canvas - 无法在S3上启用CORS

Question

我在S3存储桶上设置了CORS，如下所示:

<?xml version="1.0" encoding="UTF-8"?>
<CORSConfiguration xmlns="http://s3.amazonaws.com/doc/2006-03-01/">
    <CORSRule>
        <AllowedOrigin>*</AllowedOrigin>
        <AllowedMethod>GET</AllowedMethod>
    </CORSRule>
</CORSConfiguration>

这是AWS控制台的屏幕截图: https://dzwonsemrish7.cloudfront.net/items/341y0o1n1X2a0O1X2s38/Screen%20Shot%202012-10-09%20at%209.59.44%20PM.png?v=2478ad83

当我将 color-thief javascript指向同一域中托管的镜像时，一切 works as expected，但是当我指向S3存储桶中的 Assets 时，无论我是否从本地主机lvh.me(指向127.0.0.1)运行脚本)，或从真正的互联网络中，我在Chrome 22中收到如下错误:

Unable to get image data from canvas because the canvas has been tainted by cross-origin data.
Uncaught Error: SECURITY_ERR: DOM Exception 18

在Firefox 15中是这样的:

SecurityError: The operation is insecure.

header 在Google Chrome网络检查器中的外观如下:

Request URL:https://s3.amazonaws.com/assets-zeke.heroku.com/addons-zeke.heroku.com/catalogs/58/original.png
Request Method:GET
Status Code:304 Not Modified

Request Headers
Accept:*/*
Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8
Cache-Control:max-age=0
Connection:keep-alive
Host:s3.amazonaws.com
If-Modified-Since:Tue, 09 Oct 2012 22:52:57 GMT
If-None-Match:"6de1a52294934c5e288894b84100d99b"
Referer:http://localhost:5000/marketplace/addons/sendgrid/edit
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_4) AppleWebKit/537.4 (KHTML, like Gecko) Chrome/22.0.1229.79 Safari/537.4

Response Headers
HTTP/1.1 304 Not Modified
x-amz-id-2: qGvoGlvpKeSSzelanWsIPDF3zd5wQzHTr27NZoUbhNqAM1QzmKcWHnTqIkKVxF/m
x-amz-request-id: FD24FB8CA244E327
Date: Wed, 10 Oct 2012 05:20:53 GMT
Last-Modified: Tue, 09 Oct 2012 22:52:57 GMT
ETag: "6de1a52294934c5e288894b84100d99b"
Server: AmazonS3

这是我将URL结构更改为 {bucket}.s3.amazonaws.com(并删除句点)后的标题的样子
从我的存储桶名称中

Request URL:http://assets-zeke.s3.amazonaws.com/addons-zeke.heroku.com/catalogs/58/original.png
Request Method:GET
Status Code:200 OK
Request Headers

Request Headers
Accept:*/*
Accept-Charset:ISO-8859-1,utf-8;q=0.7,*;q=0.3
Accept-Encoding:gzip,deflate,sdch
Accept-Language:en-US,en;q=0.8
Cache-Control:no-cache
Connection:keep-alive
Host:assets-zeke.s3.amazonaws.com
Pragma:no-cache
Referer:http://lvh.me:5000/marketplace/addons/airbrake/edit
User-Agent:Mozilla/5.0 (Macintosh; Intel Mac OS X 10_7_4) AppleWebKit/537.4 (KHTML, like Gecko) Chrome/22.0.1229.79 Safari/537.4

Response Headers
Accept-Ranges:bytes
Content-Length:6696
Content-Type:image/png
Date:Wed, 10 Oct 2012 17:56:17 GMT
ETag:"6de1a52294934c5e288894b84100d99b"
Last-Modified:Wed, 10 Oct 2012 17:50:38 GMT
Server:AmazonS3
x-amz-id-2:UGVKQ9VQbJ82DLDxR53uDP0ZUMgla+e0GU5vO9yLr6MsY8wijl9KnM7fOyDlT+ta
x-amz-request-id:8A16CF1E02A0106C

我不应该在这里看到 Access-Control-Allow-Origin: *吗？ 304是否表示Amazon正在缓存响应？

Answer 1

Request URL:https://s3.amazonaws.com/assets-zeke.heroku.com/addons-zeke.heroku.com/catalogs/58/original.png

好吧，那是你的问题。由于CORS和其他跨域功能的工作方式，您需要使用DNS样式的寻址来访问您的存储桶。

假设您的原始URL是正确的(看起来不正确，但我可能完全错了)，则您想改用以下URL:

http://assets-zeke.heroku.com.s3.amazonaws.com/addons-zeke.heroku.com/catalogs/58/original.png

换句话说:

http://{bucket}.s3.amazonaws.com/path/object.ext

退房: http://docs.amazonwebservices.com/AmazonS3/latest/dev/cors.html了解更多说明。