Add JoinMessages

Fixes #441.

Issue #441 specified a message separator. This PR has a message terminator. A message terminator can be read immediately following a message. A message separator cannot be read until the start of the next message. The message terminator is more useful when the reader is scanning to the terminator before performing some action.
This commit is contained in:
Steven Scott 2019-02-04 16:42:47 -08:00 committed by Gary Burd
parent 95ba29eb98
commit 8ab6030ad9
2 changed files with 78 additions and 0 deletions

42
join.go Normal file
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// Copyright 2019 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.
package websocket
import (
"io"
"strings"
)
// JoinMessages concatenates received messages to create a single io.Reader.
// The string term is appended to each message. The returned reader does not
// support concurrent calls to the Read method.
func JoinMessages(c *Conn, term string) io.Reader {
return &joinReader{c: c, term: term}
}
type joinReader struct {
c *Conn
term string
r io.Reader
}
func (r *joinReader) Read(p []byte) (int, error) {
if r.r == nil {
var err error
_, r.r, err = r.c.NextReader()
if err != nil {
return 0, err
}
if r.term != "" {
r.r = io.MultiReader(r.r, strings.NewReader(r.term))
}
}
n, err := r.r.Read(p)
if err == io.EOF {
err = nil
r.r = nil
}
return n, err
}

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join_test.go Normal file
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// Copyright 2019 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.
package websocket
import (
"bytes"
"io"
"strings"
"testing"
)
func TestJoinMessages(t *testing.T) {
messages := []string{"a", "bc", "def", "ghij", "klmno", "0", "12", "345", "6789"}
for _, readChunk := range []int{1, 2, 3, 4, 5, 6, 7} {
for _, term := range []string{"", ","} {
var connBuf bytes.Buffer
wc := newTestConn(nil, &connBuf, true)
rc := newTestConn(&connBuf, nil, false)
for _, m := range messages {
wc.WriteMessage(BinaryMessage, []byte(m))
}
var result bytes.Buffer
_, err := io.CopyBuffer(&result, JoinMessages(rc, term), make([]byte, readChunk))
if IsUnexpectedCloseError(err, CloseAbnormalClosure) {
t.Errorf("readChunk=%d, term=%q: unexpected error %v", readChunk, term, err)
}
want := strings.Join(messages, term) + term
if result.String() != want {
t.Errorf("readChunk=%d, term=%q, got %q, want %q", readChunk, term, result.String(), want)
}
}
}
}