96 lines
2.1 KiB
Go
96 lines
2.1 KiB
Go
package serverevents
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import (
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"encoding/json"
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"fmt"
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di "git.apihub24.de/admin/generic-di"
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"github.com/gorilla/websocket"
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"net/http"
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)
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func init() {
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di.Injectable(newServerEventsMiddleware)
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}
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type MiddlewareOptions struct {
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Path string
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}
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type IServerEventsMiddleware interface {
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Use(MiddlewareOptions, *http.ServeMux)
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}
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type serverEventsMiddleware struct {
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upgrader websocket.Upgrader
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streamSubscribers map[string]bool
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}
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func newServerEventsMiddleware() IServerEventsMiddleware {
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return &serverEventsMiddleware{
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upgrader: websocket.Upgrader{
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CheckOrigin: func(r *http.Request) bool {
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return true
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},
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},
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streamSubscribers: make(map[string]bool),
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}
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}
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func (middleware *serverEventsMiddleware) Use(options MiddlewareOptions, muxer *http.ServeMux) {
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middleware.selectMethod(options.Path, func(w http.ResponseWriter, r *http.Request) {
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middleware.handleEventStream(w, r)
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}, muxer)
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}
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func (middleware *serverEventsMiddleware) handleEventStream(w http.ResponseWriter, r *http.Request) {
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emitter := di.Inject[IEventEmitter]()
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conn, err := middleware.upgrader.Upgrade(w, r, nil)
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if err != nil {
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fmt.Println("Error upgrading:", err)
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return
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}
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defer func() {
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// do not handle Error
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_ = conn.Close()
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}()
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id := r.URL.Query().Get("id")
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if _, ok := middleware.streamSubscribers[id]; !ok {
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subscription := emitter.OnAll(func(event Event) {
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if !event.IsBackendOnly {
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jsonData, jsonErr := json.Marshal(event)
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if jsonErr != nil {
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fmt.Println("Error make json string", jsonErr)
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return
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}
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_ = conn.WriteMessage(websocket.TextMessage, jsonData)
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}
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})
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defer func() {
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subscription.Unsubscribe()
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delete(middleware.streamSubscribers, id)
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}()
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middleware.streamSubscribers[id] = true
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}
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ctx := r.Context()
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for {
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_, _, err := conn.ReadMessage()
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if err != nil {
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return
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}
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select {
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case <-ctx.Done():
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return
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}
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}
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}
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func (middleware *serverEventsMiddleware) selectMethod(path string, todo http.HandlerFunc, muxer *http.ServeMux) {
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if muxer == nil {
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http.HandleFunc(path, todo)
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} else {
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muxer.HandleFunc(path, todo)
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}
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}
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