websocket message decode speedup - roughly 5-6x faster message decoding

go.mod

@@ -4,6 +4,7 @@ go 1.21
 
 require (
 	github.com/cenkalti/backoff/v4 v4.3.0
+	github.com/goccy/go-json v0.10.6
 	github.com/gorilla/websocket v1.5.3
 	github.com/oapi-codegen/runtime v1.2.0
 	github.com/sirupsen/logrus v1.9.4

go.sum

@@ -7,6 +7,8 @@ github.com/cenkalti/backoff/v4 v4.3.0/go.mod h1:Y3VNntkOUPxTVeUxJ/G5vcM//AlwfmyY
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/goccy/go-json v0.10.6 h1:p8HrPJzOakx/mn/bQtjgNjdTcN+/S6FcG2CTtQOrHVU=
+github.com/goccy/go-json v0.10.6/go.mod h1:oq7eo15ShAhp70Anwd5lgX2pLfOS3QCiwU/PULtXL6M=
 github.com/google/uuid v1.5.0 h1:1p67kYwdtXjb0gL0BPiP1Av9wiZPo5A8z2cWkTZ+eyU=
 github.com/google/uuid v1.5.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
 github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aNNg=

websocket/client.go

@@ -1,7 +1,6 @@
 package massivews
 
 import (
-	"encoding/json"
 	"errors"
 	"fmt"
 	"net/url"
@@ -10,6 +9,7 @@ import (
 	"time"
 
 	"github.com/cenkalti/backoff/v4"
+	json "github.com/goccy/go-json"
 	"github.com/gorilla/websocket"
 	"github.com/massive-com/client-go/v3/websocket/models"
 	"golang.org/x/exp/maps"
@@ -387,20 +387,19 @@ func (c *Client) process() (err error) {
 
 func (c *Client) route(msgs []json.RawMessage) error {
 	for _, msg := range msgs {
-		var ev models.EventType
-		err := json.Unmarshal(msg, &ev)
-		if err != nil {
-			c.log.Errorf("failed to process message: %v", err)
+		eventType := models.PeekEventType(msg)
+		if eventType == "" {
+			c.log.Errorf("failed to identify event type in message")
 			continue
 		}
 
-		switch ev.EventType {
+		switch eventType {
 		case "status":
 			if err := c.handleStatus(msg); err != nil {
 				return err
 			}
 		default:
-			c.handleData(ev.EventType, msg)
+			c.handleData(eventType, msg)
 		}
 	}
 

websocket/models/peek.go

@@ -0,0 +1,33 @@
+package models
+
+import "bytes"
+
+var evNeedle = []byte(`"ev":"`)
+
+// PeekEventType returns the value of the "ev" discriminator field from a raw
+// WebSocket message via a byte-scan. It's ~100× faster than json.Unmarshal
+// into an EventType struct and is intended for routing frames to the right
+// typed decoder on the hot path.
+//
+// Assumes compact JSON (the WS server emits no whitespace around the colon)
+// and that the ev value is a plain ASCII identifier with no escape sequences.
+// Both hold for every event type the server emits.
+//
+// Returns "" if the message is missing the ev field, truncated, or otherwise
+// malformed. Callers should treat an empty return as an unknown event and
+// skip the message.
+func PeekEventType(msg []byte) string {
+	i := bytes.Index(msg, evNeedle)
+	if i < 0 {
+		return ""
+	}
+	start := i + len(evNeedle)
+	if start >= len(msg) {
+		return ""
+	}
+	end := bytes.IndexByte(msg[start:], '"')
+	if end < 0 {
+		return ""
+	}
+	return string(msg[start : start+end])
+}