Thanks a lot Chris for the reply. i think even if i parse the request myself i have to always load the content in memory/disk. Because in order to extract the file uploaded from the request , i have to go through the whole request stream and trim down the boundaries.
Best Regards, Saurav On Thu, Jan 3, 2019 at 3:20 AM Christopher Schultz < ch...@christopherschultz.net> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > Saurav, > > On 1/2/19 12:20, Saurav Sarkar wrote: > > Hi All, > > > > This is regarding the reading of multi part content in java server > > side. > > > > ServletRequest has an API getParts() API for reading the parts of a > > multi part request > > https://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletReq > uest.html#getParts() > <https://docs.oracle.com/javaee/6/api/javax/servlet/http/HttpServletRequest.html#getParts()> > > > > > . > > > > It has part.getInputStream which can be used to read the content of > > a specific part. > > > > Tomcat also provides an implementation for this API. > > > > But this API parses the multi part content and keeps it in memory. > > If the size increase then the content can be offloaded to disk. > > > > Why does the getPart API or any multi part parsing need to load the > > content in memory ? Why can't direct streaming of content happen ? > > Loading the content in memory and reading/writing to disk brings > > extra cost. This will be specially costly when large files are > > getting uploaded. > > True. You can always limit the part-size or request-size, but you > can't stream huge uploads if you want to use getParts(). > > > Is there no way where at least the file content loading could be > > avoided ? > > Yes, there is a way. > > Instead of calling HttpServletRequest.getParameter* or > HttpServletRequest.getPart*, you can call > HttpServletRequest.getInputStream and parse everything yourself. > > > It may be not be a very specific question for tomcat but more > > applicable to any servlet container. > > Correct, this is applicable to any servlet container. > > The multipart code in Tomcat parses everything to memory/disk at once > because servlet code needs to be able to call > HttpServletRequest.getParameter(String) in any order regardless of > what how the request data is actually ordered. Also, getParts must > return before the calling code can actually do anything with the data. > There is no "register a stream handler for a multipart request part > called 'foo'" or anything like that. > > If you want those semantics, you'll have to parse the request yourself. > > - -chris > -----BEGIN PGP SIGNATURE----- > Comment: Using GnuPG with Thunderbird - https://www.enigmail.net/ > > iQIzBAEBCAAdFiEEMmKgYcQvxMe7tcJcHPApP6U8pFgFAlwtMjkACgkQHPApP6U8 > pFgtJA//eRy6nI9gSj10Ok1PYRSYNGJHcblGieiK8aicWqq0xV/RQgMVarq6PK8i > OHaBt3e/plA9Z5fr7tNs0jyT6dEhrVONYgkLJmyNxLC/EBtYXFD4M2q2R+YnIZbO > GZBjse/O5xzJAK3jJbWVe9w+rJfz6FCp6mPn/0AUNMUVhOgzC5/1oeKvMkyooEHY > 598ULLioK0ZvHWHeVJNe/hNdggjwm9jNuDrxuvrNLX6fY44ed/jlfzUh3G0tAw8B > Ik1Ug8AJi1EQU0sVPfik5Fos7D740DI0KiRcQWsjvEqvelJhWfNTQkkY9GWUmPzW > EMvCJH1T+ehGYo8HD1w+I74SsFlfTRyI/muzzlT5Gy2hCzN56JN4QU+oUQhGfS1E > njF0SAmB47XYdMq2fKSaaqmi+zfsvr1AgaPBE/TyfXhCRUYe7K34ThXBpbqon0dd > UdphHvka7gyBp/dqrufyhr/EjfnCi6MWUoLSWEIhrMvfeEFsrKshRlql3B+aE9Vk > iuwb0p2TT7vu79oCeHr+eANdIurM8vrBx5+PYWJ8AbMqarHeCyvyR0tfgAzokI9w > 2rVlg2NuiVN3ByuK9ytDGp94m5BwxdQ1jC8zeJUgCpKesXxzrB4c1IhaY6CRTEFa > S3K6IfGtc1zSKGMaN/gz8Mqq5ljm2P8GfkwrzxoDLETjjgVjxKE= > =DKX3 > -----END PGP SIGNATURE----- > > --------------------------------------------------------------------- > To unsubscribe, e-mail: users-unsubscr...@tomcat.apache.org > For additional commands, e-mail: users-h...@tomcat.apache.org > >
