Conforms to w3.org standard + experimental decoder

sse-decoder.go

@@ -0,0 +1,115 @@
+// Copyright 2014 Manu Martinez-Almeida.  All rights reserved.
+// Use of this source code is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package sse
+
+import (
+	"bytes"
+	"io"
+	"io/ioutil"
+)
+
+type decoder struct {
+	events []Event
+}
+
+func Decode(r io.Reader) ([]Event, error) {
+	var dec decoder
+	return dec.decode(r)
+}
+
+func (d *decoder) dispatchEvent(event Event, data string) {
+	dataLength := len(data)
+	if dataLength > 0 {
+		//If the data buffer's last character is a U+000A LINE FEED (LF) character, then remove the last character from the data buffer.
+		data = data[:dataLength-1]
+		dataLength--
+	}
+	if dataLength == 0 && event.Event == "" {
+		return
+	}
+	if event.Event == "" {
+		event.Event = "message"
+	}
+	event.Data = data
+	d.events = append(d.events, event)
+}
+
+func (d *decoder) decode(r io.Reader) ([]Event, error) {
+	buf, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, err
+	}
+
+	var currentEvent Event
+	var dataBuffer *bytes.Buffer = new(bytes.Buffer)
+	// TODO (and unit tests)
+	// Lines must be separated by either a U+000D CARRIAGE RETURN U+000A LINE FEED (CRLF) character pair,
+	// a single U+000A LINE FEED (LF) character,
+	// or a single U+000D CARRIAGE RETURN (CR) character.
+	lines := bytes.Split(buf, []byte{'\n'})
+	for _, line := range lines {
+		if len(line) == 0 {
+			// If the line is empty (a blank line). Dispatch the event.
+			d.dispatchEvent(currentEvent, dataBuffer.String())
+
+			// reset current event and data buffer
+			currentEvent = Event{}
+			dataBuffer.Reset()
+			continue
+		}
+		if line[0] == byte(':') {
+			// If the line starts with a U+003A COLON character (:), ignore the line.
+			continue
+		}
+
+		var field, value []byte
+		colonIndex := bytes.IndexRune(line, ':')
+		if colonIndex != -1 {
+			// If the line contains a U+003A COLON character character (:)
+			// Collect the characters on the line before the first U+003A COLON character (:),
+			// and let field be that string.
+			field = line[:colonIndex]
+			// Collect the characters on the line after the first U+003A COLON character (:),
+			// and let value be that string.
+			value = line[colonIndex+1:]
+			// If value starts with a single U+0020 SPACE character, remove it from value.
+			if len(value) > 0 && value[0] == ' ' {
+				value = value[1:]
+			}
+		} else {
+			// Otherwise, the string is not empty but does not contain a U+003A COLON character character (:)
+			// Use the whole line as the field name, and the empty string as the field value.
+			field = line
+			value = []byte{}
+		}
+		// The steps to process the field given a field name and a field value depend on the field name,
+		// as given in the following list. Field names must be compared literally,
+		// with no case folding performed.
+		switch string(field) {
+		case "event":
+			// Set the event name buffer to field value.
+			currentEvent.Event = string(value)
+		case "id":
+			// Set the event stream's last event ID to the field value.
+			currentEvent.Id = string(value)
+		case "retry":
+			// If the field value consists of only characters in the range U+0030 DIGIT ZERO (0) to U+0039 DIGIT NINE (9),
+			// then interpret the field value as an integer in base ten, and set the event stream's reconnection time to that integer.
+			// Otherwise, ignore the field.
+			currentEvent.Id = string(value)
+		case "data":
+			// Append the field value to the data buffer,
+			dataBuffer.Write(value)
+			// then append a single U+000A LINE FEED (LF) character to the data buffer.
+			dataBuffer.WriteString("\n")
+		default:
+			//Otherwise. The field is ignored.
+			continue
+		}
+	}
+	d.dispatchEvent(currentEvent, dataBuffer.String())
+
+	return d.events, nil
+}

sse-decoder_test.go

@@ -0,0 +1,116 @@
+// Copyright 2014 Manu Martinez-Almeida.  All rights reserved.
+// Use of this source code is governed by a MIT style
+// license that can be found in the LICENSE file.
+
+package sse
+
+import (
+	"bytes"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestDecodeSingle1(t *testing.T) {
+	events, err := Decode(bytes.NewBufferString(
+		`data: this is a text
+event: message
+fake:
+id: 123456789010
+: we can append data
+: and multiple comments should not break it
+data: a very nice one`))
+
+	assert.NoError(t, err)
+	assert.Len(t, events, 1)
+	assert.Equal(t, events[0].Event, "message")
+	assert.Equal(t, events[0].Id, "123456789010")
+}
+
+func TestDecodeSingle2(t *testing.T) {
+	events, err := Decode(bytes.NewBufferString(
+		`: starting with a comment
+fake:
+
+data:this is a \ntext
+event:a message\n\n
+fake
+:and multiple comments\n should not break it\n\n
+id:1234567890\n10
+:we can append data
+data:a very nice one\n!
+
+
+`))
+	assert.NoError(t, err)
+	assert.Len(t, events, 1)
+	assert.Equal(t, events[0].Event, "a message\\n\\n")
+	assert.Equal(t, events[0].Id, "1234567890\\n10")
+}
+
+func TestDecodeSingle3(t *testing.T) {
+	events, err := Decode(bytes.NewBufferString(
+		`
+id:123456ABCabc789010
+event: message123
+: we can append data
+data:this is a text
+data: a very nice one
+data:
+data
+: ending with a comment`))
+
+	assert.NoError(t, err)
+	assert.Len(t, events, 1)
+	assert.Equal(t, events[0].Event, "message123")
+	assert.Equal(t, events[0].Id, "123456ABCabc789010")
+}
+
+func TestDecodeMulti1(t *testing.T) {
+	events, err := Decode(bytes.NewBufferString(
+		`
+id:
+event: weird event
+data:this is a text
+:data: this should NOT APER
+data:  second line
+
+: a comment
+event: message
+id:123
+data:this is a text
+:data: this should NOT APER
+data:  second line
+
+
+: a comment
+event: message
+id:123
+data:this is a text
+data:  second line
+
+:hola
+
+data
+
+event:
+
+id`))
+	assert.NoError(t, err)
+	assert.Len(t, events, 3)
+	assert.Equal(t, events[0].Event, "weird event")
+	assert.Equal(t, events[0].Id, "")
+}
+
+func TestDecodeW3C(t *testing.T) {
+	events, err := Decode(bytes.NewBufferString(
+		`data
+
+data
+data
+
+data:
+`))
+	assert.NoError(t, err)
+	assert.Len(t, events, 1)
+}

sse-encoder.go

@@ -22,7 +22,14 @@ const ContentType = "text/event-stream"
 
 var contentType = []string{ContentType}
 var noCache = []string{"no-cache"}
-var replacer = strings.NewReplacer("\n", "\\n", "\r", "\\r")
+
+var fieldReplacer = strings.NewReplacer(
+	"\n", "\\n",
+	"\r", "\\r")
+
+var dataReplacer = strings.NewReplacer(
+	"\n", "\ndata:",
+	"\r", "\\r")
 
 type Event struct {
 	Event string
@@ -41,30 +48,30 @@ func Encode(writer io.Writer, event Event) error {
 
 func writeId(w stringWriter, id string) {
 	if len(id) > 0 {
-		w.WriteString("id: ")
-		writeEscape(w, id)
+		w.WriteString("id:")
+		fieldReplacer.WriteString(w, id)
 		w.WriteString("\n")
 	}
 }
 
 func writeEvent(w stringWriter, event string) {
 	if len(event) > 0 {
-		w.WriteString("event: ")
-		writeEscape(w, event)
+		w.WriteString("event:")
+		fieldReplacer.WriteString(w, event)
 		w.WriteString("\n")
 	}
 }
 
 func writeRetry(w stringWriter, retry uint) {
 	if retry > 0 {
-		w.WriteString("retry: ")
+		w.WriteString("retry:")
 		w.WriteString(strconv.FormatUint(uint64(retry), 10))
 		w.WriteString("\n")
 	}
 }
 
 func writeData(w stringWriter, data interface{}) error {
-	w.WriteString("data: ")
+	w.WriteString("data:")
 	switch kindOfData(data) {
 	case reflect.Struct, reflect.Slice, reflect.Map:
 		err := json.NewEncoder(w).Encode(data)
@@ -73,8 +80,7 @@ func writeData(w stringWriter, data interface{}) error {
 		}
 		w.WriteString("\n")
 	default:
-		text := fmt.Sprint(data)
-		writeEscape(w, text)
+		dataReplacer.WriteString(w, fmt.Sprint(data))
 		w.WriteString("\n\n")
 	}
 	return nil
@@ -98,9 +104,3 @@ func kindOfData(data interface{}) reflect.Kind {
 	}
 	return valueType
 }
-
-func writeEscape(w stringWriter, str string) {
-	// any-char		= %x0000-0009 / %x000B-000C / %x000E-10FFFF
-	// ; a Unicode character other than U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN (CR)
-	replacer.WriteString(w, str)
-}

sse_test.go

@@ -14,21 +14,42 @@ import (
 
 func TestEncodeOnlyData(t *testing.T) {
 	w := new(bytes.Buffer)
-	err := Encode(w, Event{
+	event := Event{
 		Data: "junk\n\njk\nid:fake",
-	})
+	}
+	err := Encode(w, event)
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "data: junk\\n\\njk\\nid:fake\n\n")
+	assert.Equal(t, w.String(),
+		`data:junk
+data:
+data:jk
+data:id:fake
+
+`)
+
+	decoded, _ := Decode(w)
+	assert.Equal(t, decoded, []Event{event})
 }
 
 func TestEncodeWithEvent(t *testing.T) {
 	w := new(bytes.Buffer)
-	err := Encode(w, Event{
+	event := Event{
 		Event: "t\n:<>\r\test",
 		Data:  "junk\n\njk\nid:fake",
-	})
+	}
+	err := Encode(w, event)
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "event: t\\n:<>\\r\test\ndata: junk\\n\\njk\\nid:fake\n\n")
+	assert.Equal(t, w.String(),
+		`event:t\n:<>\r	est
+data:junk
+data:
+data:jk
+data:id:fake
+
+`)
+
+	decoded, _ := Decode(w)
+	assert.Equal(t, decoded, []Event{event})
 }
 
 func TestEncodeWithId(t *testing.T) {
@@ -38,7 +59,14 @@ func TestEncodeWithId(t *testing.T) {
 		Data: "junk\n\njk\nid:fa\rke",
 	})
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "id: t\\n:<>\\r\test\ndata: junk\\n\\njk\\nid:fa\\rke\n\n")
+	assert.Equal(t, w.String(),
+		`id:t\n:<>\r	est
+data:junk
+data:
+data:jk
+data:id:fa\rke
+
+`)
 }
 
 func TestEncodeWithRetry(t *testing.T) {
@@ -48,7 +76,15 @@ func TestEncodeWithRetry(t *testing.T) {
 		Data:  "junk\n\njk\nid:fake\n",
 	})
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "retry: 11\ndata: junk\\n\\njk\\nid:fake\\n\n\n")
+	assert.Equal(t, w.String(),
+		`retry:11
+data:junk
+data:
+data:jk
+data:id:fake
+data:
+
+`)
 }
 
 func TestEncodeWithEverything(t *testing.T) {
@@ -60,7 +96,7 @@ func TestEncodeWithEverything(t *testing.T) {
 		Data:  "some data",
 	})
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "id: 12345\nevent: abc\nretry: 10\ndata: some data\n\n")
+	assert.Equal(t, w.String(), "id:12345\nevent:abc\nretry:10\ndata:some data\n\n")
 }
 
 func TestEncodeMap(t *testing.T) {
@@ -73,7 +109,7 @@ func TestEncodeMap(t *testing.T) {
 		},
 	})
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "event: a map\ndata: {\"bar\":\"id: 2\",\"foo\":\"b\\n\\rar\"}\n\n")
+	assert.Equal(t, w.String(), "event:a map\ndata:{\"bar\":\"id: 2\",\"foo\":\"b\\n\\rar\"}\n\n")
 }
 
 func TestEncodeSlice(t *testing.T) {
@@ -83,7 +119,7 @@ func TestEncodeSlice(t *testing.T) {
 		Data:  []interface{}{1, "text", map[string]interface{}{"foo": "bar"}},
 	})
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "event: a slice\ndata: [1,\"text\",{\"foo\":\"bar\"}]\n\n")
+	assert.Equal(t, w.String(), "event:a slice\ndata:[1,\"text\",{\"foo\":\"bar\"}]\n\n")
 }
 
 func TestEncodeStruct(t *testing.T) {
@@ -98,7 +134,7 @@ func TestEncodeStruct(t *testing.T) {
 		Data:  myStruct,
 	})
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "event: a struct\ndata: {\"A\":1,\"value\":\"number\"}\n\n")
+	assert.Equal(t, w.String(), "event:a struct\ndata:{\"A\":1,\"value\":\"number\"}\n\n")
 
 	w.Reset()
 	err = Encode(w, Event{
@@ -106,7 +142,7 @@ func TestEncodeStruct(t *testing.T) {
 		Data:  &myStruct,
 	})
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "event: a struct\ndata: {\"A\":1,\"value\":\"number\"}\n\n")
+	assert.Equal(t, w.String(), "event:a struct\ndata:{\"A\":1,\"value\":\"number\"}\n\n")
 }
 
 func TestEncodeInteger(t *testing.T) {
@@ -116,7 +152,7 @@ func TestEncodeInteger(t *testing.T) {
 		Data:  1,
 	})
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "event: an integer\ndata: 1\n\n")
+	assert.Equal(t, w.String(), "event:an integer\ndata:1\n\n")
 }
 
 func TestEncodeFloat(t *testing.T) {
@@ -126,7 +162,7 @@ func TestEncodeFloat(t *testing.T) {
 		Data:  1.5,
 	})
 	assert.NoError(t, err)
-	assert.Equal(t, w.String(), "event: Float\ndata: 1.5\n\n")
+	assert.Equal(t, w.String(), "event:Float\ndata:1.5\n\n")
 }
 
 func TestEncodeStream(t *testing.T) {
@@ -147,7 +183,7 @@ func TestEncodeStream(t *testing.T) {
 		Event: "chat",
 		Data:  "hi! dude",
 	})
-	assert.Equal(t, w.String(), "event: float\ndata: 1.5\n\nid: 123\ndata: {\"bar\":\"foo\",\"foo\":\"bar\"}\n\nid: 124\nevent: chat\ndata: hi! dude\n\n")
+	assert.Equal(t, w.String(), "event:float\ndata:1.5\n\nid:123\ndata:{\"bar\":\"foo\",\"foo\":\"bar\"}\n\nid:124\nevent:chat\ndata:hi! dude\n\n")
 }
 
 func TestRenderSSE(t *testing.T) {
@@ -159,7 +195,7 @@ func TestRenderSSE(t *testing.T) {
 	}).Render(w)
 
 	assert.NoError(t, err)
-	assert.Equal(t, w.Body.String(), "event: msg\ndata: hi! how are you?\n\n")
+	assert.Equal(t, w.Body.String(), "event:msg\ndata:hi! how are you?\n\n")
 	assert.Equal(t, w.Header().Get("Content-Type"), "text/event-stream")
 	assert.Equal(t, w.Header().Get("Cache-Control"), "no-cache")
 }