File input element

Allows user to upload files.

Type	file_input
Available in	Modals, Home tab
Works in blocks	Input block

Usage

Use the file input inside an input block. Each file is uploaded to Repzo storage as soon as it’s picked; when the person submits the modal, your app receives the files in view.state.values[block_id][action_id]:

{
  "type": "file_input",
  "files": [
    {
      "id": "<media id>",
      "name": "northwind-contract-signed.pdf",
      "mimetype": "application/pdf",
      "size": 284113,
      "url_private": "https://<your workspace host>/api/bot/files/<media id>?exp=…&sig=…"
    }
  ]
}

To download a file, GET its url_private with your app’s token (Authorization: Bearer foxa-…, an app of the same workspace) and follow redirects — the response may redirect to a short-lived storage link. Each url_private works for 7 days; copy the file if you need it longer.

Before calling your app, Repzo checks that a required input has at least one file and that there are no more than max_files (“Attach at most 3 files.”). Every file id is checked on the server too: it must be a file that reader uploaded in this workspace.

Fields

Field	Type	Description	Required?
type	String	The type of element. In this case type is always file_input.	Required
action_id	String	An identifier for the input value when the parent view is submitted. You can use this when you receive a view_submission payload to identify the value of the input element (view.state.values[block_id][action_id]). Should be unique among all other action_ids in the containing block. Maximum length is 255 characters. If you leave it out, Repzo generates one.	Optional
filetypes	String[]	An array of valid file extensions (for example pdf, png) that will be accepted for this element. All file extensions will be accepted if filetypes is not specified. This check is for convenience only — check the files you receive yourself.	Optional
max_files	Integer	Maximum number of files that can be uploaded for this file_input element. Minimum of 1, maximum of 10. Defaults to 10 if not specified.	Optional

How Repzo Chat differs from Slack

• Files are stored in Repzo, not Slack. The file objects carry only id, name, mimetype, size and url_private, and no files:read scope is needed — your app token and the signed link are enough.
• The upload size follows the workspace’s upload limits rather than Slack’s 100 MB.
• An input block holding a file input can’t use dispatch_action (reported as a warning).
• Works in the Home tab as well as in modals.
• In a message, an input block is shown as a disabled stand-in and the API returns a warning instead of refusing the message.

Examples

A file input in a form

This example belongs in a modal view — the screenshot shows it in a modal.

{
  "blocks": [
    {
      "type": "input",
      "block_id": "signed_contract",
      "label": {
        "type": "plain_text",
        "text": "Signed contract"
      },
      "element": {
        "type": "file_input",
        "action_id": "contract_files",
        "filetypes": [
          "pdf",
          "jpg",
          "png"
        ],
        "max_files": 3
      },
      "hint": {
        "type": "plain_text",
        "text": "PDF or photos of the signed pages, up to 3 files."
      }
    }
  ]
}

Related

• Block elements
• Block Kit overview