HTTP

Understanding HTTP is very usefull when working with servlets. In a servlet you can set many HTTP headers and take advantage of their funtionality.
This page has HTTP only information. For more information on servlets see the Servlets page directly.

Common HTTP 1.1 Response Headers [1]

• Cache-Control (1.1) and Pragma (1.0)
  A no-cache value prevents browsers from caching page.
   
• Content-Disposition
  Lets you request that the browser ask the user to save the response to disk in a file of the given name
  Ex.:
  Content-Disposition: attachment; filename=file-name
   
• Content-Encoding
  The way document is encoded.
   
• Content-Length
  The number of bytes in the response.
  See setContentLength on previous slide.
  Use ByteArrayOutputStream to buffer document before sending it, so that you can determine size.
   
• Content-Type
  The MIME type of the document being returned.
  Use setContentType to set this header.
   
• Expires
  The time at which document should be considered out-of-date and thus should no longer be cached.
  In java servlets use setDateHeader to set this header.
   
• Last-Modified
  The time document was last changed.
  Don’t set this header explicitly; provide a getLastModified method instead.
   
• Location
  The URL to which browser should reconnect.
  Use sendRedirect instead of setting this directly.
   
• Refresh
  The number of seconds until browser should reload page.
  Can also include URL to connect to.
   
• Set-Cookie
  The cookies that browser should remember. Don’t set this header directly, use addCookie instead.
   
• WWW-Authenticate
  The authorization type and realm needed in Authorization header.

References:

• [1] - Generating the Server Response: HTTP Response Headers