Skip to content

Commit 781b732

Browse files
dugenkui03dugenkui03
authored
optimize capability and notification (#184)
1 parent 6760d87 commit 781b732

File tree

4 files changed

+92
-23
lines changed

4 files changed

+92
-23
lines changed

‎client/client.go

Lines changed: 36 additions & 10 deletions
Original file line numberDiff line numberDiff line change
@@ -16,11 +16,21 @@ import (
1616
type Client struct {
1717
transport transport.Interface
1818

19-
initialized bool
20-
notifications []func(mcp.JSONRPCNotification)
21-
notifyMu sync.RWMutex
22-
requestID atomic.Int64
23-
capabilities mcp.ServerCapabilities
19+
initialized bool
20+
notifications []func(mcp.JSONRPCNotification)
21+
notifyMu sync.RWMutex
22+
requestID atomic.Int64
23+
clientCapabilities mcp.ClientCapabilities
24+
serverCapabilities mcp.ServerCapabilities
25+
}
26+
27+
type ClientOption func(*Client)
28+
29+
// WithClientCapabilities sets the client capabilities for the client.
30+
func WithClientCapabilities(capabilities mcp.ClientCapabilities) ClientOption {
31+
return func(c *Client) {
32+
c.clientCapabilities = capabilities
33+
}
2434
}
2535

2636
// NewClient creates a new MCP client with the given transport.
@@ -31,10 +41,16 @@ type Client struct {
3141
// if err != nil {
3242
// log.Fatalf("Failed to create client: %v", err)
3343
// }
34-
func NewClient(transport transport.Interface) *Client {
35-
return &Client{
44+
func NewClient(transport transport.Interface, options ...ClientOption) *Client {
45+
client := &Client{
3646
transport: transport,
3747
}
48+
49+
for _, opt := range options {
50+
opt(client)
51+
}
52+
53+
return client
3854
}
3955

4056
// Start initiates the connection to the server.
@@ -115,7 +131,7 @@ func (c *Client) Initialize(
115131
params := struct {
116132
ProtocolVersion string `json:"protocolVersion"`
117133
ClientInfo mcp.Implementation `json:"clientInfo"`
118-
Capabilities mcp.ClientCapabilities `json:"capabilities"`
134+
Capabilities mcp.ClientCapabilities `json:"serverCapabilities"`
119135
}{
120136
ProtocolVersion: request.Params.ProtocolVersion,
121137
ClientInfo: request.Params.ClientInfo,
@@ -132,8 +148,8 @@ func (c *Client) Initialize(
132148
return nil, fmt.Errorf("failed to unmarshal response: %w", err)
133149
}
134150

135-
// Store capabilities
136-
c.capabilities = result.Capabilities
151+
// Store serverCapabilities
152+
c.serverCapabilities = result.Capabilities
137153

138154
// Send initialized notification
139155
notification := mcp.JSONRPCNotification{
@@ -406,3 +422,13 @@ func listByPage[T any](
406422
func (c *Client) GetTransport() transport.Interface {
407423
return c.transport
408424
}
425+
426+
// GetServerCapabilities returns the server capabilities.
427+
func (c *Client) GetServerCapabilities() mcp.ServerCapabilities {
428+
return c.serverCapabilities
429+
}
430+
431+
// GetClientCapabilities returns the client capabilities.
432+
func (c *Client) GetClientCapabilities() mcp.ClientCapabilities {
433+
return c.clientCapabilities
434+
}

‎mcp/types.go

Lines changed: 19 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -46,6 +46,20 @@ const (
4646
// Invokes a specific tool with provided parameters.
4747
// https://modelcontextprotocol.io/specification/2024-11-05/server/tools/
4848
MethodToolsCall MCPMethod = "tools/call"
49+
50+
// Notifies when the list of available resources changes.
51+
// https://modelcontextprotocol.io/specification/2025-03-26/server/resources#list-changed-notification
52+
MethodNotificationResourcesListChanged = "notifications/resources/list_changed"
53+
54+
MethodNotificationResourceUpdated = "notifications/resources/updated"
55+
56+
// Notifies when the list of available prompt templates changes.
57+
// https://modelcontextprotocol.io/specification/2025-03-26/server/prompts#list-changed-notification
58+
MethodNotificationPromptsListChanged = "notifications/prompts/list_changed"
59+
60+
// Notifies when the list of available tools changes.
61+
// https://spec.modelcontextprotocol.io/specification/2024-11-05/server/tools/list_changed/
62+
MethodNotificationToolsListChanged = "notifications/tools/list_changed"
4963
)
5064

5165
type URITemplate struct {
@@ -226,6 +240,11 @@ const (
226240
INTERNAL_ERROR = -32603
227241
)
228242

243+
// MCP error codes
244+
const (
245+
RESOURCE_NOT_FOUND = -32002
246+
)
247+
229248
/* Empty result */
230249

231250
// EmptyResult represents a response that indicates success but carries no data.

‎server/server.go

Lines changed: 29 additions & 5 deletions
Original file line numberDiff line numberDiff line change
@@ -419,6 +419,12 @@ func (s *MCPServer) AddResource(
419419
resource: resource,
420420
handler: handler,
421421
}
422+
423+
// When the list of available resources changes, servers that declared the listChanged capability SHOULD send a notification
424+
if s.capabilities.resources.listChanged {
425+
// Send notification to all initialized sessions
426+
s.SendNotificationToAllClients(mcp.MethodNotificationResourcesListChanged, nil)
427+
}
422428
}
423429

424430
// RemoveResource removes a resource from the server
@@ -450,6 +456,12 @@ func (s *MCPServer) AddResourceTemplate(
450456
template: template,
451457
handler: handler,
452458
}
459+
460+
// When the list of available resources changes, servers that declared the listChanged capability SHOULD send a notification
461+
if s.capabilities.resources.listChanged {
462+
// Send notification to all initialized sessions
463+
s.SendNotificationToAllClients(mcp.MethodNotificationResourcesListChanged, nil)
464+
}
453465
}
454466

455467
// AddPrompt registers a new prompt handler with the given name
@@ -464,6 +476,12 @@ func (s *MCPServer) AddPrompt(prompt mcp.Prompt, handler PromptHandlerFunc) {
464476
defer s.promptsMu.Unlock()
465477
s.prompts[prompt.Name] = prompt
466478
s.promptHandlers[prompt.Name] = handler
479+
480+
// When the list of available resources changes, servers that declared the listChanged capability SHOULD send a notification.
481+
if s.capabilities.prompts.listChanged {
482+
// Send notification to all initialized sessions
483+
s.SendNotificationToAllClients(mcp.MethodNotificationPromptsListChanged, nil)
484+
}
467485
}
468486

469487
// AddTool registers a new tool and its handler
@@ -485,8 +503,11 @@ func (s *MCPServer) AddTools(tools ...ServerTool) {
485503
}
486504
s.toolsMu.Unlock()
487505

488-
// Send notification to all initialized sessions
489-
s.SendNotificationToAllClients("notifications/tools/list_changed", nil)
506+
// When the list of available tools changes, servers that declared the listChanged capability SHOULD send a notification.
507+
if s.capabilities.tools.listChanged {
508+
// Send notification to all initialized sessions
509+
s.SendNotificationToAllClients(mcp.MethodNotificationToolsListChanged, nil)
510+
}
490511
}
491512

492513
// SetTools replaces all existing tools with the provided list
@@ -505,8 +526,11 @@ func (s *MCPServer) DeleteTools(names ...string) {
505526
}
506527
s.toolsMu.Unlock()
507528

508-
// Send notification to all initialized sessions
509-
s.SendNotificationToAllClients("notifications/tools/list_changed", nil)
529+
// When the list of available tools changes, servers that declared the listChanged capability SHOULD send a notification.
530+
if s.capabilities.tools.listChanged {
531+
// Send notification to all initialized sessions
532+
s.SendNotificationToAllClients(mcp.MethodNotificationToolsListChanged, nil)
533+
}
510534
}
511535

512536
// AddNotificationHandler registers a new handler for incoming notifications
@@ -737,7 +761,7 @@ func (s *MCPServer) handleReadResource(
737761

738762
return nil, &requestError{
739763
id: id,
740-
code: mcp.INVALID_PARAMS,
764+
code: mcp.RESOURCE_NOT_FOUND,
741765
err: fmt.Errorf("handler not found for resource URI '%s': %w", request.Params.URI, ErrResourceNotFound),
742766
}
743767
}

‎server/server_test.go

Lines changed: 8 additions & 8 deletions
Original file line numberDiff line numberDiff line change
@@ -199,7 +199,7 @@ func TestMCPServer_Tools(t *testing.T) {
199199
},
200200
expectedNotifications: 1,
201201
validate: func(t *testing.T, notifications []mcp.JSONRPCNotification, toolsList mcp.JSONRPCMessage) {
202-
assert.Equal(t, "notifications/tools/list_changed", notifications[0].Method)
202+
assert.Equal(t, mcp.MethodNotificationToolsListChanged, notifications[0].Method)
203203
tools := toolsList.(mcp.JSONRPCResponse).Result.(mcp.ListToolsResult).Tools
204204
assert.Len(t, tools, 2)
205205
assert.Equal(t, "test-tool-1", tools[0].Name)
@@ -241,7 +241,7 @@ func TestMCPServer_Tools(t *testing.T) {
241241
expectedNotifications: 5,
242242
validate: func(t *testing.T, notifications []mcp.JSONRPCNotification, toolsList mcp.JSONRPCMessage) {
243243
for _, notification := range notifications {
244-
assert.Equal(t, "notifications/tools/list_changed", notification.Method)
244+
assert.Equal(t, mcp.MethodNotificationToolsListChanged, notification.Method)
245245
}
246246
tools := toolsList.(mcp.JSONRPCResponse).Result.(mcp.ListToolsResult).Tools
247247
assert.Len(t, tools, 2)
@@ -269,8 +269,8 @@ func TestMCPServer_Tools(t *testing.T) {
269269
},
270270
expectedNotifications: 2,
271271
validate: func(t *testing.T, notifications []mcp.JSONRPCNotification, toolsList mcp.JSONRPCMessage) {
272-
assert.Equal(t, "notifications/tools/list_changed", notifications[0].Method)
273-
assert.Equal(t, "notifications/tools/list_changed", notifications[1].Method)
272+
assert.Equal(t, mcp.MethodNotificationToolsListChanged, notifications[0].Method)
273+
assert.Equal(t, mcp.MethodNotificationToolsListChanged, notifications[1].Method)
274274
tools := toolsList.(mcp.JSONRPCResponse).Result.(mcp.ListToolsResult).Tools
275275
assert.Len(t, tools, 2)
276276
assert.Equal(t, "test-tool-1", tools[0].Name)
@@ -294,9 +294,9 @@ func TestMCPServer_Tools(t *testing.T) {
294294
expectedNotifications: 2,
295295
validate: func(t *testing.T, notifications []mcp.JSONRPCNotification, toolsList mcp.JSONRPCMessage) {
296296
// One for SetTools
297-
assert.Equal(t, "notifications/tools/list_changed", notifications[0].Method)
297+
assert.Equal(t, mcp.MethodNotificationToolsListChanged, notifications[0].Method)
298298
// One for DeleteTools
299-
assert.Equal(t, "notifications/tools/list_changed", notifications[1].Method)
299+
assert.Equal(t, mcp.MethodNotificationToolsListChanged, notifications[1].Method)
300300

301301
// Expect a successful response with an empty list of tools
302302
resp, ok := toolsList.(mcp.JSONRPCResponse)
@@ -312,7 +312,7 @@ func TestMCPServer_Tools(t *testing.T) {
312312
for _, tt := range tests {
313313
t.Run(tt.name, func(t *testing.T) {
314314
ctx := context.Background()
315-
server := NewMCPServer("test-server", "1.0.0")
315+
server := NewMCPServer("test-server", "1.0.0", WithToolCapabilities(true))
316316
_ = server.HandleMessage(ctx, []byte(`{
317317
"jsonrpc": "2.0",
318318
"id": 1,
@@ -929,7 +929,7 @@ func TestMCPServer_HandleUndefinedHandlers(t *testing.T) {
929929
"uri": "undefined-resource"
930930
}
931931
}`,
932-
expectedErr: mcp.INVALID_PARAMS,
932+
expectedErr: mcp.RESOURCE_NOT_FOUND,
933933
validateCallbacks: func(t *testing.T, err error, beforeResults beforeResult) {
934934
assert.Equal(t, mcp.MethodResourcesRead, beforeResults.method)
935935
assert.True(t, errors.Is(err, ErrResourceNotFound))

0 commit comments

Comments
 (0)
pFad - Phonifier reborn

Pfad - The Proxy pFad of © 2024 Garber Painting. All rights reserved.

Note: This service is not intended for secure transactions such as banking, social media, email, or purchasing. Use at your own risk. We assume no liability whatsoever for broken pages.


Alternative Proxies:

Alternative Proxy

pFad Proxy

pFad v3 Proxy

pFad v4 Proxy