87 lines
1.7 KiB
Go
87 lines
1.7 KiB
Go
package downloader
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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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"strings"
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req "github.com/levigross/grequests"
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"github.com/schollz/progressbar/v3"
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)
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var (
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ErrAccessDenied = errors.New("restricted access (credentials required)")
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ErrInvalidURL = errors.New("invalid url")
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ErrUnknownAuthority = errors.New("certificate from unknown authority")
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)
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type Context struct {
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Filename string
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Link string
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}
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func NewContext(filename, link string) *Context {
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return &Context{
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Filename: filename,
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Link: link,
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}
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}
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func (c *Context) Download() error {
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resp, err := req.Head(c.Link, nil)
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if err != nil {
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if strings.Contains(err.Error(), "no such host") {
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return ErrInvalidURL
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}
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if strings.Contains(err.Error(), "certificate signed by unknown authority") {
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return ErrUnknownAuthority
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}
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return err
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}
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defer resp.Close()
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if resp.StatusCode == http.StatusNotFound {
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return ErrInvalidURL
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}
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if resp.StatusCode == http.StatusUnauthorized {
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return ErrAccessDenied
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}
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if resp.StatusCode != http.StatusOK {
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return errors.New(resp.RawResponse.Status)
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}
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resp.Close()
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resp, err = req.Get(c.Link, nil)
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if err != nil {
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return err
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}
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var filesize int64
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if resp.RawResponse.ContentLength > -1 {
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filesize = resp.RawResponse.ContentLength
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}
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destFile, err := os.OpenFile(c.Filename, os.O_CREATE|os.O_WRONLY, 0644)
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if err != nil {
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return err
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}
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defer destFile.Close()
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bar := progressbar.DefaultBytes(
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filesize,
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"downloading",
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)
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_, err = io.Copy(io.MultiWriter(destFile, bar), resp.RawResponse.Body)
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if err != nil {
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return err
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}
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return nil
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}
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func (c *Context) FileExists() bool {
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_, err := os.Stat(c.Filename)
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return !errors.Is(err, os.ErrNotExist)
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}
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