Relaxes split_if_relative_reference validation constraints in C++ a…

…nd Python.

See also: https://www.hl7.org/fhir/references.html#literal.

Closes #24.

PiperOrigin-RevId: 345316065

cc/google/fhir/json_parser.cc

@@ -41,6 +41,7 @@
 #include "google/fhir/status/statusor.h"
 #include "google/fhir/stu3/profiles.h"
 #include "google/fhir/util.h"
+#include "google/fhir/references.h"
 #include "proto/google/fhir/proto/annotations.pb.h"
 #include "include/json/json.h"
 #include "re2/re2.h"

cc/google/fhir/references.cc

@@ -173,14 +173,8 @@ absl::Status SplitIfRelativeReference(Message* reference) {
     return absl::OkStatus();
   }
 
-  // We're permissive about various full url schemes.
-  static LazyRE2 kUrlReference = {"(http|https|urn):.*"};
-  if (RE2::FullMatch(uri_string, *kUrlReference)) {
-    // There's no way to rewrite the URI, but it's valid as is.
-    return absl::OkStatus();
-  }
-  return InvalidArgumentError(absl::StrCat(
-      "String \"", uri_string, "\" cannot be parsed as a reference."));
+  // There's no way to rewrite the URI, but it's valid as is.
+  return absl::OkStatus();
 }
 
 namespace internal {

cc/google/fhir/references.h

@@ -40,6 +40,25 @@ absl::StatusOr<const ::google::protobuf::FieldDescriptor*> GetReferenceFieldForR
 
 }  // namespace internal
 
+// If possible, parses a reference `uri` field into more structured fields.
+// This is only possible for two forms of reference uris:
+// * Relative references of the form $TYPE/$ID, e.g., "Patient/1234"
+//    In this case, this will be parsed to a proto of the form:
+//    {patient_id: {value: "1234"}}
+// * Fragments of the form "#$FRAGMENT", e.g., "#vs1".  In this case, this would
+//    be parsed into a proto of the form:
+//    {fragment: {value: "vs1"} }
+//
+// If the reference URI matches one of these schemas, the `uri` field will be
+// cleared, and the appropriate structured fields set.
+//
+// If it does not match any of these schemas, the reference will be unchanged,
+// and an OK status will be returned.
+//
+// If the message is not a valid FHIR Reference proto, this will return a
+// failure status.
+absl::Status SplitIfRelativeReference(::google::protobuf::Message* reference);
+
 // Return the full string representation of a reference.
 absl::StatusOr<std::string> ReferenceProtoToString(
     const ::google::protobuf::Message& reference);

cc/google/fhir/testutil/generator.cc

@@ -21,6 +21,7 @@
 #include "google/fhir/annotations.h"
 #include "google/fhir/fhir_types.h"
 #include "google/fhir/proto_util.h"
+#include "google/fhir/references.h"
 #include "google/fhir/util.h"
 #include "include/json/json.h"
 

cc/google/fhir/util.h

@@ -49,10 +49,6 @@
 namespace google {
 namespace fhir {
 
-// Splits relative references into their components, for example, "Patient/ABCD"
-// will result in the patientId field getting the value "ABCD".
-absl::Status SplitIfRelativeReference(::google::protobuf::Message* reference);
-
 // Builds an absl::Time from a time-like fhir Element.
 // Must have a value_us field.
 template <class T>

py/google/fhir/r4/references_test.py

@@ -70,14 +70,5 @@ def testSplitIfRelativeReference_withUrlScheme_succeeds(self):
         datatypes_pb2.String(
             value='http://acme.com/ehr/fhir/Practitioner/2323-33-4'))
 
-  def testSplitIfRelativeReference_withMalformedUri_raises(self):
-    ref = datatypes_pb2.Reference(uri=datatypes_pb2.String(value='InvalidUri'))
-
-    with self.assertRaises(ValueError) as e:
-      references.split_if_relative_reference(ref)
-
-    self.assertIsInstance(e.exception, ValueError)
-
-
 if __name__ == '__main__':
   absltest.main()

py/google/fhir/references.py

@@ -27,7 +27,6 @@
 _INTERNAL_REFERENCE_PATTERN = re.compile(
     r'^(?P<resource_type>[0-9A-Za-z_]+)/(?P<resource_id>[A-Za-z0-9.-]{1,64})'
     r'(?:/_history/(?P<version>[A-Za-z0-9.-]{1,64}))?$')
-_URL_REFERENCE_PATTERN = re.compile(r'^(http|https|urn):.*$')
 
 
 def _validate_reference(reference: message.Message):
@@ -68,13 +67,25 @@ def populate_typed_reference_id(reference_id: message.Message, resource_id: str,
 
 
 def split_if_relative_reference(reference: message.Message):
-  """Splits relative references into their components.
+  """If possible, parses a `Reference` `uri` into more structured fields.
 
-  For example, a reference with the uri set to "Patient/ABCD" will be changed
-  into a reference with the patientId set to "ABCD".
+  This is only possible for two forms of reference uris:
+  * Relative references of the form $TYPE/$ID, e.g., "Patient/1234"
+    In this case, this will be parsed to a proto of the form:
+    {patient_id: {value: "1234"}}
+  * Fragments of the form "#$FRAGMENT", e.g., "#vs1".  In this case, this would
+    be parsed into a proto of the form:
+    {fragment: {value: "vs1"} }
+
+  If the reference URI matches one of these schemas, the `uri` field will be
+  cleared, and the appropriate structured fields set. Otherwise, the reference
+  will be unchanged.
 
   Args:
     reference: The FHIR reference to potentially split.
+
+  Raises:
+    ValueError: If the message is not a valid FHIR Reference proto.
   """
   _validate_reference(reference)
   uri_field = reference.DESCRIPTOR.fields_by_name.get('uri')
@@ -83,12 +94,6 @@ def split_if_relative_reference(reference: message.Message):
 
   uri = proto_utils.get_value_at_field(reference, uri_field)
 
-  # We're permissive about various full URL schemes. If we're able to find a
-  # match, the URI is valid as-is.
-  url_match = re.fullmatch(_URL_REFERENCE_PATTERN, uri.value)
-  if url_match is not None:
-    return  # URI is valid
-
   internal_match = re.fullmatch(_INTERNAL_REFERENCE_PATTERN, uri.value)
   if internal_match is not None:
     # Note that we make the reference_id off of the reference before adding it,
@@ -125,8 +130,6 @@ def split_if_relative_reference(reference: message.Message):
     proto_utils.set_value_at_field(reference, fragment_field, fragment)
     return
 
-  raise ValueError(f'String {uri.value!r} cannot be parsed as a reference.')
-
 
 def reference_to_string(reference: message.Message) -> str:
   """Returns a reference URI for a typed reference message."""

py/google/fhir/stu3/references_test.py

@@ -70,14 +70,6 @@ def testSplitIfRelativeReference_withUrlScheme_succeeds(self):
         datatypes_pb2.String(
             value='http://acme.com/ehr/fhir/Practitioner/2323-33-4'))
 
-  def testSplitIfRelativeReference_withMalformedUri_raises(self):
-    ref = datatypes_pb2.Reference(uri=datatypes_pb2.String(value='InvalidUri'))
-
-    with self.assertRaises(ValueError) as e:
-      references.split_if_relative_reference(ref)
-
-    self.assertIsInstance(e.exception, ValueError)
-
 
 if __name__ == '__main__':
   absltest.main()

testdata/r4/validation/reference.invalid.ndjson

@@ -1,7 +1,4 @@
-{"reference": "Patient/spaces not allowed"}
-{"reference": "Patient/\"notallowed"}
 {"reference": "Unknown/resourceType"}
-{"reference": "#spaces not allowed"}
 {"uri": "invalidField"}
 {"patient_id": "unknownField"}
 {"patientId": "unknownField"}

testdata/r4/validation/reference.valid.ndjson

@@ -5,3 +5,4 @@
 {"reference": "FamilyMemberHistory/1"}
 {"reference": "urn:uuid:49a86246-4004-42eb-9bdc-f542f93f9228"}
 {"display": "Display Field Only"}
+{"reference": "Practitioner?identifier=http://hl7.org/fhir/sid/us-npi|9999999959"}

testdata/stu3/validation/reference.invalid.ndjson

@@ -1,7 +1,4 @@
-{"reference": "Patient/spaces not allowed"}
-{"reference": "Patient/\"notallowed"}
 {"reference": "Unknown/resourceType"}
-{"reference": "#spaces not allowed"}
 {"uri": "invalidField"}
 {"patient_id": "unknownField"}
 {"patientId": "unknownField"}

testdata/stu3/validation/reference.valid.ndjson

@@ -5,3 +5,4 @@
 {"reference": "FamilyMemberHistory/1"}
 {"reference": "urn:uuid:49a86246-4004-42eb-9bdc-f542f93f9228"}
 {"display": "Display Field Only"}
+{"reference": "Practitioner?identifier=http://hl7.org/fhir/sid/us-npi|9999999959"}