PretendYoureXyzzy/WebContent/js/cah.longpoll.js

148 lines
4.8 KiB
JavaScript

/*
* Copyright (c) 2012, Andy Janata
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification, are permitted
* provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice, this list of conditions
* and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice, this list of
* conditions and the following disclaimer in the documentation and/or other materials provided
* with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR
* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY
* WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/**
* AJAX long polling library.
*
* @author Andy Janata (ajanata@socialgamer.net)
*/
cah.longpoll = {};
cah.longpoll.TIMEOUT = 45 * 1000;
// cah.longpoll.TIMEOUT = 30 * 1000;
/**
* Backoff when there was an error.
*
* @type {number}
*/
cah.longpoll.INITIAL_BACKOFF = 500;
/**
* Backoff after a successful request.
*
* @type {number}
*/
cah.longpoll.NORMAL_BACKOFF = 1;
/**
* Current backkoff.
*
* @type {number}
*/
cah.longpoll.Backoff = cah.longpoll.INITIAL_BACKOFF;
cah.longpoll.Resume = true;
cah.longpoll.ErrorCodeHandlers = {};
cah.longpoll.EventHandlers = {};
/**
* Start a long polling operation.
*/
cah.longpoll.longPoll = function() {
cah.log.debug("starting long poll");
$.ajax({
cache : false,
complete : cah.longpoll.complete,
error : cah.longpoll.error,
success : cah.longpoll.done,
timeout : cah.longpoll.TIMEOUT,
url : cah.LONGPOLL_URI,
});
};
/**
* Called when a long polling operation completes, success or failure. Will start another poll
* unless the previous one ended in a terminal failure (likely because the server restarted and we
* no longer have a session on it).
*/
cah.longpoll.complete = function() {
if (cah.longpoll.Resume) {
setTimeout("cah.longpoll.longPoll()", cah.longpoll.Backoff);
}
};
/**
* Called when a long polling operation completes successfully. Dispatches the events to the
* appropriate handler.
*
* @param {Array}
* data_list A list of events to process.
*/
cah.longpoll.done = function(data_list) {
cah.log.debug("long poll done", data_list);
var data_list_work;
// we need to handle non-array data, too, so just make it look like an array
if (data_list[cah.$.LongPollResponse.TIMESTAMP] || data_list[cah.$.LongPollResponse.ERROR]) {
data_list_work = {};
data_list_work[0] = data_list;
} else {
data_list_work = data_list;
}
for ( var index in data_list_work) {
var data = data_list_work[index];
if (data[cah.$.LongPollResponse.ERROR]) {
// TODO cancel any timers or whatever we may have, and disable interface
// this probably should be done in the appropriate error code handler because we may not
// want to always be that extreme.
var errorCode = data[cah.$.LongPollResponse.ERROR_CODE];
if (cah.longpoll.ErrorCodeHandlers[errorCode]) {
cah.longpoll.ErrorCodeHandlers[errorCode](data);
} else {
cah.log.error(cah.$.ErrorCode_msg[errorCode]);
}
} else {
// FIXME giant hack
if (data[cah.$.LongPollResponse.PLAY_TIMER]) {
$("#current_timer").text(data[cah.$.LongPollResponse.PLAY_TIMER] / 1000);
}
var event = data[cah.$.LongPollResponse.EVENT];
if (cah.longpoll.EventHandlers[event]) {
cah.longpoll.EventHandlers[event](data);
} else {
cah.log.error("Unhandled event " + event);
}
}
}
// reset the backoff to normal when there's a successful operation
cah.longpoll.Backoff = cah.longpoll.NORMAL_BACKOFF;
};
/**
* Called when a long polling operation completes with an error.
*/
cah.longpoll.error = function(jqXHR, textStatus, errorThrown) {
// TODO deal with this somehow
cah.log.debug(textStatus);
if (cah.longpoll.Backoff < cah.longpoll.INITIAL_BACKOFF) {
cah.longpoll.Backoff = cah.longpoll.INITIAL_BACKOFF;
} else {
cah.longpoll.Backoff *= 2;
}
cah.log
.error("Error communicating with server. Will try again in " + (cah.longpoll.Backoff / 1000)
+ " second" + (cah.longpoll.Backoff != 1000 ? "s" : "") + ".");
};