<html>
<!--AD_DND-->
<head>
<title>News</title>
</head>
<body bgcolor=#ffffff text=#000000>
<h2>News</h2>
part of the <a href="">ArsDigita Community System</a>
by <a href="http://photo.net/philg/">Philip Greenspun</a> and <a href="mailto:jkoontz@arsdigita.com">Jesse Koontz</a>
<hr>
<ul>
<li>User-accessible directory: <a href="/news/">/news/</a>
<li>Site administrator directory: <a href="/admin/news/">/admin/news/</a>
<li>data model : <a href="/doc/sql/display-sql.tcl?url=/doc/sql/news.sql">/doc/sql/news.sql</a>
<li>Tcl procs: /tcl/news-defs.tcl
</ul>
<h3>The Big Idea</h3>
A news item is something that is interesting for awhile and then should
disappear into the archives without further administrator intervention.
We want a news article to serve as the focus of user comments. You
could use the /bboard system to accomplish the same function. If you
did, you'd get the advantages of file attachments, group-based
administration, etc. But we think that news truly is different from
discussion. We want to present it by date, not by topic. The publisher
probably wants to be very selective about what gets posted (as news if
not as comments on news). So it gets a separate module.
<p>
However, a <b>Newsgroup</b> approach allows a small about of administrative
control over group scoped news postings.
<blockquote>
A message area in the Usenet News, each newsgroup can be either 'moderated' with only
postings approved by a moderator publically posted, or 'unmoderated' where all messages
are distributed to the newsgroup immediately.
</blockquote>
<p>
This module has three special newsgroups. The public newsgroup contains news
items that are accessed at the site wide scope. The all_users newsgroup contains
news items that show up on all newsgroups. The registered_users
newsgroup contains news items that show up for all registered users.
<h3>Under the Hood</h3>
The data model has a two tables; one for describing newsgroup and another for holding the news items.
<blockquote>
<pre><code>
create sequence newsgroup_id_sequence start with 1;
create table newsgroups (
newsgroup_id integer primary key,
-- if scope=all_users, this is the news for all newsgroups
-- is scope=registered_users, this is the news for all registered users
-- if scope=public, this is the news for the main newsgroup
-- if scope=group, this is news associated with a group
scope varchar(20) not null,
group_id references user_groups,
check ((scope='group' and group_id is not null) or
(scope='public') or
(scope='all_users') or
(scope='registered_users'))
);
create sequence news_item_id_sequence start with 100000;
create table news_items (
news_item_id integer primary key,
newsgroup_id references newsgroups not null,
title varchar(200) not null,
body clob not null,
-- is the body in HTML or plain text (the default)
html_p char(1) default 'f' check(html_p in ('t','f')),
approval_state varchar(15) default 'unexamined' check(approval_state in ('unexamined','approved', 'disapproved')),
approval_date date,
approval_user references users(user_id),
approval_ip_address varchar(50),
release_date date not null,
expiration_date date not null,
creation_date date not null,
creation_user not null references users(user_id),
creation_ip_address varchar(50) not null
);
</code></pre>
</blockquote>
Comments are handled by the general comments facility and are attached to news items.
<p>
Permissions are handled by the general permissions system, and are attached
to the newsgroup rows.
<p>
This module requires that a row exists in the newsgroups table before news
items can be stored for a group (or scope). The all_users, registered_users, and
public newsgroups are created by default. The group newsgroups are created when
a group administrator or site-wide admin attempts to add an item or set the
newsgroup permissions. The default permissions for a non-existent group scope
newsgroup is to allow members to view and admins to modify.
<h3>Related Modules</h3>
The <a href="calendar.html">/calendar module</a> is better if the news
is about an upcoming event. In this module, the non-expired items that
are closest are displayed. Also, there is some support for
personalization by state or country. See <a
href="http://www.harpcolumn.com">www.harpcolumn.com</a> for a good
running example that distinguishes /news from /calendar.
<p>
The <a href="bboard.html">/bboard system</a> is better if you want to
support lively discussion and archive the exchanges.
<h3>Future Enhancements</h3>
This module will eventually be designed to produce an XML document of the
news items to be displayed. This can then be displayed in an adp templating
system or incorporated as a part of a larger XML document.
<p>
The module may also eventually support the deletion of items (and associated
permissions and comments).
<hr>
<a href="http://photo.net/philg/"><address>philg@mit.edu</address></a>
</body>
</html>