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Multi-part Downloading/Uploading?

Posted: Fri Aug 07, 2009 3:31 pm
by claws
Hey all,

I know about Multi-Part Downloading, which is used by all Download Accelerators. If the server allows it, just modification in the request header makes it possible to download multi threaded download using HTTP Multi-part downloading technology.

I was wondering, if we have anything like Multi-Part uploading in HTTP? I mean, a technology, to accelerate file uploads. Some times we may have to upload large files (say to google video, some file hosting sites). We have tons of file hosting sites. popular ones like Rapidshare & Megauploads have their own upload managers, which does upload a file with much more speed than uploading the browser upload. How is this possible? What is technology behind it? Is there any difference in the role of server side PHP script in either of these (browser & upload manager) uploading methods?

I was googling on this, but I didn't get any fruitful results. Please enlighten me on this.

Thank you.

Re: Multi-part Downloading/Uploading?

Posted: Fri Aug 07, 2009 5:53 pm
by Weirdan
claws wrote:I know about Multi-Part Downloading, which is used by all Download Accelerators.
Just a small correction: this is called partial downloads, not multipart. In context of HTTP (and, actually, MIME) multipart means sending several separate entities in response to one request.

From what I know, there's no direct support in HTTP to upload different parts of the same files simultaneously, but you can invent your own protocol extension quite easily.

Re: Multi-part Downloading/Uploading?

Posted: Sat Aug 08, 2009 11:54 am
by claws
Thanks for the correction.
but you can invent your own protocol extension quite easily.
I'm wondering how? I'm not very clear about it. Downloading & UPloading are not the same. Downloading is much obvious. Use partial downloading then the download manager/client will merge them back into single file.

In case of uploading, would be the case? My php script merges them into one file?

Re: Multi-part Downloading/Uploading?

Posted: Sat Aug 08, 2009 2:29 pm
by Weirdan
claws wrote:My php script merges them into one file?
Exactly. I envision something simple, like sending X-Upload-Part: 2/10 header to notify the script it's second part of 10 parts total. Once the script received the part (and it's actually when php starts executing) it checks if all other parts already received and, if they are, assembles entire file. You will need custom upload program able to split files in parts and send parts concurrently, of course (I believe you can use flash to do this).