Magic settings for upload large files under IIS and .NET

I remember when I started this blog; I talked about upload large files using .NET and IIS. This time I’ll share with you some interesting points to be aware of when trying to upload large files. I consider large when the size is bigger than 2GB, because this is the actual limit is almost all web servers under Microsoft technology.
Based on my experience with this kind of situations, I can say that the web environment is not ready to transfer that much information. Remember the beginnings of WWW, when everything that roamed through the wires were just text and small graphics, I say more, remember what HTTP stands for (Hypertext Transfer Protocol) and what is HyperText?
However, the file transfer to and from the server is something very common nowadays, therefore, it’s necessary to know how to handle it. For those who doesn’t need to upload files greater than 500 MB, I recommend the solution I presented through the my firsts posts in this blog, even for upload a bit bigger files, but when the size start over the 1 GB it’s better to think about another solution.
The larger sizes you could upload the bigger security risk you have. I explain, solutions like NeatUpload and many others (open source or not) expect to make the upload in a big single request, although there are modules that make the copy block by block in order to be sure of not making big memory peaks, the web server must allow a very large request, exposing it to a DOS attack, just an example. Another possible problem may be if the client doesn’t have a fast connection (like me) there’s a (high) risk that a large file might be interrupted, and then? Start over again. On the server side the risk of execution timed out exists too (I’ve faced that), so the value of this setting must be increased.
If you wish to upload small/medium files there’s no problem using this kind of solution, but if you want go over the size, I suggest another kind of workaround.
Alongside my research for the best solution I’ve found the following links I hope to be useful to you, I let MSDN articles, Stack Overflow questions, among others very interesting sources written by the most involved people in this matter, where one can drink the honeys of knowledge.

• http://blogs.msdn.com/b/prashant_upadhyay/archive/2011/07/13/large-file-upload-issue-in-asp-net.aspx
• http://www.iis.net/ConfigReference/system.webServer/security/requestFiltering/requestLimits
• http://www.webtrenches.com/post.cfm/iis7-file-upload-size-limits
• http://stackoverflow.com/questions/6802519/how-to-upload-files-over-2gb-to-iis-7-5-net-4
• http://weblogs.asp.net/jgalloway/archive/2008/01/08/large-file-uploads-in-asp-net.aspx
• http://www.mojoportal.com/supporting-large-file-uploads.aspx

As a quick conclusion, I can say the following in order to configure properly your application:
The default value for the request size in ASP.NET 2.0 and later is 4 MB. Under IIS6 the setting is configured by the httpRuntime node, example:

 <configuration> 
  <system.web>
   <httpRuntime maxRequestLength="102400" executionTimeout="3600" />
  </system.web>
 </configuration> 

Important to say here, the value of maxRequestLength is given in KB and the executionTimeout is given in seconds.
Under IIS7+ the setting is configured by the requestLimits node, example:

 <system.webServer>
  <security>
   <requestFiltering>
    <requestLimits maxAllowedContentLength="1024000000" />
   </requestFiltering>
  </security>
 </system.webServer>

In this case the value of maxAllowedContentLength is given in bytes. This must combined with the applicationHost.config file usually located at (C:\Windows\System32\inetsrv\Configs) whose section should look like:

 <section name="requestFiltering" overrideModeDefault="Allow" />

As I said before, I hope this compilation saves you time of google-research, in a further post I’ll talk about another solution that I consider that more fits better in web environment.

I became a member of NeatUpload Open Source Project

I’ll start with a question: who hasn’t ever borrowed at least a small piece of code from the community? I think the number is very close to zero, and why? Is it something about do not reinvent the wheel? And why the community is as huge as nowadays is? The truth is the times have changed, and the old times when a small group of hackers had access to the technology and they were too jealous with their achievements and there were too much selfishness in the air.

Now, as the internet and the communication media have globalized, the exchanges between developers around the world is something common, and probably that’s why you are reading this post. When you start learning a new technology/language/framework (the list might go on), you face many typical problems that a big number of developers around the world faced to, and without the help of some of these experienced developers the work becomes tortuous.

I recently read this post from Scott Hanselman about involving in open source projects and he explains how easy is, even with an example. But, why am I talking about all this? about a year ago, I had to develop a jquery plugin (which occupies several post in this blog) and I decided to publish it for the community. After all, the problem I solved might be the same for other people around the world and, why not to return back the favor to the community? When I needed, I had a lot of code available for just download it and use it. I know, it’s true, not always the documentation is as good as I’d like it was, but that’s something with I have to deal with.

A few weeks ago, I asked myself, what about to show my work to the NeatUpload team? I appreciate their opinion about and that’s what I did. Surprise for me! I received an email from Dean Brettle and Joe Audette celebrating my job and inviting me to join in the project.

My answer was very fast and now I am a member of NeatUpload project. My first contribution was to make the translations for Spanish language in the resources. According to joe and Dean, in the next release, will be included the plugin, documentation and examples mentioned in the early post in this blog. And of course, the further NeatUpload releases will include the last version of jquery.neatupload.

Conclusion, contribute to open source has no cost, is not hard to do, and the benefits you give to the community is returned back when you search for doubt in stackoverflow or just Google. So, contribute!