Initial commit

vendor/github.com/gin-contrib/sse/sse-decoder.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"
+	"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
+		}
+	}
+	// Once the end of the file is reached, the user agent must dispatch the event one final time.
+	d.dispatchEvent(currentEvent, dataBuffer.String())
+
+	return d.events, nil
+}