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GUACAMOLE-250: Implement Guacamole.SessionRecording having basic play/pause support.

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Michael Jumper
2017-04-12 23:59:42 -07:00
parent e8f4cd5515
commit 052bb9b36b
1 changed files with 573 additions and 0 deletions
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guacamole-common-js/src/main/webapp/modules/SessionRecording.js Normal file
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/*
* Licensed to the Apache Software Foundation (ASF) under one
* or more contributor license agreements. See the NOTICE file
* distributed with this work for additional information
* regarding copyright ownership. The ASF licenses this file
* to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance
* with the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
var Guacamole = Guacamole || {};
/**
* A recording of a Guacamole session. Given a {@link Guacamole.Tunnel}, the
* Guacamole.SessionRecording automatically handles incoming Guacamole
* instructions, storing them for playback. Playback of the recording may be
* controlled through function calls to the Guacamole.SessionRecording, even
* while the recording has not yet finished being created or downloaded.
*
* @constructor
* @param {Guacamole.Tunnel} tunnel
* The Guacamole.Tunnel from which the instructions of the recording should
* be read.
*/
Guacamole.SessionRecording = function SessionRecording(tunnel) {
/**
* Reference to this Guacamole.SessionRecording.
*
* @private
* @type {Guacamole.SessionRecording}
*/
var recording = this;
/**
* All frames parsed from the provided tunnel.
*
* @private
* @type {Guacamole.SessionRecording._Frame[]}
*/
var frames = [];
/**
* All instructions which have been read since the last frame was added to
* the frames array.
*
* @private
* @type {Guacamole.SessionRecording._Frame.Instruction[]}
*/
var instructions = [];
/**
* Tunnel which feeds arbitrary instructions to the client used by this
* Guacamole.SessionRecording for playback of the session recording.
*
* @private
* @type {Guacamole.SessionRecording._PlaybackTunnel}
*/
var playbackTunnel = new Guacamole.SessionRecording._PlaybackTunnel();
/**
* Guacamole.Client instance used for visible playback of the session
* recording.
*
* @private
* @type {Guacamole.Client}
*/
var playbackClient = new Guacamole.Client(playbackTunnel);
/**
* The current frame rendered within the playback client. If no frame is
* yet rendered, this will be -1.
*
* @private
* @type {Number}
*/
var currentFrame = -1;
/**
* The timestamp of the frame when playback began, in milliseconds. If
* playback is not in progress, this will be null.
*
* @private
* @type {Number}
*/
var startVideoTimestamp = null;
/**
* The real-world timestamp when playback began, in milliseconds. If
* playback is not in progress, this will be null.
*
* @private
* @type {Number}
*/
var startRealTimestamp = null;
/**
* The ID of the timeout which will play the next frame, if playback is in
* progress. If playback is not in progress, the ID stored here (if any)
* will not be valid.
*
* @private
* @type {Number}
*/
var playbackTimeout = null;
// Start playback client connected
playbackClient.connect();
// Hide cursor unless mouse position is received
playbackClient.getDisplay().showCursor(false);
// Read instructions from provided tunnel, extracting each frame
tunnel.oninstruction = function handleInstruction(opcode, args) {
// Store opcode and arguments for received instruction
instructions.push(new Guacamole.SessionRecording._Frame.Instruction(opcode, args.slice()));
// Once a sync is received, store all instructions since the last
// frame as a new frame
if (opcode === 'sync') {
// Parse frame timestamp from sync instruction
var timestamp = parseInt(args[0]);
// Add a new frame containing the instructions read since last frame
var frame = new Guacamole.SessionRecording._Frame(timestamp, instructions);
frames.push(frame);
// Clear set of instructions in preparation for next frame
instructions = [];
// Notify that additional content is available
if (recording.onprogress)
recording.onprogress(recording.getDuration());
}
};
/**
* Converts the given absolute timestamp to a timestamp which is relative
* to the first frame in the recording.
*
* @private
* @param {Number} timestamp
* The timestamp to convert to a relative timestamp.
*
* @returns {Number}
* The difference in milliseconds between the given timestamp and the
* first frame of the recording, or zero if no frames yet exist.
*/
var toRelativeTimestamp = function toRelativeTimestamp(timestamp) {
// If no frames yet exist, all timestamps are zero
if (frames.length === 0)
return 0;
// Calculate timestamp relative to first frame
return timestamp - frames[0].timestamp;
};
/**
* Replays the instructions associated with the given frame, sending those
* instructions to the playback client.
*
* @private
* @param {Number} index
* The index of the frame within the frames array which should be
* replayed.
*/
var replayFrame = function replayFrame(index) {
var frame = frames[index];
// Replay all instructions within the retrieved frame
for (var i = 0; i < frame.instructions.length; i++) {
var instruction = frame.instructions[i];
playbackTunnel.receiveInstruction(instruction.opcode, instruction.args);
}
};
/**
* Moves the playback position to the given frame, resetting the state of
* the playback client and replaying frames as necessary.
*
* @private
* @param {Number} index
* The index of the frame which should become the new playback
* position.
*/
var seekToFrame = function seekToFrame(index) {
var startIndex;
// Back up until startIndex represents current state
for (startIndex = index; startIndex > currentFrame; startIndex--) {
var frame = frames[startIndex];
// If frame has associated absolute state, make that frame the
// current state
if (frame.clientState) {
playbackClient.importState(frame.clientState);
break;
}
}
// Advance to frame index after current state
startIndex++;
// Replay any applicable incremental frames
for (; startIndex <= index; startIndex++)
replayFrame(startIndex);
// Current frame is now at requested index
currentFrame = index;
// Notify of changes in position
if (recording.onseek)
recording.onseek(recording.getPosition());
};
/**
* Advances playback to the next frame in the frames array and schedules
* playback of the frame following that frame based on their associated
* timestamps. If no frames exist after the next frame, playback is paused.
*
* @private
*/
var continuePlayback = function continuePlayback() {
// Advance to next frame
seekToFrame(currentFrame + 1);
// If frames remain after advancing, schedule next frame
if (currentFrame + 1 < frames.length) {
// Pull the upcoming frame
var next = frames[currentFrame + 1];
// Calculate the real timestamp corresponding to when the next
// frame begins
var nextRealTimestamp = next.timestamp - startVideoTimestamp + startRealTimestamp;
// Calculate the relative delay between the current time and
// the next frame start
var delay = Math.max(nextRealTimestamp - new Date().getTime(), 0);
// Advance to next frame after enough time has elapsed
playbackTimeout = window.setTimeout(function frameDelayElapsed() {
continuePlayback();
}, delay);
}
// Otherwise stop playback
else
recording.pause();
};
/**
* Fired when new frames have become available while the recording is
* being downloaded.
*
* @event
* @param {Number} duration
* The new duration of the recording, in milliseconds.
*/
this.onprogress = null;
/**
* Fired whenever playback of the recording has started.
*
* @event
*/
this.onplay = null;
/**
* Fired whenever playback of the recording has been paused. This may
* happen when playback is explicitly paused with a call to pause(), or
* when playback is implicitly paused due to reaching the end of the
* recording.
*
* @event
*/
this.onpause = null;
/**
* Fired whenever the playback position within the recording changes.
*
* @event
* @param {Number} position
* The new position within the recording, in milliseconds.
*/
this.onseek = null;
/**
* Connects the underlying tunnel, beginning download of the Guacamole
* session. Playback of the Guacamole session cannot occur until at least
* one frame worth of instructions has been downloaded.
*
* @param {String} data
* The data to send to the tunnel when connecting.
*/
this.connect = function connect(data) {
tunnel.connect(data);
};
/**
* Disconnects the underlying tunnel, stopping further download of the
* Guacamole session.
*/
this.disconnect = function disconnect() {
tunnel.disconnect();
};
/**
* Returns the underlying display of the Guacamole.Client used by this
* Guacamole.SessionRecording for playback. The display contains an Element
* which can be added to the DOM, causing the display (and thus playback of
* the recording) to become visible.
*
* @return {Guacamole.Display}
* The underlying display of the Guacamole.Client used by this
* Guacamole.SessionRecording for playback.
*/
this.getDisplay = function getDisplay() {
return playbackClient.getDisplay();
};
/**
* Returns whether playback is currently in progress.
*
* @returns {Boolean}
* true if playback is currently in progress, false otherwise.
*/
this.isPlaying = function isPlaying() {
return !!startVideoTimestamp;
};
/**
* Returns the current playback position within the recording, in
* milliseconds, where zero is the start of the recording.
*
* @returns {Number}
* The current playback position within the recording, in milliseconds.
*/
this.getPosition = function getPosition() {
// Position is simply zero if playback has not started at all
if (currentFrame === -1)
return 0;
// Return current position as a millisecond timestamp relative to the
// start of the recording
return toRelativeTimestamp(frames[currentFrame].timestamp);
};
/**
* Returns the duration of this recording, in milliseconds. If the
* recording is still being downloaded, this value will gradually increase.
*
* @returns {Number}
* The duration of this recording, in milliseconds.
*/
this.getDuration = function getDuration() {
// If no frames yet exist, duration is zero
if (frames.length === 0)
return 0;
// Recording duration is simply the timestamp of the last frame
return toRelativeTimestamp(frames[frames.length - 1].timestamp);
};
/**
* Begins continuous playback of the recording downloaded thus far.
* Playback of the recording will continue until pause() is invoked or
* until no further frames exist. Playback is initially paused when a
* Guacamole.SessionRecording is created, and must be explicitly started
* through a call to this function. If playback is already in progress,
* this function has no effect.
*/
this.play = function play() {
// If playback is not already in progress and frames remain,
// begin playback
if (!recording.isPlaying() && currentFrame + 1 < frames.length) {
// Notify that playback is starting
if (recording.onplay)
recording.onplay();
// Store timestamp of playback start for relative scheduling of
// future frames
var next = frames[currentFrame + 1];
startVideoTimestamp = next.timestamp;
startRealTimestamp = new Date().getTime();
// Begin playback of video
continuePlayback();
}
};
/**
* Pauses playback of the recording, if playback is currently in progress.
* If playback is not in progress, this function has no effect. Playback is
* initially paused when a Guacamole.SessionRecording is created, and must
* be explicitly started through a call to play().
*/
this.pause = function pause() {
// Stop playback only if playback is in progress
if (recording.isPlaying()) {
// Notify that playback is stopping
if (recording.onpause)
recording.onpause();
// Stop playback
window.clearTimeout(playbackTimeout);
startVideoTimestamp = null;
startRealTimestamp = null;
}
};
};
/**
* A single frame of Guacamole session data. Each frame is made up of the set
* of instructions used to generate that frame, and the timestamp as dictated
* by the "sync" instruction terminating the frame. Optionally, a frame may
* also be associated with a snapshot of Guacamole client state, such that the
* frame can be rendered without replaying all previous frames.
*
* @private
* @constructor
* @param {Number} timestamp
* The timestamp of this frame, as dictated by the "sync" instruction which
* terminates the frame.
*
* @param {Guacamole.SessionRecording._Frame.Instruction[]} instructions
* All instructions which are necessary to generate this frame relative to
* the previous frame in the Guacamole session.
*/
Guacamole.SessionRecording._Frame = function _Frame(timestamp, instructions) {
/**
* The timestamp of this frame, as dictated by the "sync" instruction which
* terminates the frame.
*
* @type {Number}
*/
this.timestamp = timestamp;
/**
* All instructions which are necessary to generate this frame relative to
* the previous frame in the Guacamole session.
*
* @type {Guacamole.SessionRecording._Frame.Instruction[]}
*/
this.instructions = instructions;
/**
* A snapshot of client state after this frame was rendered, as returned by
* a call to exportState(). If no such snapshot has been taken, this will
* be null.
*
* @type {Object}
*/
this.clientState = null;
};
/**
* A Guacamole protocol instruction. Each Guacamole protocol instruction is
* made up of an opcode and set of arguments.
*
* @private
* @constructor
* @param {String} opcode
* The opcode of this Guacamole instruction.
*
* @param {String[]} args
* All arguments associated with this Guacamole instruction.
*/
Guacamole.SessionRecording._Frame.Instruction = function Instruction(opcode, args) {
/**
* The opcode of this Guacamole instruction.
*
* @type {String}
*/
this.opcode = opcode;
/**
* All arguments associated with this Guacamole instruction.
*
* @type {String[]}
*/
this.args = args;
};
/**
* A read-only Guacamole.Tunnel implementation which streams instructions
* received through explicit calls to its receiveInstruction() function.
*
* @private
* @constructor
* @augments {Guacamole.Tunnel}
*/
Guacamole.SessionRecording._PlaybackTunnel = function _PlaybackTunnel() {
/**
* Reference to this Guacamole.SessionRecording._PlaybackTunnel.
*
* @private
* @type {Guacamole.SessionRecording._PlaybackTunnel}
*/
var tunnel = this;
this.connect = function connect(data) {
// Do nothing
};
this.sendMessage = function sendMessage(elements) {
// Do nothing
};
this.disconnect = function disconnect() {
// Do nothing
};
/**
* Invokes this tunnel's oninstruction handler, notifying users of this
* tunnel (such as a Guacamole.Client instance) that an instruction has
* been received. If the oninstruction handler has not been set, this
* function has no effect.
*
* @param {String} opcode
* The opcode of the Guacamole instruction.
*
* @param {String[]} args
* All arguments associated with this Guacamole instruction.
*/
this.receiveInstruction = function receiveInstruction(opcode, args) {
if (tunnel.oninstruction)
tunnel.oninstruction(opcode, args);
};
};