How to efficiently send large files from the database to the browser?

In my web application I am working with files. Some files are very large. I use Response.Write() to write the file to the browser. This goes well for the smaller files, but for large files this can take a while and the bandwidth is fully used.

Is it possible to split large docum开发者_开发百科ents and send it piece by piece to the browser? Are there other ways to send the document quicker to the browser?

I hold the document as a property of an object.

Why don't you compress the file and store it in the DB and decompress it will extracting it?

You can do a lot of things depending on this questions:

1. How often does the file change?

2. Do I really need the files in the DB?

3. Why not store the File path in the DB and the File on disk?

Anyhow, since your files are extremely high bandwidth and you would want your app to respond appropriately you might want to use AJAX load the files Asynchronously. You can have a WebHandler .ashx for this.

Here's a few examples:

http://www.dotnetcurry.com/ShowArticle.aspx?ID=193&AspxAutoDetectCookieSupport=1

http://www.viawindowslive.com/Articles/VirtualEarth/InvokingserversidecodeusingAJAX.aspx

My question is, is it possible to split large documents and send it piece by piece to the browser?

It depends on the file type, but in general no. If you are sending something like an excel file or a word doc etc. the receiving application will need all of the information (bytes) to fully form the document. You could physically separate the document into multiple ones, and that would allow you to do so.

If the bandwidth is fully used, then there is nothing you can do to "speed it up" short of compressing the document prior to send. In other words, zip it up.

Depending on the document (I know you said .mht, but we're talking content here) you will see the size go down by some amount. Maybe it's enough, maybe not.

Either way, this is entirely a function of the amount of content you want to send versus the size of the pipe available to send it. One of those is more difficult to change than the other.

Try setting IIS's dynamic compression. By default, it's set fairly low, but you can try setting it for a higher compression level and see how much that helps.

I'm not up to speed with ASP.NET but you might be able to buffer from a FileStream to some sort of output stream.

You can use the Flush method to send the currently buffered data to the client (the browser).

Note that this has some implications, as is described aptly here.

I've considered using it myself, a project sent documents that became fairly large and I was cautious about storing the whole data in memory. In the end I decided the data was not large enough to be a problem though.

Sadly the MSDN documentation is very, very vague on what Flush implies and you will probably have to use Google to troubleshoot.