Question

I am trying to determine where Asp.Net and/or IIS store file uploads when you upload a file BUT before you call the SaveAs() method.

I looked on MSDN and I kind of get the idea that it’s in memory and not put on the file system, but I can’t find it anywhere it says this explicitely.

I am trying to verify to IT that uploaded files (whose streams are passed on to FTP without ever calling SaveAs()) will not be automatically replicated by our server replication system.

Answer 1

The following is from How to change the default TempFile upload location for the ASP.NET 2.0 FileUpload control?

Dumping out the HttpRawUploadedContent from a memory dump, I can see that the file is buffered in the C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\fileupload20\d909613c\d78e07ba\uploads files folder and is called f-zqaz-r.post 


0:008> !do 017c3fbc 
Name: System.Web.HttpRawUploadedContent+TempFile
MethodTable: 68a870e0
EEClass: 68a87070
Size: 20(0x14) bytes
GC Generation: 0
 (C:\WINDOWS\assembly\GAC_32\System.Web\2.0.0.0__b03f5f7f11d50a3a\System.Web.dll)
Fields:
      MT    Field   Offset                 Type VT     Attr    Value Name
7a754a14  4000fb0        4 ...empFileCollection  0 instance 017c4944 _tempFiles
790fa3e0  4000fb1        8        System.String  0 instance 017c54e4 _filename
790fe3c8  4000fb2        c     System.IO.Stream  0 instance 017c55f8 _filestream


0:008> !do 017c54e4 
Name: System.String
MethodTable: 790fa3e0
EEClass: 790fa340
Size: 262(0x106) bytes
GC Generation: 0
 (C:\WINDOWS\assembly\GAC_32\mscorlib\2.0.0.0__b77a5c561934e089\mscorlib.dll)
String: C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\Temporary ASP.NET Files\fileupload20\d909613c\d78e07ba\uploads\f-zqaz-r.post


If you want to change the default location, The tempDirectory attribute of the <compilation> element allows you to specify the directory to use for temporary file storage during compilation. The default is an empty string (""). In the case of an empty string, and if the current process has the required access permissions, the files are stored in the %FrameworkInstallLocation%\ Temporary ASP.NET Files directory.

compilation Element (ASP.NET Settings Schema) shows the compilation element where the tempDirectoryattribute holds the location for the temp files while a upload is in progress.