JSON List Processor

Processes each element of a JSON list concurrently using user-provided Python logic. It validates code for safety, executes with a per-item timeout, captures outputs/warnings, and aggregates results into a JSON string along with an execution log. Designed for scalable per-item transformations with configurable worker count.

Usage

Use this node when you have a JSON array (e.g., from an API) and you need to run the same Python transformation on each item in parallel. Typical workflow: fetch or build a JSON list, pass it here with concise Python code that uses 'input_data' to produce a result per item, then consume the aggregated 'results_json' and review 'execution_log'.

Inputs

Field	Required	Type	Description	Example
json_list	True	STRING	A JSON-encoded array of items to process. Must be valid JSON and an array type.	[{"id":1,"title":"Example"},{"id":2,"title":"Another"}]
python_code	True	STRING	Python code executed for each item. Use 'input_data' (current item), 'input_index' (0-based), 'all_inputs' (the full list), and 'logger' for logging. Must return a value (e.g., dict) per item.	Python code that reads 'input_data' and returns a transformed dictionary
max_workers	True	INT	Maximum number of concurrent workers used to process items in parallel.	4
timeout_seconds	True	FLOAT	Timeout for each item execution (seconds). Items exceeding this timeout are marked as timed out.	30.0

Outputs

Field	Type	Description	Example
results_json	STRING	JSON-encoded array of results returned by your code for each processed item. Non-serializable results are converted to strings with a warning noted in the log.	[{"post_id":1,"processed":true},{"post_id":2,"processed":true}]
execution_log	STRING	Concatenated log lines for each item (success, warnings, errors, or timeouts) plus a summary.	Item 0: SUCCESS \| Item 1: SUCCESS \| Processed 2 items. Success: 2, Failed: 0
success_count	INT	Number of items that executed successfully.	2
total_items	INT	Total number of items in the input list.	2

Important Notes

• Code safety restrictions apply: dangerous patterns such as imports of system modules, exec/eval, file I/O, and similar are blocked. Invalid patterns or syntax will cause validation failure.
• The node runs items in parallel. Result ordering follows completion order, not necessarily the original input order.
• Per-item timeout applies; total collection waits up to timeout_seconds × number_of_items.
• If results contain non-JSON-serializable types, they are converted to strings and a warning is appended to the execution log.
• Provide a valid JSON array in 'json_list'. Objects or strings that are not arrays will be rejected.
• Available variables inside your code: 'input_data', 'input_index', 'all_inputs', and 'logger'. Ensure your code returns a result for each item.

Troubleshooting

• Error: Invalid JSON format — Ensure 'json_list' is valid JSON and is an array. Validate the JSON with a linter if needed.
• Error: Invalid Python code provided — Remove restricted operations (e.g., imports of os/sys/subprocess, exec/eval, file I/O) and fix syntax errors. Keep code minimal and self-contained.
• Items timing out — Increase 'timeout_seconds' or reduce workload per item. Also consider lowering 'max_workers' if the environment is resource-constrained.
• Empty list provided — Supply a non-empty JSON array; otherwise, the node returns empty results with an informational log.
• Unexpected non-serializable results — Ensure your code returns JSON-serializable values (e.g., dict/list/str/int/float/bool) to avoid string coercion and warnings.
• Results appear out of order — This is expected due to parallel execution. If order matters, include 'input_index' in your result and sort downstream.