sse.go RawHistoryFolder

1package provider
2
3import (
4	"bufio"
5	"io"
6	"strings"
7)
8
9// sseEvent is one parsed event from a text/event-stream.
10type sseEvent struct {
11	Event string // value of "event:" field (may be empty)
12	Data  string // concatenated "data:" lines
13}
14
15// readSSE reads events from r and sends them on out. It closes out when r
16// is exhausted or a read error occurs.
17func readSSE(r io.Reader, out chan<- sseEvent) {
18	defer close(out)
19	sc := bufio.NewScanner(r)
20	sc.Buffer(make([]byte, 0, 64*1024), 10*1024*1024)
21
22	var ev sseEvent
23	flush := func() {
24		if ev.Data == "" && ev.Event == "" {
25			return
26		}
27		out <- ev
28		ev = sseEvent{}
29	}
30
31	for sc.Scan() {
32		line := sc.Text()
33		if line == "" {
34			flush()
35			continue
36		}
37		if strings.HasPrefix(line, ":") {
38			// comment / keep-alive
39			continue
40		}
41		field, value, ok := strings.Cut(line, ":")
42		if !ok {
43			field = line
44			value = ""
45		}
46		// optional single leading space after ':'
47		value = strings.TrimPrefix(value, " ")
48		switch field {
49		case "event":
50			ev.Event = value
51		case "data":
52			if ev.Data != "" {
53				ev.Data += "\n"
54			}
55			ev.Data += value
56		}
57	}
58	flush()
59}