package utils import ( "archive/zip" "crypto/sha256" "encoding/hex" "fmt" "io" "net/http" "os" "path" "github.com/pkg/errors" "github.com/spf13/viper" ) type Progresser struct { io.Reader total int64 running int64 updates chan GenericUpdate } func (pt *Progresser) Read(p []byte) (int, error) { n, err := pt.Reader.Read(p) pt.running += int64(n) if err == nil { if pt.updates != nil { select { case pt.updates <- GenericUpdate{Progress: float64(pt.running) / float64(pt.total)}: default: } } } if err == io.EOF { return n, io.EOF } return n, errors.Wrap(err, "failed to read") } type GenericUpdate struct { Progress float64 } func DownloadOrCache(cacheKey string, hash string, url string, updates chan GenericUpdate) (r io.ReaderAt, size int64, err error) { downloadCache := path.Join(viper.GetString("cache-dir"), "downloadCache") if err := os.MkdirAll(downloadCache, 0777); err != nil { if !os.IsExist(err) { return nil, 0, errors.Wrap(err, "failed creating download cache") } } location := path.Join(downloadCache, cacheKey) stat, err := os.Stat(location) if err == nil { existingHash := "" if hash != "" { f, err := os.Open(location) if err != nil { return nil, 0, errors.Wrap(err, "failed to open file: "+location) } existingHash, err = SHA256Data(f) if err != nil { return nil, 0, errors.Wrap(err, "could not compute hash for file: "+location) } } if hash == existingHash { f, err := os.Open(location) if err != nil { return nil, 0, errors.Wrap(err, "failed to open file: "+location) } return f, stat.Size(), nil } if err := os.Remove(location); err != nil { return nil, 0, errors.Wrap(err, "failed to delete file: "+location) } } else { if !os.IsNotExist(err) { return nil, 0, errors.Wrap(err, "failed to stat file: "+location) } } out, err := os.Create(location) if err != nil { return nil, 0, errors.Wrap(err, "failed creating file at: "+location) } defer out.Close() resp, err := http.Get(url) if err != nil { return nil, 0, errors.Wrap(err, "failed to fetch: "+url) } defer resp.Body.Close() if resp.StatusCode != http.StatusOK { return nil, 0, fmt.Errorf("bad status: %s on url: %s", resp.Status, url) } progresser := &Progresser{ Reader: resp.Body, total: resp.ContentLength, updates: updates, } _, err = io.Copy(out, progresser) if err != nil { return nil, 0, errors.Wrap(err, "failed writing file to disk") } f, err := os.Open(location) if err != nil { return nil, 0, errors.Wrap(err, "failed to open file: "+location) } if updates != nil { select { case updates <- GenericUpdate{Progress: 1}: default: } } return f, resp.ContentLength, nil } func SHA256Data(f io.Reader) (string, error) { h := sha256.New() if _, err := io.Copy(h, f); err != nil { return "", errors.Wrap(err, "failed to compute hash") } return hex.EncodeToString(h.Sum(nil)), nil } func ExtractMod(f io.ReaderAt, size int64, location string, updates chan GenericUpdate) error { if err := os.MkdirAll(location, 0777); err != nil { if !os.IsExist(err) { return errors.Wrap(err, "failed to create mod directory: "+location) } } else { if err := os.RemoveAll(location); err != nil { return errors.Wrap(err, "failed to remove directory: "+location) } if err := os.MkdirAll(location, 0777); err != nil { return errors.Wrap(err, "failed to create mod directory: "+location) } } reader, err := zip.NewReader(f, size) if err != nil { return errors.Wrap(err, "failed to read file as zip") } for i, file := range reader.File { if !file.FileInfo().IsDir() { outFileLocation := path.Join(location, file.Name) if err := os.MkdirAll(path.Dir(outFileLocation), 0777); err != nil { return errors.Wrap(err, "failed to create mod directory: "+location) } if err := writeZipFile(outFileLocation, file); err != nil { return err } } if updates != nil { select { case updates <- GenericUpdate{Progress: float64(i) / float64(len(reader.File)-1)}: default: } } } if updates != nil { select { case updates <- GenericUpdate{Progress: 1}: default: } } return nil } func writeZipFile(outFileLocation string, file *zip.File) error { outFile, err := os.OpenFile(outFileLocation, os.O_CREATE|os.O_RDWR, 0644) if err != nil { return errors.Wrap(err, "failed to write to file: "+outFileLocation) } defer outFile.Close() inFile, err := file.Open() if err != nil { return errors.Wrap(err, "failed to process mod zip") } if _, err := io.Copy(outFile, inFile); err != nil { return errors.Wrap(err, "failed to write to file: "+outFileLocation) } return nil }