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Show HN: A Chrome extension that prevents duplicate downloads

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Re: Show HN: A Chrome extension that prevents duplicate downloads

#12

Post by yefim323 »

anigbrowl wrote: post #10
yefim323 wrote: post #5

Earlier quoted context omitted.

I apologize for the lack of support. Chrome's download API ( https://developer.chrome.com/dev/extensions/downloads.html ) is very flaky and has just been added full support in Chrome 27.0.1448.0 dev-m according to http://stackoverflow.com/questions/15451313/closed-uncaught-...

Ah, that explains a lot. This looks useful because I often have an itchy trigger finger and download more than one copy. But you know what I really miss in Chrome would be a decent download manager that lets me select multiple files from one page instead of DLing them one at a time. Last time I looked the only extension for this practically announced itself as malware.

Funnily enough, this extension exists as a sample extension in the Chrome extension docs. Apparently, you can't link to specific samples, so just go to https://developer.chrome.com/dev/extensions/samples.html and filter by "downloads." The extension you're looking for is "Download Selected Links."

It looks like this: http://i.imgur.com/XF6S0mu.png

Re: Show HN: A Chrome extension that prevents duplicate downloads

#13

Post by irrelative »

yefim323 wrote: post #7
quasque wrote: post #6

It's a good idea, but downloading something from the same URL (or filename fragment from an URL) does not necessarily imply that it's a duplicate. Would be interesting to see something similar to this extension that uses attributes sent at the start of an HTTP response - e.g. entity tag or content length - for duplicate checking.

I was thinking of also checking for the same file size. Would that improve the accuracy of detecting duplicates?

It would, but you'd have to first download the whole file to check which is probably counter productive. Consider storing some http header values such as a reference to the Etag header if provided, and checking that value before saving twice. Also consider storing Cache-Control headers, and Expires headers. The Content-Length header would be a way to detect same file size before transferring the whole file, but for large file downloads which used chunked encoding.

Some resources:

http://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html

http://en.wikipedia.org/wiki/Chunked_transfer_encoding

http://en.wikipedia.org/wiki/HTTP_ETag

I'm glad you're addressing this problem! I always end up with file(1).zip in my downloads folder.

Re: Show HN: A Chrome extension that prevents duplicate downloads

#14

Post by anigbrowl »

yefim323 wrote: post #12
anigbrowl wrote: post #10

Earlier quoted context omitted.

Ah, that explains a lot. This looks useful because I often have an itchy trigger finger and download more than one copy. But you know what I really miss in Chrome would be a decent download manager that lets me select multiple files from one page instead of DLing them one at a time. Last time I looked the only extension for this practically announced itself as malware.

Funnily enough, this extension exists as a sample extension in the Chrome extension docs. Apparently, you can't link to specific samples, so just go to https://developer.chrome.com/dev/extensions/samples.html and filter by "downloads." The extension you're looking for is "Download Selected Links." It looks like this: http://i.imgur.com/XF6S0mu.png

+20 internets to you - that's a serious time-saver for me!
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