92 lines
2.2 KiB
Go
92 lines
2.2 KiB
Go
package api
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import (
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"bytes"
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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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"time"
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"github.com/julienschmidt/httprouter"
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log "github.com/sirupsen/logrus"
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"github.com/baez90/goveal/events"
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)
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type ContentEventHandler chan events.ContentEvent
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func (h ContentEventHandler) OnEvent(ce events.ContentEvent) error {
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const enqueueTimeout = 50 * time.Millisecond
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select {
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case h <- ce:
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return nil
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case <-time.After(enqueueTimeout):
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return errors.New("failed to enqueue due to timeout")
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}
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}
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func (h ContentEventHandler) Close() (err error) {
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defer func() {
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if rec := recover(); rec != nil {
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err = fmt.Errorf("failed to close event handler: %v", rec)
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}
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}()
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close(h)
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return
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}
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type Events struct {
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logger *log.Logger
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hub *events.EventHub
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}
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func RegisterEventsAPI(router *httprouter.Router, hub *events.EventHub, logger *log.Logger) {
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ev := &Events{hub: hub, logger: logger}
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router.GET("/api/v1/events", ev.EventHandler)
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}
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func (e *Events) EventHandler(writer http.ResponseWriter, req *http.Request, _ httprouter.Params) {
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writer.Header().Set("Content-Type", "text/event-stream")
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writer.Header().Set("Cache-Control", "no-cache")
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writer.Header().Set("Connection", "keep-alive")
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writer.Header().Set("Access-Control-Allow-Origin", "*")
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writer.Header().Set("Transfer-Encoding", "chunked")
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writer.Header().Set("Access-Control-Allow-Headers", "Cache-Control")
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writer.Header().Set("Access-Control-Allow-Credentials", "true")
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var (
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handler = make(ContentEventHandler)
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clientID = e.hub.Subscribe(handler)
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buf = new(bytes.Buffer)
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enc = json.NewEncoder(buf)
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)
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defer func() {
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if err := e.hub.Unsubscribe(clientID); err != nil {
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e.logger.Warnf("Error occurred while unsubscribing: %v", err)
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}
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}()
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for {
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select {
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case ev := <-handler:
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if err := enc.Encode(ev); err != nil {
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e.logger.Errorf("Failed to marshal to JSON: %v", err)
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continue
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} else if _, err = fmt.Fprintf(writer, "data: %s\n\n", buf.String()); err != nil {
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e.logger.Errorf("Failed to write to client: %v", err)
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return
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} else if f, ok := writer.(http.Flusher); !ok {
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e.logger.Errorf("Cannot flush data")
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writer.WriteHeader(http.StatusBadRequest)
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return
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} else {
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f.Flush()
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}
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case <-req.Context().Done():
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return
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}
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}
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}
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