dify - 💡(How to fix) Fix [Feature]: Support array[string] and array[number] for "in" / "not in" metadata filtering in Knowledge Base [1 comments, 2 participants]

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1. Is this request related to a challenge you're experiencing? Tell me about your story.

Currently, when trying to filter knowledge base documents using metadata, Dify does not seem to support passing an array of strings (array[string]) or an array of numbers (array[number]) to perform "contains" (in) or "does not contain" (not in) filtering on string or number metadata fields.

I was trying to retrieve specific chunks by filtering metadata against multiple possible values (for example, fetching documents that belong to a list of specific category IDs or tags). It is frustrating because without the in or not in operators for arrays, I either have to make multiple separate queries for each value or retrieve more documents than needed and filter them on the client side, which is inefficient.

2. Additional context or comments

Expected behavior: The knowledge base metadata filter should accept an array of values and support in and not in operators for string and number type metadata.

For example, the API/UI should support filters like:

• {"category_id": {"in": [1, 2, 3]}} (Array of numbers)
• {"tags": {"not_in": ["tagA", "tagB"]}} (Array of strings)

Most underlying vector databases (such as Qdrant, Milvus, Pinecone, Weaviate) already natively support array-based in/not in filtering. Exposing this capability through Dify's Retrieval API and workflow UI would greatly enhance the precision and flexibility of RAG applications.

3. Can you help us with this feature?

• I am interested in contributing to this feature.