Item7592: INCLUDE to take shortcut with attachment URLs regardless of file name extension

When an attachment URL such as %ATTACHURL%/filename.txt is INCLUDE'd, TWiki retrieves the attachment directly rather than issuing an HTTP request to itself. But that shortcut works only for .txt, .htm, and .html. Attachment files of other extensions result in HTTP requests to itself. This behavior is not optimal.

A better behavior

INCLUDE is supposed to:

• Handle all attachment URLs on the TWiki site directly regardless of file name extension
• Determine MIME type of an attachment based on file name extension in the same manner as the viewfile script and behave accordingly
• Observe the allowanytype parameter even when it retrieves an attachment directly

Implementation details

File name extension to MIME type conversion takes place in TWiki::UI::View::_suffixToMimeType(). For INCLUDE to behave consistently with the viewfile script regarding file name extension to MIME type correspondence, that function needs to be used by INCLUDE.

TWiki::UI::View::_suffixToMimeType() should change in the following two aspects.

• TWiki::UI::View::_suffixToMimeType() is a local function of TWiki::UI::View and not supposed be called from TWiki::_includeUrl(). As such, TWiki::UI::View::_suffixToMimeType() should be moved to TWiki::suffixToMimeType().
• TWiki::UI::View::_suffixToMimeType() takes two arguments: $session and $fileName. There is no need for $session to determine MIME type. So TWiki::suffixToMimeType() takes one argument, $fileName, only.

-- TWiki:Main/HideyoImazu - 2014-11-30