APIPark/mcp-server/tool.go

package mcp_server

import (
	"context"
	"encoding/json"
	"fmt"
	"io"
	"net/http"
	"net/url"
	"strings"

	"github.com/eolinker/go-common/utils"

	"github.com/mark3labs/mcp-go/mcp"
	"github.com/mark3labs/mcp-go/server"
)

type ITool interface {
	RegisterMCP(s *server.MCPServer)
}

const (
	MCPBody   = "Body"
	MCPHeader = "Header"
	MCPQuery  = "Query"
	MCPPath   = "Path"
)

type Tool struct {
	name        string
	url         string
	method      string
	contentType string
	opts        []mcp.ToolOption
}

func NewTool(name string, uri string, method string, contentType string, opts ...mcp.ToolOption) ITool {
	return &Tool{
		name:        name,
		url:         uri,
		method:      method,
		contentType: contentType,
		opts:        opts,
	}
}

func (t *Tool) RegisterMCP(s *server.MCPServer) {
	s.AddTool(mcp.NewTool(t.name, t.opts...), func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
		invokeAddress := utils.GatewayInvoke(ctx)
		if invokeAddress == "" {
			return nil, fmt.Errorf("invoke address is empty")
		}
		u, err := url.Parse(invokeAddress)
		if err != nil {
			return nil, fmt.Errorf("invalid invoke address %s", invokeAddress)
		}
		if u.Scheme == "" {
			u.Scheme = "http"
		}

		path := t.url
		queries := url.Values{}
		headers := make(map[string]string)
		body := ""
		for k, v := range request.Params.Arguments {
			if k == "Body" {
				switch a := v.(type) {
				case string:
					body = a
				case map[string]interface{}:
					switch t.contentType {
					case "application/json":
						tmp, _ := json.Marshal(a)
						body = string(tmp)
					case "application/x-www-form-urlencoded":
						bodyValue := url.Values{}
						for kk, vv := range a {
							bodyValue.Set(kk, fmt.Sprintf("%v", vv))
						}
						body = bodyValue.Encode()
					}
				default:
					tmp, _ := json.Marshal(a)
					body = string(tmp)
				}
				continue
			}
			tmp, ok := v.(map[string]interface{})
			if !ok {
				continue
			}
			switch k {
			case MCPHeader:
				for kk, vv := range tmp {
					headers[kk] = fmt.Sprintf("%v", vv)
				}

			case MCPQuery:
				for kk, vv := range tmp {
					queries.Set(kk, fmt.Sprintf("%v", vv))
				}
			case MCPPath:
				for kk, vv := range tmp {
					p, ok := vv.(string)
					if !ok {
						return nil, fmt.Errorf("invalid path %s", v)
					}
					path = strings.Replace(path, fmt.Sprintf("{%s}", kk), p, -1)
				}
			}
		}
		u.Path = path
		u.RawQuery = queries.Encode()

		req, err := http.NewRequest(t.method, u.String(), strings.NewReader(body))
		if err != nil {
			return nil, err
		}
		for k, v := range headers {
			req.Header.Set(k, v)
		}
		if t.contentType != "" {
			req.Header.Set("Content-Type", t.contentType)
		}
		apikey := utils.Label(ctx, "apikey")
		if apikey != "" {
			req.Header.Set("Authorization", apikey)
		}

		resp, err := client.Do(req)
		if err != nil {
			return nil, err
		}
		defer resp.Body.Close()
		d, err := io.ReadAll(resp.Body)
		if err != nil {
			return nil, err
		}
		if resp.StatusCode != http.StatusOK {
			return nil, fmt.Errorf("status code %d, %s", resp.StatusCode, string(d))
		}

		return mcp.NewToolResultText(string(d)), nil
	})
}

var client = http.Client{}