API Fetcher

Fetches data from healthcare-related APIs with optional presets and simple auth. Supports single GET requests or parallel batches, auto-detects response format, limits JSON list size, and includes retry and timeout handling.

Usage

Use this node to retrieve healthcare data such as FHIR resources or clinical datasets. Choose a preset for common endpoints or provide a custom URL. For multiple calls, switch to parallel mode and supply a JSON array of request configs; the node aggregates responses and provides an execution log.

Inputs

Field	Required	Type	Description	Example
preset_endpoint	True	enum ['custom', 'fhir_patients', 'fhir_observations', 'fhir_medications', 'fhir_conditions', 'fhir_diagnostic_reports', 'covid_tracker', 'drug_interaction_checker', 'medical_codes_icd10', 'clinical_trials']	Selects a predefined healthcare API endpoint or 'custom' to use your own URL.	fhir_patients
api_url	True	STRING	Full API URL used when preset_endpoint is 'custom'. Ignored when a preset is selected.	https://hapi.fhir.org/baseR4/Patient
execution_mode	True	enum ['single', 'parallel']	Single request or parallel batch execution.	single
max_workers	False	INT	Concurrent worker count for parallel execution.	4
batch_requests	False	STRING	JSON array of request configs for parallel execution. Each item may include 'url' and 'params' (JSON string).	[{"url": "https://hapi.fhir.org/baseR4/Patient", "params": "{\"name\": \"Smith\"}"}, {"url": "https://api.covidtracking.com/v1/us/current.json"}]
auth_token	False	STRING	Authentication token sent as Bearer Authorization header.	eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
query_params	False	STRING	JSON object string of query parameters appended to the URL.	{"name": "John", "_count": 10}
max_items	False	INT	Maximum number of items to retain from JSON list responses (single mode).	10

Outputs

Field	Type	Description	Example
response_data	STRING	Fetched data as a string. JSON responses are pretty-printed and may be truncated to max_items; parallel mode returns a JSON array of per-request results.	{"resourceType": "Bundle", ...}
status_message	STRING	Human-readable outcome summary for the request(s).	Successfully fetched 10 items from API
success	BOOLEAN	True if the request succeeded (parallel: true if at least one request succeeded).	True
status_code	INT	HTTP status code for single requests; in parallel mode, returns 200 for the aggregated operation.	200
response_headers	STRING	JSON string of response headers (single). In parallel mode, contains a JSON object with 'execution_log'.	{"Content-Type": "application/json", ...}
response_time	FLOAT	Total elapsed time in seconds for the operation.	1.42

Important Notes

• When preset_endpoint is not 'custom', the preset URL is used and the 'api_url' field is ignored.
• Only GET requests are supported via the main function. For parallel mode, each request uses GET.
• In parallel mode with a preset selected, the preset URL is applied to all batch items, ignoring each item's 'url'. Use 'custom' to honor per-item URLs.
• query_params must be a valid JSON object string; invalid JSON is ignored with a warning.
• batch_requests must be a valid JSON array string; invalid JSON fails the node with an error message.
• JSON list responses in single mode are truncated to 'max_items'. In parallel mode, an internal high limit is used per response.
• Retries with exponential backoff are applied (default 3 attempts, ~30s timeout per request).
• Authentication is simplified to a single Bearer token via 'auth_token' header.
• response_headers is serialized to a JSON string; in parallel mode it contains {"execution_log": [...]} rather than real response headers.
• success is true if the HTTP request(s) completed successfully; network or server errors return success=false and status_code=0 (single).

Troubleshooting

• Invalid batch_requests JSON: Ensure the value is a JSON array string like [{"url": "https://...", "params": "{...}"}].
• Invalid query_params JSON: Provide a JSON object string (e.g., "{\"name\": \"John\"}").
• 401/403 Unauthorized: Verify 'auth_token' is correct and required by the endpoint.
• Timeout errors: Increase reliability by reducing batch size, increasing 'max_workers' sensibly, or trying again later. Default per-request timeout is about 30 seconds.
• Preset vs URL mismatch: If using a preset, the node ignores 'api_url' and (in parallel) each item's 'url'. Set preset_endpoint='custom' to use custom URLs.
• Empty response_data with error message: Check 'status_message' for details (e.g., network errors, invalid endpoint, or server errors).
• Unexpected response format: The node auto-detects format; if JSON parsing fails, data is returned as text and the status message will indicate formatting issues.