Golang实现http文件上传小功能的案例

package main
import (
	"fmt"
	"io"
	"net/http"
	"os"
)
func main() {
	http.HandleFunc("/", index)
	http.HandleFunc("/upload", upload)
	http.ListenAndServe(":1789", nil)
}
func upload(w http.ResponseWriter, r *http.Request) {
	r.ParseMultipartForm(32  20)
	file, handler, err := r.FormFile("uploadfile")
	if err != nil {
		fmt.Println(err)
		return
	}
	defer file.Close()
	f, err := os.OpenFile(handler.Filename, os.O_WRONLY|os.O_CREATE, 0666)
	if err != nil {
		fmt.Println(err)
		return
	}
	defer f.Close()
	io.Copy(f, file)
	fmt.Fprintln(w, "upload ok!")
}
func index(w http.ResponseWriter, r *http.Request) {
	w.Write([]byte(tpl))
}
const tpl = `html>
head>
title>上传文件/title>
/head>
body>
form enctype="multipart/form-data" action="/upload" method="post">
 input type="file" name="uploadfile" />
 input type="hidden" name="token" value="{...{.}...}"/>
 input type="submit" value="upload" />
/form>
/body>
/html>`

func UploadFileToLocal(c echo.Context) error {
 r := c.Request()  //无论用的什么路由，原理是要从request获取数据
 t := echotools.NewEchoTools(c)
 reader, err := r.MultipartReader() //request 获得文件 reader
 if err != nil {
  return t.BadRequest(err.Error())
 }
 if reader == nil {
  return t.BadRequest(`未接受到文件`)
 }
    //遍历操作 获得的
 for {
  part, err := reader.NextPart()
  if err == io.EOF {
   break
  }
  fmt.Printf("FileName=[%s],FormName[%s]\n",part.FileName(),part.FormName())
  if part.FileName() == "" {
   data, _ := ioutil.ReadAll(part)
   fmt.Printf("FormData=[%s]\n", string(data))
            continue
  } else {
            //创建一个空文件
   dst, er:= os.Create("static/uploadfiles/" + part.FileName())
   if er != nil {
    return t.BadRequest(err.Error())
   }
   defer dst.Close()
            //将获取到的文件复制 给 创建的文件
   _,err := io.Copy(dst, part)
   if err != nil {
    return t.BadRequest(err.Error())
   }
  }
 }
  return t.OK(`OK`)
}

func SendFile(c echo.Context) error{
 t := echotools.NewEchoTools(c)
 r := c.Request()
 file, header, err := r.FormFile("file") // 获得客户端传来的 文件 file
 if err != nil {
  return t.BadRequest("上传错误:" + err.Error())
 }
 
 bodyBuffer := bytes.Buffer{}
 bodyWriter := multipart.NewWriter(bodyBuffer)
 fileWriter, _ := bodyWriter.CreateFormFile("files", header.Filename)
 io.Copy(fileWriter, file) //将 客户端文件 复制给 用于传输的 fileWriter
 contentType := bodyWriter.FormDataContentType() //contentType
 bodyWriter.Close()
 ip := config.Opts.UploadServerAddr //配置
 resp, _ := http.Post("http://"+ip+"/uploadToLocal/"+header.Filename, contentType, bodyBuffer)
 defer resp.Body.Close()
 resp_body, _ := ioutil.ReadAll(resp.Body)
 
 if resp.Status == `200 OK` {
  return t.OK(string(resp_body))
 }else {
  return t.BadRequest(string(resp_body))
 }
}