Response Object

Another important function of Response object is the control of ASP engine for the HTML output.

Response.Buffer Property

Response.Buffer Property sets a flag to indicate whether the HTML output is buffered or not.

Syntax:

Response.Buffer [=flag]

 Or in an ASP file. Imply

<% Response.Buffer [=flag] %>

Parameters:

flag

The parameter "flag" is the flag to indicate whether the HTML output should be buffered or not. The data type of "flag" is boolean. The possible values of flag are

Value	Description
FALSE	No buffering. The response output is sent to the client after processing. For  IIS 4.0 and earlier, the default value is False
True	Buffer enabled. The response output is stored in the buffer after processing. The response output is sent to the client until all the ASP scripts on the page have been processed, or the Response.Flush method or Response.End method is called. For  IIS 5.0 and later, the default value is True.

Remarks:

The Response.Buffer Property is a read and write property. The Response.Buffer Property can be considered as a flag. The buffer can be enable by assigning True to Response.Buffer Property. The buffer can also be disabled by assigning False to Response.Buffer Property.

And, the value of Response.Buffer Property is True when buffer is enabled. Or the value of Response.Buffer Property is False when the buffer is disabled.

However, the Response.Buffer Property should be set before sending any output to the client. And therefore, the Response.Buffer Property should be set at the first line of the ASP file.

By default, there is alway a predefined value for the Response.Buffer Property. For  IIS 4.0 and earlier, the default value is False. And For  IIS 5.0 and later, the default value is True. The setting of Response.Buffer Property only modify the value of Response.Buffer Property

If buffer is enabled, the response output is stored in the buffer after processing. The response output is sent to the client until all the ASP scripts on the page have been processed.

When a buffer is enabled for a ASP file, the buffered response output will be honor keep-alive by the client if the sending of the buffered response output to the client is not called by the Response.Flush. The making use of buffered response output to response other client request can save time for creating new connection to the same ASP file request.

However, buffering will casue a perceptible delay for ASP file with long script processing time since no response output will be sent to the client until the server has finished all script processing for the current page.

Besides, the metabase AspBufferingOn property can also be used to set the default value for script buffering.

Examples:

• Disable buffering with Response.Buffer=False

  ASP script command:

  <% Response.Buffer=False %>
  <%="One"&"<br />"%>
  Two<br />
  <% Response.End %>
  Three<br />
  <%="Four"&"<br />"%>
  

  HTTP response output:

  One<br />
  Two<br />
  

  HTML web page ouput:

  One
  Two
  

• Enable buffering with Response.Buffer=True

  ASP script command:

  <% Response.Buffer=True %>
  <%="One"&"<br />"%>
  Two<br />
  <%=Response.Buffer%><br />
  <% Response.End %>
  Three<br />
  <%="Four"&"<br />"%>
  

  HTTP response output (Buffered):

  One<br />
  Two<br />
  True<br />
  

  HTML web page ouput:

  One
  Two
  True

Response.Clear Method

Response.Clear Method clears the buffered HTML output.

Syntax:

Clear(
)

 Or in an ASP file. Imply

<% Response.Clear %>

Parameters:

void

The Response.Clear Method has no parameter.

Return Values:

void

The Response.Clear Method has no return values.

Remarks:

The Response.Clear Method can clear the buffered HTML body output only, and the response HTTP headers is not erased by the Response.Clear Method.

Sometimes the Response.Clear Method can be used to handle error cases by clear all the HTML body response output before response to the client request.

If the Response.Buffer has not been set to TRUE before calling the Response.Clear Method, a run-time error will result.

Examples:

• With Response.Clear before calling Response.End when  Response.Buffer=True

  ASP script command:

  <% Response.Buffer=True %>
  <%="One"&"<br />"%>
  Two<br />
  <% Response.Clear %>
  <% Response.End %>
  Three<br />
  <%="Four"&"<br />"%>
  

  HTTP response output (Buffered):

  HTML web page ouput:

Response.Flush Method

Response.Flush Method flushs the buffered HTML output by sending the output immediately.

Syntax:

Flush(
)

 Or in an ASP file. Imply

<% Response.Flush %>

Parameters:

void

The Response.End has no parameter.

Return Values:

void

The Response.End has no return values.

Remarks:

The Response.Flush Method sends the output immediately and the buttered HTML response ouput may be cleared. The buffered response output will not be honor keep-alive by the server for  other client with the same page request.

If the Response.Buffer has not been set to TRUE before calling the Response.Flush Method, a run-time error will result.

Examples:

• No Response.Flush when  Response.Buffer=True

  ASP script command:

  <% Response.Buffer=True %>
  <%="One"&"<br />"%>
  Two<br />
  Three<br />
  <%="Four"&"<br />"%>
  

  HTTP response output (Buffered):

  One<br />
  Two<br />
  Three<br />
  Four<br />
  

  HTML web page ouput:

  One
  Two
  Three
  Four
  

• With  Response.Flush when  Response.Buffer=True

  ASP script command:

  <% Response.Buffer=True %>
  <%="One"&"<br />"%>
  Two<br />
  <% Response.Flush %>
  Three<br />
  <%="Four"&"<br />"%>
  

  HTTP response output (Buffered):

  One<br />
  Two<br />
  ------Flush-------
  Three<br />
  Four<br />
  

  HTML web page ouput:

  Three
  Four
  

• With Response.Flush when  Response.Buffer=True

  ASP script command:

  <% Response.Buffer=True %>
  <%="One"&"<br />"%>
  Two<br />
  Three<br />
  <%="Four"&"<br />"%>
  <% Response.Flush %>
  

  HTTP response output (Buffered):

  One<br />
  Two<br />
  Three<br />
  Four<br />
  ------Flush-------
  

  HTML web page ouput: