学习Go实现上传文件，下载等接口

1个月前 ⋅ 0

- 实现，上传文件，获取元数据信息，下载文件，更新元信息，文件删除等接口；信息暂时放内存，容易丢失；

`报gopath错误先执行git mod init 先执行`

- 文件目录，和main.go接口地址
![](https://www.tanbinghao.top/uploads/markdown/20201202-224221-814.png)

- handler目录
 - handler.go 代码

```go
package handler

import (
	"encoding/json"
	"fmt"
	"io"
	"io/ioutil"
	"net/http"
	"os"
	"filestore-server/meta"
	"filestore-server/util"
	"time"
)

//处理文件上传
func UploadHandler(w http.ResponseWriter,r *http.Request) {
	if r.Method == "GET" {
		data, err := ioutil.ReadFile("./static/view/index.html")
		if err != nil {
			io.WriteString(w, "上传错误")
		}
		io.WriteString(w, string(data))
		//返回上传页面
	} else if r.Method == "POST" {
		//接收文件流存储到本地目录
		file, head, err := r.FormFile("file")
		if err != nil {
			fmt.Printf("failed to get data,err %s\n", err.Error())
			return
		}
		defer file.Close()
		fileMeta :=meta.FileMeta{
			FileName: head.Filename,
			Location: "./tmp/" + head.Filename,
			UploadAt: time.Now().Format("2006 01-02 12:30:22"),
		}
		newFile, err := os.Create(fileMeta.Location)
		if err != nil {
			fmt.Printf("Failed to create file,err %s\n", err.Error())
			return
		}
		defer newFile.Close()
		fileMeta.Filesize, err = io.Copy(newFile, file)
		if err != nil {
			fmt.Printf("Failed to save data into file err %s\n",err.Error())
			return
		}
		newFile.Seek(0,0)
		fileMeta.FileSha1 = util.FileSha1(newFile)	//哈希值
		meta.UploadFileMeta(fileMeta)	//新增，更新元数据
		http.Redirect(w,r,"/file/upload/suc",http.StatusFound)
	}
}

//上传完成
func UploadSunHandler(w http.ResponseWriter,r *http.Request)  {
	io.WriteString(w,"上传成功")
}

//获取元数据信息
func GetFileMetaHandler(w http.ResponseWriter,r *http.Request) {
	r.ParseForm()
	filehash := r.Form["filehash"][0]		//获取文件hash
	fMeta := meta.GetFileMeta(filehash)		//通过hash获取元数信息
	data, err := json.Marshal(fMeta)		//转换为json
	if err!=nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	w.Write(data)
}

//更新元信息接口(重命名)
func FileMetaUpdateHandle(w http.ResponseWriter,r *http.Request) {
	r.ParseForm()
	opType := r.Form.Get("op")
	filesha1 := r.Form.Get("filehash")
	NewFileName := r.Form.Get("filename")
	if opType != "0" {
		w.WriteHeader(http.StatusForbidden)
		return
	}
	if r.Method != "POST" {
		w.WriteHeader(http.StatusMethodNotAllowed)
	}
	curFileMeta := meta.GetFileMeta(filesha1) //通过sha1值获取文件的元信息对象
	curFileMeta.FileName = NewFileName        //接口的哈希值
	meta.UploadFileMeta(curFileMeta)          //更新元信息到内存
	w.WriteHeader(http.StatusOK)
	data, err := json.Marshal(curFileMeta)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
	}
	w.WriteHeader(http.StatusOK)
	w.Write(data)
}

//删除文件
func FileDeleteHandle(w http.ResponseWriter,r *http.Request) {
	r.ParseForm()
	filesha1 := r.Form.Get("filehash")
	fMeta := meta.GetFileMeta(filesha1)
	os.Remove(fMeta.Location)
	meta.RemoveFileMeta(filesha1)
	w.WriteHeader(http.StatusOK)
}

//文件下载
func DownloadHandler(w http.ResponseWriter,r *http.Request) {
	r.ParseForm()
	fsha1 := r.Form.Get("filehash")
	fm := meta.GetFileMeta(fsha1)  //哈希值从内存拿到信息
	f, err := os.Open(fm.Location) //打开文件
	if err != nil {                //判断是否能打开
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	defer f.Close()

data, err := ioutil.ReadAll(f)
	if err != nil {
		w.WriteHeader(http.StatusInternalServerError)
		return
	}
	w.Header().Set("Content-Type","application/octect-stream")
	w.Header().Set("Content-disposition","attachment;filename=\""+fm.FileName+"\"")
	w.Write(data)
}
```

- meta目录
 - filemeta.go //更新元信息，删除文件，存储元信息
 
```go
package meta

//文件元信息
type FileMeta struct {
	FileSha1 string
	FileName string
	Filesize int64
	Location string
	UploadAt string
}

var fileMetas map[string]FileMeta

func init()  {
	fileMetas = make(map[string]FileMeta)

}

//新增/更新文件元信息
func UploadFileMeta(fmeta FileMeta)  {
	fileMetas[fmeta.FileSha1] = fmeta
}

//通过sha1值获取文件的元信息对象
func GetFileMeta(fileSha1 string)FileMeta  {
	return fileMetas[fileSha1]
}

//通过哈希值删除文件
func RemoveFileMeta(fileSha1 string) {
	delete(fileMetas, fileSha1)
}

```

- util目录
 - util.go //封装生成hash文件，转json数据方法

```go
 package util

import (
	"crypto/md5"
	"crypto/sha1"
	"encoding/hex"
	"hash"
	"io"
	"os"
	"path/filepath"
)

type Sha1Stream struct {
	_sha1 hash.Hash
}

func (obj *Sha1Stream) Update(data []byte) {
	if obj._sha1 == nil {
		obj._sha1 = sha1.New()
	}
	obj._sha1.Write(data)
}

func (obj *Sha1Stream) Sum() string {
	return hex.EncodeToString(obj._sha1.Sum([]byte("")))
}

func Sha1(data []byte) string {
	_sha1 := sha1.New()
	_sha1.Write(data)
	return hex.EncodeToString(_sha1.Sum([]byte("")))
}

func FileSha1(file *os.File) string {
	_sha1 := sha1.New()
	io.Copy(_sha1, file)
	return hex.EncodeToString(_sha1.Sum(nil))
}

func MD5(data []byte) string {
	_md5 := md5.New()
	_md5.Write(data)
	return hex.EncodeToString(_md5.Sum([]byte("")))
}

func FileMD5(file *os.File) string {
	_md5 := md5.New()
	io.Copy(_md5, file)
	return hex.EncodeToString(_md5.Sum(nil))
}

func PathExists(path string) (bool, error) {
	_, err := os.Stat(path)
	if err == nil {
		return true, nil
	}
	if os.IsNotExist(err) {
		return false, nil
	}
	return false, err
}

func GetFileSize(filename string) int64 {
	var result int64
	filepath.Walk(filename, func(path string, f os.FileInfo, err error) error {
		result = f.Size()
		return nil
	})
	return result
}
 
 ```