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106 lines
2.0 KiB
106 lines
2.0 KiB
package file
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import (
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"errors"
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"io"
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"net/http"
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"os"
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"strconv"
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)
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/**
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* 文件是否存在
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*/
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func IsFileExist(filename string, filesize int64) (bool, error) {
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info, err := os.Stat(filename)
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if os.IsNotExist(err) {
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return false, err
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}
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if filesize == info.Size() {
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// fmt.Println("已存在！", info.Name(), info.Size(), info.ModTime())
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return true, nil
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}
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err = os.Remove(filename)
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return false, err
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}
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/**
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* 文件下载
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* param url 要下载的文件URL
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* param localPath 文件保存路径（或文件保存名称）
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* fb 回调下载进度
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*/
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func DownProgress(url string, localPath string, fb func(length, downLen int64)) error {
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var (
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fsize int64
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buf = make([]byte, 32*1024)
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written int64
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)
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tmpFilePath := localPath + ".download"
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//创建一个http client
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client := new(http.Client)
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//client.Timeout = time.Second * 60 //设置超时时间
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//get方法获取资源
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resp, err := client.Get(url)
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if err != nil {
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return err
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}
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//读取服务器返回的文件大小
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fsize, err = strconv.ParseInt(resp.Header.Get("Content-Length"), 10, 32)
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if err != nil {
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// fmt.Println(err)
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}
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if ok, _ := IsFileExist(localPath, fsize); ok {
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return err
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}
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//创建文件
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file, err := os.Create(tmpFilePath)
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if err != nil {
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return err
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}
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defer file.Close()
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if resp.Body == nil {
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return errors.New("body is null")
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}
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defer resp.Body.Close()
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//下面是 io.copyBuffer() 的简化版本
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for {
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//读取bytes
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nr, er := resp.Body.Read(buf)
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if nr > 0 {
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//写入bytes
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nw, ew := file.Write(buf[0:nr])
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//数据长度大于0
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if nw > 0 {
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written += int64(nw)
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}
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//写入出错
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if ew != nil {
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err = ew
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break
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}
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//读取是数据长度不等于写入的数据长度
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if nr != nw {
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err = io.ErrShortWrite
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break
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}
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}
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if er != nil {
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if er != io.EOF {
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err = er
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}
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break
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}
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//没有错误了快使用 callback
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fb(fsize, written)
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}
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if err == nil {
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file.Close()
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err = os.Rename(tmpFilePath, localPath)
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}
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return err
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}
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