golang文件上传和下载
//下载（支持断电续传）（client）package main
import (
"http"
"os"
"io"
"strconv"
)
const (
UA = "Golang Downloader from Kejibo.com"
)
func main() {
f, err := os.OpenFile("./file.exe", os.O_RDWR, 0666)//其实这里的 O_RDWR应该是 O_RDWR|O_CREATE，也就是文件不存在的情况下就建一个空文件，但是因为windows下还有BUG，如果使用这个O_CREATE，就会直接清空文件，所以这里就不用了这个标志，你自己事先建立好文件。
if err != nil { panic(err) }
stat, err := f.Stat() //获取文件状态
if err != nil { panic(err) }
f.Seek(stat.Size, 0) //把文件指针指到文件末，当然你说为何不直接用 O_APPEND 模式打开，没错是可以。我这里只是试验。
url := "http://dl.google.com/chrome/install/696.57/chrome_installer.exe"
var req http.Request
req.Method = "GET"
req.UserAgent = UA
req.Close = true
req.URL, err = http.ParseURL(url)
if err != nil { panic(err) }
header := http.Header{}
header.Set("Range", "bytes=" + strconv.Itoa64(stat.Size) + "-")
req.Header = header
resp, err := http.DefaultClient.Do(&req)
if err != nil { panic(err) }
written, err := io.Copy(f, resp.Body)
if err != nil { panic(err) }
println("written: ", written)
}
//下载（server）
package main
import (
"flag"
"fmt"
"io"
"log"
"net/http"
"os"
"path"
"strconv"
)
var dir string
var port int
var staticHandler http.Handler
// 初始化参数
func init() {
dir = path.Dir(os.Args)
flag.IntVar(&port, "port", 800, "服务器端口")
flag.Parse()
fmt.Println("dir:", http.Dir(dir))
staticHandler = http.FileServer(http.Dir(dir))
}
func main() {
http.HandleFunc("/", StaticServer)
err := http.ListenAndServe(":"+strconv.Itoa(port), nil)
if err != nil {
log.Fatal("ListenAndServe: ", err)
}
}
// 静态文件处理
func StaticServer(w http.ResponseWriter, req *http.Request) {
fmt.Println("path:" + req.URL.Path)
if req.URL.Path != "/down/" {
staticHandler.ServeHTTP(w, req)
return
}
io.WriteString(w, "hello, world!\n")
}
//上传（client）
package main
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"mime/multipart"
"net/http"
"os"
)
func postFile(filename string, targetUrl string) error {
bodyBuf := &bytes.Buffer{}
bodyWriter := multipart.NewWriter(bodyBuf)
//关键的一步操作
fileWriter, err := bodyWriter.CreateFormFile("uploadfile", filename)
if err != nil {
fmt.Println("error writing to buffer")
return err
}
//打开文件句柄操作
fh, err := os.Open(filename)
if err != nil {
fmt.Println("error opening file")
return err
}
//iocopy
_, err = io.Copy(fileWriter, fh)
if err != nil {
return err
}
contentType := bodyWriter.FormDataContentType()
bodyWriter.Close()
resp, err := http.Post(targetUrl, contentType, bodyBuf)
if err != nil {
return err
}
defer resp.Body.Close()
resp_body, err := ioutil.ReadAll(resp.Body)
if err != nil {
return err
}
fmt.Println(resp.Status)
fmt.Println(string(resp_body))
return nil
}
// sample usage
func main() {
target_url := "http://localhost:9090/upload"
filename := "./astaxie.pdf"
postFile(filename, target_url)
}
//上传（server）
package main
import (
"crypto/md5"
"flag"
"fmt"
"html/template"
"io"
"log"
"net/http"
"os"
"path"
"strconv"
"time"
)
var dir string
var port int
// 初始化参数
func init() {
dir = path.Dir(os.Args)
flag.IntVar(&port, "port", 800, "服务器端口")
flag.Parse()
fmt.Println("dir:", http.Dir(dir))
}
func main() {
http.HandleFunc("/upload", upload)
err := http.ListenAndServe(":"+strconv.Itoa(port), nil)
if err != nil {
log.Fatal("ListenAndServe: ", err)
}
}
// 处理/upload 逻辑
func upload(w http.ResponseWriter, r *http.Request) {
fmt.Println("method:", r.Method) //获取请求的方法
if r.Method == "GET" {
crutime := time.Now().Unix()
h := md5.New()
io.WriteString(h, strconv.FormatInt(crutime, 10))
token := fmt.Sprintf("%x", h.Sum(nil))
t, _ := template.ParseFiles("upload.gtpl")
t.Execute(w, token)
} else {
r.ParseMultipartForm(32
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