2.2. Setup and Administration

2.2.1.1.1. Predefined Content Types

The ACS content repository package includes two pre-defined content types, the basic item -- or content_revision type -- and the image type. Other predefined content types include the acs_message_revision, which is used by the ACS messaging package. All other content types should have content_revision as an ancestor type.

2.2.1.1.2. Using Methods from the content_type package

You may also define content types to suit your own needs by using the create_type procedure in the content_type package:

    
    procedure create_type (
      --/** Create a new content type. Automatically create the attribute table
      --    for the type if the table does not already exist.
      --    @author Karl Goldstein
      --    @param content_type  The name of the new type
      --    @param supertype     The supertype, defaults to content_revision
      --    @param pretty_name   Pretty name for the type, singular
      --    @param pretty_plural Pretty name for the type, plural
      --    @param table_name    The name for the attribute table, defaults to
      --                         the name of the supertype
      --    @param id_column     The primary key for the table, defaults to 'XXX'
      --    @param name_method   As in acs_object_type.create_type
      --    @see {acs_object_type.create_type}
      --*/
      content_type          in acs_object_types.object_type%TYPE,
      supertype             in acs_object_types.object_type%TYPE
                               default 'content_revision',
      pretty_name           in acs_object_types.pretty_name%TYPE,
      pretty_plural         in acs_object_types.pretty_plural%TYPE,
      table_name            in acs_object_types.table_name%TYPE,
      id_column             in acs_object_types.id_column%TYPE default 'XXX',
      name_method           in acs_object_types.name_method%TYPE default null
    );
    

• content_type denotes the name of the new content type you wish to define.

• supertype defaults to content_revision, the root object type for content types.

Content types can also be defined by sub-classing other content types -- i.e. sub-types of the content_revision object type. Sub-classing another content type gives the designer the added benefit of any pre-existing attributes associated with the sub-typed content type. [include a compelling example of why that might be a good idea]

2.2.1.1.3. Example

Here's an example of a content type definition; we made cr_demo_article_image a sub-class of the image content type so that it would inherit the properties of a basic image, but also included the caption field for text information to be included with the image:

    
    
    declare
      attr_id integer;
    begin
    
     content_type.create_type (
       content_type  => 'cr_demo_article_image',
       supertype     => 'image',
       pretty_name   => 'Captioned image',
       pretty_plural => 'Captioned images',
       table_name    => 'cr_demo_article_images',
       id_column     => 'article_image_id'
     );
    
      attr_id := content_type.create_attribute (
       content_type   => 'cr_demo_article_image',
       attribute_name => 'caption',
       datatype       => 'text',
       pretty_name    => 'Caption',
       pretty_plural  => 'Captions'
     );
    
     cm_form_widget.register_attribute_widget(
       content_type   => 'cr_demo_article_image',
       attribute_name => 'caption',
       widget         => 'text',
       is_required    => 't'
     );
    
    end;
    /
    show errors
    

The other procedural calls, content_type.create_attribute and cm_form_widget.register_attribute_widget are used for creating content type-specific attributes and for registering those attributes with the CMS form-builder.

2.2.1.2.1. Registering Attributes for Your Content Type

Register content type attributes with the create_attribute function in the content_type package:

    
    function create_attribute (
      --/** Create a new attribute for the specified type. Automatically creates
      --    the column for the attribute if the column does not already exist.
      --    @author Karl Goldstein
      --    @param content_type   The name of the type to alter
      --    @param attribute_name The name of the attribute to create
      --    @param pretty_name    Pretty name for the new attribute, singular
      --    @param pretty_plural  Pretty name for the new attribute, plural
      --    @param default_value  The default value for the attribute, defaults to null
      --    @return The id of the newly created attribute
      --*/
      content_type          in acs_attributes.object_type%TYPE,
      attribute_name        in acs_attributes.attribute_name%TYPE,
      datatype              in acs_attributes.datatype%TYPE,
      pretty_name           in acs_attributes.pretty_name%TYPE,
      pretty_plural in acs_attributes.pretty_plural%TYPE default null,
      sort_order            in acs_attributes.sort_order%TYPE default null,
      default_value in acs_attributes.default_value%TYPE default null,
      column_spec           in varchar2  default 'varchar2(4000)'
    ) return acs_attributes.attribute_id%TYPE;
    
        

• content_type contains the name of the content type with which the attribute is associated.

• datatype should contain the one of the keyword datatype values contained in the acs_datatypes table, e.g. boolean, date, integer, money. If you wish to designate a datatype not already recorded in the acs_datatypes table, be sure to first insert your datatype into the table before registering your attribute.

content_type.create_attribute returns the attribute_id associated with your newly created attribute. See Defining Content Types [put ref links here to ch 2.2.1 when you learn how to do that] for an example of content_type.attribute_create in use.

2.2.1.3.1. CMS Default Mime Types

A listing of file types, or mime types, whose storage is supported by the ACS content repository is stored in the cr_mime_types table. The ACS Content Repository supports four pre-registered mime types: plain and html text, as well as image GIFs and jpegs. The CMS News Demo also registers upon installation a few mime types designating audio files and video files:

    
    begin
    
      /* Insert audio and video MIME types */
      dbms_output.put_line('Inserting audio and video MIME types...');
    
      insert into cr_mime_types (
        label, mime_type, file_extension
      ) values (
        'Wave Audio File','audio/x-wav','wav'
      );
    
      insert into cr_mime_types (
        label, mime_type, file_extension
      ) values (
        'Basic Audio File','audio/basic','au'
      );
    
    
      insert into cr_mime_types (
        label, mime_type, file_extension
      ) values (
        'QuickTime Video','video/quicktime','qt'
      );
    
      insert into cr_mime_types (
        label, mime_type, file_extension
      ) values (
        'Mpeg Video','video/mpeg','mpg'
      );
    
    end;
    /
    show errors
    

2.2.1.3.2. Registering Mime Types to Your Content Types

Each content object stored in CMS -- such as an image, text article or movie clip -- must be associated with a specific mime type. Also, each content type must also be pre-registered with all of the possible mime types with which that content type might be associated. For example, the image content type is registered to hold jpeg and gif files, but each instance of the image type -- that is, each image revision stored in the CMS -- will contain only one file of either the jpeg or gif file type.

Use content_type.register_mime_type to register pre-defined mime types with your newly created content type:

    
    procedure register_mime_type (
      content_type  in cr_content_mime_type_map.content_type%TYPE,
      mime_type     in cr_content_mime_type_map.mime_type%TYPE
    );
    

If the mime type you wish to register is not yet defined in the ACS content repository, define it by inserting a row in the cr_mime_types table as you saw done in CMS Default Mime Types.

2.2.1.4.1. Overview

Each piece of content requires atleast one template on which to be displayed before the content piece can be published by CMS. Templates serve as the framework upon which a content item is mounted. Templates are associated to content types, and each individual content item published by CMS will be displayed upon one of the templates associated to its content type. Multiple templates can be associated to multiple content types, allowing a single piece of content to be framed upon multiple templates, such as an image published with borders of various colors, or a single template to display multiple content types, such as using a common background for all text, images and video feeds.

2.2.1.4.2. Registering Templates to a Content Type

Register templates through the CMS clipboard system, first by marking or adding items to the CMS clipboard, then by clicking on by going to the "Templates" tabbed page of the appropriate content type.

2.2.1.5.1. Using the cm_form_widget Package

The CMS cm_form_widget package can be used to generate metadata forms for creating items or adding revisions to existing items.

    
    cm_form_widget.register_attribute_widget(
        content_type   => 'book_report',
        attribute_name => 'summary',
        widget         => 'textarea',
        is_required    => 'f'
    );
          

    
    cm_form_widget.set_attribute_param_value(
        content_type   => 'book_report',
        attribute_name => 'summary',
        param          => 'rows',
        param_type     => 'onevalue',
        param_source   => 'literal',
        value          => 10
    );
    

    
    begin
      
      -- register the attribute to a pick list
      cm_form_widget.register_attribute_widget(
          content_type   => 'content_revision', 
          attribute_name => 'mime_type', 
          widget         => 'select',
          is_required    => 't'
      );
    
      -- set the 'options' list
      cm_form_widget.set_attribute_param_value(
          content_type   => 'content_revision', 
          attribute_name => 'mime_type',
          param          => 'options', 
          param_type     => 'multilist', 
          param_source   => 'query',
          value          => 'select 
                               label, map.mime_type
                             from 
                               cr_mime_types types, 
                               cr_content_mime_type_map map 
                             where 
                               types.mime_type = map.mime_type 
                             and 
                               content_type = :content_type 
                             order by 
                               label'
      );
    
      -- set the 'size' param
      cm_form_widget.set_attribute_param_value(
          content_type   => 'content_revision', 
          attribute_name => 'mime_type',
          param          => 'size', 
          param_type     => 'onevalue', 
          param_source   => 'eval',
          value          => 'a_tcl_proc_that_gets_the_pick_list_size' 
      );
    
    end;
    /
    show errors
    

2.2.1.5.2. Using Metadata Forms

The CMS is able to generate and process metadata forms based on the form widgets registered to each attribute of a content type. If the metadata forms are not sufficient, custom forms can be supplied instead.

    
    # a metadata form for creating new "book report" content types.
    form create create_book_report
    element create create_book_report item_id -datatype integer
    
    set db [ns_db gethandle]
    content::get_revision_form $db book_report $item_id create_book_report
    ns_db releasehandle $db
    
    if { [form is_request create_book_report] } {
      query item_id onevalue "select acs_object_id_seq.nextval from dual"
      element set_properties create_book_report item_id -value $item_id
    }
          

    
    # process a metadata form for adding a revision to "book report" content types
    if { [form is_valid add_revision] } {
      form get_values add_revision item_id
      set db [ns_db gethandle]
    
      set revision_id [content::process_revision_form add_revision book_report $item_id $db]
    
      ns_db releasehandle $db
      template::forward "view_book_report_revision.acs?revision_id=$revision_id"
    }
          

    
    proc content::create_form_element {
      db form_name attribute_name args
    } {
      ...
    }
          

    
    content::create_form_element $db my_form width -revision_id $revision_id
    	

2.2.1.6.1. Overview

Many applications of the content repository require that content items be related to each other as well as to other classes of objects. Examples include:

• Content to non-content object: User portraits are linked to specific users.

• Content to content: An article may be linked to any number of photos or charts that are embedded in the article.

• Content within content: A long article is divided into multiple sections, each of which is intended for separate display.

• Multiple content items to a category: News stories may be linked to other stories on the same topic.

When relating content types, it is important to establish whether your related items of content can exist separately of each other, such as an article and piece of stock footage or photography, or whether the one of the content items should exist only within the context of another, as in the example from above of a sectioned article with individual portions meant for separate display. We refer to these latter relationships as parent-child relationships. The former can be generically grouped as Item-Object Relationships; relationships between items of content to non-content objects (example 1) would also fall under this category.

Of the above examples, the first three types of relationship are handled by the content_type package API, and the last managed through CMS itself.

2.2.1.6.2. Item-Object Relationships

Define item-object relationships with the content_type.register_relation_type API:

    
    procedure register_relation_type (
      content_type  in cr_type_relations.content_type%TYPE,
      target_type   in cr_type_relations.target_type%TYPE,
      relation_tag  in cr_type_relations.relation_tag%TYPE default 'generic',
      min_n         in integer default 0,
      max_n         in integer default null
    );
    

• content_type refers to the name of the content type from which the relationship originates.

• target_type takes the name of the object type to which the content is related.

• relation_tag accepts a simple token identifier used in distinguishing relationships

• min_n and max_n refer to the minimum/maximum relationships of this type required before the item of content goes live.

After a relationship between one content type and another object type (content or not) has been registered, you may use content_item.is_valid_relation to confirm potential relationships.

2.2.1.6.3. Parent-Child Relationships

Parent-child relationships are also registered using the content_type package API:

    
    
    procedure register_child_type (
      parent_type  in cr_type_children.parent_type%TYPE,
      child_type    in cr_type_children.child_type%TYPE,
      relation_tag  in cr_type_children.relation_tag%TYPE default 'generic',
      min_n         in integer default 0,
      max_n         in integer default null
    );
    

The parameters for content_type.register_child_type are largely analagous to those for content_type.register_relation_type , except parent_type and child_type must both be content types ( content_revision or a sub-class of it). content_item.is_valid_relation can also be used to verify the validity of a potential parent-child relationship.

2.2.4.2.1. Overview

Permissions provide a way of answering the question, "may the user X perform some action Y on an object Z" ? The CMS UI provides forms for viewing and maintaining permissions, as well as a set of standard permissions which should be useful for web publishing applications. For a more complete description of the various permissions, see the CMS developer guide.

2.2.4.2.2. Viewing Permissions

To view permissions on folders, select the folder on the tree and click the "Folder Attributes" link. To view permissions on items, simply select the item in the folder and scroll down to the bottom of the page. In both cases, the permissions listing for the item/folder appears on the screen:

To grant permissions to another user, mark the user on the clipboard and click "[ Grant ] more permissions to a marked user". You will only be allowed to grant permissions which you already possess, unless you have the "Modify Any Permissions" privilege.

To edit permissions for a particular user, click the icon next to the user's name. The icon will not be visible unless you are allowed to edit permissions for that particular user.

2.2.4.2.3. Granting and Editing permissions

In both cases, a permission editing form will appear on the screen:

The privileges are arranged on the form in a tree-like hierarchy; possession of a parent permission entails the possession of all of its child permissions, as well. For example, a user with "Admin-level Read" would also have read access to anything requiring "User-level Read."

Check any permissions that you wish to grant to the user and uncheck any permissions that you wish to revoke. If you select "Yes" for the "Apply changes to child items and subfolders" option, your changes will affect the current item or folder, all the items in the folder, all subfolders of the folder, all the items in the subfolders, etc. If you select "No", only the current item or folder will be affected.

Note that if you revoke a permission, all of its descendants will remain granted to the user. For example, if you revoke the "Admin-Level Read" permission from a user, the user will retain the "User-level Read" permission.

Also note that you may not be able to modify some permissions on certain items; for example, you may not revoke somebody's "Administrator" permission if you yourself do not possess the "Administrator" permission on the item.