The following diagram describes the exchange flows for registration and retrieval of documents hosted in OFF 
Exchange flow to retrieve document from the OFF digital library | # | Operation | endpoint |
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| 1 | OSF sends a document retrieval request to WIPO DAS and receives a request acknowledgement id issued by WIPO DAS | POST /das/v1/requests/retrievals | | 2 | WIPO DAS forwards the retrieval request to the OFF | POST /das/v1/requests/retrievals | | 3 | OFF prepares the requested document for download and notify WIPO DAS of the document availability by referring to the request acknowledgement id returned by WIPO DAS | POST /das/v1/requests/notifications | | 4 | WIPO DAS retrieves the file location URL based on the provided URL | POST /das/v1/requests/files/url-downloads | | 5 | WIPO DAS download the document file content from OFF |
| | 6 | WIPO DAS prepares the requested document for download by OSF and notifies the OSF of the document availability by referring to the request acknowledgement id returned in step 1 | POST /das/v1/requests/notifications | | 7 | OSF retrieves the file location URL for document download by referring to the request acknowledgement id returned in step 1 | POST /das/v1/requests/files/url-downloads | | 8 | OSF uses the given file location URL obtained in step 7 to download the document file content |
| 9 | Optionally OSF deletes the download files from the DAS transit zone | DELETE /das/v1/requests/files |
| If OSF does not delete the downloaded file, WIPO DAS will delete it after a pre-defined period (e.g. 1 week) |
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