You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: http_getDfsFile.go
    path of file: ./repos/teamgram-server/app/service/dfs/internal/server/http
    
    the code of the file until where you have to start completion: /*
 * WARNING! All changes made in this file will be lost!
 * Created from 'scheme.tl' by 'mtprotoc'
 *
 * Copyright (c) 2022-present,  Teamgram Authors.
 *  All rights reserved.
 *
 * Author: teagramio (teagram.io@gmail.com)
 */

package http

import (
	"context"
	"net/http"
	"strconv"
	"strings"
	"time"

	"github.com/teamgram/teamgram-server/app/service/dfs/internal/model"
	"github.com/teamgram/teamgram-server/app/service/dfs/internal/svc"

	"github.com/zeromicro/go-zero/core/logx"
	"github.com/zeromicro/go-zero/rest/httpx"
)

func GetDfsFile(ctx *svc.Ser
    
func GetDfsFile(ctx *svc.ServiceContext) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		var (
			err     error
			creator int64
			fileId  int64
		)

		var (
			fileName struct {
				FileName string `path:"file"`
			}
		)

		err = httpx.ParsePath(r, &fileName)
		if err != nil {
			logx.Errorf("getDfsFile - error: %v", err)
			httpx.Error(w, err)
			return
		}

		v := strings.Split(fileName.FileName, "_")
		if len(v) != 2 {
			logx.Errorf("getDfsFile - error: invalid fileName: %s", fileName)
			http.NotFound(w, r)
			return
		}

		if creator, err = strconv.ParseInt(v[0], 10, 64); err != nil {
			logx.Errorf("getDfsFile - error: invalid fileName: %s", fileName)
			http.NotFound(w, r)
			return
		}
		_ = creator

		if fileId, err = strconv.ParseInt(strings.Split(v[1], ".")[0], 10, 64); err != nil {
			logx.Errorf("getDfsFile - error: invalid fileName: %s", fileName)
			http.NotFound(w, r)
			return
		}
		_ = fileId

		f, err := DfsOpenFile(ctx, creator, fileId)
		if err != nil {
			logx.Errorf("getDfsFile(%d, %d) - error: invalid fileName: %s", creator, fileId, fileName)
			http.NotFound(w, r)
			return
		}

		http.ServeContent(w, r, fileName.FileName, f.Modtime, f.ReadSeeker)
	}
}