Golang ChangesOptions.Terminator方法代码示例

// 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")
	}
}

func (h *handler) sendContinuousChangesByWebSocket(inChannels base.Set, options db.ChangesOptions) error {
	handler := func(conn *websocket.Conn) {
		h.logStatus(101, "Upgraded to WebSocket protocol")
		defer func() {
			conn.Close()
			base.LogTo("HTTP+", "#%03d:     --> WebSocket closed", h.serialNumber)
		}()

		// Read changes-feed options from an initial incoming WebSocket message in JSON format:
		if msg, err := readWebSocketMessage(conn); err != nil {
			return
		} else {
			var channelNames []string
			var err error
			if _, options, _, channelNames, err = readChangesOptionsFromJSON(msg); err != nil {
				return
			}
			if channelNames != nil {
				inChannels, _ = channels.SetFromArray(channelNames, channels.ExpandStar)
			}
		}

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

		caughtUp := false
		h.generateContinuousChanges(inChannels, options, func(changes []*db.ChangeEntry) error {
			var data []byte
			if changes != nil {
				data, _ = json.Marshal(changes)
			} else if !caughtUp {
				caughtUp = true
				data, _ = json.Marshal([]*db.ChangeEntry{})
			} else {
				data = []byte{}
			}
			_, err := conn.Write(data)
			return err
		})
	}
	server := websocket.Server{
		Handshake: func(*websocket.Config, *http.Request) error { return nil },
		Handler:   handler,
	}
	server.ServeHTTP(h.response, h.rq)
	return nil
}

// 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")
	}
}