56. 上传文件（CS版）

这个版本的上传文件是服务端和客户端是分离的。
也在单机上做了大文件测试。测通。
因为走的还是表单提交的模式。所以客户端收不到文件传递的结果。这个还需要抽时间改进。
服务端的根上要建立 upload 和 staticfile 路径。不然会影响文件上传。
服务端代码示例

/**
* MyFileUpload02
* @Author:  Jian Junbo
* @Email:   junbojian@qq.com
* @Create:  2017/9/17 16:30
* Copyright (c) 2017 Jian Junbo All rights reserved.
*
* Description:  
*/
package main

import (
    "io"
    "net/http"
    "os"
    "log"
    "time"
    "strconv"
    "path"
)

func uploadHandler(w http.ResponseWriter, r *http.Request) {
    switch r.Method {
    //POST takes the uploaded file(s) and saves it to disk.
    case "POST":
        //parse the multipart form in the request
        err := r.ParseMultipartForm(100000)
        if err != nil {
            http.Error(w, err.Error(), http.StatusInternalServerError)
            return
        }

        //get a ref to the parsed multipart form
        m := r.MultipartForm

        //get the *fileheaders
        files := m.File["uploadfile"]
        for i, _ := range files {
            //save file as filename
            filename := string(time.Now().Format("20060102150405")) + strconv.Itoa(time.Now().Nanosecond()) + path.Ext(files[i].Filename)

            //for each fileheader, get a handle to the actual file
            file, err := files[i].Open()
            defer file.Close()
            if err != nil {
                http.Error(w, err.Error(), http.StatusInternalServerError)
                return
            }
            //create destination file making sure the path is writeable.
            dst, err := os.Create("./upload/" + filename)
            defer dst.Close()
            if err != nil {
                http.Error(w, err.Error(), http.StatusInternalServerError)
                return
            }
            //copy the uploaded file to the destination file
            if _, err := io.Copy(dst, file); err != nil {
                http.Error(w, err.Error(), http.StatusInternalServerError)
                return
            }
            //fmt.Fprintln(w, dst.Name())
            log.Println(dst.Name())
        }

    default:
        w.WriteHeader(http.StatusMethodNotAllowed)
    }
}

func main() {
    http.HandleFunc("/upload", uploadHandler)

    //static file handler.
    http.Handle("/staticfile/", http.StripPrefix("/staticfile/", http.FileServer(http.Dir("./staticfile"))))

    //Listen on port 8080
    http.ListenAndServe(":8080", nil)
}

客户端代码示例

/**
* MyFileUpload02Client
* @Author:  Jian Junbo
* @Email:   junbojian@qq.com
* @Create:  2017/9/17 21:34
* Copyright (c) 2017 Jian Junbo All rights reserved.
*
* Description:  上传文件客户端
*/
package main

import (
    "bytes"
    "mime/multipart"
    "log"
    "os"
    "io"
    "net/http"
)

func main() {
    //创建一个表单
    server := "http://localhost:8080/upload"
    myfile := "F:\\Temp\\qwqwqw.mp4"
    buf := new(bytes.Buffer)
    writer := multipart.NewWriter(buf)
    formFile, err := writer.CreateFormFile("uploadfile", myfile)
    if err != nil{
        log.Fatal("Create form file failed: %s\n", err)
    }

    //从文件读取数据，写入表单
    srcFile, err := os.Open(myfile)
    if err != nil{
        log.Fatal("Open source file failed: %s\n", err)
    }
    defer srcFile.Close()
    _, err = io.Copy(formFile, srcFile)
    if err != nil{
        log.Fatal("Write to formfile failed: %s\n", err)
    }

    //发送表单
    contentType := writer.FormDataContentType()
    writer.Close()  //发送之前必须调用close()，以便写入文件结尾行
    _, err = http.Post(server, contentType, buf)
    if err != nil{
        log.Fatal("Post failed: %s\n", err)
    }
}