fix json object validate

[fatelei]

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Dify version

1.11.1

Cloud or Self Hosted

Self Hosted (Docker)

Steps to reproduce

in start node config json object
in chat input json object

✔️ Expected Behavior

it will pass

❌ Actual Behavior

it failed pass

[dosubot]

Dify v1.11.1 supports JSON object validation in the backend for start node config and chat input, but there are some important limitations and bugs:

• The UI does not expose the "Object" input type for the start node, so you can't select or configure it directly in workflows, even though backend validation is implemented using JSON schema and the jsonschema library (source, source).
• Validation expects the input to be a Python dictionary/object, not a JSON string. If you pass a string (even valid JSON), it will fail with a "must be a JSON object" error (source, source).
• If your input matches the schema, it passes; if not, you get a descriptive error. However, there's a bug: optional JSON_OBJECT variables that are not provided still trigger a validation error, even though they shouldn't (source).
• As a workaround, use a "Paragraph" input type and manually parse the JSON string in a code block within your workflow (source, source). Make sure your input is a valid JSON object and matches the expected schema.

If you want help debugging a specific case, please share your input example, schema, and the exact error message you see. For advanced users, you can review the validation logic in the StartNode class and related unit tests (source, source). Native UI support for JSON object input is on the roadmap.

To reply, just mention @dosu.

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