code.gitea.io/gitea@v1.21.7/routers/web/events/events.go (about)

     1  // Copyright 2020 The Gitea Authors. All rights reserved.
     2  // SPDX-License-Identifier: MIT
     3  
     4  package events
     5  
     6  import (
     7  	"net/http"
     8  	"time"
     9  
    10  	"code.gitea.io/gitea/modules/context"
    11  	"code.gitea.io/gitea/modules/eventsource"
    12  	"code.gitea.io/gitea/modules/graceful"
    13  	"code.gitea.io/gitea/modules/log"
    14  	"code.gitea.io/gitea/routers/web/auth"
    15  )
    16  
    17  // Events listens for events
    18  func Events(ctx *context.Context) {
    19  	// FIXME: Need to check if resp is actually a http.Flusher! - how though?
    20  
    21  	// Set the headers related to event streaming.
    22  	ctx.Resp.Header().Set("Content-Type", "text/event-stream")
    23  	ctx.Resp.Header().Set("Cache-Control", "no-cache")
    24  	ctx.Resp.Header().Set("Connection", "keep-alive")
    25  	ctx.Resp.Header().Set("X-Accel-Buffering", "no")
    26  	ctx.Resp.WriteHeader(http.StatusOK)
    27  
    28  	if !ctx.IsSigned {
    29  		// Return unauthorized status event
    30  		event := &eventsource.Event{
    31  			Name: "close",
    32  			Data: "unauthorized",
    33  		}
    34  		_, _ = event.WriteTo(ctx)
    35  		ctx.Resp.Flush()
    36  		return
    37  	}
    38  
    39  	// Listen to connection close and un-register messageChan
    40  	notify := ctx.Done()
    41  	ctx.Resp.Flush()
    42  
    43  	shutdownCtx := graceful.GetManager().ShutdownContext()
    44  
    45  	uid := ctx.Doer.ID
    46  
    47  	messageChan := eventsource.GetManager().Register(uid)
    48  
    49  	unregister := func() {
    50  		eventsource.GetManager().Unregister(uid, messageChan)
    51  		// ensure the messageChan is closed
    52  		for {
    53  			_, ok := <-messageChan
    54  			if !ok {
    55  				break
    56  			}
    57  		}
    58  	}
    59  
    60  	if _, err := ctx.Resp.Write([]byte("\n")); err != nil {
    61  		log.Error("Unable to write to EventStream: %v", err)
    62  		unregister()
    63  		return
    64  	}
    65  
    66  	timer := time.NewTicker(30 * time.Second)
    67  
    68  loop:
    69  	for {
    70  		select {
    71  		case <-timer.C:
    72  			event := &eventsource.Event{
    73  				Name: "ping",
    74  			}
    75  			_, err := event.WriteTo(ctx.Resp)
    76  			if err != nil {
    77  				log.Error("Unable to write to EventStream for user %s: %v", ctx.Doer.Name, err)
    78  				go unregister()
    79  				break loop
    80  			}
    81  			ctx.Resp.Flush()
    82  		case <-notify:
    83  			go unregister()
    84  			break loop
    85  		case <-shutdownCtx.Done():
    86  			go unregister()
    87  			break loop
    88  		case event, ok := <-messageChan:
    89  			if !ok {
    90  				break loop
    91  			}
    92  
    93  			// Handle logout
    94  			if event.Name == "logout" {
    95  				if ctx.Session.ID() == event.Data {
    96  					_, _ = (&eventsource.Event{
    97  						Name: "logout",
    98  						Data: "here",
    99  					}).WriteTo(ctx.Resp)
   100  					ctx.Resp.Flush()
   101  					go unregister()
   102  					auth.HandleSignOut(ctx)
   103  					break loop
   104  				}
   105  				// Replace the event - we don't want to expose the session ID to the user
   106  				event = &eventsource.Event{
   107  					Name: "logout",
   108  					Data: "elsewhere",
   109  				}
   110  			}
   111  
   112  			_, err := event.WriteTo(ctx.Resp)
   113  			if err != nil {
   114  				log.Error("Unable to write to EventStream for user %s: %v", ctx.Doer.Name, err)
   115  				go unregister()
   116  				break loop
   117  			}
   118  			ctx.Resp.Flush()
   119  		}
   120  	}
   121  	timer.Stop()
   122  }