Streaming (#49)

Add new status and notification websocket streaming capabilities

internal/processing/synchronous/streaming/openstream.go

@@ -0,0 +1,100 @@
+package streaming
+
+import (
+	"errors"
+	"fmt"
+
+	"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(account *gtsmodel.Account, streamType string) (*gtsmodel.Stream, gtserror.WithCode) {
+	l := p.log.WithFields(logrus.Fields{
+		"func":       "OpenStreamForAccount",
+		"account":    account.ID,
+		"streamType": streamType,
+	})
+	l.Debug("received open stream request")
+
+	// each stream needs a unique ID so we know to close it
+	streamID, err := id.NewRandomULID()
+	if err != nil {
+		return nil, gtserror.NewErrorInternalError(fmt.Errorf("error generating stream id: %s", err))
+	}
+
+	thisStream := &gtsmodel.Stream{
+		ID:        streamID,
+		Type:      streamType,
+		Messages:  make(chan *gtsmodel.Message, 100),
+		Hangup:    make(chan interface{}, 1),
+		Connected: true,
+	}
+	go p.waitToCloseStream(account, thisStream)
+
+	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
+		streamsForAccount := &gtsmodel.StreamsForAccount{
+			Streams: []*gtsmodel.Stream{
+				thisStream,
+			},
+		}
+		p.streamMap.Store(account.ID, streamsForAccount)
+	} else {
+		// there is an entry in the streamMap for this account
+		// parse the interface as a streamsForAccount
+		streamsForAccount, ok := v.(*gtsmodel.StreamsForAccount)
+		if !ok {
+			return nil, gtserror.NewErrorInternalError(errors.New("stream map error"))
+		}
+
+		// append this stream to it
+		streamsForAccount.Lock()
+		streamsForAccount.Streams = append(streamsForAccount.Streams, thisStream)
+		streamsForAccount.Unlock()
+	}
+
+	return thisStream, nil
+}
+
+// waitToCloseStream waits until the hangup channel is closed for the given stream.
+// It then iterates through the map of streams stored by the processor, removes the stream from it,
+// and then closes the messages channel of the stream to indicate that the channel should no longer be read from.
+func (p *processor) waitToCloseStream(account *gtsmodel.Account, thisStream *gtsmodel.Stream) {
+	<-thisStream.Hangup // wait for a hangup message
+
+	// lock the stream to prevent more messages being put in it while we work
+	thisStream.Lock()
+	defer thisStream.Unlock()
+
+	// indicate the stream is no longer connected
+	thisStream.Connected = false
+
+	// load and parse the entry for this account from the stream map
+	v, ok := p.streamMap.Load(account.ID)
+	if !ok || v == nil {
+		return
+	}
+	streamsForAccount, ok := v.(*gtsmodel.StreamsForAccount)
+	if !ok {
+		return
+	}
+
+	// lock the streams for account while we remove this stream from its slice
+	streamsForAccount.Lock()
+	defer streamsForAccount.Unlock()
+
+	// put everything into modified streams *except* the stream we're removing
+	modifiedStreams := []*gtsmodel.Stream{}
+	for _, s := range streamsForAccount.Streams {
+		if s.ID != thisStream.ID {
+			modifiedStreams = append(modifiedStreams, s)
+		}
+	}
+	streamsForAccount.Streams = modifiedStreams
+
+	// finally close the messages channel so no more messages can be read from it
+	close(thisStream.Messages)
+}