多线程分片下载

app/wails/pkg/sdk/downloader/download_test.go

@@ -0,0 +1,28 @@
+package downloader
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"testing"
+	"time"
+)
+
+func TestDownloader(t *testing.T) {
+	url := "https://mirrors.tuna.tsinghua.edu.cn/Adoptium/8/jdk/x64/windows/OpenJDK8U-jdk_x64_windows_hotspot_8u382b05.zip"
+	dir := os.TempDir()
+	fmt.Println(dir)
+	fileName := "OpenJDK8U-jdk_x64_windows_hotspot_8u382b05.zip"
+
+	a, _ := getRedirectInfo(url, UserAgent)
+	location := a.Header.Get("Location")
+	if len(location) == 0 {
+		location = url
+	}
+	startTime := time.Now()
+	d := NewDownloader(location, dir, fileName, 5)
+	if err := d.Run(); err != nil {
+		log.Fatal(err)
+	}
+	fmt.Printf("\n 文件下载完成耗时: %f second\n", time.Now().Sub(startTime).Seconds())
+}

app/wails/pkg/sdk/downloader/downloader.go

@@ -0,0 +1,286 @@
+package downloader
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"mime"
+	"net/http"
+	"net/url"
+	"os"
+	"path/filepath"
+	"strconv"
+	"sync"
+)
+
+const UserAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36"
+
+// PartFile 文件切片
+type PartFile struct {
+	Index int64
+	From  int64
+	To    int64
+	Data  []byte
+	Done  bool
+}
+
+type Downloader struct {
+	FileSize int64
+	Url      string
+	FileName string
+	Path     string
+	PartNum  int64
+	donePart []PartFile
+}
+
+// NewDownloader 创建下载器
+func NewDownloader(url, outputDir, outputFileName string, partNum int64) *Downloader {
+	if outputDir == "" {
+		wd, err := os.Getwd() //获取当前工作目录
+		if err != nil {
+			log.Println(err)
+		}
+		outputDir = wd
+	}
+	return &Downloader{
+		FileSize: 0,
+		Url:      url,
+		FileName: outputFileName,
+		Path:     outputDir,
+		PartNum:  partNum,
+		donePart: make([]PartFile, partNum),
+	}
+}
+
+func (d *Downloader) getNewRequest(method string) (*http.Request, error) {
+	req, err := http.NewRequest(
+		method,
+		d.Url,
+		nil)
+
+	return req, err
+}
+
+func (d *Downloader) head() (int64, error) {
+	req, err := d.getNewRequest(http.MethodHead)
+	req = setNewHeader(req)
+
+	if err != nil {
+		return 0, err
+	}
+	resp, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return 0, err
+	}
+	if resp.StatusCode > 299 {
+		return 0, errors.New(fmt.Sprintf("Can't process, response is %v", resp.StatusCode))
+	}
+
+	if resp.Header.Get("Accept-Ranges") != "bytes" {
+		return 0, errors.New("服务器不支持文件断点续传")
+	}
+
+	d.FileName = GetFileInfoFromResponse(resp)
+	length, err := strconv.Atoi(resp.Header.Get("Content-Length"))
+
+	return int64(length), err
+}
+
+// 下载切片
+func (d *Downloader) downloadPart(c PartFile, f *os.File) error {
+	r, err := d.getNewRequest("GET")
+	r = setNewHeader(r)
+	if err != nil {
+		return err
+	}
+	log.Printf("开始[%d]下载from:%d to:%d\n", c.Index, c.From, c.To)
+	r.Header.Set("Range", fmt.Sprintf("bytes=%v-%v", c.From, c.To))
+	resp, err := http.DefaultClient.Do(r)
+	if err != nil {
+		return err
+	}
+	if resp.StatusCode > 299 {
+		return errors.New(fmt.Sprintf("服务器错误状态码: %v", resp.StatusCode))
+	}
+	defer func(Body io.ReadCloser) {
+		_ = Body.Close()
+	}(resp.Body)
+
+	bs, err := ioutil.ReadAll(resp.Body)
+	if err != nil {
+		return err
+	}
+	if len(bs) != int(c.To-c.From+1) {
+	}
+	c.Data = bs
+	c.Done = true
+
+	d.donePart[c.Index] = c
+
+	_, err = f.WriteAt(bs, c.From)
+
+	if err != nil {
+		c.Done = true
+	}
+
+	log.Printf("结束[%d]下载", c.Index)
+	return err
+}
+
+func (d *Downloader) checkIntegrity(t *os.File) error {
+	log.Println("开始合并文件")
+
+	totalSize := 0
+
+	for _, s := range d.donePart {
+		//hash.Write(s.Data)
+		totalSize += len(s.Data)
+	}
+
+	if int64(totalSize) != d.FileSize {
+		return errors.New("文件不完整")
+	}
+
+	_ = t.Close()
+	return os.Rename(filepath.Join(d.Path, d.FileName+".tmp"), filepath.Join(d.Path, d.FileName))
+}
+
+// Run 开始下载任务
+func (d *Downloader) Run() error {
+	fileTotalSize, err := d.head()
+	if err != nil {
+		return err
+	}
+	d.FileSize = fileTotalSize
+
+	jobs := make([]PartFile, d.PartNum)
+	eachSize := fileTotalSize / d.PartNum
+
+	path := filepath.Join(d.Path, d.FileName+".tmp")
+
+	tmpFile := new(os.File)
+
+	fByte := make([]byte, d.FileSize)
+
+	if exists(path) {
+		tmpFile, err = os.OpenFile(path, os.O_RDWR, 0)
+		if err != nil {
+			return err
+		}
+		fByte, err = ioutil.ReadAll(tmpFile)
+	} else {
+		tmpFile, err = os.Create(path)
+	}
+	if err != nil {
+		return err
+	}
+	defer func(tmpFile *os.File) {
+		_ = tmpFile.Close()
+	}(tmpFile)
+
+	for i := range jobs {
+		i64 := int64(i)
+		jobs[i64].Index = i64
+		if i == 0 {
+			jobs[i64].From = 0
+		} else {
+			jobs[i64].From = jobs[i64-1].To + 1
+		}
+		if i64 < d.PartNum-1 {
+			jobs[i64].To = jobs[i64].From + eachSize
+		} else {
+			//the last filePart
+			jobs[i64].To = fileTotalSize - 1
+		}
+	}
+
+	for i, j := range jobs {
+		tmpJob := j
+		emptyTmp := make([]byte, tmpJob.To-j.From)
+		if bytes.Compare(emptyTmp, fByte[tmpJob.From:j.To]) != 0 {
+			tmpJob.Data = fByte[j.From : j.To+1]
+			tmpJob.Done = true
+			d.donePart[tmpJob.Index] = tmpJob
+		} else {
+			tmpJob.Done = false
+		}
+		jobs[i] = tmpJob
+	}
+
+	var wg sync.WaitGroup
+	for _, j := range jobs {
+		if !j.Done {
+			wg.Add(1)
+			go func(job PartFile) {
+				defer wg.Done()
+				err := d.downloadPart(job, tmpFile)
+				if err != nil {
+					log.Println("下载文件失败:", err, job)
+				}
+			}(j)
+		}
+	}
+	wg.Wait()
+	return d.checkIntegrity(tmpFile)
+}
+
+func getRedirectInfo(u, userAgent string) (*http.Response, error) {
+	log.Println("获取重定向信息")
+	var a *url.URL
+	a, _ = url.Parse(u)
+	header := http.Header{}
+
+	//header.Add("Cookie", rawCookies)
+	header.Add("User-Agent", userAgent)
+	request := http.Request{
+		Header: header,
+		Method: "GET",
+		URL:    a,
+	}
+
+	client := &http.Client{
+		CheckRedirect: func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		},
+	}
+	response, err := client.Do(&request)
+	if err != nil {
+		return nil, err
+	}
+
+	return response, nil
+}
+
+func setNewHeader(r *http.Request) *http.Request {
+	r.Header.Add("User-Agent", UserAgent)
+	r.Header.Add("Upgrade-Insecure-Requests", "1")
+	return r
+}
+
+func exists(path string) bool {
+	_, err := os.Stat(path) //os.Stat获取文件信息
+	if err != nil {
+		if os.IsExist(err) {
+			return true
+		}
+		return false
+	}
+	return true
+}
+
+func GetFileInfoFromResponse(resp *http.Response) string {
+	contentDisposition := resp.Header.Get("Content-Disposition")
+	if contentDisposition != "" {
+		_, params, err := mime.ParseMediaType(contentDisposition)
+
+		if err != nil {
+			panic(err)
+		}
+		return params["filename"]
+	}
+	filename := filepath.Base(resp.Request.URL.Path)
+	return filename
+}

app/wails/pkg/sdk/downloader/support.go

@@ -0,0 +1,13 @@
+package downloader
+
+import "skapp/pkg/core"
+
+type Support struct {
+	app *core.App
+}
+
+func New(app *core.App) *Support {
+	return &Support{
+		app,
+	}
+}