Allow a custom working dir to be configured

README.md

@@ -36,3 +36,13 @@ The boost will set the concurrency level. In typical concurrency scenarios you w
 ```
 dl <file url> -boost 8
 ```
+
+### Custom Working Directory
+
+By default, `dl` will use the current working directory to store the temporary downloaded parts. If you are downloading to an external disk, you may want to use an internal disk as the working directory. This will speed up the concatenation process after the download is complete.
+
+To override this and set your own working directory you can:
+
+```
+dl <file url> -workdir ~/Somewhere/Else
+```

dl.go

@@ -4,9 +4,11 @@ import (
  "flag"
  "fmt"
  "io"
+ "log"
  "mime"
  "net/http"
  "os"
+ "path"
  "strconv"
  "strings"
  "sync"
@@ -17,13 +19,15 @@ import (
 func main() {
  filenamePtr := flag.String("filename", "", "custom filename")
  boostPtr := flag.Int("boost", 8, "number of concurrent downloads")
+ workingDirPtr := flag.String("workdir", "", "working directory for downloads")
 
  flag.Parse()
 
  file_uris := flag.Args()
 
  var filesize uint64
  var filename string
+ var workingDir string
  var err error
 
  for _, uri := range file_uris {
@@ -37,13 +41,20 @@ func main() {
  filename = *filenamePtr
  }
 
+ if *workingDirPtr != "" {
+ workingDir = *workingDirPtr
+ } else {
+ workingDir, err = os.Getwd()
+ if err != nil {
+ log.Println(err)
+ }
+ }
+
  fmt.Println(filename)
 
- fetch(uri, filesize, *boostPtr)
- concatFiles(filename, filesize, *boostPtr)
+ fetch(uri, filesize, workingDir, *boostPtr)
+ concatFiles(filename, filesize, *boostPtr, workingDir)
  }
-
- return
 }
 
 func fetchMetadata(uri string) (filesize uint64, filename string, err error) {
@@ -75,7 +86,7 @@ func fetchMetadata(uri string) (filesize uint64, filename string, err error) {
  return
 }
 
-func fetch(uri string, filesize uint64, boost int) {
+func fetch(uri string, filesize uint64, dir string, boost int) {
  var wg sync.WaitGroup
 
  bar := progressbar.DefaultBytes(
@@ -86,15 +97,13 @@ func fetch(uri string, filesize uint64, boost int) {
  for part := 0; part < boost; part++ {
  start, end := calculatePartBoundary(filesize, boost, part)
  wg.Add(1)
- go fetchPart(&wg, part, uri, start, end, bar)
+ go fetchPart(&wg, part, uri, dir, start, end, bar)
  }
 
  wg.Wait()
-
- return
 }
 
-func fetchPart(wg *sync.WaitGroup, part int, uri string, startByte uint64, endByte uint64, bar *progressbar.ProgressBar) {
+func fetchPart(wg *sync.WaitGroup, part int, uri string, dir string, startByte uint64, endByte uint64, bar *progressbar.ProgressBar) {
  defer wg.Done()
 
  byteRange := fmt.Sprintf("bytes=%d-%d", startByte, endByte)
@@ -110,17 +119,15 @@ func fetchPart(wg *sync.WaitGroup, part int, uri string, startByte uint64, endBy
  defer resp.Body.Close()
 
  // Create the file
- filename := downloadPartFilename(part)
+ filename := downloadPartFilename(part, dir)
  out, err := os.Create(filename)
  if err != nil {
  return
  }
  defer out.Close()
 
  // Write the body to file
- _, err = io.Copy(io.MultiWriter(out, bar), resp.Body)
-
- return
+ _, _ = io.Copy(io.MultiWriter(out, bar), resp.Body)
 }
 
 func calculatePartBoundary(filesize uint64, totalParts int, part int) (startByte uint64, endByte uint64) {
@@ -145,16 +152,16 @@ func calculatePartBoundary(filesize uint64, totalParts int, part int) (startByte
  return
 }
 
-func downloadPartFilename(part int) string {
- return fmt.Sprintf("download.part%d", part)
+func downloadPartFilename(part int, dir string) string {
+ return path.Join(dir, fmt.Sprintf("download.part%d", part))
 }
 
 func filenameFromURI(uri string) string {
  splitURI := strings.Split(uri, "/")
  return splitURI[len(splitURI)-1]
 }
 
-func concatFiles(filename string, filesize uint64, parts int) {
+func concatFiles(filename string, filesize uint64, parts int, dir string) {
  var readers []io.Reader
 
  bar := progressbar.DefaultBytes(
@@ -163,11 +170,11 @@ func concatFiles(filename string, filesize uint64, parts int) {
  )
 
  for part := 0; part < parts; part++ {
- downloadPart, err := os.Open(downloadPartFilename(part))
+ downloadPart, err := os.Open(downloadPartFilename(part, dir))
  if err != nil {
  panic(err)
  }
- defer os.Remove(downloadPartFilename(part))
+ defer os.Remove(downloadPartFilename(part, dir))
  defer downloadPart.Close()
  readers = append(readers, downloadPart)
  }
@@ -183,6 +190,4 @@ func concatFiles(filename string, filesize uint64, parts int) {
  if err != nil {
  panic(err)
  }
-
- return
 }