/
event_parser.go
91 lines (78 loc) · 2.14 KB
/
event_parser.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
package sse
import (
"bytes"
"fmt"
"strconv"
)
var (
headerID = []byte("id:")
headerData = []byte("data:")
)
type EventParser struct {
eventsToParse map[EventType]string
}
func NewEventParser() *EventParser {
return &EventParser{eventsToParse: make(map[EventType]string)}
}
func (e *EventParser) RegisterEvent(eventType EventType) {
e.eventsToParse[eventType] = AllEventsNames[eventType]
}
func (e *EventParser) ParseRawEvent(data []byte) (RawEvent, error) {
var eventID []byte
var eventData []byte
for _, line := range bytes.FieldsFunc(data, func(r rune) bool { return r == '\n' || r == '\r' }) {
switch {
case bytes.HasPrefix(line, headerID):
eventID = append([]byte(nil), trimPrefix(len(headerID), line)...)
case bytes.HasPrefix(line, headerData):
// The spec allows for multiple data fields per event, concatenated them with "\n".
eventData = append([]byte(nil), append(trimPrefix(len(headerData), line), byte('\n'))...)
default:
// Ignore any garbage that doesn't match what we're looking for.
}
}
return e.parseEvenType(eventID, eventData)
}
func (e *EventParser) parseEvenType(eventID, eventData []byte) (RawEvent, error) {
var eventType EventType
for eType, typeName := range e.eventsToParse {
trimmedData := trimPrefix(len([]byte("{\"")), eventData)
if bytes.HasPrefix(trimmedData, []byte(typeName)) {
eventType = eType
break
}
}
if eventType == 0 {
return RawEvent{}, NewErrUnknownEventType(eventData)
}
if eventType == APIVersionEventType {
return RawEvent{
EventType: eventType,
Data: eventData,
}, nil
}
parsedID, err := strconv.ParseUint(string(eventID), 10, 0)
if err != nil {
return RawEvent{}, fmt.Errorf("error parsing event id, %w", err)
}
return RawEvent{
EventType: eventType,
EventID: parsedID,
Data: eventData,
}, nil
}
func trimPrefix(size int, data []byte) []byte {
if data == nil || len(data) < size {
return data
}
data = data[size:]
// Remove optional leading whitespace
if len(data) > 0 && data[0] == 32 {
data = data[1:]
}
// Remove trailing new line
if len(data) > 0 && data[len(data)-1] == 10 {
data = data[:len(data)-1]
}
return data
}