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Shut down subscriber read loop correctly #178

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Shut down subscriber read loop correctly #178

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89 changes: 57 additions & 32 deletions client.go
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Original file line number Diff line number Diff line change
Expand Up @@ -98,7 +98,7 @@ func (c *Client) SubscribeWithContext(ctx context.Context, stream string, handle
defer resp.Body.Close()

reader := NewEventStreamReader(resp.Body, c.maxBufferSize)
eventChan, errorChan := c.startReadLoop(reader)
eventChan, errorChan := c.startReadLoop(ctx, reader)

for {
select {
Expand Down Expand Up @@ -133,6 +133,8 @@ func (c *Client) SubscribeChanWithContext(ctx context.Context, stream string, ch
c.subscribed[ch] = make(chan struct{})
c.mu.Unlock()

ctx, cancel := context.WithCancel(ctx)

operation := func() error {
resp, err := c.request(ctx, stream)
if err != nil {
Expand All @@ -156,13 +158,14 @@ func (c *Client) SubscribeChanWithContext(ctx context.Context, stream string, ch
}

reader := NewEventStreamReader(resp.Body, c.maxBufferSize)
eventChan, errorChan := c.startReadLoop(reader)
eventChan, errorChan := c.startReadLoop(ctx, reader)

for {
var msg *Event
// Wait for message to arrive or exit
select {
case <-c.subscribed[ch]:
cancel()
return nil
case err = <-errorChan:
return err
Expand All @@ -173,6 +176,7 @@ func (c *Client) SubscribeChanWithContext(ctx context.Context, stream string, ch
if msg != nil {
select {
case <-c.subscribed[ch]:
cancel()
return nil
case ch <- msg:
// message sent
Expand Down Expand Up @@ -201,51 +205,72 @@ func (c *Client) SubscribeChanWithContext(ctx context.Context, stream string, ch
return err
}

func (c *Client) startReadLoop(reader *EventStreamReader) (chan *Event, chan error) {
func (c *Client) startReadLoop(ctx context.Context, reader *EventStreamReader) (chan *Event, chan error) {
outCh := make(chan *Event)
erChan := make(chan error)
go c.readLoop(reader, outCh, erChan)
go c.readLoop(ctx, reader, outCh, erChan)
return outCh, erChan
}

func (c *Client) readLoop(reader *EventStreamReader, outCh chan *Event, erChan chan error) {
func (c *Client) readLoop(ctx context.Context, reader *EventStreamReader, outCh chan *Event, erChan chan error) {
for {
// Read each new line and process the type of event
event, err := reader.ReadEvent()
if err != nil {
if err == io.EOF {
erChan <- nil
return
msg, err := c.readLoopInner(reader)
if errors.Is(err, io.EOF) {
select {
case <-ctx.Done():
case erChan <- nil:
}
break
} else if err != nil {
select {
case <-ctx.Done():
case erChan <- err:
}
// run user specified disconnect function
if c.disconnectcb != nil {
c.Connected = false
c.disconnectcb(c)
break
} else if msg != nil {
select {
case <-ctx.Done():
case outCh <- msg:
}
erChan <- err
return
}
}
}

if !c.Connected && c.connectedcb != nil {
c.Connected = true
c.connectedcb(c)
func (c *Client) readLoopInner(reader *EventStreamReader) (*Event, error) {
// Read each new line and process the type of event
event, err := reader.ReadEvent()
if err != nil {
if errors.Is(err, io.EOF) {
return nil, err
}
// run user specified disconnect function
if c.disconnectcb != nil {
c.Connected = false
c.disconnectcb(c)
}
return nil, err
}

// If we get an error, ignore it.
var msg *Event
if msg, err = c.processEvent(event); err == nil {
if len(msg.ID) > 0 {
c.LastEventID.Store(msg.ID)
} else {
msg.ID, _ = c.LastEventID.Load().([]byte)
}
if !c.Connected && c.connectedcb != nil {
c.Connected = true
c.connectedcb(c)
}

// Send downstream if the event has something useful
if msg.hasContent() {
outCh <- msg
}
// If we get an error, ignore it.
if msg, err := c.processEvent(event); err == nil {
if len(msg.ID) > 0 {
c.LastEventID.Store(msg.ID)
} else {
msg.ID, _ = c.LastEventID.Load().([]byte)
}

// Send downstream only if the event has something useful
if msg.hasContent() {
return msg, nil
}
}

return nil, nil
}

// SubscribeRaw to an sse endpoint
Expand Down