626 lines
15 KiB
Go
626 lines
15 KiB
Go
package common
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import (
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"bytes"
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"crypto/md5"
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"crypto/sha1"
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"crypto/sha256"
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"crypto/sha512"
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"encoding/hex"
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"errors"
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"fmt"
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"hash"
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"io"
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"log"
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"net/url"
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"os"
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"runtime"
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"path"
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"path/filepath"
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"strings"
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)
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import (
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"net/http"
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"github.com/jlaffeye/ftp"
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"bufio"
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)
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// DownloadConfig is the configuration given to instantiate a new
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// download instance. Once a configuration is used to instantiate
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// a download client, it must not be modified.
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type DownloadConfig struct {
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// The source URL in the form of a string.
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Url string
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// This is the path to download the file to.
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TargetPath string
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// DownloaderMap maps a schema to a Download.
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DownloaderMap map[string]Downloader
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// If true, this will copy even a local file to the target
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// location. If false, then it will "download" the file by just
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// returning the local path to the file.
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CopyFile bool
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// The hashing implementation to use to checksum the downloaded file.
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Hash hash.Hash
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// The checksum for the downloaded file. The hash implementation configuration
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// for the downloader will be used to verify with this checksum after
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// it is downloaded.
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Checksum []byte
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// What to use for the user agent for HTTP requests. If set to "", use the
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// default user agent provided by Go.
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UserAgent string
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}
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// A DownloadClient helps download, verify checksums, etc.
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type DownloadClient struct {
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config *DownloadConfig
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downloader Downloader
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}
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// HashForType returns the Hash implementation for the given string
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// type, or nil if the type is not supported.
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func HashForType(t string) hash.Hash {
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switch t {
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case "md5":
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return md5.New()
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case "sha1":
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return sha1.New()
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case "sha256":
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return sha256.New()
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case "sha512":
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return sha512.New()
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default:
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return nil
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}
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}
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// NewDownloadClient returns a new DownloadClient for the given
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// configuration.
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func NewDownloadClient(c *DownloadConfig) *DownloadClient {
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const mtu = 1500 /* ethernet */ - 20 /* ipv4 */ - 20 /* tcp */
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if c.DownloaderMap == nil {
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c.DownloaderMap = map[string]Downloader{
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"file": &FileDownloader{bufferSize: nil},
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"ftp": &FTPDownloader{userInfo: url.Userinfo{username:"anonymous", password: "anonymous@"}, mtu: mtu},
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"http": &HTTPDownloader{userAgent: c.UserAgent},
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"https": &HTTPDownloader{userAgent: c.UserAgent},
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"smb": &SMBDownloader{bufferSize: nil}
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}
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}
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return &DownloadClient{config: c}
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}
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// A downloader is responsible for actually taking a remote URL and
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// downloading it.
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type Downloader interface {
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Cancel()
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Download(*os.File, *url.URL) error
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Progress() uint
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Total() uint
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}
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func (d *DownloadClient) Cancel() {
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// TODO(mitchellh): Implement
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}
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func (d *DownloadClient) Get() (string, error) {
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// If we already have the file and it matches, then just return the target path.
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if verify, _ := d.VerifyChecksum(d.config.TargetPath); verify {
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log.Println("[DEBUG] Initial checksum matched, no download needed.")
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return d.config.TargetPath, nil
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}
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u, err := url.Parse(d.config.Url)
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if err != nil {
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return "", err
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}
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log.Printf("Parsed URL: %#v", u)
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/* FIXME:
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handle the special case of d.config.CopyFile which returns the path
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in an os-specific format.
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*/
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// Files when we don't copy the file are special cased.
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var f *os.File
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var finalPath string
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sourcePath := ""
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if u.Scheme == "file" && !d.config.CopyFile {
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// This is special case for relative path in this case user specify
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// file:../ and after parse destination goes to Opaque
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if u.Path != "" {
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// If url.Path is set just use this
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finalPath = u.Path
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} else if u.Opaque != "" {
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// otherwise try url.Opaque
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finalPath = u.Opaque
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}
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// This is a special case where we use a source file that already exists
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// locally and we don't make a copy. Normally we would copy or download.
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log.Printf("[DEBUG] Using local file: %s", finalPath)
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// transform the actual file uri to a windowsy path if we're being windowsy.
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if runtime.GOOS == "windows" {
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// FIXME: cwd should point to a path relative to the TEMPLATE path,
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// but since this isn't exposed to us anywhere, we use os.Getwd()
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// and assume the user ran packer in the same directory that
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// any relative files are located at.
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cwd,err := os.Getwd()
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if err != nil {
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return "", fmt.Errorf("Unable to get working directory")
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}
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finalPath = NormalizeWindowsURL(cwd, *url)
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}
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// Keep track of the source so we can make sure not to delete this later
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sourcePath = finalPath
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if _, err = os.Stat(finalPath); err != nil {
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return "", err
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}
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} else {
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finalPath = d.config.TargetPath
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var ok bool
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d.downloader, ok = d.config.DownloaderMap[u.Scheme]
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if !ok {
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return "", fmt.Errorf("No downloader for scheme: %s", u.Scheme)
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}
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// Otherwise, download using the downloader.
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f, err = os.OpenFile(finalPath, os.O_RDWR|os.O_CREATE, os.FileMode(0666))
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if err != nil {
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return "", err
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}
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log.Printf("[DEBUG] Downloading: %s", u.String())
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err = d.downloader.Download(f, u)
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f.Close()
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if err != nil {
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return "", err
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}
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}
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if d.config.Hash != nil {
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var verify bool
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verify, err = d.VerifyChecksum(finalPath)
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if err == nil && !verify {
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// Only delete the file if we made a copy or downloaded it
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if sourcePath != finalPath {
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os.Remove(finalPath)
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}
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err = fmt.Errorf(
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"checksums didn't match expected: %s",
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hex.EncodeToString(d.config.Checksum))
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}
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}
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return finalPath, err
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}
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// PercentProgress returns the download progress as a percentage.
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func (d *DownloadClient) PercentProgress() int {
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if d.downloader == nil {
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return -1
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}
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return int((float64(d.downloader.Progress()) / float64(d.downloader.Total())) * 100)
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}
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// VerifyChecksum tests that the path matches the checksum for the
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// download.
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func (d *DownloadClient) VerifyChecksum(path string) (bool, error) {
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if d.config.Checksum == nil || d.config.Hash == nil {
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return false, errors.New("Checksum or Hash isn't set on download.")
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}
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f, err := os.Open(path)
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if err != nil {
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return false, err
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}
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defer f.Close()
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log.Printf("Verifying checksum of %s", path)
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d.config.Hash.Reset()
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io.Copy(d.config.Hash, f)
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return bytes.Equal(d.config.Hash.Sum(nil), d.config.Checksum), nil
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}
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// HTTPDownloader is an implementation of Downloader that downloads
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// files over HTTP.
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type HTTPDownloader struct {
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progress uint
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total uint
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userAgent string
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}
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func (*HTTPDownloader) Cancel() {
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// TODO(mitchellh): Implement
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}
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func (d *HTTPDownloader) Download(dst *os.File, src *url.URL) error {
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log.Printf("Starting download over HTTP: %s", src.String())
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// Seek to the beginning by default
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if _, err := dst.Seek(0, 0); err != nil {
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return err
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}
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// Reset our progress
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d.progress = 0
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// Make the request. We first make a HEAD request so we can check
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// if the server supports range queries. If the server/URL doesn't
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// support HEAD requests, we just fall back to GET.
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req, err := http.NewRequest("HEAD", src.String(), nil)
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if err != nil {
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return err
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}
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if d.userAgent != "" {
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req.Header.Set("User-Agent", d.userAgent)
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}
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httpClient := &http.Client{
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Transport: &http.Transport{
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Proxy: http.ProxyFromEnvironment,
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},
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}
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resp, err := httpClient.Do(req)
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if err == nil && (resp.StatusCode >= 200 && resp.StatusCode < 300) {
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// If the HEAD request succeeded, then attempt to set the range
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// query if we can.
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if resp.Header.Get("Accept-Ranges") == "bytes" {
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if fi, err := dst.Stat(); err == nil {
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if _, err = dst.Seek(0, os.SEEK_END); err == nil {
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req.Header.Set("Range", fmt.Sprintf("bytes=%d-", fi.Size()))
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d.progress = uint(fi.Size())
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}
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}
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}
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}
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// Set the request to GET now, and redo the query to download
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req.Method = "GET"
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resp, err = httpClient.Do(req)
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if err != nil {
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return err
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}
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d.total = d.progress + uint(resp.ContentLength)
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var buffer [4096]byte
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for {
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n, err := resp.Body.Read(buffer[:])
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if err != nil && err != io.EOF {
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return err
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}
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d.progress += uint(n)
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if _, werr := dst.Write(buffer[:n]); werr != nil {
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return werr
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}
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if err == io.EOF {
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break
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}
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}
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return nil
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}
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func (d *HTTPDownloader) Progress() uint {
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return d.progress
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}
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func (d *HTTPDownloader) Total() uint {
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return d.total
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}
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// FTPDownloader is an implementation of Downloader that downloads
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// files over FTP.
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type FTPDownloader struct {
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userInfo url.UserInfo
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mtu uint
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active bool
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progress uint
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total uint
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}
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func (*FTPDownloader) Cancel() {
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d.active = false
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}
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func (d *FTPDownloader) Download(dst *os.File, src *url.URL) error {
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var userinfo *url.Userinfo
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userinfo = d.userInfo
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d.active = false
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// check the uri is correct
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uri, err := url.Parse(src)
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if err != nil { return err }
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if uri.Scheme != "ftp" {
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return fmt.Errorf("Unexpected uri scheme: %s", uri.Scheme)
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}
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// connect to ftp server
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var cli *ftp.ServerConn
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log.Printf("Starting download over FTP: %s : %s\n", uri.Host, Uri.Path)
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cli,err := ftp.Dial(uri.Host)
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if err != nil { return nil }
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defer cli.Close()
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// handle authentication
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if uri.User != nil { userinfo = uri.User }
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log.Printf("Authenticating to FTP server: %s : %s\n", uri.User.username, uri.User.password)
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err = cli.Login(userinfo.username, userinfo.password)
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if err != nil { return err }
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// locate specified path
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path := path.Dir(uri.Path)
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log.Printf("Changing to FTP directory : %s\n", path)
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err = cli.ChangeDir(path)
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if err != nil { return nil }
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curpath,err := cli.CurrentDir()
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if err != nil { return err }
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log.Printf("Current FTP directory : %s\n", curpath)
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// collect stats about the specified file
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var name string
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var entry *ftp.Entry
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_,name = path.Split(uri.Path)
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entry = nil
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entries,err := cli.List(curpath)
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for _,e := range entries {
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if e.Type == ftp.EntryTypeFile && e.Name == name {
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entry = e
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break
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}
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}
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if entry == nil {
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return fmt.Errorf("Unable to find file: %s", uri.Path)
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}
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log.Printf("Found file : %s : %v bytes\n", entry.Name, entry.Size)
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d.progress = 0
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d.total = entry.Size
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// download specified file
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d.active = true
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reader,err := cli.RetrFrom(uri.Path, d.progress)
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if err != nil { return nil }
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// do it in a goro so that if someone wants to cancel it, they can
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errch := make(chan error)
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go func(d *FTPDownloader, r *io.Reader, w *bufio.Writer, e chan error) {
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defer w.Flush()
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for ; d.active {
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n,err := io.CopyN(writer, reader, d.mtu)
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if err != nil { break }
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d.progress += n
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}
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d.active = false
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e <- err
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}(d, reader, bufio.NewWriter(dst), errch)
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// spin until it's done
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err = <-errch
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reader.Close()
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if err == nil && d.progress != d.total {
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err = fmt.Errorf("FTP total transfer size was %d when %d was expected", d.progress, d.total)
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}
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// log out and quit
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cli.Logout()
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cli.Quit()
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return err
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}
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func (d *FTPDownloader) Progress() uint {
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return d.progress
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}
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func (d *FTPDownloader) Total() uint {
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return d.total
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}
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// FileDownloader is an implementation of Downloader that downloads
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// files using the regular filesystem.
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type FileDownloader struct {
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bufferSize *uint
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active bool
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progress uint
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total uint
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}
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func (*FileDownloader) Cancel() {
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d.active = false
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}
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func (d *FileDownloader) Progress() uint {
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return d.progress
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}
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func (d *FileDownloader) Download(dst *os.File, src *url.URL) error {
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d.active = false
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/* parse the uri using the net/url module */
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uri, err := url.Parse(src)
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if uri.Scheme != "file" {
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return fmt.Errorf("Unexpected uri scheme: %s", uri.Scheme)
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}
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/* use the current working directory as the base for relative uri's */
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cwd,err := os.Getwd()
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if err != nil {
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return "", fmt.Errorf("Unable to get working directory")
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}
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/* determine which uri format is being used and convert to a real path */
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var realpath string, basepath string
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basepath = filepath.ToSlash(cwd)
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// absolute path -- file://c:/absolute/path
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if strings.HasSuffix(uri.Host, ":") {
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realpath = path.Join(uri.Host, uri.Path)
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// semi-absolute path (current drive letter) -- file:///absolute/path
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} else if uri.Host == "" && strings.HasPrefix(uri.Path, "/") {
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realpath = path.Join(filepath.VolumeName(basepath), uri.Path)
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// relative path -- file://./relative/path
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} else if uri.Host == "." {
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realpath = path.Join(basepath, uri.Path)
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// relative path -- file://relative/path
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} else {
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realpath = path.Join(basepath, uri.Host, uri.Path)
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}
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/* download the file using the operating system's facilities */
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d.progress = 0
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d.active = true
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f, err = os.Open(realpath)
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if err != nil { return err }
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defer f.Close()
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// get the file size
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fi, err := f.Stat()
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if err != nil { return err }
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d.total = fi.Size()
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// no bufferSize specified, so copy synchronously.
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if d.bufferSize == nil {
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n,err := io.Copy(dst, f)
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d.active = false
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d.progress += n
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// use a goro in case someone else wants to enable cancel/resume
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} else {
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errch := make(chan error)
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go func(d* FileDownloader, r *bufio.Reader, w *bufio.Writer, e chan error) {
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defer w.Flush()
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for ; d.active {
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n,err := io.CopyN(writer, reader, d.bufferSize)
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if err != nil { break }
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d.progress += n
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}
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d.active = false
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e <- err
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}(d, f, bufio.NewWriter(dst), errch)
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// ...and we spin until it's done
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err = <-errch
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}
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f.Close()
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return err
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}
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func (d *FileDownloader) Total() uint {
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return d.total
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}
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// SMBDownloader is an implementation of Downloader that downloads
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// files using the "\\" path format on Windows
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type SMBDownloader struct {
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bufferSize *uint
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active bool
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progress uint
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total uint
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}
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func (*SMBDownloader) Cancel() {
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d.active = false
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}
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func (d *SMBDownloader) Progress() uint {
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return d.progress
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}
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func (d *SMBDownloader) Download(dst *os.File, src *url.URL) error {
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const UNCPrefix = string(os.PathSeparator)+string(os.PathSeparator)
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d.active = false
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if runtime.GOOS != "windows" {
|
||
return fmt.Errorf("Support for SMB based uri's are not supported on %s", runtime.GOOS)
|
||
}
|
||
|
||
/* convert the uri using the net/url module to a UNC path */
|
||
var realpath string
|
||
uri, err := url.Parse(src)
|
||
if uri.Scheme != "smb" {
|
||
return fmt.Errorf("Unexpected uri scheme: %s", uri.Scheme)
|
||
}
|
||
|
||
realpath = UNCPrefix + filepath.ToSlash(path.Join(uri.Host, uri.Path))
|
||
|
||
/* Open up the "\\"-prefixed path using the Windows filesystem */
|
||
d.progress = 0
|
||
d.active = true
|
||
|
||
f, err = os.Open(realpath)
|
||
if err != nil { return err }
|
||
defer f.Close()
|
||
|
||
// get the file size (at the risk of performance)
|
||
fi, err := f.Stat()
|
||
if err != nil { return err }
|
||
d.total = fi.Size()
|
||
|
||
// no bufferSize specified, so copy synchronously.
|
||
if d.bufferSize == nil {
|
||
n,err := io.Copy(dst, f)
|
||
d.active = false
|
||
d.progress += n
|
||
|
||
// use a goro in case someone else wants to enable cancel/resume
|
||
} else {
|
||
errch := make(chan error)
|
||
go func(d* SMBDownloader, r *bufio.Reader, w *bufio.Writer, e chan error) {
|
||
defer w.Flush()
|
||
for ; d.active {
|
||
n,err := io.CopyN(writer, reader, d.bufferSize)
|
||
if err != nil { break }
|
||
d.progress += n
|
||
}
|
||
d.active = false
|
||
e <- err
|
||
}(d, f, bufio.NewWriter(dst), errch)
|
||
|
||
// ...and as usual we spin until it's done
|
||
err = <-errch
|
||
}
|
||
f.Close()
|
||
return err
|
||
}
|
||
|
||
func (d *SMBDownloader) Total() uint {
|
||
return d.total
|
||
}
|