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Version history:

  • 27th October 2005: 1.2.9
  • 14th March 2004: 1.2.5
  • 3rd March 2004: 1.2.4
  • 6th July 2003: 1.2.1
  • 4th July 2003: 1.2
  • 22nd March 2003: 1.1b8
  • 18th March 2003: 1.1b7
  • 15th March 2003: 1.1b6
  • 8th March 2003: 1.1b5


The REALbasic 3.5.2 source project is included in the download.

See also:

MacASP-error acgi bridge for MacASP users.

Made with REALbasic

error acgi 1.2.9 open source

error acgi is a free, open source CGI application for the MacHTTP Web server, which provides virtual directory listings and dynamic error pages on the fly, support for multiple default page names (such as index.html and index.asp) and file/folder redirection.

The program requires at least 1.4 MB of RAM (cheers, REALbasic) and System 8.1. See my update resources for older Mac OS page for tips on running the program on System 7.6 and earlier. error acgi 1.2.9 has been successfully tested on System 7.5.5 on a Macintosh LC475.


  • Automatic, customisable virtual directory listing (folder listing) generation on the fly; no need to generate files by hand, nor manually refresh them when your site changes. Directory listings can display Finder comments, and the URLs of web location files. Directory listings can show custom header messages, in plain text or HTML. Listings can also be accessed in tab-separated text/plain format. For security reasons, you can specify which parts of your site are to permit listings.
  • 301-based redirection for folders and files
  • Allows you to have multiple default page names, such as index.html and index.asp
  • Dynamic error pages, which can contain any combination of code, name and message for errors that occur
  • Template-based customisation of the listing and error pages, so that they match your site’s style
  • Display of code 500 error pages for when the server has failed to send a file which does exists, as a diagnostic aid (usually either a file lacking a file extension, or a missing MIME entry in the MacHTTP config file)
  • Settings can be reloaded on the fly either from the GUI, or via an AppleEvent


  • Hubert Garrido (MacASP developer) for encouraging me to transform the program from a hard-coded personal application into a flexible application suitable for other users, and for help and advice during development (such as dealing with conditional GET requests).
  • John Silvestri for showing me that the program needed to support URL rewriting, for spotting that the trailing slashes on directory names in basic listing mode were being incorrectly encoded as ‘%2F’ and for being a fan
  • Tom Anthony for revealing the bug whereby items in the path of more than 31 chars would cause the program to unintentionally list the MacHTTP folder’s contents.
  • The late Jesse Dylan Barwick for a suggestion for the easter egg.
  • Simon Williams of 8-bit Sound and Fury for requesting a 68k version; there was not not before but there is now.

There is little use in continuing to maintain this. I no longer use it. Note that MacASP is archived here for those still needing it.