What it does

This component represents an attachment to a form.

Accepted mediatypes

By default the component accepts any mediatype.

[SINCE Orbeon Forms 2017.1]

If an upload-mediatypes custom constraint is present and not blank, it is applied to the enclosed upload control.

Otherwise, if an accept attribute or associated oxf.xforms.xbl.fr.attachment.accept property is defined and not blank, it is used. Example of system-wide property:

<property
    as="xs:string"  
    name="oxf.xforms.xbl.fr.attachment.accept"
    value="application/pdf"/>

Example of attribute on the control:

<fr:attachment
    bind="my-file"
    accept="application/pdf">

Otherwise, any mediatype is allowed.

Support for multiple files

[SINCE Orbeon Forms 2020.1]

The multiple="true" attribute enables support for multiple files:

• The file selector allows multiple selection.

• The drop area (see below) allows multiple file being dropped at the same time or serially.

• A reorderable list of multiple files shows.

Drag and drop of files

[SINCE Orbeon Forms 2020.1]

On supported browsers, you can drag and drop files from other applications (typically an operating system file explorer) to the drop area instead of selecting files with the file selector button.

As of Orbeon Forms 2020.1 the following browsers are known not to support drag and drop and the drop area is hidden:

• IE11

• Safari on iOS/iPadOS

Disallowing attachment download

[SINCE Orbeon Forms 2020.1]

By default, the user can download back the attached files. In some cases, this is not desirable. The allow-download="false" attribute allows disabling downloads.

<fr:attachment
    id="attachments-control"
    bind="attachments-bind"
    multiple="true"
    allow-download="false"
    class="fr-attachment">
    ...
</fr:attachment>

Form Builder offers an option in the "Control Settings" dialog.

Mediatype determination

Web browsers determine a mediatype (AKA content type or MIME type) for uploaded files. This determination is platform-dependent, not necessarily precise, and sometimes missing.

In all cases, the mediatype provided by the browser cannot be trusted and is indicative only. You can use the file scan API to reject files that do not satisfy the indicated mediatype.

[SINCE Orbeon Forms 2020.1]

When the browser does not provide a mediatype, or provides a generic mediatype such as application/octet-stream, Orbeon Forms uses the file extension, when present, to guess a mediatype.

This means for example that a .docx file will map to application/vnd.openxmlformats-officedocument.wordprocessingml.document even if the browser is unaware of Microsoft Word files.

Events

[SINCE Orbeon Forms 2017.1]

This component dispatches the following events following the enclosed upload control:

• xxforms-upload-start

• xxforms-upload-cancel

• xxforms-upload-done

• xxforms-upload-error

See also

• ​Image component​

• ​Image attachment component​

• Blog post: Orbeon Forms can now determine files' mediatype based on the extension​

• Blog post: The new Multiple File Attachments control​