@comunica/actor-context-preprocess-query-source-identify

Comunica Query Source Identify Context Preprocess Actor

An Context Preprocess actor that identifies all query sources in the context using the Query Source Identify bus.

This actor also contains a cache so that identical sources will be reused across multiple query executions. This cache can be invalidated via engine.invalidateHttpCache().

This module is part of the Comunica framework, and should only be used by developers that want to build their own query engine.

Click here if you just want to query with Comunica.

Install

$ yarn add @comunica/actor-context-preprocess-query-source-identify

Configure

After installing, this package can be added to your engine's configuration as follows:

{
  "@context": [
    ...
    "https://linkedsoftwaredependencies.org/bundles/npm/@comunica/actor-context-preprocess-query-source-identify/^1.0.0/components/context.jsonld"
  ],
  "actors": [
    ...
    {
      "@id": "urn:comunica:default:context-preprocess/actors#query-source-identify",
      "@type": "ActorContextPreprocessQuerySourceIdentify",
      "mediatorQuerySourceIdentify": { "@id": "urn:comunica:default:query-source-identify/mediators#main" },
      "mediatorContextPreprocess": { "@id": "urn:comunica:default:context-preprocess/mediators#main" }
    }
  ]
}

Config Parameters

• cacheSize: The maximum number of entries in the LRU cache, set to 0 to disable, defaults to 100.
• httpInvalidator: An optional actor that listens to HTTP invalidation events.
• mediatorQuerySourceIdentify: A mediator over the Query Source Identify bus.
• mediatorContextPreprocess: A mediator over the context preprocess bus.

Changelog

v4.4.1 - 2025-09-25

Fixed

• Fix unsupported extension functions always being pushed to endpoints
  • Add option to always push down extension functions
  • If extension functions are undefined, always push them down

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