问题
I am using BitmapData.draw() on a DisplayObject that includes an image from my AWS S3 bucket. The image loads fine in the swf when I set the S3 image URL as the source for an Image object but when I use BitmapData.draw() on it, it gives me this error:
SecurityError: Error #2122: Security sandbox violation: BitmapData.draw: https://www.example.com/Example.swf cannot access https://s3.amazonaws.com/example-images/example.jpg. A policy file is required, but the checkPolicyFile flag was not set when this media was loaded.
AS code:
var bmpd:BitmapData = new BitmapData(objectToDraw.width,objectToDraw.height);
bmpd.draw(objectToDraw);
I have tried putting the following crossdomain.xml file in my S3 bucket root to no avail:
<?xml version="1.0"?><!DOCTYPE cross-domain-policy SYSTEM "http://www.macromedia.com/xml/dtds/cross-domain-policy.dtd">
<cross-domain-policy>
<allow-access-from domain="*"/>
</cross-domain-policy>
回答1:
There are two ways to access files on S3:
s3.amazonaws.com/[bucket name]/file.ext[bucket name].s3.amazonaws.com/file.ext
Since the crossdomain.xml file needs to be in the root folder of the domain, and you don't have access to the root folder of s3.amazonaws.com, you can't control the crossdomain.xml file if you are using the first method
If you are using the second method, you can put a crossdomain.xml file in the root folder of your bucket and it will be used correctly by the Flash Player.
来源：https://stackoverflow.com/questions/9217973/flash-flex-crossdomain-issue-using-bitmapdata-draw-for-image-from-aws-s3-res