Build multipart request bodies as binary objects for use with KNIME REST nodes.
This component builds a valid multipart/form-data request body as a binary object, ready to be sent with KNIME’s native REST nodes.
Since REST nodes in KNIME currently do not support multipart requests directly, this component fills the gap without requiring any scripting.
To craft the request body, you need a table with the following columns (the column names can be arbitrary, as you select them in the configuration dialog):
Content → the request payload reference. This column must be of type String. The value can be:
a plain string (e.g., "Hello world")
a KNIME workflow data link (knime://...) pointing to data stored in the workflow
a file path resolved via the connected file system (absolute or relative)
Content Type → the MIME type of the payload. Supported values include:
application/json
text/plain
text/html
text/csv
image/svg+xml
application/pdf
application/zip
application/octet-stream
image/png
Field Name → the form field name required by your target API.
Filename (optional) → only needed if the API expects a filename (for file uploads).
The component provides a file system input port that can be connected to different file system sources, such as:
Local File System Connector
Mountpoint Connector
Data Area Connector
When a file system is connected, file references in the Content column are resolved against it. This makes file handling more flexible and portable, and allows the use of relative paths.
In addition, the multipart Content-Type is configurable in the dialog. It defaults to multipart/form-data, but you can also set a different multipart type if required by your API.
If an unsupported MIME type is provided, the component will fail with an error.
