block/type/image should allow image_url to reference an uploaded file to Slack without having to make it public

(Describe your issue and goal here)

This should work:

1. upload an image with client.files_upload_v2(), do not want it to be visible in a channel
2. chat_postMessage(blocks=type: image, image_url: file.private_url ...)

This currently doesn't work unless the file/image is made public via client.files_sharedPublicURL(), but enabling public files is not an option in many organisations. Additionally one shouldn't have to construct urls by extracting pub_secret from file/permalink_public.

Given that slack client can show uploaded images (even when they are not public), it should also work with blocks/type/image.

Example discussion/solution (with making the file public) - https://stackoverflow.com/questions/58186399/how-to-create-a-slack-message-containing-an-uploaded-image

Category (place an x in each of the [ ])

• slack_sdk.web.WebClient (sync/async) (Web API client)
• slack_sdk.webhook.WebhookClient (sync/async) (Incoming Webhook, response_url sender)
• slack_sdk.models (UI component builders)
• slack_sdk.oauth (OAuth Flow Utilities)
• slack_sdk.socket_mode (Socket Mode client)
• slack_sdk.audit_logs (Audit Logs API client)
• slack_sdk.scim (SCIM API client)
• slack_sdk.rtm (RTM client)
• slack_sdk.signature (Request Signature Verifier)

Requirements

Please read the Contributing guidelines and Code of Conduct before creating this issue or pull request. By submitting, you are agreeing to those rules.

Commencez par slack_sdk.models, en vous concentrant sur le constructeur du bloc d’image et sur la manière dont sa valeur image_url est représentée. Vérifiez le comportement avec un fichier Slack téléversé en privé et considérez le travail comme terminé lorsque le bloc peut référencer ce fichier sans le rendre public ni extraire manuellement une URL publique.