1 files changed, 47 insertions, 0 deletions
diff --git a/danmaku/dmpkg/raw.go b/danmaku/dmpkg/raw.go
new file mode 100644
index 0000000..1cbd12e
--- /dev/null
+++ b/danmaku/dmpkg/raw.go
@@ -0,0 +1,47 @@
+package dmpkg
+
+import (
+	"encoding/json"
+	"fmt"
+	"math"
+)
+
+const kMaxBodyLength = math.MaxUint32 - kHeaderLength
+
+// NewPlainExchange creates a new exchange with raw body specified.
+// body: a struct or a raw string
+func NewPlainExchange(operation Operation, body interface{}) (exc DanmakuExchange, err error) {
+	var bodyData []byte
+
+	// convert body to []byte
+	if _, ok := body.(string); ok {
+		// a string
+		bodyData = []byte(body.(string))
+	} else if _, ok := body.([]byte); ok {
+		// a []byte
+		copy(bodyData, body.([]byte))
+	} else {
+		// a JSON struct
+		bodyData, err = json.Marshal(body)
+		if err != nil {
+			return
+		}
+	}
+
+	length := uint64(kHeaderLength + len(bodyData))
+	if length > kMaxBodyLength {
+		err = fmt.Errorf("body is too large (> %d)", kMaxBodyLength)
+		return
+	}
+	exc = DanmakuExchange{
+		DanmakuExchangeHeader: DanmakuExchangeHeader{
+			Length:       uint32(length),
+			HeaderLength: kHeaderLength,
+			ProtocolVer:  ProtoPlainJson,
+			Operation:    operation,
+			SequenceId:   kSequenceId,
+		},
+		Body: bodyData,
+	}
+	return
+}