WIP: Websocket replacement for Eventstream #20543
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,235 @@ | ||
| // Copyright 2022 The Gitea Authors. All rights reserved. | ||
| // Use of this source code is governed by a MIT-style | ||
| // license that can be found in the LICENSE file. | ||
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| package events | ||
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| import ( | ||
| "net/http" | ||
| "net/url" | ||
| "time" | ||
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| "code.gitea.io/gitea/modules/context" | ||
| "code.gitea.io/gitea/modules/eventsource" | ||
| "code.gitea.io/gitea/modules/graceful" | ||
| "code.gitea.io/gitea/modules/json" | ||
| "code.gitea.io/gitea/modules/log" | ||
| "code.gitea.io/gitea/modules/setting" | ||
| "code.gitea.io/gitea/routers/web/auth" | ||
| "github.com/gorilla/websocket" | ||
| ) | ||
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| const ( | ||
| writeWait = 10 * time.Second | ||
| pongWait = 60 * time.Second | ||
| pingPeriod = (pongWait * 9) / 10 | ||
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| maximumMessageSize = 2048 | ||
| readMessageChanSize = 20 // <- I've put 20 here because it seems like a reasonable buffer but it may to increase | ||
| ) | ||
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| type readMessage struct { | ||
| messageType int | ||
| message []byte | ||
| err error | ||
| } | ||
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| // Events listens for events | ||
| func Websocket(ctx *context.Context) { | ||
| upgrader := websocket.Upgrader{ | ||
| ReadBufferSize: 1024, | ||
| WriteBufferSize: 1024, | ||
| CheckOrigin: func(r *http.Request) bool { | ||
| origin := r.Header["Origin"] | ||
| if len(origin) == 0 { | ||
| return true | ||
| } | ||
| u, err := url.Parse(origin[0]) | ||
| if err != nil { | ||
| return false | ||
| } | ||
| appURLURL, err := url.Parse(setting.AppURL) | ||
| if err != nil { | ||
| return true | ||
| } | ||
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| return u.Host == appURLURL.Host | ||
|
There was a problem hiding this comment. I'm not sure this is safe, it should probably be stricter and include protocol and port as well. Thought we could also lean more on the cookie header. When the cookie has SameSite=strict, it could technically serve as the only authentification mechanism on the websocket. Thought, origin check is always good to have. |
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| }, | ||
| } | ||
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| // Because http proxies will tend not to pass these headers | ||
| ctx.Req.Header.Add("Upgrade", "websocket") | ||
| ctx.Req.Header.Add("Connection", "Upgrade") | ||
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| conn, err := upgrader.Upgrade(ctx.Resp, ctx.Req, nil) | ||
| if err != nil { | ||
| log.Error("Unable to upgrade due to error: %v", err) | ||
| return | ||
| } | ||
| defer conn.Close() | ||
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| notify := ctx.Done() | ||
| shutdownCtx := graceful.GetManager().ShutdownContext() | ||
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| eventChan := make(<-chan *eventsource.Event) | ||
| uid := int64(0) | ||
| unregister := func() {} | ||
| if ctx.IsSigned { | ||
| uid = ctx.Doer.ID | ||
| eventChan = eventsource.GetManager().Register(uid) | ||
| unregister = func() { | ||
| go func() { | ||
| eventsource.GetManager().Unregister(uid, eventChan) | ||
| // ensure the messageChan is closed | ||
| for { | ||
| _, ok := <-eventChan | ||
| if !ok { | ||
| break | ||
| } | ||
| } | ||
| }() | ||
| } | ||
| } | ||
| defer unregister() | ||
|
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| readMessageChan := make(chan readMessage, readMessageChanSize) | ||
| go readMessagesFromConnToChan(conn, readMessageChan) | ||
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| pingTicker := time.NewTicker(pingPeriod) | ||
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| for { | ||
| select { | ||
| case <-notify: | ||
| return | ||
| case <-shutdownCtx.Done(): | ||
| return | ||
| case <-pingTicker.C: | ||
| // ensure that we're not already cancelled | ||
| select { | ||
| case <-notify: | ||
| return | ||
| case <-shutdownCtx.Done(): | ||
| return | ||
| default: | ||
| } | ||
|
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| if err := conn.SetWriteDeadline(time.Now().Add(writeWait)); err != nil { | ||
| log.Error("unable to SetWriteDeadline: %v", err) | ||
| return | ||
| } | ||
| if err := conn.WriteMessage(websocket.PingMessage, []byte{}); err != nil { | ||
| log.Error("unable to send PingMessage: %v", err) | ||
| return | ||
| } | ||
| case message, ok := <-readMessageChan: | ||
| if !ok { | ||
| break | ||
| } | ||
|
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| // ensure that we're not already cancelled | ||
| select { | ||
| case <-notify: | ||
| return | ||
| case <-shutdownCtx.Done(): | ||
| return | ||
| default: | ||
| } | ||
|
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| // FIXME: HANDLE MESSAGES | ||
| log.Info("Got Message: %d:%s:%v", message.messageType, message.message, message.err) | ||
| case event, ok := <-eventChan: | ||
| if !ok { | ||
| break | ||
| } | ||
|
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| // ensure that we're not already cancelled | ||
| select { | ||
| case <-notify: | ||
| return | ||
| case <-shutdownCtx.Done(): | ||
| return | ||
| default: | ||
| } | ||
|
|
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| // Handle events | ||
| if event.Name == "logout" { | ||
| if ctx.Session.ID() == event.Data { | ||
| event = &eventsource.Event{ | ||
| Name: "logout", | ||
| Data: "here", | ||
| } | ||
| _ = writeEvent(conn, event) | ||
| go unregister() | ||
| auth.HandleSignOut(ctx) | ||
| break | ||
| } | ||
| // Replace the event - we don't want to expose the session ID to the user | ||
| event = &eventsource.Event{ | ||
| Name: "logout", | ||
| Data: "elsewhere", | ||
| } | ||
| } | ||
| if err := writeEvent(conn, event); err != nil { | ||
| return | ||
| } | ||
| } | ||
| } | ||
| } | ||
|
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| func readMessagesFromConnToChan(conn *websocket.Conn, messageChan chan readMessage) { | ||
| defer func() { | ||
| close(messageChan) // Please note: this has to be within a wrapping anonymous func otherwise it will be evaluated when creating the defer | ||
|
There was a problem hiding this comment. Interesting, I didn't know this. Is this evaluation behaviour something specific to the |
||
| _ = conn.Close() | ||
| }() | ||
| conn.SetReadLimit(maximumMessageSize) | ||
| if err := conn.SetReadDeadline(time.Now().Add(pongWait)); err != nil { | ||
| log.Error("unable to SetReadDeadline: %v", err) | ||
| return | ||
| } | ||
| conn.SetPongHandler(func(string) error { | ||
| if err := conn.SetReadDeadline(time.Now().Add(pongWait)); err != nil { | ||
| log.Error("unable to SetReadDeadline: %v", err) | ||
| } | ||
| return nil | ||
| }) | ||
|
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| for { | ||
| messageType, message, err := conn.ReadMessage() | ||
| messageChan <- readMessage{ | ||
| messageType: messageType, | ||
| message: message, | ||
| err: err, | ||
| } | ||
| if err != nil { | ||
| // don't need to handle the error here as it is passed down the channel | ||
| return | ||
| } | ||
| if err := conn.SetReadDeadline(time.Now().Add(pongWait)); err != nil { | ||
| log.Error("unable to SetReadDeadline: %v", err) | ||
| return | ||
| } | ||
| } | ||
| } | ||
|
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| func writeEvent(conn *websocket.Conn, event *eventsource.Event) error { | ||
| if err := conn.SetWriteDeadline(time.Now().Add(writeWait)); err != nil { | ||
| log.Error("unable to SetWriteDeadline: %v", err) | ||
| return err | ||
| } | ||
|
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| w, err := conn.NextWriter(websocket.TextMessage) | ||
| if err != nil { | ||
| log.Error("Unable to get writer for websocket %v", err) | ||
| return err | ||
| } | ||
|
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| if err := json.NewEncoder(w).Encode(event); err != nil { | ||
| log.Error("Unable to create encoder for %v %v", event, err) | ||
| return err | ||
| } | ||
| if err := w.Close(); err != nil { | ||
| log.Warn("Unable to close writer for websocket %v", err) | ||
| return err | ||
| } | ||
| return nil | ||
| } | ||
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Origin header will be present even on first-party requests, so we can require it.