About Knowledge Retrieval Metadata Filtering Automatic Current Time

[ErinLqq]

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I am using Dify version 1.11.4. When setting the time format for metadata in the knowledge base document, I want to set the metadata filtering in the knowledge retrieval node to manual, with the metadata data being later than the dynamic current time. However, I can only set a fixed time. Is there any solution?

[dosubot[bot]]

This is a known limitation in Dify — time-type metadata fields do not support variable selection in the knowledge retrieval node's manual filtering mode [1]. While string and number metadata types support dynamic variables via the {{#variable_name#}} syntax, the time-type filter only allows a fixed date picker value.

Workaround: Store your date metadata as a string (e.g., "2025-06-10") or as a numeric timestamp instead of using the time type. String and number types do support dynamic variables, so you could:

1. Use a Code node or Template Transform earlier in your workflow to get the current time and format it as a string/number.
2. In the Knowledge Retrieval node's metadata filter, set a manual condition using the > or after comparison operator with the variable referencing that computed current time value (e.g., {{#code_node.current_time#}}).

This lets you dynamically filter documents where the date metadata is later than (or before) the current time at query time.

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[ErinLqq]

I am currently using time, and I need to convert everything into strings. However, if the string is "2025-06-10," I still can't compare the sizes.

[dosubot[bot]]

You're right — string-formatted dates like "2025-06-10" won't work with comparison operators (>, <, before, after) because Dify internally attempts to cast the value to a float for those operators [1], and a date string can't be converted to a float.

The solution is to store dates as numeric Unix timestamps instead. For example, "2025-06-10" would become 1749513600 (seconds since epoch). Numeric metadata fields fully support magnitude comparison operators (>, <, ≥, ≤) with proper ordering [2].

So the workflow would be:

1. Set your document metadata field type to Number and store dates as Unix timestamps (epoch seconds).
2. In your workflow, use a Code node to generate the current time as a Unix timestamp (e.g., int(time.time()) in Python).
3. In the Knowledge Retrieval node, set a manual metadata filter using the > or < operator with the variable from your Code node (e.g., {{#code_node.current_timestamp#}}).

This way, numeric comparison works correctly and you can dynamically filter documents by date relative to the current time.

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[ErinLqq]

Which version can automatically compare metadata with the current time

[dosubot[bot]]

As of the current version, no version of Dify has a built-in "automatic current time" comparison for metadata filtering. There is no native {{sys.current_time}} or {{now}} system variable that the knowledge retrieval node can automatically use against time-type metadata.

The closest you can get today is the manual workaround using a workflow:

1. Add a Code node before the Knowledge Retrieval node that outputs the current Unix timestamp.
2. Pass that timestamp variable into the metadata filter using template syntax like {{#code_node.current_timestamp#}}.
3. Use the > or < (or after/before) operator to compare.

This does require storing your metadata as a numeric timestamp (not a time-type field), since time-type fields in the UI still don't support variable selection [1].

There's no public roadmap item or merged PR that adds automatic current-time comparison as a native feature yet. If this is something you'd find valuable, it might be worth opening a feature request for a built-in system variable like sys.current_time that could be used directly in metadata filters.

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[ErinLqq]

Are versions after 1.13 not working? Can't I set a time variable for dynamic variable selection when configuring metadata filtering at the knowledge retrieval node, or can I directly obtain dynamic time?

[dosubot[bot]]

To clarify the situation with v1.13+:

v1.13.0 had a bug where variable references in metadata filters weren't being resolved (the raw {{#node_id.variable#}} string was used literally instead of the actual value). This was fixed in v1.13.1 [1] [2].

However, the core limitation remains: time-type metadata fields in the UI only support a fixed date picker — you cannot select a variable for them [3]. This is a UI constraint specific to the time type.

Here's what does work (v1.13.1+):

1. Number-type metadata + variable: If you store your dates as numeric Unix timestamps (number type, not time type), the UI allows you to select a variable from another node. You can then use >, <, ≥, ≤ operators for comparison [4].

2. System timestamp variable: Dify has a built-in system variable called sys.current_timestamp that provides the current timestamp when the workflow runs [5]. You may be able to reference this directly.

Practical approach on v1.13.1+:

• Change your document metadata field from time type to number type, storing Unix timestamps (e.g., 1749513600 for 2025-06-10).
• In the Knowledge Retrieval node, set a manual metadata filter with operator > or <, and select your dynamic variable (either from a Code node or the system timestamp variable).

The inability to use variables with time-type fields specifically is a feature gap in the UI — switching to numeric timestamps is currently the recommended workaround.

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[ErinLqq]

Can the knowledge base pipeline include a metadata configuration step, automatically assigning metadata to the current document as the result of a specific code node after document upload? For example, if I input a document into the knowledge base pipeline and provide an expiration time, can it automatically set the metadata for this document, converting the expiration time into a timestamp?

[dosubot[bot]]

Currently, the knowledge base pipeline does not support a metadata configuration step during document processing. There's no way to run custom code (like converting an expiration time to a timestamp) as part of the ETL pipeline when a document is uploaded [1].

The pipeline only handles: extract → transform (clean/chunk) → load (index). Custom metadata assignment is not part of this flow.

What you can do instead is use the Knowledge Base API in a multi-step process:

1. Upload file: POST /files/upload
2. Create document: POST /datasets/<dataset_id>/documents
3. Update metadata: PUT /datasets/<dataset_id>/documents/<document_id>/metadata — set your custom metadata (e.g., expiration timestamp) after the document is created [2]

You'd need to pre-define custom metadata fields at the dataset level first via POST /datasets/<dataset_id>/metadata [3].

This means you could build an external automation (a script or a Dify workflow that calls the Knowledge Base API) to:

• Accept a document + expiration time as input
• Upload the document
• Convert the expiration time to a Unix timestamp
• Set the numeric metadata field via the API

Other users have requested this exact feature — automatic metadata assignment within the knowledge pipeline itself [4] — but it hasn't been implemented yet. For now, the API-based workaround is the only option.

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