Add extraction cache and wait for extraction to end to return subtitles/attachments

transcoder/main.go

@@ -190,10 +190,10 @@ func (h *Handler) GetAudioSegment(c echo.Context) error {
 
 // Identify
 //
-// # Identify metadata about a file
+// Identify metadata about a file
 //
 // Path: /:resource/:slug/info
-func GetInfo(c echo.Context) error {
+func (h *Handler) GetInfo(c echo.Context) error {
 	resource := c.Param("resource")
 	slug := c.Param("slug")
 
@@ -206,6 +206,7 @@ func GetInfo(c echo.Context) error {
 	if err != nil {
 		return err
 	}
+	h.extractor.RunExtractor(ret.Path, ret.Sha, &ret.Subtitles)
 	return c.JSON(http.StatusOK, ret)
 }
 
@@ -214,7 +215,7 @@ func GetInfo(c echo.Context) error {
 // Get a specific attachment
 //
 // Path: /:sha/attachment/:name
-func GetAttachment(c echo.Context) error {
+func (h *Handler) GetAttachment(c echo.Context) error {
 	sha := c.Param("sha")
 	name := c.Param("name")
 
@@ -225,6 +226,12 @@ func GetAttachment(c echo.Context) error {
 		return err
 	}
 
+	wait, ok := h.extractor.Extract(sha)
+	if !ok {
+		return echo.NewHTTPError(http.StatusBadRequest, "Not extracted yet. Call /info to extract.")
+	}
+	<-wait
+
 	path := fmt.Sprintf("%s/%s/att/%s", src.GetMetadataPath(), sha, name)
 	return c.File(path)
 }
@@ -233,8 +240,8 @@ func GetAttachment(c echo.Context) error {
 //
 // Get a specific subtitle
 //
-// Path: /:sha/sub/:name
-func GetSubtitle(c echo.Context) error {
+// Path: /:sha/subtitle/:name
+func (h *Handler) GetSubtitle(c echo.Context) error {
 	sha := c.Param("sha")
 	name := c.Param("name")
 
@@ -245,12 +252,19 @@ func GetSubtitle(c echo.Context) error {
 		return err
 	}
 
+	wait, ok := h.extractor.Extract(sha)
+	if !ok {
+		return echo.NewHTTPError(http.StatusBadRequest, "Not extracted yet. Call /info to extract.")
+	}
+	<-wait
+
 	path := fmt.Sprintf("%s/%s/sub/%s", src.GetMetadataPath(), sha, name)
 	return c.File(path)
 }
 
 type Handler struct {
 	transcoder *src.Transcoder
+	extractor  *src.Extractor
 }
 
 func main() {
@@ -263,7 +277,7 @@ func main() {
 		e.Logger.Fatal(err)
 		return
 	}
-	h := Handler{transcoder: transcoder}
+	h := Handler{transcoder: transcoder, extractor: src.NewExtractor()}
 
 	e.GET("/:resource/:slug/direct", DirectStream)
 	e.GET("/:resource/:slug/master.m3u8", h.GetMaster)
@@ -271,9 +285,9 @@ func main() {
 	e.GET("/:resource/:slug/audio/:audio/index.m3u8", h.GetAudioIndex)
 	e.GET("/:resource/:slug/:quality/:chunk", h.GetVideoSegment)
 	e.GET("/:resource/:slug/audio/:audio/:chunk", h.GetAudioSegment)
-	e.GET("/:resource/:slug/info", GetInfo)
-	e.GET("/:sha/attachment/:name", GetAttachment)
-	e.GET("/:sha/sub/:name", GetSubtitle)
+	e.GET("/:resource/:slug/info", h.GetInfo)
+	e.GET("/:sha/attachment/:name", h.GetAttachment)
+	e.GET("/:sha/subtitle/:name", h.GetSubtitle)
 
 	e.Logger.Fatal(e.Start(":7666"))
 }

transcoder/src/extract.go

@@ -4,8 +4,14 @@ import (
 	"fmt"
 	"os"
 	"os/exec"
+	"sync"
 )
 
+type Extractor struct {
+	extracted map[string]<-chan struct{}
+	lock      sync.RWMutex
+}
+
 func GetMetadataPath() string {
 	out := os.Getenv("GOCODER_METADATA_ROOT")
 	if out == "" {
@@ -14,29 +20,66 @@ func GetMetadataPath() string {
 	return out
 }
 
-func extract(path string, sha string, subs *[]Subtitle) {
-	fmt.Printf("Extract subs and fonts for %s", path)
-	cmd := exec.Command(
-		"ffmpeg",
-		"-dump_attachment:t", "",
-		"-i", path,
-	)
-	cmd.Dir = fmt.Sprintf("/%s/%s/att/", GetMetadataPath(), sha)
-
-	for _, sub := range *subs {
-		if ext := sub.Extension; ext != nil {
-			cmd.Args = append(
-				cmd.Args,
-				"-map", fmt.Sprintf("0:s:%d", sub.Index),
-				"-c:s", "copy",
-				fmt.Sprintf("/%s/%s/sub/%d.%s", GetMetadataPath(), sha, sub.Index, *ext),
-			)
-		}
-	}
-	fmt.Printf("Starting extraction with the command: %s", cmd)
-	cmd.Stdout = nil
-	err := cmd.Run()
-	if err != nil {
-		fmt.Println("Error starting ffmpeg extract:", err)
+func NewExtractor() *Extractor {
+	return &Extractor{
+		extracted: make(map[string]<-chan struct{}),
 	}
 }
+
+func (e *Extractor) Extract(sha string) (<-chan struct{}, bool) {
+	e.lock.RLock()
+	existing, ok := e.extracted[sha]
+	e.lock.RUnlock()
+
+	if ok {
+		return existing, true
+	}
+	return nil, false
+}
+
+func (e *Extractor) RunExtractor(path string, sha string, subs *[]Subtitle) <-chan struct{} {
+	existing, ok := e.Extract(sha)
+	if ok {
+		return existing
+	}
+
+	ret := make(chan struct{})
+	e.lock.Lock()
+	e.extracted[sha] = ret
+	e.lock.Unlock()
+
+	go func() {
+		attachment_path := fmt.Sprintf("%s/%s/att/", GetMetadataPath(), sha)
+		subs_path := fmt.Sprintf("%s/%s/sub/", GetMetadataPath(), sha)
+		os.MkdirAll(attachment_path, 0o644)
+		os.MkdirAll(subs_path, 0o644)
+
+		fmt.Printf("Extract subs and fonts for %s", path)
+		cmd := exec.Command(
+			"ffmpeg",
+			"-dump_attachment:t", "",
+			"-i", path,
+		)
+		cmd.Dir = attachment_path
+
+		for _, sub := range *subs {
+			if ext := sub.Extension; ext != nil {
+				cmd.Args = append(
+					cmd.Args,
+					"-map", fmt.Sprintf("0:s:%d", sub.Index),
+					"-c:s", "copy",
+					fmt.Sprintf("%s/%d.%s", subs_path, sub.Index, *ext),
+				)
+			}
+		}
+		fmt.Printf("Starting extraction with the command: %s", cmd)
+		cmd.Stdout = nil
+		err := cmd.Run()
+		if err != nil {
+			fmt.Println("Error starting ffmpeg extract:", err)
+		}
+		close(ret)
+	}()
+
+	return ret
+}

transcoder/src/info.go

@@ -169,8 +169,6 @@ func GetInfo(path string) (*MediaInfo, error) {
 	}
 	defer mi.Close()
 
-	// TODO: extract
-
 	sha := mi.Parameter(mediainfo.StreamGeneral, 0, "UniqueID")
 	// Remove dummy values that some tools use.
 	if len(sha) <= 5 {