {
+                jsonrpc: raw.jsonrpc,
+                id: raw.id,
+                error: raw.error.unwrap(),
+            }));
+        }
+
+        // If it has a result field, it's a response
+        if raw.result.is_some() {
+            return Ok(JsonRpcMessage::Response(JsonRpcResponse {
+                jsonrpc: raw.jsonrpc,
+                id: raw.id,
+                result: raw.result,
+                error: None,
+            }));
+        }
+
+        // If we have a method, it's either a notification or request
+        if let Some(method) = raw.method {
+            if method.starts_with("notifications/") {
+                return Ok(JsonRpcMessage::Notification(JsonRpcNotification {
+                    jsonrpc: raw.jsonrpc,
+                    method,
+                    params: raw.params,
+                }));
+            }
+
+            return Ok(JsonRpcMessage::Request(JsonRpcRequest {
+                jsonrpc: raw.jsonrpc,
+                id: raw.id,
+                method,
+                params: raw.params,
+            }));
+        }
+
+        // If we have no method and no result/error, it's a nil response
+        if raw.id.is_none() && raw.result.is_none() && raw.error.is_none() {
+            return Ok(JsonRpcMessage::Nil);
+        }
+
+        // If we get here, something is wrong with the message
+        Err(format!(
+            "Invalid JSON-RPC message format: id={:?}, method={:?}, result={:?}, error={:?}",
+            raw.id, raw.method, raw.result, raw.error
+        ))
+    }
+}
+
+// Standard JSON-RPC error codes
+pub const PARSE_ERROR: i32 = -32700;
+pub const INVALID_REQUEST: i32 = -32600;
+pub const METHOD_NOT_FOUND: i32 = -32601;
+pub const INVALID_PARAMS: i32 = -32602;
+pub const INTERNAL_ERROR: i32 = -32603;
+
+/// Error information for JSON-RPC error responses.
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct ErrorData {
+    /// The error type that occurred.
+    pub code: i32,
+
+    /// A short description of the error. The message SHOULD be limited to a concise single sentence.
+    pub message: String,
+
+    /// Additional information about the error. The value of this member is defined by the
+    /// sender (e.g. detailed error information, nested errors etc.).
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub data: Option<Value>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct InitializeResult {
+    pub protocol_version: String,
+    pub capabilities: ServerCapabilities,
+    pub server_info: Implementation,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub instructions: Option<String>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct Implementation {
+    pub name: String,
+    pub version: String,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct ServerCapabilities {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub prompts: Option<PromptsCapability>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub resources: Option<ResourcesCapability>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub tools: Option<ToolsCapability>,
+    // Add other capabilities as needed
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct PromptsCapability {
+    pub list_changed: Option<bool>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct ResourcesCapability {
+    pub subscribe: Option<bool>,
+    pub list_changed: Option<bool>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct ToolsCapability {
+    pub list_changed: Option<bool>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct ListResourcesResult {
+    pub resources: Vec<Resource>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub next_cursor: Option<String>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct ReadResourceResult {
+    pub contents: Vec<ResourceContents>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+#[serde(rename_all = "camelCase")]
+pub struct ListToolsResult {
+    pub tools: Vec<Tool>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub next_cursor: Option<String>,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub struct CallToolResult {
+    pub content: Vec<Content>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub is_error: Option<bool>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct ListPromptsResult {
+    pub prompts: Vec<Prompt>,
+}
+
+#[derive(Debug, Serialize, Deserialize, Clone, PartialEq)]
+pub struct GetPromptResult {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub description: Option<String>,
+    pub messages: Vec<PromptMessage>,
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct EmptyResult {}