CoreMedia Digital Experience Platform 8 Developer Manual, Version 7.5.45-10
6.3. Website Management | 6.3.4. Page Assembly

Requirements

For a good user experience a website should not layout each and every page in a different fancy manner but limit itself to a few carefully designed styles. For example, most pages consist of two columns of ratio 75/25, where the left column shows the main content, and the right column provides some personalized recommendations.

In the best case an editor needs to care only for the content of a page, while the layout and collateral contents are added automatically, determined by the context of the content. However, there will always be some special pages, so the editors must be able to change the layout or the collateral contents. For example for a campaign page which features a new product they may omit the recommendations section and choose a simple one-column layout without any distracting features. In order to preserve an overall design consistency of the site, editors are not supposed to create completely new layouts. They can only choose from a predefined set.

Solution

CoreMedia Blueprint addresses these requirements with the concept of a page grid and placements.

The page grid does not handle overall common page features such as navigation elements, headers, footers and the like. Those are implemented by Page templates with special views. Neither does the page grid control the layout of collections on overview pages. This is implemented by CMCollection templates with special views and view types.

You can think of a page grid as a table which defines the layout of a page with different sections. Each section has a link to a symbol document which will later be used to associate content with the section. Technically, the layout of a page is defined in form of rows, columns and the ratio between them. A page grid contains no content and can be reused by different pages. So you might define three global page grids from which an editor can select one, for instance.

The content for the page grid on the other hand, is defined in a CMChannel document in so called placements, realized as link lists in structs. Each placement is associated with a specific position of the page grid through a link to a symbol document. The editor can add content to the placement, collections for example, which will be shown at the associated position of the page grid.

Placements can also be shared between channels because a child inherits the placements of its parent. A prerequisite for inheritance is that the page grids of the parent and child page must have sections with the same name. For example, the parent channel has a two-column layout with the sections "main" and "sidebar". The child channel has a three-column layout with the sections "main", "sidebar" and "leftcolumn". For the placements this means:

Before going into the implementation details of the page grid, you will see how to work with page grids in CoreMedia Studio.

Page grids in CoreMedia Studio

Editors can manage pages directly by editing the "placements" in the page grid in CMChannel documents (localized as Page in CoreMedia Studio). A placement is a specific area on a page such as the navigation bar, the main column or the right column. A CMChannel can inherit page grid placements of its parent channel. For example, the Sports/Football section of a site can inherit the right column from the Sports section. Editors can also choose to "lock" certain placements and thus prevent subchannels from overwriting them. Each page grid editor provides a combo box to choose between different layouts for a page. Depending on the selected layout, placement may inherit their content if the same placement is defined in the layout of the parent page.

Each placement link list can configure a view type. The view type determines how the placement is rendered.

To define which placement view types are available for a page in some site, view type (CMViewtype) documents are placed in view type folders under a site-relative path or at global locations. The default paths are the site-relative path Options/Viewtypes/ and the absolute path /Settings/Options/Viewtypes/. This can be configured via the application property pagegrid.viewtype.paths, which contains a comma-separated list of repository paths. Each path may start with a slash ('/') to denote an absolute path or with a folder name to denote a path relative to a site root folder. When changing these values, please make sure that the existing view type documents are moved or copied to the new target location.

Web pages are represented in the CAE using the com.coremedia.blueprint.common.contentbeans.Page object which consists of two elements: the content to be rendered and the context in which to render the content.

Pages where the content to be rendered is the same as the context (for example, section overview) display the page grid of the context. Pages where content items (such as Articles) are displayed within a context use display the context's page grid but replace the "main" placement with the content item.

Figure 6.9. The page grid editor

Each placement has an icon symbolizing where it is located on the page. It contains a link list and several additional buttons on top of it. The order of the linked elements can be modified using drag and drop.

Figure 6.10. The main placement of a page

Instead of adding own content, a placement can inherit the linked content from a parent's page placement. If you inherit the content, you cannot edit the placement in the child page. You have to deactivate the "override" button to change the content of the placement.

Figure 6.11. An inheriting placement

A placement can be locked using the "lock" button. In this case all child placements are not able to overwrite this placement with own content.

Figure 6.12. A locked placement

The page grid editor provides a combo box with predefined layouts to apply to the current page. After changing the layout, the Studio preview will immediately reflect the new page layout.

Figure 6.13. The layout chooser combo box

The layout of a parent page grid may be changed so that it does not fit anymore with the layout of a child page which inherits some settings. A child may use a three-column layout and inherit most of its content from its parent page that also uses a three-column layout. Then, the layout of the parent may be changed to another layout with a single column that doesn't contain any of the needed layout sections. The child configuration is invalid in this case and the user has to reconfigure all child pages.

Currently there is no kind of detection for these cases in Studio, so the user has to check manually if the child configurations are still valid.

How to configure a page grid editor

The Blueprint base module bpbase-pagegrid-studio-plugin provides an implementation of the page grid editor shown above through the config class pageGridPropertyField in the package com.coremedia.blueprint.base.pagegrid.config. In many cases, you can simply use this component in a document form by setting only the standard configuration attributes bindTo, forceReadOnlyValueExpression, and propertyName

If you want to adapt the columns shown in the link list editors for the individual section, you can also provide fields and columns using the attributes fields and columns, respectively. The semantics of these attributes match those of the linkListPropertyField component.

How to configure the layout location

Pages look up layouts from global and site specific folders. By default, the site specific page grid layout path will point to Options/Settings/Pagegrid/Layouts and the global one to /Settings/Options/Settings/Pagegrid/Layouts. This can be changed via the application property pagegrid.layout.paths, which contains a comma-separated list of repository paths. Each path may start with a slash ('/') to denote an absolute path or with a folder name to denote a path relative to a site root folder. When changing these values, please make sure that the existing page layout documents are moved or copied to the new target location. Also, mind that when looking for the default page layout (see below), paths mentioned first take precedence, so it usually makes sense to start with site-relative paths and continue with absolute paths.

	Caution
	The default layout settings document PagegridNavigation must be present in at least one of the available layout folders. The page grid editor will show an error message if the document is not found.

	Caution
	If several layout folders are used, make sure that the layout settings documents have unique names.

How to configure a new layout

Every CMSettings document in a layout folder is recognized as a layout definition. The settings struct property defines a table layout with different sections. The struct defines two integer properties with the overall row and column count. The struct data may also contain two string properties name and description, which are used for the localization of page grid layout documents (see the section called “How to localize page grid objects”).

The items property contains a list of substructs, each defining a section of the page grid. The order in which the sections appear in the struct list matches the order in which the link lists of the individual sections are shown by the page grid editor.

The sections are represented by CMSymbol documents. The layout definition is inspired by the HTML table model, even though CoreMedia Blueprint's default templates do not render page grids as HTML tables but with CSS means. The sections support the following attributes:

The col, row and rowspan attributes of the section must match the grid layout defined by the colCount and colRow attributes (see Example 6.1, “Pagegrid example definition”). That is, when colCount and colRow are "3" and "4", for example, then you have 12 cells in the page grid table layout which must all be filled by the sections. No cell can be left empty, and no section can overlap with other sections.

The height attribute is only used for the preview of the layout in the page form. It has no impact on the delivered website.

The default PagegridNavigation layout settings document with a 75%/25% two column layout looks as follows:

<Struct xmlns="http://www.coremedia.com/2008/struct" xmlns:xlink="http://www.w3.org/1999/xlink">
  <IntProperty Name="colCount">2</IntProperty>
  <IntProperty Name="rowCount">1</IntProperty>
  <StructListProperty Name="items">
    <Struct>
      <LinkProperty Name="section" xlink:href="coremedia:///cap/content/550" LinkType="coremedia:///cap/contenttype/CMSymbol"/>
      <IntProperty Name="row">1</IntProperty>
      <IntProperty Name="col">1</IntProperty>
      <IntProperty Name="height">100</IntProperty>
      <IntProperty Name="width">75</IntProperty>
      <IntProperty Name="colspan">1</IntProperty>
    </Struct>
    <Struct>
      <LinkProperty Name="section" xlink:href="coremedia:///cap/content/544" LinkType="coremedia:///cap/contenttype/CMSymbol"/>
      <IntProperty Name="row">1</IntProperty>
      <IntProperty Name="col">2</IntProperty>
      <IntProperty Name="height">100</IntProperty>
      <IntProperty Name="width">25</IntProperty>
      <IntProperty Name="colspan">1</IntProperty>
    </Struct>
  </StructListProperty>
  <StringProperty Name="name">2-Column Layout (75%, 25%)</StringProperty>
  <StringProperty Name="description">Two column layout with main and sidebar sections</StringProperty>
</Struct>

	Caution
	The main content of a document will always be rendered into the main section of a layout. Therefore, every layout must define a main section.

How to configure a read-only placement

The page grid layout definition provides the possibility to declare a read-only section. The Boolean property "editable" has to be declared for the struct element of the corresponding section, for example:

<Struct>
  <LinkProperty Name="section" xlink:href="coremedia:///cap/content/120" LinkType="coremedia:///cap/contenttype/CMSymbol"/>
  <IntProperty Name="row">2</IntProperty>
  <IntProperty Name="col">1</IntProperty>
  <IntProperty Name="colspan">1</IntProperty>
  <IntProperty Name="height">75</IntProperty>
  <IntProperty Name="width">25</IntProperty>
  <BooleanProperty Name="editable">false</BooleanProperty>
</Struct>

The section that matches the given symbol will be shown as disabled in Studio. The matching placements will not appear in the editor.

How to populate a page grid with content

Page grids are defined in the struct property CMNavigation.placement of a channel. Such structs are typically created using the page grid editor shown above. Example:

<Struct xmlns="http://www.coremedia.com/2008/struct" xmlns:xlink="http://www.w3.org/1999/xlink">
  <StructListProperty Name="placements">
    <Struct>
      <LinkProperty Name="section" LinkType="coremedia:///cap/contenttype/CMSymbol" xlink:href="coremedia:///cap/content/550"/>
      <LinkProperty Name="viewtype" LinkType="coremedia:///cap/contenttype/CMViewtype" xlink:href="coremedia:///cap/content/1784"/>
      <LinkListProperty Name="items" LinkType="coremedia:///cap/contenttype/CMArticle">
        <Link xlink:href="coremedia:///cap/content/134"/>
        <Link xlink:href="coremedia:///cap/content/498"/>
      </LinkListProperty>
    </Struct>
    <Struct>
      <LinkProperty Name="section" LinkType="coremedia:///cap/contenttype/CMSymbol" xlink:href="coremedia:///cap/content/544"/>
      <LinkListProperty Name="items" LinkType="coremedia:///cap/contenttype/CMArticle">
        <Link xlink:href="coremedia:///cap/content/776"/>
      </LinkListProperty>
    </Struct>
  </StructListProperty>
  <StructProperty Name="placements_2">
    <Struct>
      <LinkProperty Name="layout" LinkType="coremedia:///cap/contenttype/CMLayout" xlink:href="coremedia:///cap/content/3488"/>
    </Struct>
  </StructProperty>
</Struct>

A placement struct contains a list of section structs placements. The placements_2 struct contains another struct, placements and a link property layout, which determines the layout for this channel.

The placements struct property consists of substructs for the single placements, each of which refers to a section and lists its contents in the items property. Additionally, each placement can declare a view type.

Layouts and placements are connected by the section documents. Let's assume you have two sections, "main" and "sidebar". Your channel declares some latest news for the main section and some personalized recommendations for the sidebar. The layout definition consists of one row with two columns, the left column refers to the "main" section, the right column refers to the "sidebar". This will make your channel be rendered with the main content left and the recommendations on the right. If you don't like it, you can simply choose another layout, for example with a different width ratio of the columns or with the sidebar left to the main section.

The rendering of a page grid is layout-driven, because the sections of the table-like layout model must be passed to the template in an order which is suitable for the output format (usually HTML). CoreMedia Blueprint's web application processes a page grid as follows:

Blueprint's default templates (namely PageGrid.jsp) do not render page grids as HTML tables but as nested <div> elements and suitable CSS styles. The beginning of a rendered page grid looks like this:

  <div id="row1" class="row">
      <div id="main" class="col1 column col1of2 width67">

The outer <div> elements represent the rows of the page grid, the inner <div> elements represent the columns. The ids of the rows are generated by the template as an enumeration. The ids of the columns are the section names of the placements. The column <div> elements are rendered with several class attributes:

You can use these attributes to define appropriate styles for the columns. CoreMedia Blueprint's default CSS provides styles which reflect the width ratios of some typical multi-column layouts. You find them in the document /Themes/basic/css/basic.css in the content repository where you can enhance or adapt them to your needs.

In the inner <div> elements the placements are included, and their section names determine the views. For example a "sidebar" placement is included by the PageGridPlacement.sidebar.jsp template.

How to localize page grid objects

To localize a layout name, create a resource bundle entry with the key <layoutname>_text in the resource bundle PageGridLayouts_properties, where <layoutname> is the name of the layout document or, preferably, the name property of the settings struct of the layout. Similarly, a layout description can be localized with entries of the form <layoutname>_description. If no corresponding resource bundle entries are found, the description property of the settings struct of the layout is used. If that property is empty, too, the name is used as the description. The resource bundle is available in the package com.coremedia.blueprint.base.pagegrid of module bpbase-pagegrid-studio-plugin.

For the purposes of localization, placements are treated as pseudo-properties and localized according to the standard rules for content properties as described in the [Studio Developer Manual]. The name of the pseudo-property is <structname>-<placementname>, where <structname> is the name of the struct property storing the page grid and <placementname> is the name of the section document. For example, a placement with the name main that is referred from the standard page grid struct placement of a CMChannel document would obtain its localization using the key CMChannel_placement-main_text. You can add localization entries to the resource bundle BlueprintDocumentTypes_properties of module blueprint-forms, which is applied to the built-in resource bundle ContentTypes_properties at runtime.

To localize a view type name or a view description, you can add a property <viewtypename>_text or <viewtypename>_description to the bundle Viewtypes_properties. Here <viewtypename> is the name of the view type document or, preferably, the string stored in its layout property. Because view types are also used in other contexts, this bundle has been placed in the package com.coremedia.blueprint.base.components.viewtypes of module bpbase-studio-components.

CoreMedia Blueprint defines three resource bundles BlueprintPageGridLayouts_properties, BlueprintPlacements_properties, and BlueprintViewtypes_properties. Entries of these bundles are copied to the bundles described above, providing a convenient way to add custom entries.