Requirements

by Joseph Bank, Joel Aufrecht


OpenACS docs are written by the named authors, and may be edited by OpenACS documentation staff.

Introduction

Gatekeeper allows an OpenACS installation to provide users authenticated access to other web sites. This is particularly useful for dealing with "mounting" another legacy website on our own site, while adding a security layer. We can then only allow access to the legacy website from the main ACS server.

System/Application Overview

Gatekeeper provides an application for managing seamless remote viewing of other web pages with optional security layers. It consists of the following components:

  • A web interface for retrieving foreign urls.

  • An API for adding security restrictions.

Use-cases and User Scenarios

  • Jane Webmaster wants to build an ACS site that provides paid access to a currently existing web site. This other site uses significantly different technology, so full integration would require a great deal of effort.

    1. Jane creates an instance of the gatekeeper package which points to the existing site.

    2. She sets up a security restriction for the gatekeeper instance using ACS permissions by only allowing read access for a newly created user group.

    3. She modifies the ACS Ecommerce system to insert and remove users from the new user group based on their subscription payments.

    4. She modifies the existing site to only serve requests from her ACS server's IP address.

  • --------------------------------------------
    Use case
    --------------------------------------------
    
    Integration of an external web mail client: Squirrelmail (PHP-based) and
    IMAP-Server.
    
    Administrator
    --------------------------------------------
    The institution has to have an IMAP server up and running. OpenACS must
    be installed using the external authentication via pam-imap/ldap/passwd
    (etc.) to authenticate and synchronize openacs users.
    
    The administrator has to have a webmail client like IMP or Squirrelmail
    installed on Apache+PHP. The AOLServer has to have access to Apache for
    instance over localhost.
    
    The administrator has sucessfully installed the external authentication
    package using pam.
    
    The administrator has to do the following to integrate the external
    webmail client squirrelmail using the gatekeeper.
    
    1. Create a new Gatekeeper Instance: Name: Squirrelmail
    2. Indicate the required parameters for the gatekeeper instance:
    - URL to guard:
    http://localhost/squirrel/
    - Gatekeeper Type:
    
    requires external authentication
    - Path to an optional header/footer template
    /www/service0/packages/dotlrn/dotlrn-master.adp
    - Name of the authority used (local, pam, ldap...) or database table
    with account informations:
    pam
    - used login form input field:
    login_username
    - used password form input field:
    secretkey
    - logout/sign-out path:
    http:/localhost/squirrel/src/signout.php
    - request method:
    post
    - form action:
    http:/localhost/squirrel/redirect.php
    - where to add the startpage of the webmail in openacs:
    /dotlrn/?&page-num=3
    
    The timeout of squirrelmail has to be set to a higher value than that of
    OpenACS to make sure that the webmail session is valid as long as the
    OpenACS session is valid.
    
    
    Gatekeeper
    --------------------------------------------
    The Gatekeeper Instance registers itself for auto logon on to that
    authority. Thus after a sucessful login the login information is also
    used to login to the webmail client and the cookies are forwarded to the
    users browser. Thus the authentication package has to be extended for
    post-login and logout procedure-calls. On request the gatekeeper checks
    the content type (html, xhtml, compressed or not, usage of frames or
    not) and rewrites the links appropriately. As soon as the user logs out
    the webmail client is also logged out.
    
    User
    --------------------------------------------
    The user simply logs into the system once and is served a link where he
    can access the webmail-client. In this case over My Space-->My Mails as
    Page three under dotLRN. The documentation of the webmail client has to
    
    be made accessible to the user.
    
    The current Gatekeeper has to be improved by the following:
    - allow usage of templates (done already)
    - allow xml, xhtml
    - allow compressed data
    - auto-check of frames --> if frames are used then the template is
    useless or the frame has to be embedded inside another frameset.
    - cookies forwarding for external application (not sure if that already
    exists)
    
    Restrictions
    --------------------------------------------
    - Different locale between OpenACS and Webmail
    - Different designs (depending on the webmail client this can be changed
    via templates).
    - no true integration into MySpace possible to notify user that she/he
    has new unread emails.
    
  • --------------------------------------------
    Other Use-Case:
    --------------------------------------------
    Integration of PHPWiki (xhtml) via Gatekeeper and LDAP/PAM/SQL...
    
    Username Inputfield: auth[userid]
    Password Inputfield: auth[passwd]
    Form action:    HomePage?action=browse
    For OpenACS-Authority: PAM
    PHPWiki can use many different types of authentication: LDAP, IMAP,
    PASSWD, DB,...
            

Related Links

Lots of other web sites do related things. For example, anonymizer sites allow you to surf the web while doing seamless translation of the page.

Functional Requirements

Req #PriorityStatus in 5.0Description
10.0A?Seamless Viewing. The gatekeeper should provide seamless viewing of URLs. This means that the URLs should look like they belong to the ACS site, not the original site.

Does this refer to web pages or to URL? Ie, does this mean that "user can click on a link and see (password-protected) web pages from a remote site, within the OpenACS site's look and feel," or does it mean, "user can click URLs that look like http://myopenacssite.test/foo/bar"?

20.0A?Restricted Browsing. A given instance of the gatekeeper package should only provide access to a single site. The user must not be able to modify the URL so that arbitrary sites can be retrieved through the server.
30.0A?Link Translation. All links from the gatekeeper page to the given site should be translated to use the gatekeeper.
40.0A?User Tracking. The ability to track all pages viewed via the gatekeeper should exist.

50.0 Flexible Restrictions

50.1 ACS Permissions

The gatekeeper package should support standard ACS permissioning. Access can thus be limited by setting up limited read access to an instance of the gatekeeper package.

50.2 Callbacks

The gatekeepers should be provide access control via registered callbacks.

60.0 Full HTTP Support

The gatekeeper should support the entire HTTP specification.

60.1 POST Support

POST form submission must be supported.

60.2 Non-HTML Pages

Retrieval of non-HTML pages, such as GIFs and JPEGs, must be supported.

60.3 Cookie Support

The system should have the ability to store and respond with cookies sent from the guarded site.

Revision History

Document Revision #Action Taken, NotesWhen?By Whom?
1Creation23 Nov 2000Joseph Bank
2Revised to add Nima Mazloumi's use case.13 Jan 2004Joel Aufrecht
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