Add the NoInfoDownload option

Set it to true if you don't want to use the result.Info structure.

If it is set to true, then the New() call won't call youtube-dl to request info
about the source in JSON format, and result.Info structure will not be
populated. The given URL will be downloaded in a single pass in the Download()
call.

goutubedl.go

@@ -213,6 +213,10 @@ type Options struct {
 	HTTPClient        *http.Client                  // Client for download thumbnail and subtitles (nil use http.DefaultClient)
 	MergeOutputFormat string                        // --merge-output-format
 	SortingFormat     string                        // --format-sort
+
+	// Set to true if you don't want to use the result.Info structure after the goutubedl.New() call,
+	// so the given URL will be downloaded in a single pass in the Download() call.
+	NoInfoDownload bool
 }
 
 // Version of youtube-dl.
@@ -233,6 +237,13 @@ func New(ctx context.Context, rawURL string, options Options) (result Result, er
 		options.DebugLog = nopPrinter{}
 	}
 
+	if options.NoInfoDownload {
+		return Result{
+			RawURL:  rawURL,
+			Options: options,
+		}, nil
+	}
+
 	info, rawJSON, err := infoFromURL(ctx, rawURL, options)
 	if err != nil {
 		return Result{}, err
@@ -243,6 +254,7 @@ func New(ctx context.Context, rawURL string, options Options) (result Result, er
 
 	return Result{
 		Info:    info,
+		RawURL:  rawURL,
 		RawJSON: rawJSONCopy,
 		Options: options,
 	}, nil
@@ -421,6 +433,7 @@ func infoFromURL(ctx context.Context, rawURL string, options Options) (info Info
 // Result metadata for a URL
 type Result struct {
 	Info    Info
+	RawURL  string
 	RawJSON []byte  // saved raw JSON. Used later when downloading
 	Options Options // options passed to New
 }
@@ -452,18 +465,24 @@ type DownloadOptions struct {
 func (result Result) DownloadWithOptions(ctx context.Context, options DownloadOptions) (*DownloadResult, error) {
 	debugLog := result.Options.DebugLog
 
-	if (result.Info.Type == "playlist" || result.Info.Type == "multi_video") && options.PlaylistIndex == 0 {
+	if !result.Options.NoInfoDownload {
-		return nil, fmt.Errorf("can't download a playlist when the playlist index options is not set")
+		if (result.Info.Type == "playlist" || result.Info.Type == "multi_video") && options.PlaylistIndex == 0 {
+			return nil, fmt.Errorf("can't download a playlist when the playlist index options is not set")
+		}
 	}
 
 	tempPath, tempErr := ioutil.TempDir("", "ydls")
 	if tempErr != nil {
 		return nil, tempErr
 	}
-	jsonTempPath := path.Join(tempPath, "info.json")
+
-	if err := ioutil.WriteFile(jsonTempPath, result.RawJSON, 0600); err != nil {
+	var jsonTempPath string
-		os.RemoveAll(tempPath)
+	if !result.Options.NoInfoDownload {
-		return nil, err
+		jsonTempPath = path.Join(tempPath, "info.json")
+		if err := ioutil.WriteFile(jsonTempPath, result.RawJSON, 0600); err != nil {
+			os.RemoveAll(tempPath)
+			return nil, err
+		}
 	}
 
 	dr := &DownloadResult{
@@ -478,9 +497,36 @@ func (result Result) DownloadWithOptions(ctx context.Context, options DownloadOp
 		"--ignore-errors",
 		"--newline",
 		"--restrict-filenames",
-		"--load-info", jsonTempPath,
 		"-o", "-",
 	)
+
+	if result.Options.NoInfoDownload {
+		// provide URL via stdin for security, youtube-dl has some run command args
+		cmd.Args = append(cmd.Args, "--batch-file", "-")
+		cmd.Stdin = bytes.NewBufferString(result.RawURL + "\n")
+
+		if result.Options.Type == TypePlaylist {
+			cmd.Args = append(cmd.Args, "--yes-playlist")
+
+			if result.Options.PlaylistStart > 0 {
+				cmd.Args = append(cmd.Args,
+					"--playlist-start", strconv.Itoa(int(result.Options.PlaylistStart)),
+				)
+			}
+			if result.Options.PlaylistEnd > 0 {
+				cmd.Args = append(cmd.Args,
+					"--playlist-end", strconv.Itoa(int(result.Options.PlaylistEnd)),
+				)
+			}
+		} else {
+			cmd.Args = append(cmd.Args,
+				"--no-playlist",
+			)
+		}
+	} else {
+		cmd.Args = append(cmd.Args, "--load-info", jsonTempPath)
+	}
+
 	// don't need to specify if direct as there is only one
 	// also seems to be issues when using filter with generic extractor
 	if !result.Info.Direct && options.Filter != "" {