Javascript RAR reader • Hacker News Board

Re: Javascript RAR reader

#11

Post by kybernetyk » Tue, Nov 05, 2013, 12:48 PM UTC

lmm wrote: post #7

goggles99 wrote: post #4

Is this just a POC to prove that JavaScript can be fast? This is a serious question. I am having a difficult time thinking of practical uses for this.

Imagine a photo-sharing webapp that allowed users to drag a rar file in and then pick which images to upload. I'm sure there are other use cases, but that one immediately comes to mind.

I don't know ... that sounds like a pretty rare edge case.

Photos you usually want to share are JPGs and 'raring' them doesn't do much good in terms of space saving.

The only image files you'd like to compress are those that are taking too much space (tiffs, raw images, etc). And if you take the extra effort to put them into an archive it's likely that they are taking up really a lot of space.

Thus it's very very likely that even one of those images is too big to upload it to the internet (tens of megabytes if not more) with today's common end user internet connections.

Re: Javascript RAR reader

#12

Post by bigd » Tue, Nov 05, 2013, 12:56 PM UTC

$(document).ready(unrar(totallyL3git.rar))

Re: Javascript RAR reader

#13

Post by bigd » Tue, Nov 05, 2013, 12:59 PM UTC

bigd wrote: post #12

$(document).ready(unrar(totallyL3git.rar))

Better explain before the shitstorm: I find it a neat idea, but is is something like this possibly dangerous?

Re: Javascript RAR reader

#14

Post by justincormack » Tue, Nov 05, 2013, 1:27 PM UTC

thristian wrote: post #3

That's interesting. So far as I know, the only documentation of the RAR compression algorithm is the official UnRAR tool¹, which (among other things) restricts you from using it to create a RAR-writer. There's also the GPL'd "unrar" based on UnRAR 2 (which doesn't handle modern RAR 3.x archives), and the GPL'd "unar"². Given that this is under the MIT licence, it can't be derived from any of those other tool, so I gu…

The GPL is a copyright license and does not apply to a reimplementation.

Re: Javascript RAR reader

#15

Post by lmm » Tue, Nov 05, 2013, 3:34 PM UTC

kybernetyk wrote: post #11

lmm wrote: post #7

Earlier quoted context omitted.

Imagine a photo-sharing webapp that allowed users to drag a rar file in and then pick which images to upload. I'm sure there are other use cases, but that one immediately comes to mind.

I don't know ... that sounds like a pretty rare edge case. Photos you usually want to share are JPGs and 'raring' them doesn't do much good in terms of space saving. The only image files you'd like to compress are those that are taking too much space (tiffs, raw images, etc). And if you take the extra effort to put them into an archive it's likely that they are taking up really a lot of space. Thus it's very very lik…

People often have collections of images that are kept in rars or zips not for compression (which as you say this is no good for) but for convenience and organization. Or consider e.g. the "cbr" pseudo-format, where comics are stored as a rar of images, one per page. I can well imagine a web-based CBR viewer.