Yeah, sendfile() is how I've done this in the past, although I was using mod_perl 1.x for it.
On Sat, Mar 28, 2015 at 5:55 AM, André Warnier <a...@ice-sa.com> wrote: > Randolf Richardson wrote: > >> I know that it's possible(and arguably best practice) to use Apache to >>> download large files efficiently and quickly, without passing them >>> through >>> mod_perl. However, the data I need to download from my application is >>> both >>> dynamically generated and sensitive so I cannot expose it to the internet >>> for anonymous download via Apache. So, I'm wondering if mod_perl has a >>> capability similar to the output stream of a java servlet. Specifically, >>> I >>> want to return bits and pieces of the file at a time over the wire so >>> that >>> I can avoid loading the entire file into memory prior to sending it to >>> the >>> browser. Currently, I'm loading the entire file into memory before >>> sending >>> it and >>> >>> Is this possible with mod_perl and, if so, how should I go about >>> implementing it? >>> >> >> Yes, it is possible -- instead of loading the entire contents of >> a file into RAM, just read blocks in a loop and keep sending them until you >> reach EoF (End of File). >> >> You can also use $r->flush along the way if you like, but as I >> understand it this isn't necessary because Apache HTTPd will send the data >> as soon as its internal buffers contain enough data. Of course, if you can >> tune your block size in your loop to match Apache's output buffer size, >> then that will probably help. (I don't know much about the details of >> Apache's output buffers because I've not read up too much on them, so I >> hope my assumptions about this are correct.) >> >> One of the added benefits you get from using a loop is that you >> can also implement rate limiting if that becomes useful. You can certainly >> also implement access controls as well by cross-checking the file being >> sent with whatever internal database queries you'd normally use to ensure >> it's okay to send the file first. >> >> > You can also : > 1) write the data to a file > 2) $r->sendfile(...); > 3) add a cleanup handler, to delete the file when the request has been > served. > See here for details : http://perl.apache.org/docs/2. > 0/api/Apache2/RequestIO.html#C_sendfile_ > > For this to work, there is an Apache configuration directive which must be > set to "on". I believe it is called "UseSendFile". > Essentially what senfile() does, is to delegate the actual reading and > sending of the file to Apache httpd and the underlying OS, using code which > is specifically optimised for this purpose. It is much kore efficient than > doing this in a read/write loop by yourself, at the cost of having less > fine control over the operation. >
