83 lines
1.4 KiB
Go
83 lines
1.4 KiB
Go
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package tools
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import (
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"context"
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"encoding/json"
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"errors"
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"fmt"
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"net/http"
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"sync"
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"time"
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)
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var (
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ErrEventsUnsupported = errors.New("events unsupported")
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)
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type EventHelper struct {
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m sync.Mutex
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c context.Context
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w http.ResponseWriter
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r *http.Request
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f http.Flusher
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}
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func NewEventHelper(ctx context.Context, w http.ResponseWriter, r *http.Request) (*EventHelper, error) {
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// Setup Connection
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flusher, ok := w.(http.Flusher)
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if !ok {
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return nil, ErrEventsUnsupported
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}
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w.Header().Set("Content-Type", "text/event-stream")
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w.Header().Set("Cache-Control", "no-cache")
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w.Header().Set("Connection", "keep-alive")
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sse := &EventHelper{f: flusher, c: ctx, w: w, r: r}
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// Heartbeat Generator
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go func(h *EventHelper) {
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t := time.NewTicker(5 * time.Second)
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defer t.Stop()
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for {
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select {
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case <-h.c.Done():
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return
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case <-t.C:
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h.m.Lock()
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fmt.Fprintf(h.w, ": ping\n\n")
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h.f.Flush()
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h.m.Unlock()
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}
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}
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}(sse)
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return sse, nil
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}
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func (h *EventHelper) SendJSON(eventName string, eventData any) {
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b, err := json.Marshal(map[string]any{
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"name": eventName,
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"data": eventData,
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})
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if err != nil {
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return
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}
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h.m.Lock()
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fmt.Fprintf(h.w, "data: %s\n\n", b)
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h.f.Flush()
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h.m.Unlock()
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}
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func (h *EventHelper) SendServerError(err error) {
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SendServerError(nil, h.r, err)
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h.SendClientError(ERROR_GENERIC_SERVER)
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}
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func (h *EventHelper) SendClientError(err APIError) {
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h.SendJSON("error", err)
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}
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