The PDC [2.1] expects application/json output. For unhandled formats (like PDFs), the solution is to share the download address and security token as application/json metadata through the Connector [2.1].
The PDC [2.1] is designed to operate mainly with structured and governable data exchanges. Therefore, it is expected that data flows are expressed in an application/json format. This requirement can facilitate interoperability among participants, content validity, policy enforcement and data space traceability of data exchanges. To learn more, please click here.
Nevertheless, in some cases, data that wants to be exchanged is available in formats non-directly manageable by the exchange protocol, such as PDF documents, binary files, images and other non-structured formats, which are not transferred by the PDC plane (see: https://github.com/Prometheus-X-association/dataspace-connector/wiki/MIME-Types#mime-types-in-the-data-exchange-protocol).
To provide support in such cases, the recommended approach consists not only on transferring the file itself, but also, to share, through the connector, and application/json outputs that acts as access metadata to the resource. This JSON object includes content downloadable content addresses (URLs) with the security information needed to access, such as a token, temporary credentials and other mechanisms. In such a manner, exchange continues to use a compatible format with the PDC, even though the final content is obtained outside the Data Plane’s final flow.
This mechanism enables the Control Plane to continue applying all the usual verifications, before authorizing access to the metadata. The distinction between Control Plane and Data Plane, described here, ensures that data exchange governance is not compromised, even when real data is stored or downloaded from external locations.
Thanks to this metadata-based approach, the PDC can integrate heterogeneous formats without breaking either the interoperability models or the governance assurance within the data space. This consistent use of format ensures that all access operations, including those that report non-structured content, are traceable, enforceable and controlled according to the PTX Protocol pre-established rules.
