sync.js

这是一个ajax的例子大家好好的看看就是一个鱼眼的效果

if(!dojo._hasResource["dojox.off.sync"]){ //_hasResource checks added by build. Do not use _hasResource directly in your code.
dojo._hasResource["dojox.off.sync"] = true;
dojo.provide("dojox.off.sync");

dojo.require("dojox.storage.GearsStorageProvider");
dojo.require("dojox.off._common");
dojo.require("dojox.off.files");

// Author: Brad Neuberg, [e-mail], http://codinginparadise.org

// summary:
//		Exposes syncing functionality to offline applications
dojo.mixin(dojox.off.sync, {
	// isSyncing: boolean
	//		Whether we are in the middle of a syncing session.
	isSyncing: false,
	
	// cancelled: boolean
	//		Whether we were cancelled during our last sync request or not. If
	//		we are cancelled, then successful will be false.
	cancelled: false,
	
	// successful: boolean
	//		Whether the last sync was successful or not.  If false, an error
	//		occurred.
	successful: true,
	
	// details: String[]
	//		Details on the sync. If the sync was successful, this will carry
	//		any conflict or merging messages that might be available; if the
	//		sync was unsuccessful, this will have an error message.  For both
	//		of these, this should be an array of Strings, where each string
	//		carries details on the sync. 
	//	Example: 
	//		dojox.off.sync.details = ["The document 'foobar' had conflicts - yours one",
	//						"The document 'hello world' was automatically merged"];
	details: [],
	
	// error: boolean
	//		Whether an error occurred during the syncing process.
	error: false,
	
	// actions: dojox.off.sync.ActionLog
	//		Our ActionLog that we store offline actions into for later
	//		replaying when we go online
	actions: null,
	
	// autoSync: boolean
	//		For advanced usage; most developers can ignore this.
	//		Whether we do automatically sync on page load or when we go online.
	//		If true we do, if false syncing must be manually initiated.
	//		Defaults to true.
	autoSync: true,
	
	// summary:
	//	An event handler that is called during the syncing process with
	//	the state of syncing. It is important that you connect to this
	//	method and respond to certain sync events, especially the 
	//	"download" event.
	// description:
	//	This event handler is called during the syncing process. You can
	//	do a dojo.connect to receive sync feedback:
	//
	//		dojo.connect(dojox.off.sync, "onSync", someFunc);
	//
	//	You will receive one argument, which is the type of the event
	//	and which can have the following values.
	//
	//	The most common two types that you need to care about are "download"
	//	and "finished", especially if you are using the default
	//	Dojo Offline UI widget that does the hard work of informing
	//	the user through the UI about what is occuring during syncing.
	//
	//	If you receive the "download" event, you should make a network call
	//	to retrieve and store your data somehow for offline access. The
	//	"finished" event indicates that syncing is done. An example:
	//	
	//		dojo.connect(dojox.off.sync, "onSync", function(type){
	//			if(type == "download"){
	//				// make a network call to download some data
	//				// for use offline
	//				dojo.xhrGet({
	//					url: 		"downloadData.php",
	//					handleAs:	"javascript",
	//					error:		function(err){
	//						dojox.off.sync.finishedDownloading(false, "Can't download data");
	//					},
	//					load:		function(data){
	//						// store our data
	//						dojox.storage.put("myData", data);
	//
	//						// indicate we are finished downloading
	//						dojox.off.sync.finishedDownloading(true);
	//					}
	//				});
	//			}else if(type == "finished"){
	//				// update UI somehow to indicate we are finished,
	//				// such as using the download data to change the 
	//				// available data
	//			}
	//		})
	//
	//	Here is the full list of event types if you want to do deep
	//	customization, such as updating your UI to display the progress
	//	of syncing (note that the default Dojo Offline UI widget does
	//	this for you if you choose to pull that in). Most of these
	//	are only appropriate for advanced usage and can be safely
	//	ignored:
	//
	//		* "start"
	//				syncing has started
	//		* "refreshFiles"
	//				syncing will begin refreshing
	//				our offline file cache
	//		* "upload"
	//				syncing will begin uploading
	//				any local data changes we have on the client.
	//				This event is fired before we fire
	//				the dojox.off.sync.actions.onReplay event for
	//				each action to replay; use it to completely
	//				over-ride the replaying behavior and prevent
	//				it entirely, perhaps rolling your own sync
	//				protocol if needed.
	//		* "download"
	//				syncing will begin downloading any new data that is
	//				needed into persistent storage. Applications are required to
	//				implement this themselves, storing the required data into
	//				persistent local storage using Dojo Storage.
	//		* "finished"
	//				syncing is finished; this
	//				will be called whether an error ocurred or not; check
	//				dojox.off.sync.successful and dojox.off.sync.error for sync details
	//		* "cancel"
	//				Fired when canceling has been initiated; canceling will be
	//				attempted, followed by the sync event "finished".
	onSync: function(/* String */ type){},
	
	synchronize: function(){ /* void */
		// summary: Starts synchronizing

		//dojo.debug("synchronize");
		if(this.isSyncing || dojox.off.goingOnline || (!dojox.off.isOnline)){
			return;
		}
	
		this.isSyncing = true;
		this.successful = false;
		this.details = [];
		this.cancelled = false;
		
		this.start();
	},
	
	cancel: function(){ /* void */
		// summary:
		//	Attempts to cancel this sync session
		
		if(!this.isSyncing){ return; }
		
		this.cancelled = true;
		if(dojox.off.files.refreshing){
			dojox.off.files.abortRefresh();
		}
		
		this.onSync("cancel");
	},
	
	finishedDownloading: function(successful /* boolean? */, 
									errorMessage /* String? */){
		// summary:
		//		Applications call this method from their
		//		after getting a "download" event in
		//		dojox.off.sync.onSync to signal that
		//		they are finished downloading any data 
		//		that should be available offline
		// successful: boolean?
		//		Whether our downloading was successful or not.
		//		If not present, defaults to true.
		// errorMessage: String?
		//		If unsuccessful, a message explaining why
		if(typeof successful == "undefined"){
			successful = true;
		}
		
		if(!successful){
			this.successful = false;
			this.details.push(errorMessage);
			this.error = true;
		}
		
		this.finished();
	},
	
	start: function(){ /* void */
		// summary:
		//	For advanced usage; most developers can ignore this.
		//	Called at the start of the syncing process. Advanced
		//	developers can over-ride this method to use their
		//	own sync mechanism to start syncing.
		
		if(this.cancelled){
			this.finished();
			return;
		}
		this.onSync("start");
		this.refreshFiles();
	},
	
	refreshFiles: function(){ /* void */
		// summary:
		//	For advanced usage; most developers can ignore this.
		//	Called when we are going to refresh our list
		//	of offline files during syncing. Advanced developers 
		//	can over-ride this method to do some advanced magic related to
		//	refreshing files.
		
		//dojo.debug("refreshFiles");
		if(this.cancelled){
			this.finished();
			return;
		}
		
		this.onSync("refreshFiles");
		
		dojox.off.files.refresh(dojo.hitch(this, function(error, errorMessages){
			if(error){
				this.error = true;
				this.successful = false;
				for(var i = 0; i < errorMessages.length; i++){
					this.details.push(errorMessages[i]);
				}
				
				// even if we get an error while syncing files,
				// keep syncing so we can upload and download
				// data
			}
			
			this.upload();
		}));
	},
	
	upload: function(){ /* void */
		// summary:
		//	For advanced usage; most developers can ignore this.
		//	Called when syncing wants to upload data. Advanced
		//	developers can over-ride this method to completely
		//	throw away the Action Log and replaying system
		//	and roll their own advanced sync mechanism if needed.
		
		if(this.cancelled){
			this.finished();
			return;
		}
		
		this.onSync("upload");
		
		// when we are done uploading start downloading
		dojo.connect(this.actions, "onReplayFinished", this, this.download);
		
		// replay the actions log
		this.actions.replay();
	},
	
	download: function(){ /* void */
		// summary:
		//	For advanced usage; most developers can ignore this.
		//	Called when syncing wants to download data. Advanced
		//	developers can over-ride this method to use their
		//	own sync mechanism.
		
		if(this.cancelled){
			this.finished();
			return;
		}
		
		// apps should respond to the "download"
		// event to download their data; when done
		// they must call dojox.off.sync.finishedDownloading()
		this.onSync("download");
	},
	
	finished: function(){ /* void */
		// summary:
		//	For advanced usage; most developers can ignore this.
		//	Called when syncing is finished. Advanced
		//	developers can over-ride this method to clean
		//	up after finishing their own sync
		//	mechanism they might have rolled.
		this.isSyncing = false;
		
		this.successful = (!this.cancelled && !this.error);
		
		this.onSync("finished");
	},
	
	_save: function(callback){
		this.actions._save(function(){
			callback();
		});
	},
	
	_load: function(callback){
		this.actions._load(function(){
			callback();
		});
	}
});


// summary:
//		A class that records actions taken by a user when they are offline,
//		suitable for replaying when the network reappears. 
// description:
//		The basic idea behind this method is to record user actions that would
//		normally have to contact a server into an action log when we are
//		offline, so that later when we are online we can simply replay this log
//		in the order user actions happened so that they can be executed against
//		the server, causing synchronization to happen. 
//		
//		When we replay, for each of the actions that were added, we call a 
//		method named onReplay that applications should connect to and 
//		which will be called over and over for each of our actions -- 
//		applications should take the offline action
//		information and use it to talk to a server to have this action
//		actually happen online, 'syncing' themselves with the server. 
//
//		For example, if the action was "update" with the item that was updated, we
//		might call some RESTian server API that exists for updating an item in
//		our application.  The server could either then do sophisticated merging
//		and conflict resolution on the server side, for example, allowing you
//		to pop up a custom merge UI, or could do automatic merging or nothing
//		of the sort. When you are finished with this particular action, your
//		application is then required to call continueReplay() on the actionLog object
//		passed to onReplay() to continue replaying the action log, or haltReplay()
//		with the reason for halting to completely stop the syncing/replaying
//		process.
//
//		For example, imagine that we have a web application that allows us to add
//		contacts. If we are offline, and we update a contact, we would add an action;
//		imagine that the user has to click an Update button after changing the values
//		for a given contact:
//	
//		dojox.off.whenOffline(dojo.byId("updateButton"), "onclick", function(evt){
//			// get the updated customer values
//			var customer = getCustomerValues();
//