chat.unfurl

View other methods

Provide custom unfurl behavior for user-posted URLs

Reference docs Tester

Facts

Method access

HTTP

JavaScript

Python

Java

HTTP

POSThttps://slack-gov.com/api/chat.unfurl

Bolt for Java

app.client().chatUnfurl

Bolt for Python

app.client.chat_unfurl

Bolt for JavaScript

app.client.chat.unfurl

Required scopes

Bot tokenslinks:write

User tokenslinks:write

Content types

application/x-www-form-urlencodedapplication/json

Rate limits

Tier 3

Arguments

Required arguments

token

token

·Required

Authentication token bearing required scopes. Tokens should be passed as an HTTP Authorization header or alternatively, as a POST parameter.

Example

xxxx-xxxxxxxxx-xxxx

channel

string

·Required

Channel ID of the message. Both channel and ts must be provided together, or unfurl_id and source must be provided together.

Example

C1234567890

ts

string

·Required

Timestamp of the message to add unfurl behavior to.

unfurls

string

·Required

URL-encoded JSON map with keys set to URLs featured in the the message, pointing to their unfurl blocks or message attachments.

Optional arguments

source

enum

·Optional

The source of the link to unfurl. The source may either be composer, when the link is inside the message composer, or conversations_history, when the link has been posted to a conversation.

Value should be one ofcomposerconversations_history

Example

composer

unfurl_id

string

·Optional

The ID of the link to unfurl. Both unfurl_id and source must be provided together, or channel and ts must be provided together.

Example

Uxxxxxxx-909b5454-75f8-4ac4-b325-1b40e230bbd8

user_auth_blocks

·Optional

Provide a JSON based array of structured blocks presented as URL-encoded string to send as an ephemeral message to the user as invitation to authenticate further and enable full unfurling behavior

user_auth_message

null

·Optional

Provide a simply-formatted string to send as an ephemeral message to the user as invitation to authenticate further and enable full unfurling behavior. Provides two buttons, Not now or Never ask me again.

user_auth_required

boolean

·Optional

Set to true or 1 to indicate the user must install your Slack app to trigger unfurls for this domain

Default

0

Example

true

user_auth_url

null

·Optional

Send users to this custom URL where they will complete authentication in your app to fully trigger unfurling. Value should be properly URL-encoded.

Example

https://example.com/onboarding?user_id=xxx

Usage info

This method unfurls a link—either in the message composer or in a posted message.

Ensure that the links:write scope is added to your app settings for apps that will be performing app unfurling.

This method supports both granular bot and user tokens. The bot token is recommended.

Both unfurl_id and source must be provided together, or channel and ts must be provided together.

The first time this method is executed with a particular ts and channel (or unfurl_id and source) combination, the valid unfurls attachments you provide will be attached to the message. Subsequent attempts with the same ts and channel values will modify the same attachments, rather than adding more.

The ts value you supply must correspond to a message in the specified channel. Also, the message must contain a fully-qualified URL pointing to a domain that is already registered and associated with your Slack app.

The unfurls parameter expects a URL-encoded string of JSON. Unlike chat.postMessage's attachments parameter, it does not expect a JSON array but instead, a hash keyed on the specific URLs you're offering an unfurl for. Each URL can have a single attachment, including message buttons.

You can define your own preview for a link that you're unfurling inside the message composer by passing the preview field:

"unfurls": {
  "https://example.com": {
    "blocks": [...],
    "preview": {
        "title": {
          "type": "plain_text",
          "text": "custom preview"
        },
        "icon_url":
          "https://images.pexels.com/photos/774731/pexels-photo-774731.jpeg?auto=compress&cs=tinysrgb&dpr=1&w=500"
      }
    }
}

This preview field is optional, however, if preview and title are not provided, Canvas app unfurls will be unable to render title text. In the absence of preview for uses outside of Canvas, we will generate the preview based on the blocks layout or legacy attachment. If the preview is provided in an unfurl for a posted message, rather than a link inside the message composer, we will simply ignore this property.

Read the unfurling docs for more guidance on this parameter.

For use specifically with a file unfurl, you can set the hide_color field to true to remove the color bar from a message as in the following example:

"unfurls": {
  "https://example.com": {
    "hide_color": true,
    "blocks": [{
      "type": "file",
      "external_id": "ABCD1",
      "source": "remote",
    }]
  }
}

This property works only with a file block; if this property is included along with other blocks (for example, a section block), this method will throw an error.

The user_auth_required parameter is optional. By providing a 1 or true value, it will require the user posting the link first authenticate themselves with your app. See also the authenticated unfurling docs.

If you'd rather directly point users to a specific page on your server to authenticate, pass a valid URL using the user_auth_url parameter. When sending this parameter via application/x-www-form-urlencoded GETs or POSTs, values must be URL-encoded such that https://example.com/onboarding?user_id=xxx becomes https%3A%2F%2Fexample.com%2Fonboarding%3Fuser_id%3Dxxx.

Or, you can send an ephemeral message to that user by providing a simple string-based user_auth_message value or JSON array of blocks using user_auth_blocks. Simple slack message formatting like *bold*, _italics_, and linking is supported, so you can wrap your custom URLs in a blanket of situationally accurate, actionable text.

user_auth_message offers two default buttons, Not now and Never ask me again which allows your app to prompt a user multiple times before opting out of an install. To make your ephemeral message extra fancy, you can also use user_auth_blocks which will override the default buttons. Using both properties shows the user_auth_message in a notification and the user_auth_blocks in the ephemeral message.

Specifying user_auth_url or user_auth_message will automatically imply user_auth_required being set to true. If both user_auth_url and user_auth_message are provided, user_auth_message takes precedence.

As you can see, we provide a minimal positive response when your unfurl attempt is successful. When it is not, you'll receive one of the errors below and ok will be false.

Example responses

Common successful response

Typical, minimal success response

{
    "ok": true
}

Common error response

Typical error response

{
    "ok": false,
    "error": "cannot_unfurl_url"
}

Errors

This table lists the expected errors that this method could return. However, other errors can be returned in the case where the service is down or other unexpected factors affect processing. Callers should always check the value of the ok params in the response.

Error	Description
`cannot_auth_user`	The current user cannot be authenticated.
`cannot_find_channel`	The specified channel could not be located for this token.
`cannot_find_message`	The `ts` value in the request does not match a message.
`cannot_find_service`	A record of your app being allowed to unfurl for this workspace could not be found.
`cannot_parse_attachment`	The provided `unfurls` argument could not be parsed or understood.
`cannot_prompt`	The current user has already interacted with and dismissed a prompt for this application.
`cannot_unfurl_message`	The URL cannot be unfurled because the URL provided does not appear in the message.
`cannot_unfurl_url`	The URL cannot be unfurled. This error may be returned if you haven't acknowledged a `link_shared` event tied to the same URL. It is also returned when the domain appears in a workspace's administrative blocklists.
`invalid_unfurl_id`	The unfurl ID is invalid.
`invalid_unfurls_format`	The `unfurls` parameter cannot be JSON-decoded into a map of URLs to attachments.
`invalid_source`	The unfurl source is invalid.
`missing_channel`	The request is missing the `channel` parameter
`missing_source`	The request is missing the `source` parameter.
`missing_ts`	The request is missing the `ts` parameter
`missing_unfurl_id`	The request is missing the `unfurl_id` parameter.
`missing_unfurls`	The request is missing the `unfurls` parameter.
`access_denied`	Access to a resource specified in the request is denied.
`account_inactive`	Authentication token is for a deleted user or workspace when using a `bot` token.
`deprecated_endpoint`	The endpoint has been deprecated.
`ekm_access_denied`	Administrators have suspended the ability to post a message.
`enterprise_is_restricted`	The method cannot be called from an Enterprise.
`invalid_auth`	Some aspect of authentication cannot be validated. Either the provided token is invalid or the request originates from an IP address disallowed from making the request.
`is_bot`	This method cannot be called by a legacy bot.
`method_deprecated`	The method has been deprecated.
`missing_scope`	The token used is not granted the specific scope permissions required to complete this request.
`not_allowed_token_type`	The token type used in this request is not allowed.
`not_authed`	No authentication token provided.
`no_permission`	The workspace token used in this request does not have the permissions necessary to complete the request. Make sure your app is a member of the conversation it's attempting to post a message to.
`org_login_required`	The workspace is undergoing an enterprise migration and will not be available until migration is complete.
`token_expired`	Authentication token has expired
`token_revoked`	Authentication token is for a deleted user or workspace or the app has been removed when using a `user` token.
`two_factor_setup_required`	Two factor setup is required.
`team_access_not_granted`	The token used is not granted the specific workspace access required to complete this request.
`accesslimited`	Access to this method is limited on the current network
`fatal_error`	The server could not complete your operation(s) without encountering a catastrophic error. It's possible some aspect of the operation succeeded before the error was raised.
`internal_error`	The server could not complete your operation(s) without encountering an error, likely due to a transient issue on our end. It's possible some aspect of the operation succeeded before the error was raised.
`invalid_arg_name`	The method was passed an argument whose name falls outside the bounds of accepted or expected values. This includes very long names and names with non-alphanumeric characters other than `_`. If you get this error, it is typically an indication that you have made a very malformed API call.
`invalid_arguments`	The method was either called with invalid arguments or some detail about the arguments passed is invalid, which is more likely when using complex arguments like blocks or attachments.
`invalid_array_arg`	The method was passed an array as an argument. Please only input valid strings.
`invalid_charset`	The method was called via a `POST` request, but the `charset` specified in the `Content-Type` header was invalid. Valid charset names are: `utf-8` `iso-8859-1`.
`invalid_form_data`	The method was called via a `POST` request with `Content-Type` `application/x-www-form-urlencoded` or `multipart/form-data`, but the form data was either missing or syntactically invalid.
`invalid_post_type`	The method was called via a `POST` request, but the specified `Content-Type` was invalid. Valid types are: `application/json` `application/x-www-form-urlencoded` `multipart/form-data` `text/plain`.
`missing_post_type`	The method was called via a `POST` request and included a data payload, but the request did not include a `Content-Type` header.
`ratelimited`	The request has been ratelimited. Refer to the `Retry-After` header for when to retry the request.
`request_timeout`	The method was called via a `POST` request, but the `POST` data was either missing or truncated.
`service_unavailable`	The service is temporarily unavailable
`team_added_to_org`	The workspace associated with your request is currently undergoing migration to an Enterprise Organization. Web API and other platform operations will be intermittently unavailable until the transition is complete.

Warnings

This table lists the expected warnings that this method will return. However, other warnings can be returned in the case where the service is experiencing unexpected trouble.

Warning	Description
`missing_charset`	The method was called via a `POST` request, and recommended practice for the specified `Content-Type` is to include a `charset` parameter. However, no `charset` was present. Specifically, non-form-data content types (e.g. `text/plain`) are the ones for which `charset` is recommended.
`superfluous_charset`	The method was called via a `POST` request, and the specified `Content-Type` is not defined to understand the `charset` parameter. However, `charset` was in fact present. Specifically, form-data content types (e.g. `multipart/form-data`) are the ones for which `charset` is superfluous.

API response

URL

POST body

Submit your arguments to see the API response