The Atom Publishing Protocol (APP) is an application-level protocol
   for publishing and editing Web resources.  The protocol is based on
   HTTP transfer of Atom-formatted representations.  The Atom format is
   documented in the Atom Syndication Format [RFC4287].

 Protocol Model

   The Atom Publishing Protocol uses HTTP methods to author Member
   Resources as follows:

   o  GET is used to retrieve a representation of a known resource. ( currently the plugin supports pages and news )

   o  POST is used to create a new, dynamically-named, resource.  When
      the client submits non-Atom-Entry representations to a Collection
      for creation, two resources are always created - a Media Entry for
      the requested resource, and a Media Link Entry for metadata (in
      Atom Entry format) about the resource.

   o  PUT is used to update a known resource.

   o  DELETE is used to remove a known resource.
   
This plugin implements the draft version of the atom publisihing protocl - http://www.ietf.org/html.charters/atompub-charter.html
APP is emerging as the leading content publishing api and there are a host of clients on the way.

Purpose :
Provide access to confluence content via a universal publishing api - allow the usages of WYSIWYG xhtml publishing editors.

Usage :

Once deployed the plugin exposes the Service Document (the entry point for clients ) at http://your-confluence-server:your-port/plugins/servlet/app 
currenty resources are provided in raw wiki markup and accepted in wiki format with a "text" content type or html/xhtml with the "xhtml" or "html" content types 
further work is required to provide a seamless wiki<->xhtml translation.


Testing :

Simplest way to test is by using wget :

{code}
C:\dev\apps\confluence-2.4.5-std\bin>wget  -O - http://localhost:8086/plugins/servlet/app/

--13:15:19--  http://localhost:8086/plugins/servlet/app/
           => `-'
Resolving localhost... 127.0.0.1
Connecting to localhost|127.0.0.1|:8086... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/atomsvc+xml]

    [<=>                                                                          ] 0             --.--K/s             <
?xml version="1.0" encoding="UTF-8"?>
<app:service xmlns:app="http://purl.org/atom/app#">
  <app:workspace xmlns:atom="http://www.w3.org/2005/Atom" atom:type="text">
    <atom:title>Demonstration Space</atom:title>
    <app:collection href="http://localhost:8086/plugins/servlet/app/ds/pages" atom:type="text">
      <atom:title>pages</atom:title>
      <app:accept>entry</app:accept>
    </app:collection>
    <app:collection href="http://localhost:8086/plugins/servlet/app/ds/news" atom:type="text">
      <atom:title>news</atom:title>
      <app:accept>entry</app:accept>
    </app:collection>
  </app:workspace>
  <app:workspace xmlns:atom="http://www.w3.org/2005/Atom" atom:type="text">
    <atom:title>Space Cadets</atom:title>
    <app:collection href="http://localhost:8086/plugins/servlet/app/SCD/pages" atom:type="text">
      <atom:title>pages</atom:title>
      <app:accept>entry</app:accept>
    </app:collection>
    <app:collection href="http://localhost:8086/plugins/servlet/app/SCD/news" atom:type="text">
      <atom:title>news</atom:title>
      <app:accept>entry</app:accept>
    </app:collection>
  </app:workspace>
</app:service>


    [ <=>                                                                         ] 1,180         --.--K/s

13:15:20 (21.09 MB/s) - `-' saved [1180]
{code}
The above service document describes 2 workspaces ( a workspace mapps to a confluence space ), each with two collections - "pages" and "news"


you can retrieve a collection using the href attribute specified by the service document - lets get the collection of pages for the Deomonstration Space:

{code}

wget  -O - http://localhost:8086/plugins/servlet/app/ds/pages


Resolving localhost... 127.0.0.1
Connecting to localhost|127.0.0.1|:8086... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/atom+xml]

<?xml version="1.0" encoding="UTF-8"?>

<feed xmlns="http://www.w3.org/2005/Atom" xmlns:taxo="http://purl.org/rss/1.0/modules/taxonomy/" xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:sy="http://purl.org/rss/1.0/modules/syndication/" xmlns:dc="http://purl.org/dc/elements/1.1/">

  <title>pages</title>

  <link rel="self" href="http://localhost:8086/plugins/servlet/app/ds/pages" />

  <author>

    <name>admin</name>

  </author>

  <id>http://localhost:8086/display/dspages</id>

  <updated>2007-04-27T18:56:26Z</updated>

  <entry>

    <title>Thumbnail gallery</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Thumbnail+gallery" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32770" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32770</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-21T18:44:10Z</published>

    <summary type="text">Images look very effective when included within Confluence. We've provided thumbnail and thumbnail gallery macro http://confluence.atlassian.com/display/DOC/GalleryMacro functionality.   Confluence builds a gallery of thumbnailed images, to the page, by use of the gallery macro. .   Including ...</summary>

  </entry>

  <entry>

    <title>Tasklist</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Tasklist" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32771" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32771</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-21T15:57:13Z</published>

    <summary type="text">More information about the tasklist macro is available at Tasklist macro http://confluence.atlassian.com/display/CONFEXT/TaskListMacro   The tasklist macro comes packaged with Confluence (since version 1.3). It allows you to create lists of tasks which need to be performed and keeps ...</summary>

  </entry>

  <entry>

    <title>News</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/News" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32772" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32772</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-17T23:24:05Z</published>

    <summary type="text">Creating RSS feeds in Confluence is easy.  Usage: \   Parameter Required Default Description  myrssurl yes none the url to the RSS feed  Example: \    Insert CNN feed here</summary>

  </entry>

  <entry>

    <title>Creating pages and linking</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Creating+pages+and+linking" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32773" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32773</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-22T00:34:03Z</published>

    <summary type="text">documentation below is an abbreviated version of our online documentation for creating pages and links http://confluence.atlassian.com/display/DOC/LinkingInConfluence in Confluence. You may also find our online discussion of Page families http://confluence.atlassian.com/display/DOC ...</summary>

  </entry>

  <entry>

    <title>Breadcrumb demonstration</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Breadcrumb+demonstration" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32774" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32774</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-22T00:40:11Z</published>

    <summary type="text">more in depth information on breadcrumbs and page hierarchies visit our online documentation at Page families http://confluence.atlassian.com/display/DOC/PageFamilies  As a child of Creating pages and linking, this page is ideal for demonstrating the concept of breadcrumbs. \\  Breadcrumbs designate a pathway through ...</summary>

  </entry>

  <entry>

    <title>Index</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Index" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32776" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32776</id>

    <updated>2007-05-10T00:33:34Z</updated>

    <published>2004-11-15T18:17:00Z</published>

    <summary type="text">{index}...</summary>

  </entry>

  <entry>

    <title>Formatting Content</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Formatting+Content" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32777" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32777</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-18T02:13:31Z</published>

    <summary type="text">Confluence markup is easy to learn and quick to use. Below you will find a quick overview of markup, but not a comprehensive one. It is enough to get you started. You can also visit our online documentation for Confluence Markup http://confluence.atlassian.com/display ...</summary>

  </entry>

  <entry>

    <title>Source code</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Source+code" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32778" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32778</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-18T02:06:53Z</published>

    <summary type="text">other macros, besides that of the source code macro discussed below, please visit The Guide to Confluence Macros http://confluence.atlassian.com/display/DOC/GuidetoConfluenceMacros.   The source code macro is a useful way of presenting technical information to a group of users online. It's use ...</summary>

  </entry>

  <entry>

    <title>Search Confluence content</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Search+Confluence+content" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32779" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32779</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-15T19:09:56Z</published>

    <summary type="text">Confluence search engine is based on Lucene http://jakarta.apache.org/lucene. It begins working as soon as you install Confluence and can build search indices on a wide range of document types: blogs, pages, comments, attachments, etc..   Confluence can search ...</summary>

  </entry>

  <entry>

    <title>Using Spaces</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Using+Spaces" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32780" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32780</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-22T18:32:19Z</published>

    <summary type="text">more detailed introduction to spaces please refer to our online documentation http://confluence.atlassian.com/pages/viewpage.action?pageId=390.   Spaces bind Confluence content together beneath a name. They are the containers for pages, blogs, and email.  As you've probably guessed by now ...</summary>

  </entry>

  <entry>

    <title>Example Index</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Example+Index" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32781" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32781</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-21T16:32:20Z</published>

    <summary type="text">{index:exampleIndex}

...</summary>

  </entry>

  <entry>

    <title>Email archiving</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Email+archiving" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32784" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32784</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-21T23:14:24Z</published>

    <summary type="text">Email functionality is discussed in greater detail in the release notes http://confluence.atlassian.com/pages/viewpage.action?pageId=9919 for mail archiving   Confluence can archive emails which is useful for tracking information over a long period of time and referencing emails in documents ...</summary>

  </entry>

  <entry>

    <title>RSS Capabilities</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/RSS+Capabilities" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32785" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32785</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-15T18:41:35Z</published>

    <summary type="text">Below you will find a quick introduction to the use of RSS on Confluence. If you wish to find more information then please visit our online introduction to RSS http://confluence.atlassian.com/display/DOC/RSS.  Alternatively, you can view online documentation ...</summary>

  </entry>

  <entry>

    <title>Confluence Overview</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Confluence+Overview" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32787" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32787</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-15T18:51:54Z</published>

    <summary type="text">Confluence space is a living example of how to share information with others. You may to the space whenever you wish. In fact, we encourage you to do so. :)  Please direct any sales related questions to mailto:sales@atlassian.com or please view ...</summary>

  </entry>

  <entry>

    <title>Jira integration</title>

    <link rel="alternate" href="http://localhost:8086/display/ds/Jira+integration" />

    <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32788" />

    <author>

      <name>admin</name>

    </author>

    <id>http://localhost:8086/plugins/servlet/app/ds/pages/32788</id>

    <updated>2007-04-27T18:56:27Z</updated>

    <published>2004-11-18T01:59:25Z</published>

    <summary type="text">Below you will find a brief introduction to Jira. For more information on Atlassian's founding product please see the Jira webpage http://atlassian.com/software/jira for more information or, alternatively, learn how to pronounce "Jira" http://atlassian.com/software/jira ...</summary>

  </entry>

</feed>

{code}

The result is a std Atom 1.0 feed of all the pages in the space.
To get a single page we use the edit link of the entry :

{code}
C:\dev\apps\confluence-2.4.5-std\bin>wget  -O - http://localhost:8086/plugins/servlet/app/ds/pages/32788
--13:23:15--  http://localhost:8086/plugins/servlet/app/ds/pages/32788
           => `-'
Resolving localhost... 127.0.0.1
Connecting to localhost|127.0.0.1|:8086... connected.
HTTP request sent, awaiting response... 200 OK
Length: unspecified [application/atom+xml]

    [<=>                                                                          ] 0             --.--K/s             <
entry xmlns="http://www.w3.org/2005/Atom">
  <title>Jira integration</title>
  <link rel="alternate" href="http://localhost:8086/display/ds/Jira+integration" />
  <link rel="edit" href="http://localhost:8086/plugins/servlet/app/ds/pages/32788" />
  <author>
    <name>admin</name>
  </author>
  <id>http://localhost:8086/plugins/servlet/app/ds/pages/32788</id>
  <updated>2007-04-27T18:56:27Z</updated>
  <published>2004-11-18T01:59:25Z</published>
  <content type="text">{panel}
Below you will find a brief introduction to Jira. For more information on Atlassian's founding product please see the [J
ira webpage|http://atlassian.com/software/jira] for more information or, alternatively, learn [how to pronounce "Jira" |
http://atlassian.com/software/jira/docs/latest/faq.html#what_does_jira_mean]
{panel}

{excerpt}
Jira is Atlassian's issue tracking system. Confluence can watch issues created within Jira, allowing the integration of
a content management solution with an issue tracking system.
{excerpt}

{jiraissues:url=http://jira.atlassian.com/secure/IssueNavigator.jspa?view=rss&amp;order=DESC&amp;tempMax=25&amp;reset=tr
ue|columns=type;key;summary;priority;assignee;status|cache=no}</content>
  <summary type="text">Below you will find a brief introduction to Jira. For more information on Atlassian's founding pr
oduct please see the Jira webpage http://atlassian.com/software/jira for more information or, alternatively, learn how t
o pronounce "Jira" http://atlassian.com/software/jira ...</summary>
    [ <=>                                                                         ] 1,542         --.--K/s
    
{code}

To try the protocol with a GUI client get the python based APP Test Client from http://bitworking.org/projects/apptestclient/