Function Repository Resource:

FileDownloadResponse

Source Notebook

Generate an HTTP response that prompts the browser to download as a given file name

Contributed by: Richard Hennigan (Wolfram Research)

ResourceFunction["FileDownloadResponse"][expr,"filename"]

generates an HTTPResponse that informs the browser that the content should be downloaded as the given filename.

ResourceFunction["FileDownloadResponse"][expr,"filename",fmt]

uses fmt as the ExportForm.

ResourceFunction["FileDownloadResponse"][expr,"filename",fmt,metadata]

includes metadata as part of the HTTPResponse.

Details and Options

ResourceFunction["FileDownloadResponse"] is usually stored in a CloudObject or specified as the result in an APIFunction or FormFunction.

The value for metadata in ResourceFunction["FileDownloadResponse"][expr,"filename",fmt,metadata] is an Association including the following possible elements:

"StatusCode"

200

HTTP status code

"ContentType"

"text/html"

MIME type for content

"Cookies"

{}

cookies to handle (using CookieFunction)

"Headers"

{}

a list of rules giving HTTP response headers

Properties of the resulting HTTPResponse object can be accessed using HTTPResponse[…]["prop"].

Possible properties include all metadata items, together with:

"Body"

response body as a string

"BodyByteArray"

response body as a ByteArray object

"BodyBytes"

response body as a list of byte values

"CharacterEncoding"

character encoding in the response body (e.g. "UTF8")

"Properties"

list of available properties

"StatusCodeDescription"

plain text description of status code

ResourceFunction["FileDownloadResponse"] has the following options:

CharacterEncoding

Automatic

character encoding to apply to the response

CachePersistence

Inherited

how long to keep server-side cached versions of computations that are done

"ContentType"

Automatic

specify a content-type header

The setting CharacterEncoding→"enc" specifies that the body in the resulting HTTPResponse[body,…] should be encoded using the encoding enc before being returned from a server as an HTTP response.

The setting CharacterEncoding→None specifies that no change should be made to body before returning it.

The Automatic setting for the CharacterEncoding option will use an encoding given from the "ContentType" metadata property if it includes a charset specification (as in "text/html; charset=latin1"). It will also use an encoding from the "CharacterEncoding" metadata property. If no encoding is otherwise given, then the "UTF8" encoding is used for text-based MIME types and None for other MIME types.

If a specific encoding is given for the CharacterEncoding option, and the "ContentType" metadata property is a text-based MIME type, a charset specification will be automatically added to indicate the encoding to browsers.