jumpsfromplanes wrote: > It is probably a Windows/memory problem. You just can't make file streams > that big.
20 MB? Of course you can. > Your filestream code tries to swallow the entire PDF file whole into memory > and *then* send it via HTTP to the client. Doug's file-stream code doesn't do anything with the contents of the file. Where do you see that? He opens the file and gives the stream to the TWebResponse. TFileStream never caches the contents of the file. > If you try to read a file that is too large, your filestream read code will > fail. Trying to allocate too much memory will yield an EOutOfMemory exception. Has that happened in this case? > You probably should use a small (16-64K) buffer and "loop" through the PDF > file, one buffer load at a time. Send the buffer to the client and repeat. A > small buffer created as a local variable will work fine. Using a buffer lets > you work on files of any size - multiple gigabytes, if necessary. > > Remember that the last buffer load is probably only partially filled - you > will have to count the number of actual bytes read into the buffer and make > sure you only send that many to the client. Yeah, I know this is the old > school way to do file transfers, but it actually works with (very) large > files. Notice that Doug didn't *write* any code for for copying the stream. Nor should he. The SendStream methods of TApacheResponse and TApacheTwoResponse copy the stream contents already. They use an 8 KB buffer. > I have a similar problem with a ^...@#&! web browser unit/component I use to > spider an SSL-secured web site and download files. The guy that wrote the > component also used TFileStream, and it bombs on files larger than about 20MB > - great planning in this day and age of large files. I have a bunch of 2-4 GB > files to download, so the component is useless to me until I get around to > rewriting the idiot thing. :-( You and Doug should be more specific about what happens when the file is larger than 20 MB. Doug says the file "won't correctly transfer," and you say you have a "similar problem." What's incorrect about the transfer? How much gets sent? How much arrives? Does Apache log anything about the request? Is the ContentLength header correct? -- Rob
