additional faffing around with streaming

internal/processing/synchronous/streaming/openstream.go

@@ -0,0 +1,108 @@
+package streaming
+
+import (
+	"errors"
+	"fmt"
+	"sync"
+	"time"
+
+	"github.com/gorilla/websocket"
+	"github.com/sirupsen/logrus"
+	"github.com/superseriousbusiness/gotosocial/internal/gtserror"
+	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
+	"github.com/superseriousbusiness/gotosocial/internal/id"
+)
+
+func (p *processor) OpenStreamForAccount(conn *websocket.Conn, account *gtsmodel.Account, streamType string) gtserror.WithCode {
+	l := p.log.WithFields(logrus.Fields{
+		"func":       "OpenStreamForAccount",
+		"account":    account.ID,
+		"streamType": streamType,
+	})
+	l.Debug("received open stream request")
+
+	streamID, err := id.NewRandomULID()
+	if err != nil {
+		return gtserror.NewErrorInternalError(fmt.Errorf("error generating stream id: %s", err))
+	}
+
+	thisStream := &stream{
+		streamID:   streamID,
+		streamType: streamType,
+		conn:       conn,
+	}
+
+	v, ok := p.streamMap.Load(account.ID)
+	if !ok || v == nil {
+		// there is no entry in the streamMap for this account yet, so make one and store it
+		streams := &streamsForAccount{
+			s: []*stream{
+				thisStream,
+			},
+		}
+		p.streamMap.Store(account.ID, streams)
+	} else {
+		// there is an entry in the streamMap for this account
+		// parse the interface as a streamsForAccount
+		streams, ok := v.(*streamsForAccount)
+		if !ok {
+			return gtserror.NewErrorInternalError(errors.New("stream map error"))
+		}
+
+		// append this stream to it
+		streams.Lock()
+		streams.s = append(streams.s, thisStream)
+		streams.Unlock()
+	}
+
+	// set the close handler to remove the given stream from the stream map so that messages stop getting put into it
+	conn.SetCloseHandler(func(code int, text string) error {
+		l.Debug("closing stream")
+		v, ok := p.streamMap.Load(account.ID)
+		if !ok || v == nil {
+			// the map doesn't contain an entry for the account anyway, so we can just return
+			// this probably should never happen but let's check anyway
+			return nil
+		}
+
+		// parse the interface as a streamsForAccount
+		streams, ok := v.(*streamsForAccount)
+		if !ok {
+			return gtserror.NewErrorInternalError(errors.New("stream map error"))
+		}
+
+		// remove thisStream from the slice of streams stored in streamsForAccount
+		streams.Lock()
+		newStreamSlice := []*stream{}
+		for _, s := range streams.s {
+			if s.streamID != thisStream.streamID {
+				newStreamSlice = append(newStreamSlice, s)
+			}
+		}
+		streams.s = newStreamSlice
+		streams.Unlock()
+		l.Debug("stream closed")
+		return nil
+	})
+
+	defer conn.Close()
+	t := time.NewTicker(60 * time.Second)
+	for range t.C {
+		if err := conn.WriteMessage(websocket.PingMessage, nil); err != nil {
+			return gtserror.NewErrorInternalError(err)
+		}
+	}
+
+	return nil
+}
+
+type streamsForAccount struct {
+	s []*stream
+	sync.Mutex
+}
+
+type stream struct {
+	streamID   string
+	streamType string
+	conn       *websocket.Conn
+}