Can Action Script FileReference object be sent to Javascript and converted to File object?

Question

In Action Script, FileReference.browse() is called.

I would like to send the chosen file to Javascript and convert it to File object, just like if I would press the Browse button of the <input type='file /> and got File object.

I need that to be able to display picture thumbnail like shown here.

Maybe instead of passing the whole object it is possible to send only the required information for the thumbnail from the object ?

Thanks !

score 1 · Answer 1 · answered Dec 15 '12 at 03:22

1

For people trying to do it. What can be done is:

Converting the fileReference data byterray to Base64 and put it in a string
Sending this string to javascript with ExternalInterface

I use this pattern in contexts where I want to have an overview of binary files content. Even a large image can be sent using this approach. The file can then be accessed in javascript using a data URI with the appropriate MIME:

data:image/png;base64,[data] or data:octet/stream,[data]

Since I'm posting almost 2 1/2 years after the first post, we can now do it in all popular browser.

answered Dec 15 '12 at 03:22

Léon Pelletier

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That's what I am doing, works in Chrome but Firefox 41 crashes horribly with files larger than 4 MBs. Firefox rules NOT. – Bill Kotsias Oct 13 '15 at 05:18
Yeah, at 4MB, it starts to be huge for an URI. – Léon Pelletier Oct 14 '15 at 02:13

score 1 · Accepted Answer · answered Jul 13 '10 at 04:09

I don't think there is any way to create a File object. For example, try this:

var f = new File;

I get an exception "Cannot convert WrappedNative to function." If you look in the docs for File, there is no constructor described. Also, most of the attributes are read-only. I would interpret this to mean that only the browser can create a File object.

Keep in mind that if you could create a File object by specifying the path to a file, it would be easy to upload files without the user's consent. That would be a serious security hole.

You may find it more practical to use only Flash or only HTML5 for this.

Can Action Script FileReference object be sent to Javascript and converted to File object?

2 Answers2