Preview handler

The preview handler is used to expand the link to display a richer data format. The preview handler will be triggered either when a user enters the link in the composer or after they send it in the chat. A map with unfurl card details will be returned in the response.

You will get the following attributes when the preview handler is executed.

Attribute	Description
domain	Domain which matches the one handled by the extension
url	Link sent by the user
chat	Details of the chat where the link was entered or sent
user	Details of the user who entered or sent the link

The unfurled card response can have the following attributes

Attribute	Type	Description
title*	String	Title for the unfurled card (max length : 500)
type*	String	The type of unfurl. Allowed Values: link \| photo \| video \| rich
provider_url*	String	Resource provider url. (max length: 1000)
description	String	Description for the unfurl card, maximum length 3000
provider_name	String	Resource provider name. (max length: 100)
favicon_url	String	Resource provider fav icon. (max length: 1000)
thumbnail_url	String	Thumbnail url. (max length: 1000). Supported for link, richand video type
actions	Array	Butons actions in unfurl card. Supported for link and rich type
dynamic_actions	Boolean	Used to add menu icon to the unfurl card. Allowed values: True \| False. Supported for link and rich type
fields	JSON Object	Option to render fields in unfurl card.

Attributes for actions:

Attribute	Type	Description
type*	String	The type of action. Allowed value: button
label*	String	Button label. (max length : 100)
hint	String	Button hint. (max length: 250)
style	String	To denote the style(positive/negative) of the button. Allowed values: + \| -
confirm	JSON Object	Properties of the confirmation dialog box before the action is executed. It can be included based on the requirement.
params	JSON Object	Dynamic key value pair for reference. A Maximum of 10 keys with 100 character value can be passed.

Attributes for fields:

Attribute	Type	Description
data*	Array	Fields data. (max 10 fields)
styles	JSON Object	Styles for fields

Atributes for fields data

Attribute	Type	Description
label*	String	Field label. (max length : 100)
value*	String	Field value. (max length: 500)

Attributes for fields styles

Attribute	Type	Description
short*	Boolean	Option to short the given fields based on key

Types specific additional mandatory keys:

Rich, Video:

Attribute	Type	Description
iframe_url*	String	Iframe url to play video or render webpage. (max length: 1000)

Photo:

Attribute	Type	Description
url*	String	Image url. (max length: 1000)

Sample code:


return {
   "title": "Graphics Artist | Notion",
   "type": "link",
   "provider_url": "https://www.notion.so/",
   "faviconlink": "https://www.notion.so/front-static/favicon.ico",
   "thumbnail_url": "https://images.unsplash.com/photo-1613909207039-6b173b755cc1?ixlib=rb-4.0.3&q=85&fm=jpg&crop=entropy&cs=srgb",
   "description": "Notion - A new tool that blends your everyday work apps into one. It's the all-in-one workspace for you and your team",
   "fields": {
      "data": [
         {
            "label": "Parent Database",
            "value": "[Vendor Management](https://www.notion.so/demoid1234)"
         },
         {
            "label": "Type",
            "value": "Page"
         },
         {
            "label": "Created By",
            "value": "John Doe (john.doe@zoho.com)"
         }
      ]
   },
   "actions": [
      {
         "hint": "Add a Block of information to the Page.",
         "style": "+",
         "label": "Add Block",
         "type": "button",
         "params": {
            "page_id": "demopageid123"
         }
      },
      {
         "hint": "Add a subpage to the page",
         "label": "Add Subpage",
         "type": "button",
         "params": {
            "page_id": "demopageid124"
         }
      }
   ],
   "dynamic_actions": true
};