Does data URL only accept binaries or base 64 for Powerpoint?

Question

There is a trick for creating files in the client using data uri. For example, to create a MS powerpoint you can do something like

<a href="data:application/vnd.openxmlformats-officedocument.presentationml.presentation;base64,UEsDBBQACAAIAGeGhT8AAAAAAAAAAAAAAAATAAAAW0NvbnRlbnRfVHlwZXNdLnhtbM2ay27bMBBF9wX6D4K2hUWbbtO0sJNFH6s+AiT9AFYa22wlkiBpN/77UnLaKEFsiNUQnY1smZw7B0MNLwFrcXnb1NkOrJNaLfNZMc0zU..."  download="jones6.pptx"> Test File 3 </a>

Is the only data that can be specified in the in the URL is the base64 or the binary representation of the file? Is it possible to express any other representation of the file?

[`data:text/plain,No, plain text is also allowed`](http://jsfiddle.net/QeQKx/show/). — Rob W, Aug 28 '12 at 14:46
@Matt Ball, that link refers to data:[][;charset=][;base64], I am referring to the part. Must that be in binary for a powerpoint? Or is there anything more user friendly? — dublintech, Aug 28 '12 at 14:51

score 3 · Answer 1 · answered Aug 28 '12 at 14:51

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Both Base64-encoded and plain content is supported. For example, you can use HTML too:

    <a href="data:text/html;charset=UTF-8,%3C!DOCTYPE%20html%3E%3Chtml%3E%3Chead%3E%3Ctitle%3ETest%3C%2Ftitle%3E%3C%2Fhead%3E%3Cbody%3E%3Ch3%3EIt%20works!%3C%2Fh3%3E%3C%2Fbody%3E%3C%2Fhtml%3E">Click Here!</a>

You should see a "It works!" after clicking the link. (Works in Firefox and Chrome, for compatibility table, see http://caniuse.com/datauri) To generate plain content that can be filled into Data URI, you need to use something like encodeURIComponent in JavaScript or rawurlencode in PHP.

answered Aug 28 '12 at 14:51

littlebtc

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+1 for the part about url encoding. This is necessary, because there's a slim chance that a `%` sequence appears in the binary data, which is not interpreted literally by the browser, but decoded. – Rob W Aug 28 '12 at 14:54
For PowerPoint files, since Both `ppt` and `pptx` are binary files, so I think they can only be represented by base64-encoded string. – littlebtc Aug 28 '12 at 14:58

score 0 · Answer 2 · edited Jul 10 '18 at 04:14

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The syntax of the data protocol is as follows:

data:[sMediaType;][sBase64Encoding;],sResourceData

(https://msdn.microsoft.com/library/cc848897)

As you can see, there isn't any option for a non-base64 encoding.

edited Jul 10 '18 at 04:14

Community

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answered Aug 28 '12 at 14:46

Waleed Khan

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The documentation is OK, but your conclusion is wrong: Base64 is not required for data-URIs. From the docs: "sBase64Encoding **Optional**..." – Rob W Aug 28 '12 at 14:47
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The square brackets mean optional – Musa Aug 28 '12 at 14:48
Though perhaps the documentation implies that `data:,resource` is valid. Which may or may not be the case. – Waleed Khan Aug 28 '12 at 14:48
It says percent coded or base64 encoded. But what you encode must be the binary - yeah?? – dublintech Aug 28 '12 at 14:49

Does data URL only accept binaries or base 64 for Powerpoint?

2 Answers2