/**
* @license
* Copyright The Closure Library Authors.
* SPDX-License-Identifier: Apache-2.0
*/
/**
* @fileoverview Definition of the BrowserChannel class. A BrowserChannel
* simulates a bidirectional socket over HTTP. It is the basis of the
* Gmail Chat IM connections to the server.
*
* Typical usage will look like
* const handler = [handler object];
* const channel = new BrowserChannel(clientVersion);
* channel.setHandler(handler);
* channel.connect('channel/test', 'channel/bind');
*
* See goog.net.BrowserChannel.Handler for the handler interface.
*/
goog.provide('goog.net.BrowserChannel');
goog.provide('goog.net.BrowserChannel.Error');
goog.provide('goog.net.BrowserChannel.Event');
goog.provide('goog.net.BrowserChannel.Handler');
goog.provide('goog.net.BrowserChannel.Hooks');
goog.provide('goog.net.BrowserChannel.LogSaver');
goog.provide('goog.net.BrowserChannel.QueuedMap');
goog.provide('goog.net.BrowserChannel.ServerReachability');
goog.provide('goog.net.BrowserChannel.ServerReachabilityEvent');
goog.provide('goog.net.BrowserChannel.Stat');
goog.provide('goog.net.BrowserChannel.StatEvent');
goog.provide('goog.net.BrowserChannel.State');
goog.provide('goog.net.BrowserChannel.TimingEvent');
goog.require('goog.Uri');
goog.require('goog.array');
goog.require('goog.asserts');
goog.require('goog.debug.TextFormatter');
goog.require('goog.events.Event');
goog.require('goog.events.EventTarget');
goog.require('goog.json');
goog.require('goog.json.NativeJsonProcessor');
goog.require('goog.log');
goog.require('goog.net.BrowserTestChannel');
goog.require('goog.net.ChannelDebug');
goog.require('goog.net.ChannelRequest');
goog.require('goog.net.XhrIo');
goog.require('goog.net.browserchannelinternal.ServerReachability');
goog.require('goog.net.browserchannelinternal.hooks');
goog.require('goog.net.browserchannelinternal.stats');
goog.require('goog.net.tmpnetwork');
goog.require('goog.object');
goog.require('goog.string');
goog.require('goog.structs');
goog.require('goog.structs.CircularBuffer');
goog.requireType('goog.debug.Formatter');
goog.requireType('goog.string.Parser');
goog.requireType('goog.structs.Map');
/**
* Encapsulates the logic for a single BrowserChannel.
*
* @param {string=} opt_clientVersion An application-specific version number
* that is sent to the server when connected.
* @param {Array<string>=} opt_firstTestResults Previously determined results
* of the first browser channel test.
* @param {boolean=} opt_secondTestResults Previously determined results
* of the second browser channel test.
* @param {boolean=} opt_asyncTest Whether to perform the test requests
* asynchronously. While the test is performed, we'll assume the worst
* (connection is buffered), in order to avoid delaying the connection
* until the test is performed.
* @constructor
*/
goog.net.BrowserChannel = function(
opt_clientVersion, opt_firstTestResults, opt_secondTestResults,
opt_asyncTest) {
'use strict';
/**
* The application specific version that is passed to the server.
* @type {?string}
* @private
*/
this.clientVersion_ = opt_clientVersion || null;
/**
* The current state of the BrowserChannel. It should be one of the
* goog.net.BrowserChannel.State constants.
* @type {!goog.net.BrowserChannel.State}
* @private
*/
this.state_ = goog.net.BrowserChannel.State.INIT;
/**
* An array of queued maps that need to be sent to the server.
* @type {Array<goog.net.BrowserChannel.QueuedMap>}
* @private
*/
this.outgoingMaps_ = [];
/**
* An array of dequeued maps that we have either received a non-successful
* response for, or no response at all, and which therefore may or may not
* have been received by the server.
* @type {Array<goog.net.BrowserChannel.QueuedMap>}
* @private
*/
this.pendingMaps_ = [];
/**
* The channel debug used for browserchannel logging
* @type {!goog.net.ChannelDebug}
* @private
*/
this.channelDebug_ = new goog.net.ChannelDebug();
/**
* Parser for a response payload. The parser should return an array.
* @type {!goog.string.Parser}
* @private
*/
this.parser_ = new goog.json.NativeJsonProcessor();
/**
* An array of results for the first browser channel test call.
* @type {Array<string>}
* @private
*/
this.firstTestResults_ = opt_firstTestResults || null;
/**
* The results of the second browser channel test. True implies the
* connection is buffered, False means unbuffered, null means that
* the results are not available.
* @private
*/
this.secondTestResults_ =
(opt_secondTestResults != null) ? opt_secondTestResults : null;
/**
* Whether to perform the test requests asynchronously. While the test is
* performed, we'll assume the worst (connection is buffered), in order to
* avoid delaying the connection until the test is performed.
* @private {boolean}
*/
this.asyncTest_ = opt_asyncTest || false;
};
/**
* Alias the internal Stat module to be used from the main BrowserChannel
* module.
* @const
*/
goog.net.BrowserChannel.Stat = goog.net.browserchannelinternal.stats.Stat;
/**
* Alias getStatEventTarget as it used to be provided from the main
* BrowserChannel module.
* @const
*/
goog.net.BrowserChannel.getStatEventTarget =
goog.net.browserchannelinternal.stats.getStatEventTarget;
/**
* Simple container class for a (mapId, map) pair.
* @param {number} mapId The id for this map.
* @param {Object|goog.structs.Map} map The map itself.
* @param {Object=} opt_context The context associated with the map.
* @constructor
* @final
*/
goog.net.BrowserChannel.QueuedMap = function(mapId, map, opt_context) {
'use strict';
/**
* The id for this map.
* @type {number}
*/
this.mapId = mapId;
/**
* The map itself.
* @type {Object}
*/
this.map = map;
/**
* The context for the map.
* @type {Object}
*/
this.context = opt_context || null;
};
/**
* Extra HTTP headers to add to all the requests sent to the server.
* @type {?Object}
* @private
*/
goog.net.BrowserChannel.prototype.extraHeaders_ = null;
/**
* Extra parameters to add to all the requests sent to the server.
* @type {?Object}
* @private
*/
goog.net.BrowserChannel.prototype.extraParams_ = null;
/**
* The current ChannelRequest object for the forwardchannel.
* @type {goog.net.ChannelRequest?}
* @private
*/
goog.net.BrowserChannel.prototype.forwardChannelRequest_ = null;
/**
* The ChannelRequest object for the backchannel.
* @type {goog.net.ChannelRequest?}
* @private
*/
goog.net.BrowserChannel.prototype.backChannelRequest_ = null;
/**
* The relative path (in the context of the page hosting the browser channel)
* for making requests to the server.
* @type {?string}
* @private
*/
goog.net.BrowserChannel.prototype.path_ = null;
/**
* The absolute URI for the forwardchannel request.
* @type {?goog.Uri}
* @private
*/
goog.net.BrowserChannel.prototype.forwardChannelUri_ = null;
/**
* The absolute URI for the backchannel request.
* @type {?goog.Uri}
* @private
*/
goog.net.BrowserChannel.prototype.backChannelUri_ = null;
/**
* A subdomain prefix for using a subdomain in IE for the backchannel
* requests.
* @type {?string}
* @private
*/
goog.net.BrowserChannel.prototype.hostPrefix_ = null;
/**
* Whether we allow the use of a subdomain in IE for the backchannel requests.
* @private
*/
goog.net.BrowserChannel.prototype.allowHostPrefix_ = true;
/**
* The next id to use for the RID (request identifier) parameter. This
* identifier uniquely identifies the forward channel request.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.nextRid_ = 0;
/**
* The id to use for the next outgoing map. This identifier uniquely
* identifies a sent map.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.nextMapId_ = 0;
/**
* Whether to fail forward-channel requests after one try, or after a few tries.
* @type {boolean}
* @private
*/
goog.net.BrowserChannel.prototype.failFast_ = false;
/**
* The handler that receive callbacks for state changes and data.
* @type {?goog.net.BrowserChannel.Handler}
* @private
*/
goog.net.BrowserChannel.prototype.handler_ = null;
/**
* Timer identifier for asynchronously making a forward channel request.
* @type {?number}
* @private
*/
goog.net.BrowserChannel.prototype.forwardChannelTimerId_ = null;
/**
* Timer identifier for asynchronously making a back channel request.
* @type {?number}
* @private
*/
goog.net.BrowserChannel.prototype.backChannelTimerId_ = null;
/**
* Timer identifier for the timer that waits for us to retry the backchannel in
* the case where it is dead and no longer receiving data.
* @type {?number}
* @private
*/
goog.net.BrowserChannel.prototype.deadBackChannelTimerId_ = null;
/**
* The BrowserTestChannel object which encapsulates the logic for determining
* interesting network conditions about the client.
* @type {goog.net.BrowserTestChannel?}
* @private
*/
goog.net.BrowserChannel.prototype.connectionTest_ = null;
/**
* Whether the client's network conditions can support chunked responses.
* @type {?boolean}
* @private
*/
goog.net.BrowserChannel.prototype.useChunked_ = null;
/**
* Whether chunked mode is allowed. In certain debugging situations, it's
* useful to disable this.
* @private
*/
goog.net.BrowserChannel.prototype.allowChunkedMode_ = true;
/**
* The array identifier of the last array received from the server for the
* backchannel request.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.lastArrayId_ = -1;
/**
* The array identifier of the last array sent by the server that we know about.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.lastPostResponseArrayId_ = -1;
/**
* The last status code received.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.lastStatusCode_ = -1;
/**
* Number of times we have retried the current forward channel request.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.forwardChannelRetryCount_ = 0;
/**
* Number of times it a row that we have retried the current back channel
* request and received no data.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.backChannelRetryCount_ = 0;
/**
* The attempt id for the current back channel request. Starts at 1 and
* increments for each reconnect. The server uses this to log if our connection
* is flaky or not.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.backChannelAttemptId_;
/**
* The base part of the time before firing next retry request. Default is 5
* seconds. Note that a random delay is added (see {@link retryDelaySeedMs_})
* for all retries, and linear backoff is applied to the sum for subsequent
* retries.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.baseRetryDelayMs_ = 5 * 1000;
/**
* A random time between 0 and this number of MS is added to the
* {@link baseRetryDelayMs_}. Default is 10 seconds.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.retryDelaySeedMs_ = 10 * 1000;
/**
* Maximum number of attempts to connect to the server for forward channel
* requests. Defaults to 2.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.forwardChannelMaxRetries_ = 2;
/**
* The timeout in milliseconds for a forward channel request. Defaults to 20
* seconds. Note that part of this timeout can be randomized.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.forwardChannelRequestTimeoutMs_ = 20 * 1000;
/**
* A throttle time in ms for readystatechange events for the backchannel.
* Useful for throttling when ready state is INTERACTIVE (partial data).
*
* This throttle is useful if the server sends large data chunks down the
* backchannel. It prevents examining XHR partial data on every
* readystate change event. This is useful because large chunks can
* trigger hundreds of readystatechange events, each of which takes ~5ms
* or so to handle, in turn making the UI unresponsive for a significant period.
*
* If set to zero no throttle is used.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.readyStateChangeThrottleMs_ = 0;
/**
* Whether cross origin requests are supported for the browser channel.
*
* See {@link goog.net.XhrIo#setWithCredentials}.
* @type {boolean}
* @private
*/
goog.net.BrowserChannel.prototype.supportsCrossDomainXhrs_ = false;
/**
* The latest protocol version that this class supports. We request this version
* from the server when opening the connection. Should match
* com.google.net.browserchannel.BrowserChannel.LATEST_CHANNEL_VERSION.
* @type {number}
*/
goog.net.BrowserChannel.LATEST_CHANNEL_VERSION = 8;
/**
* The channel version that we negotiated with the server for this session.
* Starts out as the version we request, and then is changed to the negotiated
* version after the initial open.
* @type {number}
* @private
*/
goog.net.BrowserChannel.prototype.channelVersion_ =
goog.net.BrowserChannel.LATEST_CHANNEL_VERSION;
/**
* Enum type for the browser channel state machine.
* @enum {number}
*/
goog.net.BrowserChannel.State = {
/** The channel is closed. */
CLOSED: 0,
/** The channel has been initialized but hasn't yet initiated a connection. */
INIT: 1,
/** The channel is in the process of opening a connection to the server. */
OPENING: 2,
/** The channel is open. */
OPENED: 3,
};
/**
* The timeout in milliseconds for a forward channel request.
* @type {number}
*/
goog.net.BrowserChannel.FORWARD_CHANNEL_RETRY_TIMEOUT = 20 * 1000;
/**
* Maximum number of attempts to connect to the server for back channel
* requests.
* @type {number}
*/
goog.net.BrowserChannel.BACK_CHANNEL_MAX_RETRIES = 3;
/**
* A number in MS of how long we guess the maxmium amount of time a round trip
* to the server should take. In the future this could be substituted with a
* real measurement of the RTT.
* @type {number}
*/
goog.net.BrowserChannel.RTT_ESTIMATE = 3 * 1000;
/**
* When retrying for an inactive channel, we will multiply the total delay by
* this number.
* @type {number}
*/
goog.net.BrowserChannel.INACTIVE_CHANNEL_RETRY_FACTOR = 2;
/**
* Enum type for identifying a BrowserChannel error.
* @enum {number}
*/
goog.net.BrowserChannel.Error = {
/** Value that indicates no error has occurred. */
OK: 0,
/** An error due to a request failing. */
REQUEST_FAILED: 2,
/** An error due to the user being logged out. */
LOGGED_OUT: 4,
/** An error due to server response which contains no data. */
NO_DATA: 5,
/** An error due to a server response indicating an unknown session id */
UNKNOWN_SESSION_ID: 6,
/** An error due to a server response requesting to stop the channel. */
STOP: 7,
/** A general network error. */
NETWORK: 8,
/** An error due to the channel being blocked by a network administrator. */
BLOCKED: 9,
/** An error due to bad data being returned from the server. */
BAD_DATA: 10,
/** An error due to a response that doesn't start with the magic cookie. */
BAD_RESPONSE: 11,
/** ActiveX is blocked by the machine's admin settings. */
ACTIVE_X_BLOCKED: 12,
};
/**
* Internal enum type for the two browser channel channel types.
* @enum {number}
* @private
*/
goog.net.BrowserChannel.ChannelType_ = {
FORWARD_CHANNEL: 1,
BACK_CHANNEL: 2,
};
/**
* The maximum number of maps that can be sent in one POST. Should match
* com.google.net.browserchannel.BrowserChannel.MAX_MAPS_PER_REQUEST.
* @type {number}
* @private
*/
goog.net.BrowserChannel.MAX_MAPS_PER_REQUEST_ = 1000;
/**
* Events fired by BrowserChannel and associated objects
* @const
*/
goog.net.BrowserChannel.Event = {};
/**
* Stat Event that fires when things of interest happen that may be useful for
* applications to know about for stats or debugging purposes. This event fires
* on the EventTarget returned by getStatEventTarget.
*/
goog.net.BrowserChannel.Event.STAT_EVENT = 'statevent';
/**
* An event that fires when POST requests complete successfully, indicating
* the size of the POST and the round trip time.
* This event fires on the EventTarget returned by getStatEventTarget.
*/
goog.net.BrowserChannel.Event.TIMING_EVENT = 'timingevent';
/** @const */
goog.net.BrowserChannel.StatEvent =
goog.net.browserchannelinternal.stats.StatEvent;
/**
* Event class for goog.net.BrowserChannel.Event.TIMING_EVENT
*
* @param {goog.events.EventTarget} target The stat event target for
the browser channel.
* @param {number} size The number of characters in the POST data.
* @param {number} rtt The total round trip time from POST to response in MS.
* @param {number} retries The number of times the POST had to be retried.
* @constructor
* @extends {goog.events.Event}
* @final
*/
goog.net.BrowserChannel.TimingEvent = function(target, size, rtt, retries) {
'use strict';
goog.events.Event.call(
this, goog.net.BrowserChannel.Event.TIMING_EVENT, target);
/**
* @type {number}
*/
this.size = size;
/**
* @type {number}
*/
this.rtt = rtt;
/**
* @type {number}
*/
this.retries = retries;
};
goog.inherits(goog.net.BrowserChannel.TimingEvent, goog.events.Event);
/**
* The type of event that occurs every time some information about how reachable
* the server is is discovered.
* @const {string}
*/
goog.net.BrowserChannel.Event.SERVER_REACHABILITY_EVENT = 'serverreachability';
/** @const */
goog.net.BrowserChannel.ServerReachability =
goog.net.browserchannelinternal.ServerReachability;
/**
* Event class for goog.net.BrowserChannel.Event.SERVER_REACHABILITY_EVENT.
*
* @param {goog.events.EventTarget} target The stat event target for
the browser channel.
* @param {goog.net.browserchannelinternal.ServerReachability} reachabilityType
The
* reachability event type.
* @constructor
* @extends {goog.events.Event}
* @final
*/
goog.net.BrowserChannel.ServerReachabilityEvent = function(
target, reachabilityType) {
'use strict';
goog.events.Event.call(
this, goog.net.BrowserChannel.Event.SERVER_REACHABILITY_EVENT, target);
/**
* @type {goog.net.browserchannelinternal.ServerReachability}
*/
this.reachabilityType = reachabilityType;
};
goog.inherits(
goog.net.BrowserChannel.ServerReachabilityEvent, goog.events.Event);
/**
* A guess at a cutoff at which to no longer assume the backchannel is dead
* when we are slow to receive data. Number in bytes.
*
* Assumption: The worst bandwidth we work on is 50 kilobits/sec
* 50kbits/sec * (1 byte / 8 bits) * 6 sec dead backchannel timeout
* @type {number}
*/
goog.net.BrowserChannel.OUTSTANDING_DATA_BACKCHANNEL_RETRY_CUTOFF = 37500;
/**
* Returns the browserchannel logger.
*
* @return {!goog.net.ChannelDebug} The channel debug object.
*/
goog.net.BrowserChannel.prototype.getChannelDebug = function() {
'use strict';
return this.channelDebug_;
};
/**
* Set the browserchannel logger.
* TODO(user): Add interface for channel loggers or remove this function.
*
* @param {goog.net.ChannelDebug} channelDebug The channel debug object.
*/
goog.net.BrowserChannel.prototype.setChannelDebug = function(channelDebug) {
'use strict';
if (channelDebug != null) {
this.channelDebug_ = channelDebug;
}
};
/**
* Alias for execution hooks. These are currently available as top-level
* aliases (see below), but users should prefer to use them via this alias
* instead.
* @const
*/
goog.net.BrowserChannel.Hooks = goog.net.browserchannelinternal.hooks;
/**
* Alias setStartThreadExecutionHook from the internal Hooks module, as it was
* previously available as a top-level export here.
* @const
*/
goog.net.BrowserChannel.setStartThreadExecutionHook =
goog.net.browserchannelinternal.hooks.setStartThreadExecutionHook;
/**
* Alias setEndThreadExecutionHook from the internal Hooks module, as it was
* previously available as a top-level export here.
* @const
*/
goog.net.BrowserChannel.setEndThreadExecutionHook =
goog.net.browserchannelinternal.hooks.setEndThreadExecutionHook;
/**
* Alias createChannelRequest from the internal Hooks module, as it was
* previously available as a top-level export here.
* @const
*/
goog.net.BrowserChannel.createChannelRequest =
goog.net.ChannelRequest.createChannelRequest;
/**
* Starts the channel. This initiates connections to the server.
*
* @param {string} testPath The path for the test connection.
* @param {string} channelPath The path for the channel connection.
* @param {Object=} opt_extraParams Extra parameter keys and values to add to
* the requests.
* @param {string=} opt_oldSessionId Session ID from a previous session.
* @param {number=} opt_oldArrayId The last array ID from a previous session.
*/
goog.net.BrowserChannel.prototype.connect = function(
testPath, channelPath, opt_extraParams, opt_oldSessionId, opt_oldArrayId) {
'use strict';
this.channelDebug_.debug('connect()');
goog.net.browserchannelinternal.stats.notifyStatEvent(
goog.net.browserchannelinternal.stats.Stat.CONNECT_ATTEMPT);
this.path_ = channelPath;
this.extraParams_ = opt_extraParams || {};
// Attach parameters about the previous session if reconnecting.
if (opt_oldSessionId && opt_oldArrayId !== undefined) {
this.extraParams_['OSID'] = opt_oldSessionId;
this.extraParams_['OAID'] = opt_oldArrayId;
}
if (this.asyncTest_) {
goog.net.browserchannelinternal.hooks.setTimeout(
goog.bind(this.connectTest_, this, testPath), 100);
this.connectChannel_();
} else {
this.connectTest_(testPath);
}
};
/**
* Disconnects and closes the channel.
*/
goog.net.BrowserChannel.prototype.disconnect = function() {
'use strict';
this.channelDebug_.debug('disconnect()');
this.cancelRequests_();
if (this.state_ == goog.net.BrowserChannel.State.OPENED) {
const rid = this.nextRid_++;
const uri = this.forwardChannelUri_.clone();
uri.setParameterValue('SID', this.sid_);
uri.setParameterValue('RID', rid);
uri.setParameterValue('TYPE', 'terminate');
// Add the reconnect parameters.
this.addAdditionalParams_(uri);
const request = goog.net.ChannelRequest.createChannelRequest(
this, this.channelDebug_, this.sid_, rid);
request.sendUsingImgTag(uri);
}
this.onClose_();
};
/**
* Returns the session id of the channel. Only available after the
* channel has been opened.
* @return {string} Session ID.
*/
goog.net.BrowserChannel.prototype.getSessionId = function() {
'use strict';
return this.sid_;
};
/**
* Starts the test channel to determine network conditions.
*
* @param {string} testPath The relative PATH for the test connection.
* @private
*/
goog.net.BrowserChannel.prototype.connectTest_ = function(testPath) {
'use strict';
this.channelDebug_.debug('connectTest_()');
if (!this.okToMakeRequest_()) {
return; // channel is cancelled
}
this.connectionTest_ =
new goog.net.BrowserTestChannel(this, this.channelDebug_);
this.connectionTest_.setExtraHeaders(this.extraHeaders_);
this.connectionTest_.setParser(this.parser_);
this.connectionTest_.connect(testPath);
};
/**
* Starts the regular channel which is run after the test channel is complete.
* @private
*/
goog.net.BrowserChannel.prototype.connectChannel_ = function() {
'use strict';
this.channelDebug_.debug('connectChannel_()');
this.ensureInState_(
goog.net.BrowserChannel.State.INIT, goog.net.BrowserChannel.State.CLOSED);
this.forwardChannelUri_ =
this.getForwardChannelUri(/** @type {string} */ (this.path_));
this.ensureForwardChannel_();
};
/**
* Cancels all outstanding requests.
* @private
*/
goog.net.BrowserChannel.prototype.cancelRequests_ = function() {
'use strict';
if (this.connectionTest_) {
this.connectionTest_.abort();
this.connectionTest_ = null;
}
if (this.backChannelRequest_) {
this.backChannelRequest_.cancel();
this.backChannelRequest_ = null;
}
if (this.backChannelTimerId_) {
goog.global.clearTimeout(this.backChannelTimerId_);
this.backChannelTimerId_ = null;
}
this.clearDeadBackchannelTimer_();
if (this.forwardChannelRequest_) {
this.forwardChannelRequest_.cancel();
this.forwardChannelRequest_ = null;
}
if (this.forwardChannelTimerId_) {
goog.global.clearTimeout(this.forwardChannelTimerId_);
this.forwardChannelTimerId_ = null;
}
};
/**
* Returns the extra HTTP headers to add to all the requests sent to the server.
*
* @return {Object} The HTTP headers, or null.
*/
goog.net.BrowserChannel.prototype.getExtraHeaders = function() {
'use strict';
return this.extraHeaders_;
};
/**
* Sets extra HTTP headers to add to all the requests sent to the server.
*
* @param {Object} extraHeaders The HTTP headers, or null.
*/
goog.net.BrowserChannel.prototype.setExtraHeaders = function(extraHeaders) {
'use strict';
this.extraHeaders_ = extraHeaders;
};
/**
* Sets the throttle for handling onreadystatechange events for the request.
*
* @param {number} throttle The throttle in ms. A value of zero indicates
* no throttle.
*/
goog.net.BrowserChannel.prototype.setReadyStateChangeThrottle = function(
throttle) {
'use strict';
this.readyStateChangeThrottleMs_ = throttle;
};
/**
* Sets whether cross origin requests are supported for the browser channel.
*
* Setting this allows the creation of requests to secondary domains and
* sends XHRs with the CORS withCredentials bit set to true.
*
* In order for cross-origin requests to work, the server will also need to set
* CORS response headers as per:
* https://developer.mozilla.org/en-US/docs/HTTP_access_control
*
* See {@link goog.net.XhrIo#setWithCredentials}.
* @param {boolean} supportCrossDomain Whether cross domain XHRs are supported.
*/
goog.net.BrowserChannel.prototype.setSupportsCrossDomainXhrs = function(
supportCrossDomain) {
'use strict';
this.supportsCrossDomainXhrs_ = supportCrossDomain;
};
/**
* Returns the handler used for channel callback events.
*
* @return {goog.net.BrowserChannel.Handler} The handler.
*/
goog.net.BrowserChannel.prototype.getHandler = function() {
'use strict';
return this.handler_;
};
/**
* Sets the handler used for channel callback events.
* @param {goog.net.BrowserChannel.Handler} handler The handler to set.
*/
goog.net.BrowserChannel.prototype.setHandler = function(handler) {
'use strict';
this.handler_ = handler;
};
/**
* Returns whether the channel allows the use of a subdomain. There may be
* cases where this isn't allowed.
* @return {boolean} Whether a host prefix is allowed.
*/
goog.net.BrowserChannel.prototype.getAllowHostPrefix = function() {
'use strict';
return this.allowHostPrefix_;
};
/**
* Sets whether the channel allows the use of a subdomain. There may be cases
* where this isn't allowed, for example, logging in with troutboard where
* using a subdomain causes Apache to force the user to authenticate twice.
* @param {boolean} allowHostPrefix Whether a host prefix is allowed.
*/
goog.net.BrowserChannel.prototype.setAllowHostPrefix = function(
allowHostPrefix) {
'use strict';
this.allowHostPrefix_ = allowHostPrefix;
};
/**
* Returns whether the channel is buffered or not. This state is valid for
* querying only after the test connection has completed. This may be
* queried in the goog.net.BrowserChannel.okToMakeRequest() callback.
* A channel may be buffered if the test connection determines that
* a chunked response could not be sent down within a suitable time.
* @return {boolean} Whether the channel is buffered.
*/
goog.net.BrowserChannel.prototype.isBuffered = function() {
'use strict';
return !this.useChunked_;
};
/**
* Returns whether chunked mode is allowed. In certain debugging situations,
* it's useful for the application to have a way to disable chunked mode for a
* user.
* @return {boolean} Whether chunked mode is allowed.
*/
goog.net.BrowserChannel.prototype.getAllowChunkedMode = function() {
'use strict';
return this.allowChunkedMode_;
};
/**
* Sets whether chunked mode is allowed. In certain debugging situations, it's
* useful for the application to have a way to disable chunked mode for a user.
* @param {boolean} allowChunkedMode Whether chunked mode is allowed.
*/
goog.net.BrowserChannel.prototype.setAllowChunkedMode = function(
allowChunkedMode) {
'use strict';
this.allowChunkedMode_ = allowChunkedMode;
};
/**
* Sends a request to the server. The format of the request is a Map data
* structure of key/value pairs. These maps are then encoded in a format
* suitable for the wire and then reconstituted as a Map data structure that
* the server can process.
* @param {Object} map The map to send.
* @param {?Object=} opt_context The context associated with the map.
*/
goog.net.BrowserChannel.prototype.sendMap = function(map, opt_context) {
'use strict';
if (this.state_ == goog.net.BrowserChannel.State.CLOSED) {
throw new Error('Invalid operation: sending map when state is closed');
}
// We can only send 1000 maps per POST, but typically we should never have
// that much to send, so warn if we exceed that (we still send all the maps).
if (this.outgoingMaps_.length ==
goog.net.BrowserChannel.MAX_MAPS_PER_REQUEST_) {
// severe() is temporary so that we get these uploaded and can figure out
// what's causing them. Afterwards can change to warning().
this.channelDebug_.severe(
'Already have ' + goog.net.BrowserChannel.MAX_MAPS_PER_REQUEST_ +
' queued maps upon queueing ' + this.parser_.stringify(map));
}
this.outgoingMaps_.push(new goog.net.BrowserChannel.QueuedMap(
this.nextMapId_++, map, opt_context));
if (this.state_ == goog.net.BrowserChannel.State.OPENING ||
this.state_ == goog.net.BrowserChannel.State.OPENED) {
this.ensureForwardChannel_();
}
};
/**
* When set to true, this changes the behavior of the forward channel so it
* will not retry requests; it will fail after one network failure, and if
* there was already one network failure, the request will fail immediately.
* @param {boolean} failFast Whether or not to fail fast.
*/
goog.net.BrowserChannel.prototype.setFailFast = function(failFast) {
'use strict';
this.failFast_ = failFast;
this.channelDebug_.info('setFailFast: ' + failFast);
if ((this.forwardChannelRequest_ || this.forwardChannelTimerId_) &&
this.forwardChannelRetryCount_ > this.getForwardChannelMaxRetries()) {
this.channelDebug_.info(
'Retry count ' + this.forwardChannelRetryCount_ + ' > new maxRetries ' +
this.getForwardChannelMaxRetries() + '. Fail immediately!');
if (this.forwardChannelRequest_) {
this.forwardChannelRequest_.cancel();
// Go through the standard onRequestComplete logic to expose the max-retry
// failure in the standard way.
this.onRequestComplete(this.forwardChannelRequest_);
} else { // i.e., this.forwardChannelTimerId_
goog.global.clearTimeout(this.forwardChannelTimerId_);
this.forwardChannelTimerId_ = null;
// The error code from the last failed request is gone, so just use a
// generic one.
this.signalError_(goog.net.BrowserChannel.Error.REQUEST_FAILED);
}
}
};
/**
* @return {number} The max number of forward-channel retries, which will be 0
* in fail-fast mode.
*/
goog.net.BrowserChannel.prototype.getForwardChannelMaxRetries = function() {
'use strict';
return this.failFast_ ? 0 : this.forwardChannelMaxRetries_;
};
/**
* Sets the maximum number of attempts to connect to the server for forward
* channel requests.
* @param {number} retries The maximum number of attempts.
*/
goog.net.BrowserChannel.prototype.setForwardChannelMaxRetries = function(
retries) {
'use strict';
this.forwardChannelMaxRetries_ = retries;
};
/**
* Sets the timeout for a forward channel request.
* @param {number} timeoutMs The timeout in milliseconds.
*/
goog.net.BrowserChannel.prototype.setForwardChannelRequestTimeout = function(
timeoutMs) {
'use strict';
this.forwardChannelRequestTimeoutMs_ = timeoutMs;
};
/**
* @return {number} The max number of back-channel retries, which is a constant.
*/
goog.net.BrowserChannel.prototype.getBackChannelMaxRetries = function() {
'use strict';
// Back-channel retries is a constant.
return goog.net.BrowserChannel.BACK_CHANNEL_MAX_RETRIES;
};
/**
* Returns whether the channel is closed
* @return {boolean} true if the channel is closed.
*/
goog.net.BrowserChannel.prototype.isClosed = function() {
'use strict';
return this.state_ == goog.net.BrowserChannel.State.CLOSED;
};
/**
* Returns the browser channel state.
* @return {goog.net.BrowserChannel.State} The current state of the browser
* channel.
*/
goog.net.BrowserChannel.prototype.getState = function() {
'use strict';
return this.state_;
};
/**
* Return the last status code received for a request.
* @return {number} The last status code received for a request.
*/
goog.net.BrowserChannel.prototype.getLastStatusCode = function() {
'use strict';
return this.lastStatusCode_;
};
/**
* @return {number} The last array id received.
*/
goog.net.BrowserChannel.prototype.getLastArrayId = function() {
'use strict';
return this.lastArrayId_;
};
/**
* Returns whether there are outstanding requests servicing the channel.
* @return {boolean} true if there are outstanding requests.
*/
goog.net.BrowserChannel.prototype.hasOutstandingRequests = function() {
'use strict';
return this.outstandingRequests_() != 0;
};
/**
* Sets a new parser for the response payload.
* @param {!goog.string.Parser} parser Parser.
*/
goog.net.BrowserChannel.prototype.setParser = function(parser) {
'use strict';
this.parser_ = parser;
};
/**
* Returns the number of outstanding requests.
* @return {number} The number of outstanding requests to the server.
* @private
*/
goog.net.BrowserChannel.prototype.outstandingRequests_ = function() {
'use strict';
let count = 0;
if (this.backChannelRequest_) {
count++;
}
if (this.forwardChannelRequest_) {
count++;
}
return count;
};
/**
* Ensures that a forward channel request is scheduled.
* @private
*/
goog.net.BrowserChannel.prototype.ensureForwardChannel_ = function() {
'use strict';
if (this.forwardChannelRequest_) {
// connection in process - no need to start a new request
return;
}
if (this.forwardChannelTimerId_) {
// no need to start a new request - one is already scheduled
return;
}
this.forwardChannelTimerId_ =
goog.net.browserchannelinternal.hooks.setTimeout(
goog.bind(this.onStartForwardChannelTimer_, this), 0);
this.forwardChannelRetryCount_ = 0;
};
/**
* Schedules a forward-channel retry for the specified request, unless the max
* retries has been reached.
* @param {goog.net.ChannelRequest} request The failed request to retry.
* @return {boolean} true iff a retry was scheduled.
* @private
*/
goog.net.BrowserChannel.prototype.maybeRetryForwardChannel_ = function(
request) {
'use strict';
if (this.forwardChannelRequest_ || this.forwardChannelTimerId_) {
// Should be impossible to be called in this state.
this.channelDebug_.severe('Request already in progress');
return false;
}
if (this.state_ == goog.net.BrowserChannel.State.INIT || // no retry open_()
(this.forwardChannelRetryCount_ >= this.getForwardChannelMaxRetries())) {
return false;
}
this.channelDebug_.debug('Going to retry POST');
this.forwardChannelTimerId_ =
goog.net.browserchannelinternal.hooks.setTimeout(
goog.bind(this.onStartForwardChannelTimer_, this, request),
this.getRetryTime_(this.forwardChannelRetryCount_));
this.forwardChannelRetryCount_++;
return true;
};
/**
* Timer callback for ensureForwardChannel
* @param {goog.net.ChannelRequest=} opt_retryRequest A failed request to retry.
* @private
*/
goog.net.BrowserChannel.prototype.onStartForwardChannelTimer_ = function(
opt_retryRequest) {
'use strict';
this.forwardChannelTimerId_ = null;
this.startForwardChannel_(opt_retryRequest);
};
/**
* Begins a new forward channel operation to the server.
* @param {goog.net.ChannelRequest=} opt_retryRequest A failed request to retry.
* @private
*/
goog.net.BrowserChannel.prototype.startForwardChannel_ = function(
opt_retryRequest) {
'use strict';
this.channelDebug_.debug('startForwardChannel_');
if (!this.okToMakeRequest_()) {
return; // channel is cancelled
} else if (this.state_ == goog.net.BrowserChannel.State.INIT) {
if (opt_retryRequest) {
this.channelDebug_.severe('Not supposed to retry the open');
return;
}
this.open_();
this.state_ = goog.net.BrowserChannel.State.OPENING;
} else if (this.state_ == goog.net.BrowserChannel.State.OPENED) {
if (opt_retryRequest) {
this.makeForwardChannelRequest_(opt_retryRequest);
return;
}
if (this.outgoingMaps_.length == 0) {
this.channelDebug_.debug(
'startForwardChannel_ returned: ' +
'nothing to send');
// no need to start a new forward channel request
return;
}
if (this.forwardChannelRequest_) {
// Should be impossible to be called in this state.
this.channelDebug_.severe(
'startForwardChannel_ returned: ' +
'connection already in progress');
return;
}
this.makeForwardChannelRequest_();
this.channelDebug_.debug('startForwardChannel_ finished, sent request');
}
};
/**
* Establishes a new channel session with the server.
* @private
*/
goog.net.BrowserChannel.prototype.open_ = function() {
'use strict';
this.channelDebug_.debug('open_()');
this.nextRid_ = Math.floor(Math.random() * 100000);
const rid = this.nextRid_++;
const request = goog.net.ChannelRequest.createChannelRequest(
this, this.channelDebug_, '', rid);
request.setExtraHeaders(this.extraHeaders_);
const requestText = this.dequeueOutgoingMaps_();
const uri = this.forwardChannelUri_.clone();
uri.setParameterValue('RID', rid);
if (this.clientVersion_) {
uri.setParameterValue('CVER', this.clientVersion_);
}
// Add the reconnect parameters.
this.addAdditionalParams_(uri);
request.xmlHttpPost(uri, requestText, true);
this.forwardChannelRequest_ = request;
};
/**
* Makes a forward channel request using XMLHTTP.
* @param {goog.net.ChannelRequest=} opt_retryRequest A failed request to retry.
* @private
*/
goog.net.BrowserChannel.prototype.makeForwardChannelRequest_ = function(
opt_retryRequest) {
'use strict';
let rid;
let requestText;
if (opt_retryRequest) {
if (this.channelVersion_ > 6) {
// In version 7 and up we can tack on new arrays to a retry.
this.requeuePendingMaps_();
rid = this.nextRid_ - 1; // Must use last RID
requestText = this.dequeueOutgoingMaps_();
} else {
// TODO(user): Remove this code and the opt_retryRequest passing
// once server-side support for ver 7 is ubiquitous.
rid = opt_retryRequest.getRequestId();
requestText = /** @type {string} */ (opt_retryRequest.getPostData());
}
} else {
rid = this.nextRid_++;
requestText = this.dequeueOutgoingMaps_();
}
const uri = this.forwardChannelUri_.clone();
uri.setParameterValue('SID', this.sid_);
uri.setParameterValue('RID', rid);
uri.setParameterValue('AID', this.lastArrayId_);
// Add the additional reconnect parameters.
this.addAdditionalParams_(uri);
const request = goog.net.ChannelRequest.createChannelRequest(
this, this.channelDebug_, this.sid_, rid,
this.forwardChannelRetryCount_ + 1);
request.setExtraHeaders(this.extraHeaders_);
// randomize from 50%-100% of the forward channel timeout to avoid
// a big hit if servers happen to die at once.
request.setTimeout(
Math.round(this.forwardChannelRequestTimeoutMs_ * 0.50) +
Math.round(this.forwardChannelRequestTimeoutMs_ * 0.50 * Math.random()));
this.forwardChannelRequest_ = request;
request.xmlHttpPost(uri, requestText, true);
};
/**
* Adds the additional parameters from the handler to the given URI.
* @param {goog.Uri} uri The URI to add the parameters to.
* @private
*/
goog.net.BrowserChannel.prototype.addAdditionalParams_ = function(uri) {
'use strict';
// Add the additional reconnect parameters as needed.
if (this.handler_) {
const params = this.handler_.getAdditionalParams(this);
if (params) {
goog.object.forEach(params, function(value, key) {
'use strict';
uri.setParameterValue(key, value);
});
}
}
};
/**
* Returns the request text from the outgoing maps and resets it.
* @return {string} The encoded request text created from all the currently
* queued outgoing maps.
* @private
*/
goog.net.BrowserChannel.prototype.dequeueOutgoingMaps_ = function() {
'use strict';
const count = Math.min(
this.outgoingMaps_.length, goog.net.BrowserChannel.MAX_MAPS_PER_REQUEST_);
const sb = ['count=' + count];
let offset;
if (this.channelVersion_ > 6 && count > 0) {
// To save a bit of bandwidth, specify the base mapId and the rest as
// offsets from it.
offset = this.outgoingMaps_[0].mapId;
sb.push('ofs=' + offset);
} else {
offset = 0;
}
for (let i = 0; i < count; i++) {
let mapId = this.outgoingMaps_[i].mapId;
const map = this.outgoingMaps_[i].map;
if (this.channelVersion_ <= 6) {
// Map IDs were not used in ver 6 and before, just indexes in the request.
mapId = i;
} else {
mapId -= offset;
}
try {
goog.object.forEach(map, function(value, key, coll) {
'use strict';
sb.push('req' + mapId + '_' + key + '=' + encodeURIComponent(value));
});
} catch (ex) {
// We send a map here because lots of the retry logic relies on map IDs,
// so we have to send something.
sb.push(
'req' + mapId + '_' +
'type' +
'=' + encodeURIComponent('_badmap'));
if (this.handler_) {
this.handler_.badMapError(this, map);
}
}
}
this.pendingMaps_ =
this.pendingMaps_.concat(this.outgoingMaps_.splice(0, count));
return sb.join('&');
};
/**
* Requeues unacknowledged sent arrays for retransmission in the next forward
* channel request.
* @private
*/
goog.net.BrowserChannel.prototype.requeuePendingMaps_ = function() {
'use strict';
this.outgoingMaps_ = this.pendingMaps_.concat(this.outgoingMaps_);
this.pendingMaps_.length = 0;
};
/**
* Ensures there is a backchannel request for receiving data from the server.
* @private
*/
goog.net.BrowserChannel.prototype.ensureBackChannel_ = function() {
'use strict';
if (this.backChannelRequest_) {
// already have one
return;
}
if (this.backChannelTimerId_) {
// no need to start a new request - one is already scheduled
return;
}
this.backChannelAttemptId_ = 1;
this.backChannelTimerId_ = goog.net.browserchannelinternal.hooks.setTimeout(
goog.bind(this.onStartBackChannelTimer_, this), 0);
this.backChannelRetryCount_ = 0;
};
/**
* Schedules a back-channel retry, unless the max retries has been reached.
* @return {boolean} true iff a retry was scheduled.
* @private
*/
goog.net.BrowserChannel.prototype.maybeRetryBackChannel_ = function() {
'use strict';
if (this.backChannelRequest_ || this.backChannelTimerId_) {
// Should be impossible to be called in this state.
this.channelDebug_.severe('Request already in progress');
return false;
}
if (this.backChannelRetryCount_ >= this.getBackChannelMaxRetries()) {
return false;
}
this.channelDebug_.debug('Going to retry GET');
this.backChannelAttemptId_++;
this.backChannelTimerId_ = goog.net.browserchannelinternal.hooks.setTimeout(
goog.bind(this.onStartBackChannelTimer_, this),
this.getRetryTime_(this.backChannelRetryCount_));
this.backChannelRetryCount_++;
return true;
};
/**
* Timer callback for ensureBackChannel_.
* @private
*/
goog.net.BrowserChannel.prototype.onStartBackChannelTimer_ = function() {
'use strict';
this.backChannelTimerId_ = null;
this.startBackChannel_();
};
/**
* Begins a new back channel operation to the server.
* @private
*/
goog.net.BrowserChannel.prototype.startBackChannel_ = function() {
'use strict';
if (!this.okToMakeRequest_()) {
// channel is cancelled
return;
}
this.channelDebug_.debug('Creating new HttpRequest');
this.backChannelRequest_ = goog.net.ChannelRequest.createChannelRequest(
this, this.channelDebug_, this.sid_, 'rpc', this.backChannelAttemptId_);
this.backChannelRequest_.setExtraHeaders(this.extraHeaders_);
this.backChannelRequest_.setReadyStateChangeThrottle(
this.readyStateChangeThrottleMs_);
const uri = this.backChannelUri_.clone();
uri.setParameterValue('RID', 'rpc');
uri.setParameterValue('SID', this.sid_);
uri.setParameterValue('CI', this.useChunked_ ? '0' : '1');
uri.setParameterValue('AID', this.lastArrayId_);
// Add the reconnect parameters.
this.addAdditionalParams_(uri);
if (!goog.net.ChannelRequest.supportsXhrStreaming()) {
uri.setParameterValue('TYPE', 'html');
this.backChannelRequest_.tridentGet(uri, Boolean(this.hostPrefix_));
} else {
uri.setParameterValue('TYPE', 'xmlhttp');
this.backChannelRequest_.xmlHttpGet(
uri, true /* decodeChunks */, this.hostPrefix_,
false /* opt_noClose */);
}
this.channelDebug_.debug('New Request created');
};
/**
* Gives the handler a chance to return an error code and stop channel
* execution. A handler might want to do this to check that the user is still
* logged in, for example.
* @private
* @return {boolean} If it's OK to make a request.
*/
goog.net.BrowserChannel.prototype.okToMakeRequest_ = function() {
'use strict';
if (this.handler_) {
const result = this.handler_.okToMakeRequest(this);
if (result != goog.net.BrowserChannel.Error.OK) {
this.channelDebug_.debug(
'Handler returned error code from ' +
'okToMakeRequest');
this.signalError_(result);
return false;
}
}
return true;
};
/**
* Callback from BrowserTestChannel for when the channel is finished.
* @param {goog.net.BrowserTestChannel} testChannel The BrowserTestChannel.
* @param {boolean} useChunked Whether we can chunk responses.
*/
goog.net.BrowserChannel.prototype.testConnectionFinished = function(
testChannel, useChunked) {
'use strict';
this.channelDebug_.debug('Test Connection Finished');
this.useChunked_ = this.allowChunkedMode_ && useChunked;
this.lastStatusCode_ = testChannel.getLastStatusCode();
// When using asynchronous test, the channel is already open by connect().
if (!this.asyncTest_) {
this.connectChannel_();
}
};
/**
* Callback from BrowserTestChannel for when the channel has an error.
* @param {goog.net.BrowserTestChannel} testChannel The BrowserTestChannel.
* @param {goog.net.ChannelRequest.Error} errorCode The error code of the
failure.
*/
goog.net.BrowserChannel.prototype.testConnectionFailure = function(
testChannel, errorCode) {
'use strict';
this.channelDebug_.debug('Test Connection Failed');
this.lastStatusCode_ = testChannel.getLastStatusCode();
this.signalError_(goog.net.BrowserChannel.Error.REQUEST_FAILED);
};
/**
* Callback from BrowserTestChannel for when the channel is blocked.
* @param {goog.net.BrowserTestChannel} testChannel The BrowserTestChannel.
*/
goog.net.BrowserChannel.prototype.testConnectionBlocked = function(
testChannel) {
'use strict';
this.channelDebug_.debug('Test Connection Blocked');
this.lastStatusCode_ = this.connectionTest_.getLastStatusCode();
this.signalError_(goog.net.BrowserChannel.Error.BLOCKED);
};
/**
* Callback from ChannelRequest for when new data is received
* @param {goog.net.ChannelRequest} request The request object.
* @param {string} responseText The text of the response.
*/
goog.net.BrowserChannel.prototype.onRequestData = function(
request, responseText) {
'use strict';
if (this.state_ == goog.net.BrowserChannel.State.CLOSED ||
(this.backChannelRequest_ != request &&
this.forwardChannelRequest_ != request)) {
// either CLOSED or a request we don't know about (perhaps an old request)
return;
}
this.lastStatusCode_ = request.getLastStatusCode();
if (this.forwardChannelRequest_ == request &&
this.state_ == goog.net.BrowserChannel.State.OPENED) {
if (this.channelVersion_ > 7) {
let response;
try {
response = this.parser_.parse(responseText);
} catch (ex) {
response = null;
}
if (Array.isArray(response) && response.length == 3) {
this.handlePostResponse_(response);
} else {
this.channelDebug_.debug('Bad POST response data returned');
this.signalError_(goog.net.BrowserChannel.Error.BAD_RESPONSE);
}
} else if (responseText != goog.net.ChannelDebug.MAGIC_RESPONSE_COOKIE) {
this.channelDebug_.debug(
'Bad data returned - missing/invald ' +
'magic cookie');
this.signalError_(goog.net.BrowserChannel.Error.BAD_RESPONSE);
}
} else {
if (this.backChannelRequest_ == request) {
this.clearDeadBackchannelTimer_();
}
if (!goog.string.isEmptyOrWhitespace(responseText)) {
const response = this.parser_.parse(responseText);
goog.asserts.assert(Array.isArray(response));
this.onInput_(/** @type {!Array<?>} */ (response));
}
}
};
/**
* Handles a POST response from the server.
* @param {Array<number>} responseValues The key value pairs in the POST
* response.
* @private
*/
goog.net.BrowserChannel.prototype.handlePostResponse_ = function(
responseValues) {
'use strict';
// The first response value is set to 0 if server is missing backchannel.
if (responseValues[0] == 0) {
this.handleBackchannelMissing_();
return;
}
this.lastPostResponseArrayId_ = responseValues[1];
const outstandingArrays = this.lastPostResponseArrayId_ - this.lastArrayId_;
if (0 < outstandingArrays) {
const numOutstandingBackchannelBytes = responseValues[2];
this.channelDebug_.debug(
numOutstandingBackchannelBytes + ' bytes (in ' + outstandingArrays +
' arrays) are outstanding on the BackChannel');
if (!this.shouldRetryBackChannel_(numOutstandingBackchannelBytes)) {
return;
}
if (!this.deadBackChannelTimerId_) {
// We expect to receive data within 2 RTTs or we retry the backchannel.
this.deadBackChannelTimerId_ =
goog.net.browserchannelinternal.hooks.setTimeout(
goog.bind(this.onBackChannelDead_, this),
2 * goog.net.BrowserChannel.RTT_ESTIMATE);
}
}
};
/**
* Handles a POST response from the server telling us that it has detected that
* we have no hanging GET connection.
* @private
*/
goog.net.BrowserChannel.prototype.handleBackchannelMissing_ = function() {
'use strict';
// As long as the back channel was started before the POST was sent,
// we should retry the backchannel. We give a slight buffer of RTT_ESTIMATE
// so as not to excessively retry the backchannel
this.channelDebug_.debug('Server claims our backchannel is missing.');
if (this.backChannelTimerId_) {
this.channelDebug_.debug('But we are currently starting the request.');
return;
} else if (!this.backChannelRequest_) {
this.channelDebug_.warning('We do not have a BackChannel established');
} else if (
this.backChannelRequest_.getRequestStartTime() +
goog.net.BrowserChannel.RTT_ESTIMATE <
this.forwardChannelRequest_.getRequestStartTime()) {
this.clearDeadBackchannelTimer_();
this.backChannelRequest_.cancel();
this.backChannelRequest_ = null;
} else {
return;
}
this.maybeRetryBackChannel_();
goog.net.browserchannelinternal.stats.notifyStatEvent(
goog.net.browserchannelinternal.stats.Stat.BACKCHANNEL_MISSING);
};
/**
* Determines whether we should start the process of retrying a possibly
* dead backchannel.
* @param {number} outstandingBytes The number of bytes for which the server has
* not yet received acknowledgement.
* @return {boolean} Whether to start the backchannel retry timer.
* @private
*/
goog.net.BrowserChannel.prototype.shouldRetryBackChannel_ = function(
outstandingBytes) {
'use strict';
// Not too many outstanding bytes, not buffered and not after a retry.
return outstandingBytes <
goog.net.BrowserChannel.OUTSTANDING_DATA_BACKCHANNEL_RETRY_CUTOFF &&
!this.isBuffered() && this.backChannelRetryCount_ == 0;
};
/**
* Decides which host prefix should be used, if any. If there is a handler,
* allows the handler to validate a host prefix provided by the server, and
* optionally override it.
* @param {?string} serverHostPrefix The host prefix provided by the server.
* @return {?string} The host prefix to actually use, if any. Will return null
* if the use of host prefixes was disabled via setAllowHostPrefix().
*/
goog.net.BrowserChannel.prototype.correctHostPrefix = function(
serverHostPrefix) {
'use strict';
if (this.allowHostPrefix_) {
if (this.handler_) {
return this.handler_.correctHostPrefix(serverHostPrefix);
}
return serverHostPrefix;
}
return null;
};
/**
* Handles the timer that indicates that our backchannel is no longer able to
* successfully receive data from the server.
* @private
*/
goog.net.BrowserChannel.prototype.onBackChannelDead_ = function() {
'use strict';
if (this.deadBackChannelTimerId_ != null) {
this.deadBackChannelTimerId_ = null;
this.backChannelRequest_.cancel();
this.backChannelRequest_ = null;
this.maybeRetryBackChannel_();
goog.net.browserchannelinternal.stats.notifyStatEvent(
goog.net.browserchannelinternal.stats.Stat.BACKCHANNEL_DEAD);
}
};
/**
* Clears the timer that indicates that our backchannel is no longer able to
* successfully receive data from the server.
* @private
*/
goog.net.BrowserChannel.prototype.clearDeadBackchannelTimer_ = function() {
'use strict';
if (this.deadBackChannelTimerId_ != null) {
goog.global.clearTimeout(this.deadBackChannelTimerId_);
this.deadBackChannelTimerId_ = null;
}
};
/**
* Returns whether or not the given error/status combination is fatal or not.
* On fatal errors we immediately close the session rather than retrying the
* failed request.
* @param {goog.net.ChannelRequest.Error?} error The error code for the failed
* request.
* @param {number} statusCode The last HTTP status code.
* @return {boolean} Whether or not the error is fatal.
* @private
*/
goog.net.BrowserChannel.isFatalError_ = function(error, statusCode) {
'use strict';
return error == goog.net.ChannelRequest.Error.UNKNOWN_SESSION_ID ||
error == goog.net.ChannelRequest.Error.ACTIVE_X_BLOCKED ||
(error == goog.net.ChannelRequest.Error.STATUS && statusCode > 0);
};
/**
* Callback from ChannelRequest that indicates a request has completed.
* @param {goog.net.ChannelRequest} request The request object.
*/
goog.net.BrowserChannel.prototype.onRequestComplete = function(request) {
'use strict';
this.channelDebug_.debug('Request complete');
let type;
if (this.backChannelRequest_ == request) {
this.clearDeadBackchannelTimer_();
this.backChannelRequest_ = null;
type = goog.net.BrowserChannel.ChannelType_.BACK_CHANNEL;
} else if (this.forwardChannelRequest_ == request) {
this.forwardChannelRequest_ = null;
type = goog.net.BrowserChannel.ChannelType_.FORWARD_CHANNEL;
} else {
// return if it was an old request from a previous session
return;
}
this.lastStatusCode_ = request.getLastStatusCode();
if (this.state_ == goog.net.BrowserChannel.State.CLOSED) {
return;
}
if (request.getSuccess()) {
// Yay!
if (type == goog.net.BrowserChannel.ChannelType_.FORWARD_CHANNEL) {
const size = request.getPostData() ? request.getPostData().length : 0;
goog.net.BrowserChannel.notifyTimingEvent(
size, Date.now() - request.getRequestStartTime(),
this.forwardChannelRetryCount_);
this.ensureForwardChannel_();
this.onSuccess_();
this.pendingMaps_.length = 0;
} else { // i.e., back-channel
this.ensureBackChannel_();
}
return;
}
// Else unsuccessful. Fall through.
const lastError = request.getLastError();
if (!goog.net.BrowserChannel.isFatalError_(lastError, this.lastStatusCode_)) {
// Maybe retry.
this.channelDebug_.debug(
'Maybe retrying, last error: ' +
goog.net.ChannelRequest.errorStringFromCode(
/** @type {goog.net.ChannelRequest.Error} */ (lastError),
this.lastStatusCode_));
if (type == goog.net.BrowserChannel.ChannelType_.FORWARD_CHANNEL) {
if (this.maybeRetryForwardChannel_(request)) {
return;
}
}
if (type == goog.net.BrowserChannel.ChannelType_.BACK_CHANNEL) {
if (this.maybeRetryBackChannel_()) {
return;
}
}
// Else exceeded max retries. Fall through.
this.channelDebug_.debug('Exceeded max number of retries');
} else {
// Else fatal error. Fall through and mark the pending maps as failed.
this.channelDebug_.debug('Not retrying due to error type');
}
// Can't save this session. :(
this.channelDebug_.debug('Error: HTTP request failed');
switch (lastError) {
case goog.net.ChannelRequest.Error.NO_DATA:
this.signalError_(goog.net.BrowserChannel.Error.NO_DATA);
break;
case goog.net.ChannelRequest.Error.BAD_DATA:
this.signalError_(goog.net.BrowserChannel.Error.BAD_DATA);
break;
case goog.net.ChannelRequest.Error.UNKNOWN_SESSION_ID:
this.signalError_(goog.net.BrowserChannel.Error.UNKNOWN_SESSION_ID);
break;
case goog.net.ChannelRequest.Error.ACTIVE_X_BLOCKED:
this.signalError_(goog.net.BrowserChannel.Error.ACTIVE_X_BLOCKED);
break;
default:
this.signalError_(goog.net.BrowserChannel.Error.REQUEST_FAILED);
break;
}
};
/**
* @param {number} retryCount Number of retries so far.
* @return {number} Time in ms before firing next retry request.
* @private
*/
goog.net.BrowserChannel.prototype.getRetryTime_ = function(retryCount) {
'use strict';
let retryTime = this.baseRetryDelayMs_ +
Math.floor(Math.random() * this.retryDelaySeedMs_);
if (!this.isActive()) {
this.channelDebug_.debug('Inactive channel');
retryTime =
retryTime * goog.net.BrowserChannel.INACTIVE_CHANNEL_RETRY_FACTOR;
}
// Backoff for subsequent retries
retryTime = retryTime * retryCount;
return retryTime;
};
/**
* @param {number} baseDelayMs The base part of the retry delay, in ms.
* @param {number} delaySeedMs A random delay between 0 and this is added to
* the base part.
*/
goog.net.BrowserChannel.prototype.setRetryDelay = function(
baseDelayMs, delaySeedMs) {
'use strict';
this.baseRetryDelayMs_ = baseDelayMs;
this.retryDelaySeedMs_ = delaySeedMs;
};
/**
* Processes the data returned by the server.
* @param {!Array<!Array<?>>} respArray The response array returned
* by the server.
* @private
*/
goog.net.BrowserChannel.prototype.onInput_ = function(respArray) {
'use strict';
const batch =
this.handler_ && this.handler_.channelHandleMultipleArrays ? [] : null;
for (let i = 0; i < respArray.length; i++) {
let nextArray = respArray[i];
this.lastArrayId_ = nextArray[0];
nextArray = nextArray[1];
if (this.state_ == goog.net.BrowserChannel.State.OPENING) {
if (nextArray[0] == 'c') {
this.sid_ = nextArray[1];
this.hostPrefix_ = this.correctHostPrefix(nextArray[2]);
const negotiatedVersion = nextArray[3];
if (negotiatedVersion != null) {
this.channelVersion_ = negotiatedVersion;
} else {
// Servers prior to version 7 did not send this, so assume version 6.
this.channelVersion_ = 6;
}
this.state_ = goog.net.BrowserChannel.State.OPENED;
if (this.handler_) {
this.handler_.channelOpened(this);
}
this.backChannelUri_ = this.getBackChannelUri(
this.hostPrefix_, /** @type {string} */ (this.path_));
// Open connection to receive data
this.ensureBackChannel_();
} else if (nextArray[0] == 'stop') {
this.signalError_(goog.net.BrowserChannel.Error.STOP);
}
} else if (this.state_ == goog.net.BrowserChannel.State.OPENED) {
if (nextArray[0] == 'stop') {
if (batch && !(batch.length === 0)) {
this.handler_.channelHandleMultipleArrays(this, batch);
batch.length = 0;
}
this.signalError_(goog.net.BrowserChannel.Error.STOP);
} else if (nextArray[0] == 'noop') {
// ignore - noop to keep connection happy
} else {
if (batch) {
batch.push(nextArray);
} else if (this.handler_) {
this.handler_.channelHandleArray(this, nextArray);
}
}
// We have received useful data on the back-channel, so clear its retry
// count. We do this because back-channels by design do not complete
// quickly, so on a flaky connection we could have many fail to complete
// fully but still deliver a lot of data before they fail. We don't want
// to count such failures towards the retry limit, because we don't want
// to give up on a session if we can still receive data.
this.backChannelRetryCount_ = 0;
}
}
if (batch && !(batch.length === 0)) {
this.handler_.channelHandleMultipleArrays(this, batch);
}
};
/**
* Helper to ensure the BrowserChannel is in the expected state.
* @param {...number} var_args The channel must be in one of the indicated
* states.
* @private
*/
goog.net.BrowserChannel.prototype.ensureInState_ = function(var_args) {
'use strict';
if (!goog.array.contains(arguments, this.state_)) {
throw new Error('Unexpected channel state: ' + this.state_);
}
};
/**
* Signals an error has occurred.
* @param {goog.net.BrowserChannel.Error} error The error code for the failure.
* @private
*/
goog.net.BrowserChannel.prototype.signalError_ = function(error) {
'use strict';
this.channelDebug_.info('Error code ' + error);
if (error == goog.net.BrowserChannel.Error.REQUEST_FAILED ||
error == goog.net.BrowserChannel.Error.BLOCKED) {
// Ping google to check if it's a server error or user's network error.
let imageUri = null;
if (this.handler_) {
imageUri = this.handler_.getNetworkTestImageUri(this);
}
goog.net.tmpnetwork.testGoogleCom(
goog.bind(this.testGoogleComCallback_, this), imageUri);
} else {
goog.net.browserchannelinternal.stats.notifyStatEvent(
goog.net.browserchannelinternal.stats.Stat.ERROR_OTHER);
}
this.onError_(error);
};
/**
* Callback for testGoogleCom during error handling.
* @param {boolean} networkUp Whether the network is up.
* @private
*/
goog.net.BrowserChannel.prototype.testGoogleComCallback_ = function(networkUp) {
'use strict';
if (networkUp) {
this.channelDebug_.info('Successfully pinged google.com');
goog.net.browserchannelinternal.stats.notifyStatEvent(
goog.net.browserchannelinternal.stats.Stat.ERROR_OTHER);
} else {
this.channelDebug_.info('Failed to ping google.com');
goog.net.browserchannelinternal.stats.notifyStatEvent(
goog.net.browserchannelinternal.stats.Stat.ERROR_NETWORK);
// We call onError_ here instead of signalError_ because the latter just
// calls notifyStatEvent, and we don't want to have another stat event.
this.onError_(goog.net.BrowserChannel.Error.NETWORK);
}
};
/**
* Called when messages have been successfully sent from the queue.
* @private
*/
goog.net.BrowserChannel.prototype.onSuccess_ = function() {
'use strict';
if (this.handler_) {
this.handler_.channelSuccess(this, this.pendingMaps_);
}
};
/**
* Called when we've determined the final error for a channel. It closes the
* notifiers the handler of the error and closes the channel.
* @param {goog.net.BrowserChannel.Error} error The error code for the failure.
* @private
*/
goog.net.BrowserChannel.prototype.onError_ = function(error) {
'use strict';
this.channelDebug_.debug('HttpChannel: error - ' + error);
this.state_ = goog.net.BrowserChannel.State.CLOSED;
if (this.handler_) {
this.handler_.channelError(this, error);
}
this.onClose_();
this.cancelRequests_();
};
/**
* Called when the channel has been closed. It notifiers the handler of the
* event, and reports any pending or undelivered maps.
* @private
*/
goog.net.BrowserChannel.prototype.onClose_ = function() {
'use strict';
this.state_ = goog.net.BrowserChannel.State.CLOSED;
this.lastStatusCode_ = -1;
if (this.handler_) {
if (this.pendingMaps_.length == 0 && this.outgoingMaps_.length == 0) {
this.handler_.channelClosed(this);
} else {
this.channelDebug_.debug(
'Number of undelivered maps' +
', pending: ' + this.pendingMaps_.length +
', outgoing: ' + this.outgoingMaps_.length);
const copyOfPendingMaps = goog.array.clone(this.pendingMaps_);
const copyOfUndeliveredMaps = goog.array.clone(this.outgoingMaps_);
this.pendingMaps_.length = 0;
this.outgoingMaps_.length = 0;
this.handler_.channelClosed(
this, copyOfPendingMaps, copyOfUndeliveredMaps);
}
}
};
/**
* Gets the Uri used for the connection that sends data to the server.
* @param {string} path The path on the host.
* @return {!goog.Uri} The forward channel URI.
*/
goog.net.BrowserChannel.prototype.getForwardChannelUri = function(path) {
'use strict';
const uri = this.createDataUri(null, path);
this.channelDebug_.debug('GetForwardChannelUri: ' + uri);
return uri;
};
/**
* Gets the results for the first browser channel test
* @return {Array<string>} The results.
*/
goog.net.BrowserChannel.prototype.getFirstTestResults = function() {
'use strict';
return this.firstTestResults_;
};
/**
* Gets the results for the second browser channel test
* @return {?boolean} The results. True -> buffered connection,
* False -> unbuffered, null -> unknown.
*/
goog.net.BrowserChannel.prototype.getSecondTestResults = function() {
'use strict';
return this.secondTestResults_;
};
/**
* Gets the Uri used for the connection that receives data from the server.
* @param {?string} hostPrefix The host prefix.
* @param {string} path The path on the host.
* @return {!goog.Uri} The back channel URI.
*/
goog.net.BrowserChannel.prototype.getBackChannelUri = function(
hostPrefix, path) {
'use strict';
const uri = this.createDataUri(
this.shouldUseSecondaryDomains() ? hostPrefix : null, path);
this.channelDebug_.debug('GetBackChannelUri: ' + uri);
return uri;
};
/**
* Creates a data Uri applying logic for secondary hostprefix, port
* overrides, and versioning.
* @param {?string} hostPrefix The host prefix.
* @param {string} path The path on the host (may be absolute or relative).
* @param {number=} opt_overridePort Optional override port.
* @return {!goog.Uri} The data URI.
*/
goog.net.BrowserChannel.prototype.createDataUri = function(
hostPrefix, path, opt_overridePort) {
'use strict';
let uri = goog.Uri.parse(path);
const uriAbsolute = (uri.getDomain() != '');
if (uriAbsolute) {
if (hostPrefix) {
uri.setDomain(hostPrefix + '.' + uri.getDomain());
}
uri.setPort(opt_overridePort || uri.getPort());
} else {
const locationPage = window.location;
let hostName;
if (hostPrefix) {
hostName = hostPrefix + '.' + locationPage.hostname;
} else {
hostName = locationPage.hostname;
}
const port = opt_overridePort || +locationPage.port;
uri = goog.Uri.create(locationPage.protocol, null, hostName, port, path);
}
if (this.extraParams_) {
goog.object.forEach(this.extraParams_, function(value, key) {
'use strict';
uri.setParameterValue(key, value);
});
}
// Add the protocol version to the URI.
uri.setParameterValue('VER', this.channelVersion_);
// Add the reconnect parameters.
this.addAdditionalParams_(uri);
return uri;
};
/**
* Called when BC needs to create an XhrIo object. Override in a subclass if
* you need to customize the behavior, for example to enable the creation of
* XHR's capable of calling a secondary domain. Will also allow calling
* a secondary domain if withCredentials (CORS) is enabled.
* @param {?string} hostPrefix The host prefix, if we need an XhrIo object
* capable of calling a secondary domain.
* @return {!goog.net.XhrIo} A new XhrIo object.
*/
goog.net.BrowserChannel.prototype.createXhrIo = function(hostPrefix) {
'use strict';
if (hostPrefix && !this.supportsCrossDomainXhrs_) {
throw new Error('Can\'t create secondary domain capable XhrIo object.');
}
const xhr = new goog.net.XhrIo();
xhr.setWithCredentials(this.supportsCrossDomainXhrs_);
return xhr;
};
/**
* Gets whether this channel is currently active. This is used to determine the
* length of time to wait before retrying. This call delegates to the handler.
* @return {boolean} Whether the channel is currently active.
*/
goog.net.BrowserChannel.prototype.isActive = function() {
'use strict';
return !!this.handler_ && this.handler_.isActive(this);
};
/**
* Notify the channel that a particular fine grained network event has occurred.
* Should be considered package-private.
* @param {goog.net.browserchannelinternal.ServerReachability} reachabilityType
* The reachability event type.
*/
goog.net.BrowserChannel.prototype.notifyServerReachabilityEvent = function(
reachabilityType) {
'use strict';
const target = goog.net.browserchannelinternal.stats.getStatEventTarget();
target.dispatchEvent(new goog.net.BrowserChannel.ServerReachabilityEvent(
target, reachabilityType));
};
/**
* Helper function to notify listeners about POST request performance.
*
* @param {number} size Number of characters in the POST data.
* @param {number} rtt The amount of time from POST start to response.
* @param {number} retries The number of times the POST had to be retried.
*/
goog.net.BrowserChannel.notifyTimingEvent = function(size, rtt, retries) {
'use strict';
const target = goog.net.browserchannelinternal.stats.getStatEventTarget();
target.dispatchEvent(
new goog.net.BrowserChannel.TimingEvent(target, size, rtt, retries));
};
/**
* Determines whether to use a secondary domain when the server gives us
* a host prefix. This allows us to work around browser per-domain
* connection limits.
*
* Currently, we use secondary domains when using Trident's ActiveXObject,
* because it supports cross-domain requests out of the box. Note that in IE10
* we no longer use ActiveX since it's not supported in Metro mode and IE10
* supports XHR streaming.
*
* If you need to use secondary domains on other browsers and IE10,
* you have two choices:
* 1) If you only care about browsers that support CORS
* (https://developer.mozilla.org/en-US/docs/HTTP_access_control), you
* can use {@link #setSupportsCrossDomainXhrs} and set the appropriate
* CORS response headers on the server.
* 2) Or, override this method in a subclass, and make sure that those
* browsers use some messaging mechanism that works cross-domain (e.g
* iframes and window.postMessage).
*
* @return {boolean} Whether to use secondary domains.
* @see http://code.google.com/p/closure-library/issues/detail?id=339
*/
goog.net.BrowserChannel.prototype.shouldUseSecondaryDomains = function() {
'use strict';
return this.supportsCrossDomainXhrs_ ||
!goog.net.ChannelRequest.supportsXhrStreaming();
};
/**
* A LogSaver that can be used to accumulate all the debug logs for
* BrowserChannels so they can be sent to the server when a problem is
* detected.
* @const
*/
goog.net.BrowserChannel.LogSaver = {};
/**
* Buffer for accumulating the debug log
* @type {goog.structs.CircularBuffer}
* @private
*/
goog.net.BrowserChannel.LogSaver.buffer_ =
new goog.structs.CircularBuffer(1000);
/**
* Whether we're currently accumulating the debug log.
* @type {boolean}
* @private
*/
goog.net.BrowserChannel.LogSaver.enabled_ = false;
/**
* Formatter for saving logs.
* @type {goog.debug.Formatter}
* @private
*/
goog.net.BrowserChannel.LogSaver.formatter_ = new goog.debug.TextFormatter();
/**
* Returns whether the LogSaver is enabled.
* @return {boolean} Whether saving is enabled or disabled.
*/
goog.net.BrowserChannel.LogSaver.isEnabled = function() {
'use strict';
return goog.net.BrowserChannel.LogSaver.enabled_;
};
/**
* Enables of disables the LogSaver.
* @param {boolean} enable Whether to enable or disable saving.
*/
goog.net.BrowserChannel.LogSaver.setEnabled = function(enable) {
'use strict';
if (enable == goog.net.BrowserChannel.LogSaver.enabled_) {
return;
}
const fn = goog.net.BrowserChannel.LogSaver.addLogRecord;
const logger = goog.log.getLogger('goog.net');
if (enable) {
goog.log.addHandler(logger, fn);
} else {
goog.log.removeHandler(logger, fn);
}
};
/**
* Adds a log record.
* @param {goog.log.LogRecord} logRecord the LogRecord.
*/
goog.net.BrowserChannel.LogSaver.addLogRecord = function(logRecord) {
'use strict';
goog.net.BrowserChannel.LogSaver.buffer_.add(
goog.net.BrowserChannel.LogSaver.formatter_.formatRecord(logRecord));
};
/**
* Returns the log as a single string.
* @return {string} The log as a single string.
*/
goog.net.BrowserChannel.LogSaver.getBuffer = function() {
'use strict';
return goog.net.BrowserChannel.LogSaver.buffer_.getValues().join('');
};
/**
* Clears the buffer
*/
goog.net.BrowserChannel.LogSaver.clearBuffer = function() {
'use strict';
goog.net.BrowserChannel.LogSaver.buffer_.clear();
};
/**
* Abstract base class for the browser channel handler
* @constructor
*/
goog.net.BrowserChannel.Handler = function() {};
/**
* Callback handler for when a batch of response arrays is received from the
* server.
* @type {?function(!goog.net.BrowserChannel, !Array<!Array<?>>)}
*/
goog.net.BrowserChannel.Handler.prototype.channelHandleMultipleArrays = null;
/**
* Whether it's okay to make a request to the server. A handler can return
* false if the channel should fail. For example, if the user has logged out,
* the handler may want all requests to fail immediately.
* @param {goog.net.BrowserChannel} browserChannel The browser channel.
* @return {goog.net.BrowserChannel.Error} An error code. The code should
* return goog.net.BrowserChannel.Error.OK to indicate it's okay. Any other
* error code will cause a failure.
*/
goog.net.BrowserChannel.Handler.prototype.okToMakeRequest = function(
browserChannel) {
'use strict';
return goog.net.BrowserChannel.Error.OK;
};
/**
* Indicates the BrowserChannel has successfully negotiated with the server
* and can now send and receive data.
* @param {goog.net.BrowserChannel} browserChannel The browser channel.
*/
goog.net.BrowserChannel.Handler.prototype.channelOpened = function(
browserChannel) {};
/**
* New input is available for the application to process.
*
* @param {goog.net.BrowserChannel} browserChannel The browser channel.
* @param {Array<?>} array The data array.
*/
goog.net.BrowserChannel.Handler.prototype.channelHandleArray = function(
browserChannel, array) {};
/**
* Indicates maps were successfully sent on the BrowserChannel.
*
* @param {goog.net.BrowserChannel} browserChannel The browser channel.
* @param {Array<goog.net.BrowserChannel.QueuedMap>} deliveredMaps The
* array of maps that have been delivered to the server. This is a direct
* reference to the internal BrowserChannel array, so a copy should be made
* if the caller desires a reference to the data.
*/
goog.net.BrowserChannel.Handler.prototype.channelSuccess = function(
browserChannel, deliveredMaps) {};
/**
* Indicates an error occurred on the BrowserChannel.
*
* @param {goog.net.BrowserChannel} browserChannel The browser channel.
* @param {goog.net.BrowserChannel.Error} error The error code.
*/
goog.net.BrowserChannel.Handler.prototype.channelError = function(
browserChannel, error) {};
/**
* Indicates the BrowserChannel is closed. Also notifies about which maps,
* if any, that may not have been delivered to the server.
* @param {goog.net.BrowserChannel} browserChannel The browser channel.
* @param {Array<goog.net.BrowserChannel.QueuedMap>=} opt_pendingMaps The
* array of pending maps, which may or may not have been delivered to the
* server.
* @param {Array<goog.net.BrowserChannel.QueuedMap>=} opt_undeliveredMaps
* The array of undelivered maps, which have definitely not been delivered
* to the server.
*/
goog.net.BrowserChannel.Handler.prototype.channelClosed = function(
browserChannel, opt_pendingMaps, opt_undeliveredMaps) {};
/**
* Gets any parameters that should be added at the time another connection is
* made to the server.
* @param {goog.net.BrowserChannel} browserChannel The browser channel.
* @return {!Object} Extra parameter keys and values to add to the
* requests.
*/
goog.net.BrowserChannel.Handler.prototype.getAdditionalParams = function(
browserChannel) {
'use strict';
return {};
};
/**
* Gets the URI of an image that can be used to test network connectivity.
* @param {goog.net.BrowserChannel} browserChannel The browser channel.
* @return {goog.Uri?} A custom URI to load for the network test.
*/
goog.net.BrowserChannel.Handler.prototype.getNetworkTestImageUri = function(
browserChannel) {
'use strict';
return null;
};
/**
* Gets whether this channel is currently active. This is used to determine the
* length of time to wait before retrying.
* @param {goog.net.BrowserChannel} browserChannel The browser channel.
* @return {boolean} Whether the channel is currently active.
*/
goog.net.BrowserChannel.Handler.prototype.isActive = function(browserChannel) {
'use strict';
return true;
};
/**
* Called by the channel if enumeration of the map throws an exception.
* @param {goog.net.BrowserChannel} browserChannel The browser channel.
* @param {Object} map The map that can't be enumerated.
*/
goog.net.BrowserChannel.Handler.prototype.badMapError = function(
browserChannel, map) {
'use strict';
return;
};
/**
* Allows the handler to override a host prefix provided by the server. Will
* be called whenever the channel has received such a prefix and is considering
* its use.
* @param {?string} serverHostPrefix The host prefix provided by the server.
* @return {?string} The host prefix the client should use.
*/
goog.net.BrowserChannel.Handler.prototype.correctHostPrefix = function(
serverHostPrefix) {
'use strict';
return serverHostPrefix;
};
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