FHIR Search Filter

Builds search filter parameters for FHIR resources using a visual interface.

Inputs

payload object

Input payload (passed through with searchFilter added)

payload.access_token string

Access token if chaining from authentication node

payload.resourceType string

Resource type (overrides node configuration)

payload.filterValues object

Object containing values for variable substitution in filter values

Outputs

payload object

Original payload with searchFilter property added/overridden

payload.searchFilter object

JSON object containing the search filter parameters

filterBuilder object

Metadata about the filter:

• resourceType - Selected resource type
• filterCount - Number of filters applied
• hasCommonParams - Whether common parameters are set

Details

This node provides a visual interface for building FHIR search filters without writing JSON manually.

Each filter consists of three parts:

• Parameter - The search parameter (e.g., name, birthdate, status)
• Operator - The comparison operator (equals, not equals, greater than, etc.)
• Value - The value to search for

Operators

Available operators and their FHIR equivalents:

• equals - Exact match (default)
• not equals - Not equal (ne prefix)
• greater than - Greater than (gt prefix)
• greater or equal - Greater than or equal (ge prefix)
• less than - Less than (lt prefix)
• less or equal - Less than or equal (le prefix)
• contains - Contains text (:contains modifier)
• exact - Exact match (:exact modifier)

Variable Substitution

Filter values can contain variables using {{variableName}} syntax. Variables are replaced with values from msg.payload.filterValues.

Multiple variables can be used in a single value, and variables can be placed anywhere in the string.

Examples:

• Simple: {{patientId}} → 123
• Multiple: {{resourceType}}/{{id}} → Patient/456
• With operators: ge{{startDate}} → ge2024-01-01
• Nested values: {{patient.id}} → 789

Example Output

Filter configuration:

• Parameter: patient, Value: {{patientId}}
• Parameter: practitioner, Value: {{resourceType}}/{{practitionerId}}
• Parameter: date, Value: ge{{startDate}}

With input:

msg.payload.filterValues = {
  patientId: "123",
  resourceType: "Practitioner",
  practitionerId: "456",
  startDate: "2024-01-01"
}

Output:

{
  "patient": "123",
  "practitioner": "Practitioner/456",
  "date": "ge2024-01-01"
}

Best Practices

• Use variables for dynamic values rather than hardcoding
• Enable validation to catch missing variable values early
• Set appropriate _count to limit result set size
• Use _sort for predictable result ordering
• Test filter output before connecting to FHIR Search node
• Document expected filterValues input structure