feat: add ReadJSON and WriteJSON to ws connection (#5)

* feat: add ReadJSON and WriteJSON to ws connection

* fix: add CloudWeGo license header

Co-authored-by: Nicholas <[email protected]>

json.go

@@ -0,0 +1,48 @@
+// Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+// This file may have been modified by CloudWeGo authors. All CloudWeGo
+// Modifications are Copyright 2022 CloudWeGo Authors.
+
+package websocket
+
+import (
+	"encoding/json"
+	"io"
+)
+
+// WriteJSON writes the JSON encoding of v as a message.
+//
+// See the documentation for encoding/json Marshal for details about the
+// conversion of Go values to JSON.
+func (c *Conn) WriteJSON(v interface{}) error {
+	w, err := c.NextWriter(TextMessage)
+	if err != nil {
+		return err
+	}
+	err1 := json.NewEncoder(w).Encode(v)
+	err2 := w.Close()
+	if err1 != nil {
+		return err1
+	}
+	return err2
+}
+
+// ReadJSON reads the next JSON-encoded message from the connection and stores
+// it in the value pointed to by v.
+//
+// See the documentation for the encoding/json Unmarshal function for details
+// about the conversion of JSON to a Go value.
+func (c *Conn) ReadJSON(v interface{}) error {
+	_, r, err := c.NextReader()
+	if err != nil {
+		return err
+	}
+	err = json.NewDecoder(r).Decode(v)
+	if err == io.EOF {
+		// One value is expected in the message.
+		err = io.ErrUnexpectedEOF
+	}
+	return err
+}

json_test.go

@@ -0,0 +1,94 @@
+// Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+//
+// This file may have been modified by CloudWeGo authors. All CloudWeGo
+// Modifications are Copyright 2022 CloudWeGo Authors.
+
+package websocket
+
+import (
+	"bytes"
+	"encoding/json"
+	"io"
+	"reflect"
+	"testing"
+)
+
+func TestJSON(t *testing.T) {
+	var buf bytes.Buffer
+	wc := newTestConn(nil, &buf, true)
+	rc := newTestConn(&buf, nil, false)
+
+	var actual, expect struct {
+		A int
+		B string
+	}
+	expect.A = 1
+	expect.B = "hello"
+
+	if err := wc.WriteJSON(&expect); err != nil {
+		t.Fatal("write", err)
+	}
+
+	if err := rc.ReadJSON(&actual); err != nil {
+		t.Fatal("read", err)
+	}
+
+	if !reflect.DeepEqual(&actual, &expect) {
+		t.Fatal("equal", actual, expect)
+	}
+}
+
+func TestPartialJSONRead(t *testing.T) {
+	var buf0, buf1 bytes.Buffer
+	wc := newTestConn(nil, &buf0, true)
+	rc := newTestConn(&buf0, &buf1, false)
+
+	var v struct {
+		A int
+		B string
+	}
+	v.A = 1
+	v.B = "hello"
+
+	messageCount := 0
+
+	// Partial JSON values.
+
+	data, err := json.Marshal(v)
+	if err != nil {
+		t.Fatal(err)
+	}
+	for i := len(data) - 1; i >= 0; i-- {
+		if err := wc.WriteMessage(TextMessage, data[:i]); err != nil {
+			t.Fatal(err)
+		}
+		messageCount++
+	}
+
+	// Whitespace.
+
+	if err := wc.WriteMessage(TextMessage, []byte(" ")); err != nil {
+		t.Fatal(err)
+	}
+	messageCount++
+
+	// Close.
+
+	if err := wc.WriteMessage(CloseMessage, FormatCloseMessage(CloseNormalClosure, "")); err != nil {
+		t.Fatal(err)
+	}
+
+	for i := 0; i < messageCount; i++ {
+		err := rc.ReadJSON(&v)
+		if err != io.ErrUnexpectedEOF {
+			t.Error("read", i, err)
+		}
+	}
+
+	err = rc.ReadJSON(&v)
+	if _, ok := err.(*CloseError); !ok {
+		t.Error("final", err)
+	}
+}