Implementing Public Preview

This topic describes how to implement a public preview for the Smart Hub Preview feature. A public preview shows the same preview content to all users.

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Related Info

• Application API

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Samples

• Public Preview: Server API
• Sample JSON File

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Public preview content is defined by a remotely-hosted JSON file. You can configure the JSON file to expire and refresh at a specific time. The public preview generation process is shown in the following figure.

1. The URL of the remote JSON file is defined in the application's "config.xml" file.
2. The preview is generated and shown based on the JSON data.
3. The user clicks a preview tile.
4. The JSON action_data value corresponding to the selected tile is sent to the application.
5. The application parses the action_data value and shows the detail page.

Prerequisites

To enable your application to use the public preview functionality:

1. Define the remote JSON file URL in the "config.xml" file:

   <tizen:metadata key='http://samsung.com/tv/metadata/use.preview' value='endpoint_URL=http://yourServer/JSONfile.json'></tizen:metadata> 
   

2. Disable reloading the application main page when it receives an application control request. This allows your application, if it is already running, to receive the action_data information without reloading.

   <tizen:app-control>
     <tizen:src name='index.html' reload='disable'></tizen:src>
     <tizen:operation name='http://samsung.com/appcontrol/operation/eden_resume'></tizen:operation> 
   </tizen:app-control>
   

3. If you want the application to support 2015 TV models, set the required_version attribute to "2.3" and the development API version meta data attribute to "2.4" in the "config.xml" file:

   <tizen:application ... required_version='2.3'></tizen:application>
   <tizen:metadata key='http://samsung.com/tv/metadata/devel.api.version' value='2.4'></tizen:metadata> 
   

Configuring Public Preview Data

The preview content is defined in JSON format. The application can only use 1 preview content JSON file at a time.

The following table lists the structure and parameters for the preview content JSON data.

Parameter			Type	Mandatory	Description
expires			UNIX timestamp	false	For public preview only If specified, the time at which the preview content is updated. The time is at most 1 week into the future. By default, the preview content is updated every 10 minutes, whenever the TV is switched on, or the JSON file changes.
expires_only			Boolean		For public preview only If this value is "true", the preview content is updated only at the time specified by the expires parameter. The default value is "false". It is supported in 2018 TV models and newer.
sections			Array	true	Preview sections
	title		String	false	Section title
	position		Integer		Section position If specified, sections are shown in ascending position order.
	title_display_mode		String		The following three values are supported: AlwaysOn HighlightedOnly (default) Show the title while the tile is in focus. AccessibilityOnly Title is hidden when tile is in focus, Voice Guide is provided when the accessibility setting is set to ON. For more information, see the detailed description below the table.
	subtitle_display_mode		String		The following three values are supported: AlwaysOn HighlightedOnly (default) Show the subtitle while the tile is in focus. AccessibilityOnly Subtitle is hidden when tile is in focus. Voice Guide is provided when the accessibility setting is set to ON. For more information, see the detailed description below the table.
	tiles		Array	true	Tiles within the section
		title	String	false	Tile title
		subtitle			Tile subtitle
		image_url		true	Thumbnail image URL
		image_ratio			Thumbnail image aspect ratio: "16by9" "4by3" "1by1" (default) "2by3" The thumbnail height is fixed at 250 px on presentation.
		action_data			Data to send to the application when the tile is clicked
		is_playable			If "true", a "Play" icon is shown over the thumbnail image
		display_from	UNIX timestamp	false	Time to begin showing the tile
		display_until			Time to stop showing the tile
		position	Integer		Section position If specified, sections are shown in an ascending order by the position value.

Table 1. Preview JSON parameters

For an example of a preview content JSON file, see sampleJSON.

The JSON parameters title_display_mode and subtitle_display_mode for displaying title and subtitle of tiles, respectively, support the following options:

• AlwaysOn - If this option is enabled, the title or subtitle is always displayed when the preview is visible.
  
  
• HighlightedOnly - This is the default option, which shows the title or subtitle when the tile is in focus.
  
  
• AccessibilityOnly - If this option is enabled, the title or subtitle is not displayed. There is only a Voice Guide when the accessibility setting is set to ON and the preview tile is in focus.
  
  

When the preview system requests JSON data from your server, TV information is sent in the HTTP header. You can serve different preview content depending on TV information, such as the language, and application version.

The following table lists the HTTP header fields that contain TV information.

Field	Description
ACCEPT-LANGUAGE	TV language setting, such as 'en-US'
X-SAMSUNG-APP-VERSION	Application version
X-SAMSUNG-COUNTRY-CODE	TV Smarthub country setting, such as 'US' in ISO 3166-1 Alpha 2 Format

Table 2. HTTP header fields

Implementing Public Preview Deep Links

When a tile is clicked, its associated action_data value is converted to an ApplicationControlData object with the PAYLOAD key:

{
  "key": "PAYLOAD", 
  "value": ["{\"values\": \"{\\\"videoIdx\\\": 1}\"}"] 
} 

For more information on ApplicationControlData objects, see the Application API.

To implement deep-linking:

1. To receive action_data information when the application is already running, add an event listener for the appcontrol event to the onload property:

   window.addEventListener('appcontrol', deepLink); 
   

2. In the onload property, receive and parse the PAYLOAD key value, using the getCurrentApplication().getRequestedAppControl() method:

   function deepLink() { 
     var requestedAppControl = tizen.application.getCurrentApplication().getRequestedAppControl(); 
     var appControlData;
     var actionData; 
   
     var videoIdx; 
     var pictureIdx; 
   
     if (requestedAppControl) {
       appControlData = requestedAppControl.appControl.data; 
   
       for (var i = 0; i < appControlData.length; i++) { 
         if (appControlData[i].key == 'PAYLOAD') { 
           actionData = JSON.parse(appControlData[i].value[0]).values; 
   
           if (JSON.parse(actionData).videoIdx) { 
             videoIdx = JSON.parse(actionData).videoIdx; 
             console.log(videoIdx); 
           } else if (JSON.parse(actionData).pictureIdx) { 
             pictureIdx = JSON.parse(actionData).pictureIdx; 
             console.log(pictureIdx); 
           } 
         } 
       } 
     } else { 
       console.log("no req app control"); 
     } 
   }