Parse the Content-Location manifest from a completed FHIR Bulk Data $export and download NDJSON output files with error file handling

In-depth guide

Steps

1. After the async export completes, parse the JSON response body; extract the output array (successfully exported files) and the error array (files containing OperationOutcome resources for failed resources)
2. For each entry in output[], record the type (resource type) and url; download each file via GET with Authorization: Bearer {token}; stream large files to avoid memory exhaustion
3. For each line in each downloaded NDJSON file, parse the JSON object and validate it is the expected resourceType before processing
4. For each entry in error[], download the error NDJSON file and parse each OperationOutcome to identify which resources failed export and why; log for remediation
5. Verify total resource counts in the manifest (if provided by the server) against the count of NDJSON lines downloaded to detect truncated files or download failures