Aim
The aim of this online converter is to build a migration path from the Hermes/Hosa protocol to OSDM. Thus if a railway does not support OSDM yet the Hermes Hosa to OSDM (H2O) Converter ensures that it can connect to railways supporting OSDM. Conversely, if a railway only supports OSDM it guarantees that it can connect to railways supporting Hermes Hosa only.
Initial Analysis
The initial analysis has focused on proving the feasibility of the approach.
Conversion Hermes Hosa to OSDM
This conversion is simple as can be seen in the following table for an MVP
| Use Case | Hermes Hosa | OSDM |
|---|---|---|
| get reservations offers / fare list | AvailabilityRequest |
POST /offers(searchCriteria) or POST /offers(tripSpecification) depending on the Hermes version used |
| get reservation offer | BookingRequest with informationOnly=true |
POST /offers(searchCriteria) or POST /offers(tripSpecification) depending on the Hermes version used |
| book offer | BookingRequest |
POST /bookings followed by POST /booking/{bookingId}/fulfillments |
| cancel booking | CancelRequest with reason code |
POST /bookings/{bookingId}/refundOffers followed by PATCH /bookings/{bookingId}/refund-offers/{refundOfferId} to confirm the offer and DELETE /bookings/{bookingId}/refund-offers/{refundOfferId} in case of technocal problems. |
| refund booking | CancelRequest |
POST /bookings/{booking}/refundOffers followed by PATCH /bookings/{bookingId}/refund-offers/{refundOfferId} to confirm the offer and DELETE /bookings/{bookingId}/refund-offers/{refundOfferId} in case of technocal problems |
| technical rollback | synchro request |
DELETE /bookings/{bookingId} |
SBB has the business need to support this conversion process and is working with Hitrail to build such a converter.
Additional use cases implemented in Hermes require more OSDM messages:
| Use Case | Hermes Hosa | OSDM |
|---|---|---|
| booking with personal data | BookingRequest including personal data |
PATCH /bookings/{bookingId}/passengers/{passengerId} |
| partial cancellation / reducing the number of passengers | ParcialCancellationRequest |
POST /bookings/{booking}/refundOffers followed by PATCH /bookings/{bookingId}/refund-offers/{refundOfferId} to confirm the offer and DELETE /bookings/{bookingId}/refund-offers/{refundOfferId} in case of technocal problems. |
| exchange booking | BookingRequest including an exchange reference to the original booking |
POST /bookings/{bookingId}/exchange-offers followed by POST /bookings/{bookingId}/exchange-operations to select the exchange offer and PATCH /bookings/{bookingId}/exchange-operations/{exchangeOperationId} to confirm it. DELETE /bookings/{bookingId}/exchange-operations/{exchangeOperationId} is needed for cleanup in case of technical problems. |
| ticket download | BookingReply including a download link (depending on the Hermes version in use) |
PATCH /bookings/{bookingId}/fulfillments and GET /fulfillments/{fulfillmentId} |
Technical Uses Case
Use Case: Replacement Proposal for trains in exterior inventories.
Solution sketch: If OSDM is asked for a TripOffer where the train it returns an error
message containing the inventory. The H2O converter then transform this to a
ReplacementProposal.
Conversion OSDM to Hermes Hosa
This conversion is more complex, especially mapping the /trips-offers/ calls to
BookingRequest efficiently. If some restrictions on possible reservations are
taken however the converter can be realized.
A detailed specification will conceptual work for the conversion is ongoing.
In parallel, the business need for this form of conversion is being evaluated.
