I've done it this way, but Adobe Air hangs for several seconds.
private function test():void
{
fileStream = new FileStream();
fileStream.addEventListener(IOErrorEvent.IO_ERROR, fileError);
fileStream.addEventListener(Event.COMPLETE, opened);
fileStream.openAsync(filePath, FileMode.READ);
}
protected function opened(event:Event):void
{
var bytes:ByteArray = new ByteArray();
fileStream.readBytes(bytes);
fileStream.close();
// MD5Stream from package com.adobe.crypto.MD5Stream https://github.com/mikechambers/as3corelib/blob/master/src/com/adobe/crypto/MD5Stream.as
var md5stream:MD5Stream = new MD5Stream;
trace(md5stream.complete(bytes)); // md5
}
How to make the process of getting md5 without hanging?
Try using Bloody's MD5 implementation. It's apparently a lot faster.
While it will speed up the hash calculation, perhaps even adequately, you're not really solving the underlying problem, which is that you want a non-blocking operation in a single threaded application model. In Flash/AIR, this is generally done by breaking the work up into smaller chunks, and doing only one chunk's worth of processing each frame, instead of all at once during one frame. There's even a cool framework to simplify this!
I noticed that the library you're currently using, MD5Stream, is built for incremental updates -- so you can easily feed it little chunks of the file each frame until the entire file is processed. This will allow the frame rate to stay relatively constant while the hash is computed.
Related
I need to read a part of two files, and once both parts of both files are loaded to trigger a function that does some work.
What is the best way to approach this problem.
I am currently triggering the second file load once the first is loaded, however it seems poor coding style, I think this because my OO code starts looking procedural.
EDIT: So its an Air based app so using filestream.
In the end I found I actually needed to read each file in a different way. Because I need the same part of both files, and I dont know the file size, I need to read one file first and once I have fileStream.bytesAvailable and position, I can then look for the same data from the second file. I found I must handle files smaller than my read size and the end of files beyond multiples of my read size.
You don't specified what file and from where you wont to load the file but you can actually load multiples files in parallel.
If you want to read only part of file from local machine you can use AIR's FileStream class - very easy and you don't have to load whole few hundreds MB file:
import flash.filesystem.*;
var file:File = File.documentsDirectory;
file = file.resolvePath("Apollo Test/test.txt");
var fileStream:FileStream = new FileStream();
fileStream.open(file, FileMode.READ);
var str:String = fileStream.readMultiByte(file.size, File.systemCharset);
trace(str);
fileStream.close();
Another option is to use URLStream and listen for ProgressEvent.PROGRESSevents to read data of partially loaded file.
You may also want to see NetStream class which is used to stream video.
there is many options, using File, FileStream is only available on air applications.
The File class extends the FileReference class. The FileReference
class, which is available in Flash® Player as well as Adobe® AIR®,
represents a pointer to a file, but the File class adds properties and
methods that are not exposed in Flash Player (in a SWF running in a
browser), due to security considerations.
as noted above, if you are creating a non-AIR application, FileReference should be used instead of FileStream and File classes, as you dont tagged AIR in your question.
FileReference does not provide any open("path") to you (due to security considerations), but a browse method will be available and ask's your client's for selecting a file. here is an example, which also explain how to trigger a function when opening is done:
var filereference:FileReference = new FileReference();
filereference.addEventListener(Event.SELECT, onFileSelected);
var text_files:FileFilter = new FileFilter("Text Files","*.txt; *.html;*.htm;*.php");
var all_files:FileFilter = new FileFilter("All Files (*.*)","*.*");
filereference.browse([text_files, all_files]);
// triggered when a file is selected by user
function onFileSelected(e:Event):void {
filereference.removeEventListener(Event.SELECT, onFileSelected);
filereference.addEventListener(Event.COMPLETE, onFileLoaded);
filereference.load();
}
// triggered when file loading is complete
function onFileSelected(e:Event):void {
var data:ByteArray = fileReference["data"];
filereference.removeEventListener(Event.COMPLETE, onFileSelected);
}
two more events to be listened for suddenly error's occurred and displaying a progress bar for loading progress (its sync):
IOErrorEvent.IO_ERROR and ProgressEvent.PROGRESS
So, I've been working on a project in AS3 and I've come across yet another peculiar bit of behavior.
Background: It's a turned based game. I've been optimizing it for the past week and now it runs like butter (consistently!);
Issue: However, when I try to continue playing from a saved game, it runs less consistently. Specifically, it will run the first few turns normally, then it will begin to degrade in performance dramatically until it freezes my computer. Please note, this only happens during battle, not during the menus or during any other time.
Is there something regarding Actionscript that I'm missing? I'm saving the game with cookies using the built in SharedObject class. The code I'm using to save and load the data is below (I also use the byte array class).
public static function saveGame():void
{
/// save the game using byte array
registerClassAlias("Mob", Mob);
registerClassAlias("Skill", Skill);
var ba:ByteArray = new ByteArray();
var savedData:* = Main.glblPlayer.setSaveObject();
ba.writeObject(savedData);
ba.position = 0;
so.data.game5 = ba;
so.flush();
}
public static function loadGame():Boolean
{
if (so.data.hasOwnProperty("game5"))
{
var ba:ByteArray = new ByteArray();
ba = so.data.game5;
ba.position = 0;
var loadedData:Object = ba.readObject();
glblPlayer.loadSaveObject( loadedData );
return true;
}
else
{
so.data.game = new Object();
return false;
}
}
I just double checked the above code and tested it a bit more with some variation. If it's loaded 1-3 times, it's fine, but after that the performance degrades during battle with each turn. I have no idea how the technical stuff of ActionScript works or how it saves resources aside from that it's cookies and it's in the cache.
Can anyone shed some light on this by maybe going a bit more into how saving/loading with flash games are done in AS3? Or is "use sharedObject" all there is?
Use a profiler (like Adobe scout) to see what causes the problem.
If I had to guess, it's because your (de-)serialisation routines do not work properly and have a memory leak. But again arguing about this or looking at the code wondering what might be the problem is a pointless endeavour. Use a profiler to see exactly what the problem is.
I have a few contradicting misconceptions about how Flash handles image assets. I'm going to write them down here, please correct me where I'm wrong.
I have an embedded image
[Embed(source = "../../lib/images/myImage.png")]
public var embeddedImage:Class;
How do I use it in my app without using unreasonable amounts of operating memory?
I was going to do this:
var bData:BitmapData = (new embeddedImage() as Bitmap).bitmapData;
And from that point on use bData if I ever want to display this picture anywhere, ensuring that there is only one bitmapdata per image.
But what worries me is that embeddedImage still stays, doesn't it? There are basically two copies of this image in the operating memory, right?
What should I do instead? May be I should instantiate new embeddedImage() each time I want to use it? But that looks even worse, now I'm clearly instantiating a bunch of unneeded copies.
If I loaded the image using the Loader class I would end up with only one copy of the bitmapdata if I wanted to, provided GC did a good job clearing the loader after it was done.
The [Embed] block embeds the image into the application. This doesn't use RAM*, it increases the size of the application itself (the .swf or whatever format you export to).
When you use new EmbeddedImage(), you create an instance of the embedded image. This instance is what consumes RAM. Each instance of that image will consume additional RAM.
When you access the bitmapData property of that embedded image, it does not create a new instance or consume additional RAM, it refers to existing data which is already consuming RAM.
Because the BitmapData is the data which represents an image, it is obviously the largest. Knowing this, we look at ways to use a single instance of BitmapData for any graphics we want to display. Depending on the display architecture you've opted to use, there are different ways to go about referring to that BitmapData when drawing multiple instances of the same image.
As an example, we have your instance of EmbeddedImage created:
var embeddedImage:EmbeddedImage = new EmbeddedImage();
And we have a 'canvas', which is a single Bitmap added to the stage:
var canvas:Bitmap = new Bitmap();
canvas.bitmapData = new BitmapData(500, 500, false, 0xFFFFFF);
addChild(canvas);
Using the method copyPixels(), we can copy across a section of data from the embeddedImage, to the canvas without needing to make another instance of BitmapData, which would consume RAM equivalent to the source for each time we want to draw the graphics. Example:
var drawPosition:Point = new Point();
var sourceRect:Rectangle = embeddedImage.bitmapData.rect;
// Draw the embeddedImage 50 times.
canvas.bitmapData.lock();
for(var i:int = 0; i < 50; i++)
{
canvas.bitmapData.copyPixels(embeddedImage.bitmapData, sourceRect, drawPosition);
drawPosition.x += 10;
}
canvas.bitmapData.unlock();
I found some actionscript code like that:
var s:Sound = new Sound();
s.addEventListener(Event.COMPLETE, onSoundLoaded);
var req:URLRequest = new URLRequest(XX_EXTERNAL_URL);
s.load(req);
In which case the attacker can control the XX_EXTERNAL_URL, is that vulnerable?
Most likely it will just generate a sound conversion error or garbage sound, without any extra impact on SWF player or the system. One needs to have a bug in sound code that's causing a code injection or data corruption to make this attack successful. But, with predefined code of Sound object, it's either there or not, so it won't be more vulnerable if you load a Sound from elsewhere.
I'm trying to fill some data from an xml feed we made into my Flash movie. The main action of this is in the constructor for MediaElementJS's .as file.
Anyway, the main problem is that I keep reading there is no way to load a URL synchronously in AS3 (which i still find hard to believe). This constructor calls both parse('url') and a function addEventListener(EVENT.ADDED_TO_STAGE, initializeAds);
Now the ads need info from the XML but the XML aint ready yet. I tried to call the ads at the end of the XML parser when I knew it would be prepped but it messes them up and the ad values never change from their defaults..
Oh wherefor art thou actionscript locking mechanism..
So is there anyway to preload data from a URL?
CODE:
public function LoadXML(e:Event):void
{
removeEventListener(Event.COMPLETE, LoadXML);
var xmlData:XML = new XML(e.target.data);
episodeData.pre.type = xmlData.episode.pre.ad.#type;
episodeData.pre.url = xmlData.episode.pre.ad.text();
episodeData.video = Number(xmlData.episode.video.#id); /*************** I CAN'T REMEMBER ***********/
episodeData.pageTitle = xmlData.episode.video.#pagetitle;
episodeData.title = xmlData.episode.video.#title;
episodeData.source = xmlData.episode.video.source.text();
episodeData.post.type=xmlData.episode.post.ad.#type;
episodeData.post.url=xmlData.episode.post.ad.text();
episodeData.nextEpisode=xmlData.episode.post.nextepisode.text(); //if not empty redirect to this
xmlLoading = false;
//THIS IS WHERE I TRIED TO CALL THE FUNCTION I NEED TO LOAD LATER
}
public function parse()
{
var xmlLoader:URLLoader = new URLLoader();
//var xmlData:XML = new XML();
xmlLoader.load(new URLRequest(rootURL + '/episode.aspx?associd=' + _episode));
//xmlLoader.addEventListener(Event.COMPLETE, processXML);
xmlLoader.addEventListener(Event.COMPLETE, LoadXML);
}
I've tried it with a static URL address and whatnot of course but no dice.
The code in the constructor works if I dynamically assign a static value but if I try chaining to events together to get the dynamic value and dynamic assignment it crunches.
In the constructor, definitely runs both by themselves:
parse();
// Google IMA EventListener
addEventListener(Event.ADDED_TO_STAGE, initialize);
Loading URLs is always asynchronous, so add the event listener in the response function for the URL loader.
Now your question sounds like you tried that but had some problem, so post that code and let us take a look.
Edit START
When I have multiple asynchronous calls that happen and I need something to happen after both of them are done I usually use booleans to store if each one has happened yet, then in a third function they both call I check both the booleans.
Here's how I'd do that:
protected function viewnavigatorapplication1_preinitializeHandler(event:FlexEvent):void
{
var loader1:Loader = new Loader();
var loader2:Loader = new Loader();
loader1.addEventListener(Event.COMPLETE, loader1_completeHandler);
loader1.load(new URLRequest("http://www.whitehouse.gov"));
loader2.addEventListener(Event.COMPLETE, loader2_completeHandler);
loader2.load(new URLRequest("http://www.nasa.gov"));
}
private function loader1_completeHandler():void
{
loader1Done = true;
//Maybe do some stuff here
moveOn();
}
private function loader2_completeHandler():void
{
loader2Done=true;
//Maybe do some stuff here
moveOn();
}
private function moveOn():void
{
if(!loader1Done||!loader2Done)
return;
//Do whatever needs to be done once both asynchronous events have completed
}
If this isn't your problem I think you need to provide more of the code in place of the comments that indicate other things happen, because it is a bit unclear.
For example I'm not sure what you mean by "The code in the constructor works if I dynamically assign a static value but if I try chaining to events together to get the dynamic value and dynamic assignment it crunches." Also since there's no example of the data or what the rootURL is there's no way to debug from here to understand what's going wrong.
Since there's no error we would need to be able to re-compile some portion of your code locally to give any better feedback.
Edit END
Blocking or synchronous calls are a horrible idea with regard to network communications due to the lack of reliability of networks and/or servers. If a front end application locked up to wait for a response before doing any other processing it would result in a horrible user experience, this is why there is no synchronous remote calls.
What happens with a synchronous call when the server bombs out, the client remains locked even though no response will result, the user can't interact with anything else in the front-end because it's waiting for said response which will never come? It's much better that remote calls of any sort are done in an asynchronous fashion, the same is true with local disk access in Java (or otherwise) where using asynchronous non-blocking calls is generally a better way to go to allow the other processes within an application to continue regardless of the state or use on the disk.
What you're doing should work just fine, you make a call to a remote service, it responds with some result and hits your "listener" or "callback" function then you want to do something with the results you can call another function, and the data is there.
It sounds to me like the only thing that's not happening is updates after the fact aren't being reflected in the UI, this is probably due to a lack of Bindable metadata/event dispatching for the properties. Have you inspected the result in the event that returns, have you put breakpoints in the method that is meant to be called after the data has returned? What you're doing is completely possible and it even looks like you have most of it right, but there's definitely something your doing wrong that's resulting in you not being able to make this work. If you can explain the behavior a bit clearer that will help, also what do you do here:
//THIS IS WHERE I TRIED TO CALL THE FUNCTION I NEED TO LOAD LATER