ChunkReadSize Property of ASPForm class

Property | Member of  ScriptUtils.ASPForm | Changes | Purchase | Download


Specifies length of blocks readed from the client. ASPForm will read data source data using Request.BinaryRead(ChunkReadSize) method.


vChunkReadSize = ASPForm.ChunkReadSize
ASPForm.ChunkReadSize = vChunkReadSize




1. Default value is 4kB bytes.
2. 0 (Zero) means that the source data are read in one block. There is no good idea to read whole data in one block - see note about IIS bellow.
3. If the source form size exceeds ScriptUtils.ASPForm.MaxMemoryStorage value, ASPForm will consume only 2*ChunkReadSize of physical memory. 4. ChunkReadSize should be
ChunkReadSize * n1 = PutReadSize
ChunkReadSize * n2 = UploadReadAheadSize
where n1 and n2 are integers.

Note about IIS and source binary data stream: IIS reads 48kB of data first (by default, see UploadReadAheadSize property of IIS). All other data are read in 8kB blocks (see PutReadSize property of IIS). The best value for UploadReadAheadSize is 0 (zero), please see ScriptUtils.ASPForm.Upload - Monitor and handle upload state/result article.

You can read/change this IIS values for web server, web site, folder or exact upload script:

  Dim WebServer, UploadReadAheadSize, PutReadSize
  Set WebServer = GetObject("IIS://localhost/W3SVC[/sitenum[/folder[/uploadscript.asp]]]")
  'Get UploadReadAheadSize property
  UploadReadAheadSize = WebServer.UploadReadAheadSize
  'Set another size
  WebServer.UploadReadAheadSize = 0

  'Get PutReadSize property
  PutReadSize = WebServer.PutReadSize
  'Set another size
  WebServer.PutReadSize = 65536


Upload - Read short source data in one block

'Sample file Form-ChunkSize.asp 

'Create upload form
Dim Form: Set Form = Server.CreateObject("ScriptUtils.ASPForm")

If Request.TotalBytes>0 And Request.TotalBytes<100000 Then
  'Read short source data in one block 
  Form.ChunkReadSize = 0
End If

'was the Form successfully received?
If Form.State = 0 Then
  Response.Write "<br>n of Items:" & Form.Items.Count
  Response.Write "<br>n of Fields:" & Form.Fields.Count
  Response.Write "<br>n of Files:" & Form.Files.Count
  Response.Write "<br>" & vbCrLf
End If'Form.State = 0 then
<br>sample For <A Href=>HugeASP upload</A>
<form name="file_upload" method="POST" ENCTYPE="multipart/form-data" >
<input Name=SourceFile1 Type=File>
<input Name=SourceFile2 Type=File>
<input Name=Description1>
<input Name=SubmitButton Value="Submit >>" Type=Submit>

Other links for ChunkReadSize

Methods of ASPForm class

AddConnection, CancelConnection, CheckRequirements, Read, Sleep, StringToBinary

Properties of ASPForm class

BytesRead, Files, FormType, getForm, CharSet, ChunkReadSize, Items, MaxMemoryStorage, NewUploadID, ReadTime, ReadTimeout, SizeLimit, SourceData, State, TempPath, Texts, ThreadPriority, TotalBytes, UploadID


The ASPForm collection retrieves the values of form elements posted to ASP script by a form using the POST method. ASPForm can process multipart/form-data or application/x-www-form-urlencoded data with length up to 2GB.


Huge ASP upload is easy to use, hi-performance ASP file upload component with progress bar indicator. This component lets you upload multiple files with size up to 4GB to a disk or a database along with another form fields. Huge ASP file upload is a most featured upload component on a market with competitive price and a great performance . The software has also a free version of asp upload with progress, called Pure asp upload , written in plain VBS, without components (so you do not need to install anything on server). This installation package contains also ScriptUtilities library. Script Utilities lets you create hi-performance log files , works with binary data , you can download multiple files with zip/arj compression, work with INI files and much more with the ASP utility.

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