swift-sdk/Sources/MCPConformance/Server/main.swift
yehorsobko a0ae212ebf
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Improvements and fixes (#223)
* feat: added http transport context to the task local execution

* fix: added refresh_token to the grantTypes for DCR

* chore: updated documentation
2026-04-29 14:34:21 +03:00

519 lines
26 KiB
Swift

/**
* MCP HTTP Server Wrapper
*
* HTTP server that wraps the MCP conformance server for testing with the
* official conformance framework.
*
* Usage: mcp-http-server [--port PORT]
*/
import Foundation
import Logging
import MCP
#if canImport(FoundationNetworking)
import FoundationNetworking
#endif
// MARK: - Test Data
private let testImageBase64 = "iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAADUlEQVR42mP8z8DwHwAFBQIAX8jx0gAAAABJRU5ErkJggg=="
private let testAudioBase64 = "UklGRiYAAABXQVZFZm10IBAAAAABAAEAQB8AAAB9AAACABAAZGF0YQIAAAA="
// MARK: - Server State
actor ServerState {
var resourceSubscriptions: Set<String> = []
var watchedResourceContent = "Watched resource content"
func subscribe(to uri: String) {
resourceSubscriptions.insert(uri)
}
func unsubscribe(from uri: String) {
resourceSubscriptions.remove(uri)
}
func isSubscribed(to uri: String) -> Bool {
resourceSubscriptions.contains(uri)
}
func updateWatchedResource(_ newContent: String) {
watchedResourceContent = newContent
}
}
// MARK: - Server Setup
func createConformanceServer(state: ServerState, transport: StatefulHTTPServerTransport) async -> Server {
let server = Server(
name: "mcp-conformance-test-server",
version: "1.0.0",
capabilities: Server.Capabilities(
completions: .init(),
logging: .init(),
prompts: .init(listChanged: true),
resources: .init(subscribe: true, listChanged: true),
tools: .init(listChanged: true)
)
)
// Tools
await server.withMethodHandler(ListTools.self) { _ in
.init(tools: [
Tool(name: "test_simple_text", description: "Tests simple text content response", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_image_content", description: "Tests image content response", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_audio_content", description: "Tests audio content response", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_embedded_resource", description: "Tests embedded resource content response", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_multiple_content_types", description: "Tests response with multiple content types", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_error_handling", description: "Tests error response handling", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_logging", description: "Tests logging capabilities", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_progress", description: "Tests progress notifications", inputSchema: .object(["type": "object", "properties": ["duration_ms": ["type": "number", "description": "Duration in milliseconds to report progress"]]])),
Tool(name: "add_numbers", description: "Adds two numbers together", inputSchema: .object(["type": "object", "properties": ["a": ["type": "number", "description": "First number"], "b": ["type": "number", "description": "Second number"]]])),
Tool(name: "test_tool_with_progress", description: "Tool reports progress notifications", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_tool_with_logging", description: "Tool sends log messages during execution", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_reconnection", description: "Tests SSE reconnection and resumption with Last-Event-ID", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_sampling", description: "Tests LLM sampling capabilities", inputSchema: .object(["type": "object", "properties": ["prompt": ["type": "string", "description": "Text to send to the LLM"]], "required": ["prompt"]])),
Tool(name: "test_elicitation", description: "Tests user input elicitation", inputSchema: .object(["type": "object", "properties": ["message": ["type": "string", "description": "Text displayed to user"]], "required": ["message"]])),
Tool(name: "test_elicitation_sep1034_defaults", description: "Tests elicitation with default values (SEP-1034)", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_elicitation_sep1330_enums", description: "Tests elicitation with enum variants (SEP-1330)", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "test_client_elicitation_defaults", description: "Tests that client applies defaults for omitted elicitation fields", inputSchema: .object(["type": "object", "properties": [:]])),
Tool(name: "json_schema_2020_12_tool", description: "Tool with JSON Schema 2020-12 features", inputSchema: .object([
"$schema": .string("https://json-schema.org/draft/2020-12/schema"),
"type": .string("object"),
"$defs": .object([
"address": .object([
"type": .string("object"),
"properties": .object([
"street": .object(["type": .string("string")]),
"city": .object(["type": .string("string")])
])
])
]),
"properties": .object([
"name": .object(["type": .string("string")]),
"address": .object(["$ref": .string("#/$defs/address")])
]),
"additionalProperties": .bool(false)
]))
])
}
await server.withMethodHandler(CallTool.self) { [weak server, transport] params in
switch params.name {
case "test_simple_text":
return .init(content: [.text(text: "This is a simple text response for testing.", annotations: nil, _meta: nil)], isError: false)
case "test_image_content":
return .init(content: [.image(data: testImageBase64, mimeType: "image/png", annotations: nil, _meta: nil)], isError: false)
case "test_audio_content":
return .init(content: [.audio(data: testAudioBase64, mimeType: "audio/wav", annotations: nil, _meta: nil)], isError: false)
case "test_embedded_resource":
return .init(content: [.resource(resource: .text("This is an embedded resource content.", uri: "test://embedded-resource", mimeType: "text/plain"))], isError: false)
case "test_multiple_content_types":
return .init(content: [
.text(text: "Multiple content types test:", annotations: nil, _meta: nil),
.image(data: testImageBase64, mimeType: "image/png", annotations: nil, _meta: nil),
.resource(resource: .text("{\"test\":\"data\",\"value\":123}", uri: "test://mixed-content-resource", mimeType: "application/json"))], isError: false)
case "test_error_handling":
return .init(content: [.text(text: "An error occurred during tool execution", annotations: nil, _meta: nil)], isError: true)
case "test_logging":
return .init(content: [.text(text: "Logging test completed", annotations: nil, _meta: nil)], isError: false)
case "test_progress":
let duration = params.arguments?["duration_ms"]?.intValue ?? 1000
try? await Task.sleep(for: .milliseconds(duration))
return .init(content: [.text(text: "Progress test completed", annotations: nil, _meta: nil)], isError: false)
case "add_numbers":
guard let a = params.arguments?["a"]?.intValue, let b = params.arguments?["b"]?.intValue else {
return .init(content: [.text(text: "Invalid arguments: expected numbers a and b", annotations: nil, _meta: nil)], isError: true)
}
return .init(content: [.text(text: "\(a + b)", annotations: nil, _meta: nil)], isError: false)
case "test_tool_with_progress":
if let token = params._meta?.progressToken {
let notification1 = ProgressNotification.message(
.init(progressToken: token, progress: 0, total: 100)
)
try await server?.notify(notification1)
try await Task.sleep(for: .microseconds(50))
let notification2 = ProgressNotification.message(
.init(progressToken: token, progress: 50, total: 100)
)
try await server?.notify(notification2)
try await Task.sleep(for: .microseconds(50))
let notification3 = ProgressNotification.message(
.init(progressToken: token, progress: 100, total: 100)
)
try await server?.notify(notification3)
}
return .init(content: [.text(text: "This is a simple text response for testing.", annotations: nil, _meta: nil)], isError: false)
case "json_schema_2020_12_tool":
return .init(content: [.text(text: "This is a simple text response for testing.", annotations: nil, _meta: nil)], isError: false)
case "test_tool_with_logging":
// Send first log message
let log1 = LogMessageNotification.message(
.init(level: .info, data: .string("Tool execution started"))
)
try await server?.notify(log1)
// Wait 50ms
try await Task.sleep(for: .milliseconds(50))
// Send second log message
let log2 = LogMessageNotification.message(
.init(level: .info, data: .string("Tool processing data"))
)
try await server?.notify(log2)
// Wait another 50ms
try await Task.sleep(for: .milliseconds(50))
// Send third log message
let log3 = LogMessageNotification.message(
.init(level: .info, data: .string("Tool execution completed"))
)
try await server?.notify(log3)
return .init(content: [.text(text: "Logging test completed", annotations: nil, _meta: nil)], isError: false)
case "test_reconnection":
// SEP-1699: Close the SSE stream mid-call to trigger client reconnection.
// The client should reconnect via GET with Last-Event-ID and receive the
// response on the new stream.
if let requestID = Server.currentHandlerContext?.id {
await transport.closeSSEStream(forRequestID: requestID.description)
}
// Wait briefly for the client to reconnect before sending the response.
try await Task.sleep(for: .milliseconds(100))
return .init(content: [.text(text: "Reconnection test completed successfully. If you received this, the client properly reconnected after stream closure.", annotations: nil, _meta: nil)], isError: false)
case "test_sampling":
// Test LLM sampling - request sampling/createMessage from client
guard let prompt = params.arguments?["prompt"]?.stringValue else {
return .init(content: [.text(text: "Missing required argument: prompt", annotations: nil, _meta: nil)], isError: true)
}
let samplingResult = try await server?.requestSampling(
messages: [.user(.text(prompt))],
maxTokens: 100
)
let responseText = samplingResult?.content.asArray
.compactMap { block -> String? in
if case .text(let text) = block {
return text
}
return nil
}
.joined(separator: "\n") ?? "No response"
return .init(content: [.text(text: responseText, annotations: nil, _meta: nil)], isError: false)
case "test_elicitation":
// Test elicitation - request user input for username and email
guard let message = params.arguments?["message"]?.stringValue else {
return .init(content: [.text(text: "Missing required argument: message", annotations: nil, _meta: nil)], isError: true)
}
let elicitationResult = try await server?.requestElicitation(
message: message,
requestedSchema: Elicitation.RequestSchema(
properties: [
"username": .object(["type": .string("string")]),
"email": .object(["type": .string("string")])
],
required: ["username", "email"]
)
)
return .init(
content: [.text(text: "Elicitation completed: action=\(elicitationResult?.action.rawValue ?? "unknown"), content=\(elicitationResult?.content ?? [:])", annotations: nil, _meta: nil)],
isError: false
)
case "test_elicitation_sep1034_defaults":
// Test elicitation with default values (SEP-1034)
let elicitationResult = try await server?.requestElicitation(
message: "Please provide the following information:",
requestedSchema: Elicitation.RequestSchema(
properties: [
"name": .object([
"type": .string("string"),
"default": .string("John Doe")
]),
"age": .object([
"type": .string("integer"),
"default": .int(30)
]),
"score": .object([
"type": .string("number"),
"default": .double(95.5)
]),
"status": .object([
"type": .string("string"),
"enum": .array([.string("active"), .string("inactive"), .string("pending")]),
"default": .string("active")
]),
"verified": .object([
"type": .string("boolean"),
"default": .bool(true)
])
]
)
)
return .init(
content: [.text(text: "Elicitation completed: action=\(elicitationResult?.action.rawValue ?? "unknown"), content=\(elicitationResult?.content ?? [:])", annotations: nil, _meta: nil)],
isError: false
)
case "test_elicitation_sep1330_enums":
// Test elicitation with enum variants (SEP-1330)
let elicitationResult = try await server?.requestElicitation(
message: "Select options for enum testing:",
requestedSchema: Elicitation.RequestSchema(
properties: [
// 1. Untitled single-select
"untitledSingle": .object([
"type": .string("string"),
"enum": .array([.string("option1"), .string("option2"), .string("option3")])
]),
// 2. Titled single-select
"titledSingle": .object([
"type": .string("string"),
"oneOf": .array([
.object(["const": .string("opt1"), "title": .string("Option One")]),
.object(["const": .string("opt2"), "title": .string("Option Two")]),
.object(["const": .string("opt3"), "title": .string("Option Three")])
])
]),
// 3. Legacy titled (deprecated enumNames)
"legacyEnum": .object([
"type": .string("string"),
"enum": .array([.string("legacy1"), .string("legacy2"), .string("legacy3")]),
"enumNames": .array([.string("Legacy One"), .string("Legacy Two"), .string("Legacy Three")])
]),
// 4. Untitled multi-select
"untitledMulti": .object([
"type": .string("array"),
"items": .object([
"type": .string("string"),
"enum": .array([.string("multi1"), .string("multi2"), .string("multi3")])
])
]),
// 5. Titled multi-select
"titledMulti": .object([
"type": .string("array"),
"items": .object([
"anyOf": .array([
.object(["const": .string("titled1"), "title": .string("Titled One")]),
.object(["const": .string("titled2"), "title": .string("Titled Two")]),
.object(["const": .string("titled3"), "title": .string("Titled Three")])
])
])
])
]
)
)
return .init(
content: [.text(text: "Elicitation completed: action=\(elicitationResult?.action.rawValue ?? "unknown"), content=\(elicitationResult?.content ?? [:])", annotations: nil, _meta: nil)],
isError: false
)
case "test_client_elicitation_defaults":
// Tool for client-side elicitation defaults test
let elicitationResult = try await server?.requestElicitation(
message: "Please provide your information (defaults available):",
requestedSchema: Elicitation.RequestSchema(
properties: [
"name": .object([
"type": .string("string"),
"default": .string("John Doe")
]),
"age": .object([
"type": .string("integer"),
"default": .int(30)
]),
"score": .object([
"type": .string("number"),
"default": .double(95.5)
]),
"status": .object([
"type": .string("string"),
"enum": .array([.string("active"), .string("inactive"), .string("pending")]),
"default": .string("active")
]),
"verified": .object([
"type": .string("boolean"),
"default": .bool(true)
])
]
)
)
// Verify the client applied defaults correctly
guard let content = elicitationResult?.content,
let name = content["name"]?.stringValue,
let age = content["age"]?.intValue,
let score = content["score"]?.doubleValue,
let status = content["status"]?.stringValue,
let verified = content["verified"]?.boolValue else {
return .init(content: [.text(text: "Client did not provide all required fields with defaults", annotations: nil, _meta: nil)], isError: true)
}
guard name == "John Doe", age == 30, score == 95.5, status == "active", verified == true else {
return .init(content: [.text(text: "Client defaults do not match expected values", annotations: nil, _meta: nil)], isError: true)
}
return .init(
content: [.text(text: "Client correctly applied all default values", annotations: nil, _meta: nil)],
isError: false
)
default:
return .init(content: [.text(text: "Unknown tool: \(params.name)", annotations: nil, _meta: nil)], isError: true)
}
}
// Resources
await server.withMethodHandler(ListResources.self) { _ in
.init(resources: [
Resource(name: "Static Text Resource", uri: "test://static-text", description: "A simple static text resource", mimeType: "text/plain"),
Resource(name: "Static Binary Resource", uri: "test://static-binary", description: "A simple static binary resource", mimeType: "application/octet-stream"),
Resource(name: "Watched Resource", uri: "test://watched", description: "A resource that can be subscribed to for updates", mimeType: "text/plain"),
Resource(name: "Template Resource", uri: "test://template/{id}", description: "A resource template with URI parameters", mimeType: "text/plain"),
])
}
await server.withMethodHandler(ReadResource.self) { params in
switch params.uri {
case "test://static-text":
return .init(contents: [.text("This is static text content for testing.", uri: params.uri, mimeType: "text/plain")])
case "test://static-binary":
guard let imageData = Data(base64Encoded: testImageBase64) else {
return .init(contents: [.text("Failed to decode binary data", uri: params.uri)])
}
return .init(contents: [.binary(imageData, uri: params.uri, mimeType: "application/octet-stream")])
case "test://watched":
let content = await state.watchedResourceContent
return .init(contents: [.text(content, uri: params.uri)])
default:
if params.uri.hasPrefix("test://template/") {
let id = String(params.uri.dropFirst("test://template/".count))
return .init(contents: [.text("Template resource with id: \(id)", uri: params.uri)])
}
return .init(contents: [.text("Resource not found: \(params.uri)", uri: params.uri)])
}
}
await server.withMethodHandler(ResourceSubscribe.self) { params in
await state.subscribe(to: params.uri)
return Empty()
}
await server.withMethodHandler(ResourceUnsubscribe.self) { params in
await state.unsubscribe(from: params.uri)
return Empty()
}
// Prompts
await server.withMethodHandler(ListPrompts.self) { _ in
.init(prompts: [
Prompt(name: "test_simple_prompt", description: "A simple prompt without arguments"),
Prompt(name: "test_prompt_with_arguments", description: "A prompt that accepts arguments", arguments: [Prompt.Argument(name: "arg1", description: "First test argument", required: true), Prompt.Argument(name: "arg2", description: "Second test argument", required: true)]),
Prompt(name: "test_prompt_with_embedded_resource", description: "A prompt that includes embedded resources", arguments: [Prompt.Argument(name: "resourceUri", description: "URI of the resource to embed", required: true)]),
Prompt(name: "test_prompt_with_image", description: "A prompt with image content"),
])
}
await server.withMethodHandler(GetPrompt.self) { params in
switch params.name {
case "test_simple_prompt":
return .init(description: "Simple prompt response", messages: [.user(.text(text: "This is a simple prompt for testing."))])
case "test_prompt_with_arguments":
let arg1 = params.arguments?["arg1"] ?? "default1"
let arg2 = params.arguments?["arg2"] ?? "default2"
return .init(description: "Prompt with arguments", messages: [.user(.text(text: "Prompt with arguments: arg1='\(arg1)', arg2='\(arg2)'"))])
case "test_prompt_with_embedded_resource":
let resourceUri = params.arguments?["resourceUri"] ?? "test://default"
return .init(description: "Prompt with embedded resource", messages: [
.user(.resource(resource: .text("Embedded resource content for testing.", uri: resourceUri, mimeType: "text/plain"))),
.user(.text(text: "Please process the embedded resource above."))
])
case "test_prompt_with_image":
return .init(description: "Prompt with image", messages: [
.user(.image(data: testImageBase64, mimeType: "image/png")),
.user(.text(text: "Please analyze the image above."))
])
default:
throw MCPError.invalidRequest("Unknown prompt: \(params.name)")
}
}
await server.withMethodHandler(SetLoggingLevel.self) { _ in
// Accept any logging level (debug, info, notice, warning, error, critical, alert, emergency)
// For conformance testing, we just accept it without doing anything
return Empty()
}
await server.withMethodHandler(Complete.self) { _ in
return .init(completion: .init(values: []))
}
return server
}
// MARK: - HTTP Server
// HTTPApp handles all HTTP server functionality
// MARK: - Main
struct MCPHTTPServer {
static func run() async throws {
let args = CommandLine.arguments
var port = 3001
for (index, arg) in args.enumerated() {
if arg == "--port" && index + 1 < args.count {
if let p = Int(args[index + 1]) {
port = p
}
}
}
var loggerConfig = Logger(label: "mcp.http.server", factory: { StreamLogHandler.standardError(label: $0) })
loggerConfig.logLevel = .trace
let logger = loggerConfig
let state = ServerState()
logger.info("Starting MCP HTTP Server...", metadata: ["port": "\(port)"])
// Create HTTPApp with server factory
let app = HTTPApp(
configuration: .init(
host: "127.0.0.1",
port: port,
endpoint: "/mcp",
retryInterval: 1000
),
validationPipeline: StandardValidationPipeline(validators: [
OriginValidator.localhost(port: port),
AcceptHeaderValidator(mode: .sseRequired),
ContentTypeValidator(),
ProtocolVersionValidator(),
SessionValidator(),
]),
serverFactory: { sessionID, transport in
logger.debug("Creating server for session", metadata: ["sessionID": "\(sessionID)"])
return await createConformanceServer(state: state, transport: transport)
},
logger: logger
)
try await app.start()
}
}
do {
try await MCPHTTPServer.run()
} catch {
print(error)
exit(1)
}