Unified Client Transport Layer for Streamable HTTP Support (#114)

* add transport layer interface

* universal client

* impl sse & stdio transport based on the original client

* refactor old client to provide compibility

* rename

* remove old client types

* add test for stdio transport

* rename 'done' to 'closed', to distinguish with ctx.Done

* add cancelSSEStream for better handling of close

* fix connection leak when start timeout

* avoid multiple starting

* use atomic for closed to be more natural compared to started

* fix leak of timer

* Create sse_test.go

* enforce test

* add comment

* sse: add custom header in start request

* update comment

* comment

* cover #88

* cover #107

* fix demo sse server in race test

Author: leavez

client/client.go

@@ -0,0 +1,109 @@
+// Package client provides MCP (Model Control Protocol) client implementations.
+package client
+
+import (
+	"context"
+
+	"github.com/mark3labs/mcp-go/mcp"
+)
+
+// MCPClient represents an MCP client interface
+type MCPClient interface {
+	// Initialize sends the initial connection request to the server
+	Initialize(
+		ctx context.Context,
+		request mcp.InitializeRequest,
+	) (*mcp.InitializeResult, error)
+
+	// Ping checks if the server is alive
+	Ping(ctx context.Context) error
+
+	// ListResourcesByPage manually list resources by page.
+	ListResourcesByPage(
+		ctx context.Context,
+		request mcp.ListResourcesRequest,
+	) (*mcp.ListResourcesResult, error)
+
+	// ListResources requests a list of available resources from the server
+	ListResources(
+		ctx context.Context,
+		request mcp.ListResourcesRequest,
+	) (*mcp.ListResourcesResult, error)
+
+	// ListResourceTemplatesByPage manually list resource templates by page.
+	ListResourceTemplatesByPage(
+		ctx context.Context,
+		request mcp.ListResourceTemplatesRequest,
+	) (*mcp.ListResourceTemplatesResult,
+		error)
+
+	// ListResourceTemplates requests a list of available resource templates from the server
+	ListResourceTemplates(
+		ctx context.Context,
+		request mcp.ListResourceTemplatesRequest,
+	) (*mcp.ListResourceTemplatesResult,
+		error)
+
+	// ReadResource reads a specific resource from the server
+	ReadResource(
+		ctx context.Context,
+		request mcp.ReadResourceRequest,
+	) (*mcp.ReadResourceResult, error)
+
+	// Subscribe requests notifications for changes to a specific resource
+	Subscribe(ctx context.Context, request mcp.SubscribeRequest) error
+
+	// Unsubscribe cancels notifications for a specific resource
+	Unsubscribe(ctx context.Context, request mcp.UnsubscribeRequest) error
+
+	// ListPromptsByPage manually list prompts by page.
+	ListPromptsByPage(
+		ctx context.Context,
+		request mcp.ListPromptsRequest,
+	) (*mcp.ListPromptsResult, error)
+
+	// ListPrompts requests a list of available prompts from the server
+	ListPrompts(
+		ctx context.Context,
+		request mcp.ListPromptsRequest,
+	) (*mcp.ListPromptsResult, error)
+
+	// GetPrompt retrieves a specific prompt from the server
+	GetPrompt(
+		ctx context.Context,
+		request mcp.GetPromptRequest,
+	) (*mcp.GetPromptResult, error)
+
+	// ListToolsByPage manually list tools by page.
+	ListToolsByPage(
+		ctx context.Context,
+		request mcp.ListToolsRequest,
+	) (*mcp.ListToolsResult, error)
+
+	// ListTools requests a list of available tools from the server
+	ListTools(
+		ctx context.Context,
+		request mcp.ListToolsRequest,
+	) (*mcp.ListToolsResult, error)
+
+	// CallTool invokes a specific tool on the server
+	CallTool(
+		ctx context.Context,
+		request mcp.CallToolRequest,
+	) (*mcp.CallToolResult, error)
+
+	// SetLevel sets the logging level for the server
+	SetLevel(ctx context.Context, request mcp.SetLevelRequest) error
+
+	// Complete requests completion options for a given argument
+	Complete(
+		ctx context.Context,
+		request mcp.CompleteRequest,
+	) (*mcp.CompleteResult, error)
+
+	// Close client connection and cleanup resources
+	Close() error
+
+	// OnNotification registers a handler for notifications
+	OnNotification(handler func(notification mcp.JSONRPCNotification))
+}