使用Go从 0 开发一个 MCP Server，MCP 协议全过程调用的解析

package mainimport (	"encoding/json""log""os")func main() {
	decoder := json.NewDecoder(os.Stdin)	
	// 设置日志输出到stderr
	log.SetOutput(os.Stderr)
	log.SetFlags(log.LstdFlags | log.Lmicroseconds)

	log.Printf("Starting minimal MCP server ...")	var req map[string]interface{}	if err := decoder.Decode(&req); err != nil {
		log.Printf("Error decoding request: %v", err)		return
	}

	log.Printf("Received request: %v", req)
}

/Users/user/Library/Application Support/Claude/claude_desktop_config.json

{
"method": "initialize",
"params": {
"protocolVersion": "2024-11-05",
"capabilities": {},
"clientInfo": {
"name": "claude-ai",
"version": "0.1.0"
}
},
"jsonrpc": "2.0",
"id": 0
}

	method, hasMethod := req["method"].(string)
	id, hasId := req["id"]	var response map[string]interface{}	if hasMethod && hasId && method == "initialize" {
		response = map[string]interface{}{			"jsonrpc": "2.0",			"id":id,			"result": map[string]interface{}{				"protocolVersion": "2024-11-05",				"serverInfo": map[string]interface{}{					"name":"mcp-go",					"version": "0.0.0",
				},				"capabilities": map[string]interface{}{					"tools": map[string]interface{}{},
				},
			},
		}
log.Printf("Sending response: %v", response)
		err := encoder.Encode(response)		if err != nil {
			log.Printf("Error encoding response: %v", err)
		}

}

2025-03-20T00:12:46.661Z [bytenote-go] [info] Message from server: {"jsonrpc":"2.0","id":0,"result":{"capabilities":{"tools":{}},"protocolVersion":"2024-11-05","serverInfo":{"name":"mcp-go-01","version":"0.1.0"}}}
2025-03-20T00:12:46.662Z [bytenote-go] [info] Message from client: {"method":"notifications/initialized","jsonrpc":"2.0"}
2025-03-20T00:12:46.669Z [bytenote-go] [info] Message from client: {"method":"resources/list","params":{},"jsonrpc":"2.0","id":1}
2025-03-20T00:12:46.669Z [bytenote-go] [info] Message from client: {"method":"tools/list","params":{},"jsonrpc":"2.0","id":2}如通过日志我们可务端和客户端对了上。在对上了接头的暗号后，客户端就开始跟我们要三样东西，对应了三个方法：

2025-03-20T00:54:15.397Z [bytenote-go] [info] Message from client: {"method":"tools/call","params":{"name":"generate-image","arguments":{"prompt":"A majestic elephant standing in a natural grassland habitat, with its trunk raised slightly. Detailed texture showing the wrinkled skin. Realistic lighting with soft shadows.","destination":"elephant_image.png"}},"jsonrpc":"2.0","id":67}

// 添加到main.go的switch语句中

case "tools/list":
	toolSchema := json.RawMessage(`{
		"type": "object",
		"properties": {
			"prompt": {
				"type": "string",
				"description": "Description of the image to generate"
			},
			"destination": {
				"type": "string",
				"description": "Path where the generated image should be saved"
			}
		},
		"required": ["prompt", "destination"]
	}`)

	response = JSONRPCResponse{
		JSONRPC: "2.0",
		ID:request.ID,
		Result: ListToolsResult{
			Tools: []Tool{
				{
					Name:"generate-image",
					Description: "Generate an image using a text prompt",
					InputSchema: toolSchema,
				},
			},
		},
	}

# 测试图像生成请求
echo -e "\n发送图像生成请求..."
echo '{
"jsonrpc": "2.0",
"id": 3,
"method": "tools/call",
"params": {
"name": "generate-image",
"arguments": {
"prompt": "一只可爱的猫咪在阳光下",
"width": 1024,
"height": 1024,
"guidance_scale": 7.5,
"steps": 20,
"negative_prompt": "模糊，扭曲，低质量",
"destination": "'"$HOME/Downloads/test_cat_image.webp"'"
}
}
}' | ./bin/bytenote-go