Example #1
0
// Top-level handler for _changes feed requests.
func (h *handler) handleChanges() error {
	// http://wiki.apache.org/couchdb/HTTP_database_API#Changes
	// http://docs.couchdb.org/en/latest/api/database/changes.html
	var options db.ChangesOptions
	options.Since = channels.TimedSetFromString(h.getQuery("since"))
	options.Limit = int(h.getIntQuery("limit", 0))
	options.Conflicts = (h.getQuery("style") == "all_docs")
	options.IncludeDocs = (h.getBoolQuery("include_docs"))

	options.Terminator = make(chan bool)
	defer close(options.Terminator)

	// Get the channels as parameters to an imaginary "bychannel" filter.
	// The default is all channels the user can access.
	userChannels := channels.SetOf("*")
	filter := h.getQuery("filter")
	if filter != "" {
		if filter != "sync_gateway/bychannel" {
			return base.HTTPErrorf(http.StatusBadRequest, "Unknown filter; try sync_gateway/bychannel")
		}
		channelsParam := h.getQuery("channels")
		if channelsParam == "" {
			return base.HTTPErrorf(http.StatusBadRequest, "Missing 'channels' filter parameter")
		}
		var err error
		userChannels, err = channels.SetFromArray(strings.Split(channelsParam, ","),
			channels.ExpandStar)
		if err != nil {
			return err
		}
		if len(userChannels) == 0 {
			return base.HTTPErrorf(http.StatusBadRequest, "Empty channel list")
		}
	}

	h.db.ChangesClientStats.Increment()
	defer h.db.ChangesClientStats.Decrement()

	switch h.getQuery("feed") {
	case "normal", "":
		return h.sendSimpleChanges(userChannels, options)
	case "longpoll":
		options.Wait = true
		return h.sendSimpleChanges(userChannels, options)
	case "continuous":
		return h.sendContinuousChangesByHTTP(userChannels, options)
	case "websocket":
		return h.sendContinuousChangesByWebSocket(userChannels, options)
	default:
		return base.HTTPErrorf(http.StatusBadRequest, "Unknown feed type")
	}
}
Example #2
0
func (h *handler) handleChanges() error {
	// http://wiki.apache.org/couchdb/HTTP_database_API#Changes
	var options db.ChangesOptions
	options.Since = channels.TimedSetFromString(h.getQuery("since"))
	options.Limit = int(h.getIntQuery("limit", 0))
	options.Conflicts = (h.getQuery("style") == "all_docs")
	options.IncludeDocs = (h.getBoolQuery("include_docs"))

	// Get the channels as parameters to an imaginary "bychannel" filter.
	// The default is all channels the user can access.
	userChannels := channels.SetOf("*")
	filter := h.getQuery("filter")
	if filter != "" {
		if filter != "sync_gateway/bychannel" {
			return &base.HTTPError{http.StatusBadRequest, "Unknown filter; try sync_gateway/bychannel"}
		}
		channelsParam := h.getQuery("channels")
		if channelsParam == "" {
			return &base.HTTPError{http.StatusBadRequest, "Missing 'channels' filter parameter"}
		}
		var err error
		userChannels, err = channels.SetFromArray(strings.Split(channelsParam, ","),
			channels.ExpandStar)
		if err != nil {
			return err
		}
		if len(userChannels) == 0 {
			return &base.HTTPError{http.StatusBadRequest, "Empty channel list"}
		}
	}

	switch h.getQuery("feed") {
	case "continuous":
		return h.handleContinuousChanges(userChannels, options)
	case "longpoll":
		options.Wait = true
	}
	return h.handleSimpleChanges(userChannels, options)
}
Example #3
0
func readChangesOptionsFromJSON(jsonData []byte) (feed string, options db.ChangesOptions, filter string, channelsArray []string, err error) {
	var input struct {
		Feed        string   `json:"feed"`
		Since       string   `json:"since"`
		Limit       int      `json:"limit"`
		Style       string   `json:"style"`
		IncludeDocs bool     `json:"include_docs"`
		Filter      string   `json:"filter"`
		Channels    []string `json:"channels"`
	}
	if err = json.Unmarshal(jsonData, &input); err != nil {
		return
	}
	feed = input.Feed
	options.Since = channels.TimedSetFromString(input.Since)
	options.Limit = input.Limit
	options.Conflicts = (input.Style == "all_docs")
	options.IncludeDocs = input.IncludeDocs
	filter = input.Filter
	channelsArray = input.Channels
	return
}
Example #4
0
// This is the core functionality of both the HTTP and WebSocket-based continuous change feed.
// It defers to a callback function 'send()' to actually send the changes to the client.
// It will call send(nil) to notify that it's caught up and waiting for new changes, or as
// a periodic heartbeat while waiting.
func (h *handler) generateContinuousChanges(inChannels base.Set, options db.ChangesOptions, send func([]*db.ChangeEntry) error) error {
	// Set up heartbeat/timeout
	var timeoutInterval time.Duration
	var timer *time.Timer
	var heartbeat <-chan time.Time
	if ms := h.getRestrictedIntQuery("heartbeat", 0, kMinHeartbeatMS, 0); ms > 0 {
		ticker := time.NewTicker(time.Duration(ms) * time.Millisecond)
		defer ticker.Stop()
		heartbeat = ticker.C
	} else if ms := h.getRestrictedIntQuery("timeout", kDefaultTimeoutMS, 0, kMaxTimeoutMS); ms > 0 {
		timeoutInterval = time.Duration(ms) * time.Millisecond
		defer func() {
			if timer != nil {
				timer.Stop()
			}
		}()
	}

	options.Wait = true // we want the feed channel to wait for changes
	var lastSeqID string
	var feed <-chan *db.ChangeEntry
	var timeout <-chan time.Time
	var err error

loop:
	for {
		if feed == nil {
			// Refresh the feed of all current changes:
			if lastSeqID != "" { // start after end of last feed
				options.Since = channels.TimedSetFromString(lastSeqID)
			}
			feed, err = h.db.MultiChangesFeed(inChannels, options)
			if err != nil || feed == nil {
				return err
			}
		}

		if timeoutInterval > 0 && timer == nil {
			// Timeout resets after every change is sent
			timer = time.NewTimer(timeoutInterval)
			timeout = timer.C
		}

		// Wait for either a new change, a heartbeat, or a timeout:
		select {
		case entry, ok := <-feed:
			if !ok {
				feed = nil
			} else if entry == nil {
				err = send(nil)
			} else {
				entries := []*db.ChangeEntry{entry}
				waiting := false
				// Batch up as many entries as we can without waiting:
			collect:
				for len(entries) < 20 {
					select {
					case entry, ok = <-feed:
						if !ok {
							feed = nil
							break collect
						} else if entry == nil {
							waiting = true
							break collect
						}
						entries = append(entries, entry)
					default:
						break collect
					}
				}
				base.LogTo("Changes", "sending %d change(s)", len(entries))
				err = send(entries)

				if err == nil && waiting {
					err = send(nil)
				}

				lastSeqID = entries[len(entries)-1].Seq
				if options.Limit > 0 {
					if len(entries) >= options.Limit {
						break loop
					}
					options.Limit -= len(entries)
				}
			}
			// Reset the timeout after sending an entry:
			if timer != nil {
				timer.Stop()
				timer = nil
			}
		case <-heartbeat:
			err = send(nil)
		case <-timeout:
			break loop
		}

		if err != nil {
			h.logStatus(http.StatusOK, fmt.Sprintf("Write error: %v", err))
			return nil // error is probably because the client closed the connection
		}
	}
	h.logStatus(http.StatusOK, "OK (continuous feed closed)")
	return nil
}
Example #5
0
func (h *handler) handleContinuousChanges(inChannels base.Set, options db.ChangesOptions) error {
	var timeoutInterval time.Duration
	var timer *time.Timer
	var heartbeat <-chan time.Time
	if ms := h.getIntQuery("heartbeat", 0); ms > 0 {
		ticker := time.NewTicker(time.Duration(ms) * time.Millisecond)
		defer ticker.Stop()
		heartbeat = ticker.C
	} else if ms := h.getIntQuery("timeout", 60000); ms > 0 {
		timeoutInterval = time.Duration(ms) * time.Millisecond
		defer func() {
			if timer != nil {
				timer.Stop()
			}
		}()
	}

	options.Wait = true // we want the feed channel to wait for changes
	var lastSeqID string
	var feed <-chan *db.ChangeEntry
	var timeout <-chan time.Time
	var err error

loop:
	for {
		if feed == nil {
			// Refresh the feed of all current changes:
			if lastSeqID != "" { // start after end of last feed
				options.Since = channels.TimedSetFromString(lastSeqID)
			}
			feed, err = h.db.MultiChangesFeed(inChannels, options)
			if err != nil || feed == nil {
				return err
			}
		}

		if timeoutInterval > 0 && timer == nil {
			timer = time.NewTimer(timeoutInterval)
			timeout = timer.C
		}

		// Wait for either a new change, a heartbeat, or a timeout:
		select {
		case entry := <-feed:
			if entry == nil {
				feed = nil
			} else {
				str, _ := json.Marshal(entry)
				base.LogTo("Changes", "send change: %s", str)
				err = h.writeln(str)

				lastSeqID = entry.Seq
				if options.Limit > 0 {
					options.Limit--
					if options.Limit == 0 {
						break loop
					}
				}
			}
			// Reset the timeout after sending an entry:
			if timer != nil {
				timer.Stop()
				timer = nil
			}
		case <-heartbeat:
			err = h.writeln([]byte{})
		case <-timeout:
			break loop
		}

		if err != nil {
			return nil // error is probably because the client closed the connection
		}
	}
	return nil
}
Example #6
0
// Top-level handler for _changes feed requests. Accepts GET or POST requests.
func (h *handler) handleChanges() error {
	// http://wiki.apache.org/couchdb/HTTP_database_API#Changes
	// http://docs.couchdb.org/en/latest/api/database/changes.html
	restExpvars.Add("changesFeeds_total", 1)
	restExpvars.Add("changesFeeds_active", 1)
	defer restExpvars.Add("changesFeeds_active", -1)

	var feed string
	var options db.ChangesOptions
	var filter string
	var channelsArray []string
	if h.rq.Method == "GET" {
		// GET request has parameters in URL:
		feed = h.getQuery("feed")
		options.Since = channels.TimedSetFromString(h.getQuery("since"))
		options.Limit = int(h.getIntQuery("limit", 0))
		options.Conflicts = (h.getQuery("style") == "all_docs")
		options.IncludeDocs = (h.getBoolQuery("include_docs"))
		filter = h.getQuery("filter")
		channelsParam := h.getQuery("channels")
		if channelsParam != "" {
			channelsArray = strings.Split(channelsParam, ",")
		}
	} else {
		// POST request has parameters in JSON body:
		body, err := h.readBody()
		if err != nil {
			return err
		}
		feed, options, filter, channelsArray, err = readChangesOptionsFromJSON(body)
		if err != nil {
			return err
		}
	}

	// Get the channels as parameters to an imaginary "bychannel" filter.
	// The default is all channels the user can access.
	userChannels := channels.SetOf("*")
	if filter != "" {
		if filter != "sync_gateway/bychannel" {
			return base.HTTPErrorf(http.StatusBadRequest, "Unknown filter; try sync_gateway/bychannel")
		}
		if channelsArray == nil {
			return base.HTTPErrorf(http.StatusBadRequest, "Missing 'channels' filter parameter")
		}
		var err error
		userChannels, err = channels.SetFromArray(channelsArray, channels.ExpandStar)
		if err != nil {
			return err
		}
		if len(userChannels) == 0 {
			return base.HTTPErrorf(http.StatusBadRequest, "Empty channel list")
		}
	}

	h.db.ChangesClientStats.Increment()
	defer h.db.ChangesClientStats.Decrement()

	options.Terminator = make(chan bool)
	defer close(options.Terminator)

	switch feed {
	case "normal", "":
		return h.sendSimpleChanges(userChannels, options)
	case "longpoll":
		options.Wait = true
		return h.sendSimpleChanges(userChannels, options)
	case "continuous":
		return h.sendContinuousChangesByHTTP(userChannels, options)
	case "websocket":
		return h.sendContinuousChangesByWebSocket(userChannels, options)
	default:
		return base.HTTPErrorf(http.StatusBadRequest, "Unknown feed type")
	}
}