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    Error handling

    Details of the common error handling patterns and error codes used across national FHIR APIs

    Operation outcome usage

    In the event of an error, provider systems SHALL respond by providing an OperationOutcome resource

    The OperationOutcome:

    • SHALL contain a definition of severity in the OperationOutcome.issue.severity field providing a value from the valueset-issue-severity value set. In all cases described in this guidance, the value used will be error.
    • SHALL contain a definition of the type of error in the OperationOutcome.issue.code element, providing a value from the issue-type value set.
    • SHALL contain details of the Spine error code in the OperationOutcome.issue.details.coding.code and OperationOutcome.issue.details.coding.display fields. These shall be taken from the standard set of NHS Spine error codes as defined in the spine-error-or-warning-code-1 value set. The Spine error and warning codes provide a greater degree of error handling granularity, and also ensure a standardised error handling approach across NHS APIs.
    • SHOULD provide additional diagnostic details of the error in OperationOutcome.diagnostics property where such securely provides additional error context for consumer applications.

    The specific errors that can be returned will depend on the API being called, and the individual API specifications will provide additional details about likely error conditions. The sections below provide general guidance on the error details that can come back from national FHIR APIs, and those brokered nationally.

    Identity validation errors

    HTTP code Issue Severity Issue type Spine error code - code Spine error code - display
    400 error value INVALID_NHS_NUMBER NHS number invalid
    400 error business-rule INVALID_PATIENT_DEMOGRAPHICS Invalid patient demographics (that is, PDS trace failed)
    404 error not-found ORGANISATION_NOT_FOUND Organisation record not found
    404 error not-found PATIENT_NOT_FOUND Patient record not found
    404 error not-found PRACTITIONER_NOT_FOUND Practitioner record not found
    404 error not-found NO_RECORD_FOUND No record found
    400 error invalid REQUEST_UNMATCHED Request does not match authorisation token

    Example: Invalid NHS number supplied

    If an invalid NHS number value is supplied to the GP Connect $gpc.getcarerecord operation, the following error details would be returned:

    {
    	"resourceType": "OperationOutcome",
    	"meta": {
    		"profile": ["https://fhir.nhs.uk/STU3/StructureDefinition/Spine-OperationOutcome-1"]
    	},
    	"issue": [{
    		"severity": "error",
    		"code": "value",
    		"details": {
    			"coding": [{
    				"system": "https://fhir.nhs.uk/STU3/ValueSet/Spine-ErrorOrWarningCode-1",
    				"code": "INVALID_NHS_NUMBER",
    				"dispay": "Invalid NHS number"
    			}]
    		}
    	}]
    }
    

    Example: Patient not found

    For example, if a valid NHS number value is supplied to the GP Connect $gpc.getcarerecord Operation but no GP record exists for that patient, then the following error details would be returned:

    {
    	"resourceType": "OperationOutcome",
    	"meta": {
    		"profile": ["https://fhir.nhs.uk/STU3/StructureDefinition/Spine-OperationOutcome-1"]
    	},
    	"issue": [{
    		"severity": "error",
    		"code": "not-found",
    		"details": {
    			"coding": [{
    				"system": "https://fhir.nhs.uk/STU3/ValueSet/Spine-ErrorOrWarningCode-1",
    				"code": "PATIENT_NOT_FOUND",
    				"display": "Patient not found"
    			}]
    		}
    	}]
    }
    

    Example: Resource not found

    This is a catch-all where a request for a resource instance cannot be found at the FHIR server, where more specific Spine error codes (such as PATIENT_NOT_FOUND) cannot be used.

    {
    	"resourceType": "OperationOutcome",
    	"issue": [{
    		"severity": "error",
    		"code": "not-found",
    		"details": {
    			"coding": [{
    				"system": "https://fhir.nhs.uk/STU3/ValueSet/Spine-ErrorOrWarningCode-1",
    				"code": "NO_RECORD_FOUND",
    				"display": "No record found"
    			}]
    		}
    	}]
    }
    

    Security validation errors

    HTTP code Issue Severity Issue type Spine error code - code Spine error code - display
    403 error forbidden NO_PATIENT_CONSENT Patient has not provided consent to share data
    403 error forbidden NO_ORGANISATION_CONSENT Organisation has not provided consent to share data
    403 error forbidden ACCESS_DENIED Access has been denied to process this request
    403 error forbidden ACCESS_DENIED_SSL SSL Protocol or Cipher requirements not met
    403 error forbidden ASID_CHECK_FAILED The sender or receiver’s ASID is not authorised for this interaction
    401 fatal forbidden AUTHOR_CREDENTIALS_ERROR Author credentials error

    For example, if the patient has requested that their record should not be shared then the following error details would be returned:

    {
    	"resourceType": "OperationOutcome",
    	"meta": {
    		"profile": ["https://fhir.nhs.uk/STU3/StructureDefinition/Spine-OperationOutcome-1"]
    	},
    	"issue": [{
    		"severity": "error",
    		"code": "forbidden",
    		"details": {
    			"coding": [{
    				"system": "https://fhir.nhs.uk/STU3/ValueSet/Spine-ErrorOrWarningCode-1",
    				"code": "NO_PATIENT_CONSENT",
    				"display": "Patient has not provided consent to share data" 
    			}]
    		}
    	}]
    }
    

    Resource validation errors

    HTTP code Issue Severity Issue type Spine error code - code Spine error code - display
    400 error value INVALID_REQUEST_MESSAGE Invalid Request Message
    400 error value INVALID_IDENTIFIER_SYSTEM Invalid identifier system
    400 error value INVALID_IDENTIFIER_VALUE Invalid identifier value
    400 error code-invalid INVALID_CODE_SYSTEM Invalid code system
    400 error code-invalid INVALID_CODE_VALUE Invalid code value
    400 error value INVALID_ELEMENT Invalid element
    422 error invalid INVALID_RESOURCE Invalid validation of resource.
    422 error invalid INVALID_PARAMETER Invalid parameter.
    422 error invalid REFERENCE_NOT_FOUND Referenced resource not found.
    422 error duplicate DUPLICATE_REJECTED Create would lead to creation of a duplicate resource.
    405 error forbidden MSG_RESOURCE_ID_FAIL Client is not permitted to assign an id.

    INVALID_PARAMETER would be used in the following, or similar, scenarios:

    • Unexpected parameter value for an custom operation. For example, a lowercase value is supplied to the recordSection parameter of the $gpc.getcarerecord operation.
    • An invalid date/time value specified in a custom operaion parameter. For example, a invalid timePeriod defined in the timePeriod input parameter to the $gpc.getcarerecord operation.

    INVALID_RESOURCE would be used in situations such as the following:

    • Resource does to validate against StructureDefinition

    REFERENCE_NOT_FOUND describes a scenario where a consumer POSTs a FHIR resource which contains a FHIR reference which are cannot be found.

    Example: Reference not found

    For example, when using a ‘Book an appointment’ API, a consumer includes a reference to a slot which does not exist at the server. The following error details would be returned:

    {
    	"resourceType": "OperationOutcome",
    	"meta": {
    		"profile": ["https://fhir.nhs.uk/STU3/StructureDefinition/Spine-OperationOutcome-1"]
    	},
    	"issue": [{
    		"severity": "error",
    		"code": "invalid",
    		"details": {
    			"coding": [{
    				"system": "https://fhir.nhs.uk/STU3/ValueSet/Spine-ErrorOrWarningCode-1",
    				"code": "REFERENCE_NOT_FOUND",
    				"display": "FHIR reference not found"
    			}]
    		},
    	    "diagnostics": "Reference to Slot/6 - no such slot exists at the server"
    		"location": "/f:Slot/f:6"
    	}]
    }
    

    Malformed request errors

    When the server cannot or will not process a request due to an apparent client error then the following BAD_REQUEST error SHALL be used to return debug details.

    HTTP code Issue Severity Issue type Spine error code - code Spine error code - display
    400 error invalid BAD_REQUEST Bad request.
    400 error invalid MISSING_OR_INVALID_HEADER There is a required header missing or invalid.
    400 error structure MESSAGE_NOT_WELL_FORMED Message not well formed

    MISSING_OR_INVALID_HEADER Spine error codes should be used in the following types of scenario:

    • JSON Web Tokens (JWT) claims information is not valid JSON, is null, or has an invalid value
    • invalid content in JWT claim (for example, patient identifier when practitioner expected)
    • JWT requested_record claim does not match request
    • an expected header (for example, interaction ID header) is missing or invalid
    • InteractionID header does not match request

    BAD_REQUEST Spine error codes should be used in the following types of scenario:

    • malformed JSON or XML content in request body
    • invalid HTTP verb used (for example, using POST to read a patient)

    Example: Malformed JSON claim in request

    For example, if the request contained a null aud claim in the JWT, then the following error details would be returned:

     {
    	"resourceType": "OperationOutcome",
    	"meta": {
    		"profile": ["https://fhir.nhs.uk/STU3/StructureDefinition/Spine-OperationOutcome-1"]
    	},
    	"issue": [{
    		"severity": "error",
    		"code": "invalid",
    		"details": {
    			"coding": [{
    				"system": "https://fhir.nhs.uk/STU3/ValueSet/Spine-ErrorOrWarningCode-1",
    				"code": "MISSING_OR_INVALID_HEADER",
    				"display": "There is a required header missing or invalid."
    			}]
    		},
    		"diagnostics": "Empty JWT aud claim"
    	}]
    }
    

    Internal server errors

    When the FHIR server has received an request for an operation or FHIR resource which is not (yet) implemented, then the NOT_IMPLEMENTED Spine error code SHALL be used.

    HTTP code Issue Severity Issue type Spine error code - code Spine error code - display
    501 error not-supported NOT_IMPLEMENTED FHIR resource or operation not implemented at server

    When the error is unexpected and the server can’t be more specific on the exact nature of the problem then the INTERNAL_SERVER_ERROR Spine error code SHALL be used, and diagnostics SHALL be included to provide detail of the error.

    HTTP code Issue Severity Issue type Spine error code - code Spine error code - display
    500 error processing INTERNAL_SERVER_ERROR Unexpected internal server error.

    Example: Unexpected exception

    For example, an unexpected internal exception is thrown by either an Operation or RESTful API, then the following error details would be returned:

     {
    	"resourceType": "OperationOutcome",
    	"meta": {
    		"profile": ["https://fhir.nhs.uk/STU3/StructureDefinition/Spine-OperationOutcome-1"]
    	},
    	"issue": [{
    		"severity": "error",
    		"code": "exception",
    		"details": {
    			"coding": [{
    				"system": "https://fhir.nhs.uk/STU3/ValueSet/Spine-ErrorOrWarningCode-1",
    				"code": "INTERNAL_SERVER_ERROR",
    				"display": "Internal server error"
    			}]
    		},
    		"diagnostics": "Any further internal debug details i.e. stack trace details etc."
    	}]
    }
    

    Spine Security Proxy (SSP) errors

    When the Spine security proxy cannot or will not process a request then one of the following errors SHALL be used to return debug details:

    HTTP code Issue Severity Issue type Description of error
    403 error forbidden The sender or receiver’s ASID is not authorised for this interaction.
    405 error not-supported Bad request for an unsupported HTTP verb such as TRACE.
    415 error not-supported A consumer application asked for an unsupported media type.
    502 error transient A downstream server is offline.
    504 error transient A downstream server timed out.

    SSP error example: ASID check failed

    {
    	"resourceType": "OperationOutcome",
    	"issue": [{
    		"severity": "error",
    		"code": "forbidden",
    		"diagnostics": "Any further internal debug details i.e. stack trace details etc."
    	}]
    }
    

    SSP error example: method not allowed

    {
    	"resourceType": "OperationOutcome",
    	"issue": [{
    		"severity": "error",
    		"code": "not-supported",
    		"diagnostics": "Any further internal debug details i.e. stack trace details etc."
    	}]
    }
    

    SSP error example: unsupported media type

    {
    	"resourceType": "OperationOutcome",
    	"issue": [{
    		"severity": "error",
    		"code": "not-supported",
    		"diagnostics": "Any further internal debug details i.e. stack trace details etc."
    	}]
    }
    

    SSP error example: bad gateway

    {
    	"resourceType": "OperationOutcome",
    	"issue": [{
    		"severity": "error",
    		"code": "transient",
    		"diagnostics": "Any further internal debug details i.e. stack trace details etc."
    	}]
    }
    

    SSP error example: gateway timeout

    {
    	"resourceType": "OperationOutcome",
    	"issue": [{
    		"severity": "error",
    		"code": "transient",
    		"diagnostics": "Any further internal debug details i.e. stack trace details etc."
    	}]
    }
    

    Positive / Informational Outcome codes

    In addition to errors, in some cases, an OperationOutcome might include a positive outcome or general informational code:

    HTTP code Issue Severity Issue type Spine error code - code Spine error code - display
    201 information informational RESOURCE_CREATED New resource created.
    200 information informational RESOURCE_DELETED Resource removed.

    All content is available under the Open Government Licence v3.0, except where otherwise stated