Support Parsing Shaka Packager Commands from JSON (#4)

* fix: flag typos and spellings

* feat(json-parser): added json structures

* feat(json-parser): added flag processors

* feat(json-parser): added json packager parser

* feat(json-parser): added stream builder options

* refactor(json-parser): refacted encryption grouping and added tests

Author: paulgrammer

examples/json_server/main.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"encoding/json"
+	"log"
+	"net/http"
+
+	packlit "github.com/m4urici0gm/packlit/pkg"
+)
+
+func main() {
+	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
+		if r.Method != http.MethodPost {
+			w.WriteHeader(http.StatusMethodNotAllowed)
+			return
+		}
+
+		var req packlit.PackagerOptions
+		decoder := json.NewDecoder(r.Body)
+		decoder.DisallowUnknownFields()
+		if err := decoder.Decode(&req); err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+
+		sp, err := packlit.BuildFromJSON(req)
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusBadRequest)
+			return
+		}
+
+		command, err := sp.PreviewCommand()
+		if err != nil {
+			http.Error(w, err.Error(), http.StatusInternalServerError)
+			return
+		}
+
+		w.Header().Set("Content-Type", "application/json")
+		_ = json.NewEncoder(w).Encode(map[string]interface{}{
+			"command_preview": command,
+		})
+	})
+
+	log.Println("Starting server on :8080. POST /")
+	log.Fatal(http.ListenAndServe(":8080", nil))
+}

pkg/crypto_flags.go

@@ -27,6 +27,10 @@ func (p CryptByteBlockFlag) Parse() string {
 // Apply to video streams with 'cbcs' and 'cens' protection schemes only;
 // ignored otherwise.
 func (p CryptByteBlockFlag) Validate() error {
+	if p < 0 {
+		return fmt.Errorf("crypt_byte_block cannot be negative: %d", p)
+	}
+
 	return nil
 }
 
@@ -57,6 +61,10 @@ func (s SkipByteBlockFlag) Parse() string {
 // Apply to video streams with 'cbcs' and 'cens' protection schemes only;
 // ignored otherwise.
 func (s SkipByteBlockFlag) Validate() error {
+	if s < 0 {
+		return fmt.Errorf("skip_byte_block cannot be negative: %d", s)
+	}
+
 	return nil
 }
 

pkg/generic_flags.go

@@ -0,0 +1,42 @@
+package packlit
+
+import "fmt"
+
+// Generic flag types for extensibility
+type GenericKeyValueOption struct {
+	Key   string
+	Value string
+}
+
+func (g GenericKeyValueOption) Validate() error { return nil }
+func (g GenericKeyValueOption) Parse() string   { return fmt.Sprintf("%s=%s", g.Key, g.Value) }
+
+type GenericRawFlag string
+
+func (g GenericRawFlag) Validate() error { return nil }
+func (g GenericRawFlag) Parse() string   { return string(g) }
+
+type GenericKeyValueFlag struct {
+	Key   string
+	Value string
+}
+
+func (g GenericKeyValueFlag) Validate() error {
+	if g.Key == "" {
+		return fmt.Errorf("flag key cannot be empty")
+	}
+	return nil
+}
+
+func (g GenericKeyValueFlag) Parse() string { return fmt.Sprintf("--%s=%s", g.Key, g.Value) }
+
+type GenericBoolFlag string
+
+func (g GenericBoolFlag) Validate() error {
+	if string(g) == "" {
+		return fmt.Errorf("flag name cannot be empty")
+	}
+	return nil
+}
+
+func (g GenericBoolFlag) Parse() string { return "--" + string(g) }

pkg/hls_flags.go

@@ -88,6 +88,10 @@ func (h HLSMediaSequenceNumberFlag) Parse() string {
 
 // Validate checks if the value of HLSMediaSequenceNumber is valid.
 func (h HLSMediaSequenceNumberFlag) Validate() error {
+	if h < 0 {
+		return fmt.Errorf("hls_media_sequence_number cannot be negative: %d", h)
+	}
+
 	return nil
 }
 

pkg/hls_flags_helpers.go

@@ -22,9 +22,9 @@ func WithHLSKeyURIFlag(val string) ShakaFlagFn {
 }
 
 // WithHLSPlaylistTypeFlag Adds flag '--hls_playlist_type <VOD|EVENT|LIVE>'
-func WithHLSPlaylistTypeFlag(val HLSPlaylistTypeFlag) ShakaFlagFn {
+func WithHLSPlaylistTypeFlag(val string) ShakaFlagFn {
 	return func(so *ShakaFlags) {
-		so.Add(val)
+		so.Add(HLSPlaylistTypeFlag(val))
 	}
 }