Fedora JSON-LD addons

• Compacton filter: Compacts all json-ld responses from the repository with respect to a given context.
• Deserialization filter: Accepts compacted (or uncompacted) JSON-LD, validates it, and persists it to the repository. Uses cached or pre-loaded contexts where possible.
• JSON Merge Patch filter: Accepts compacted JSON-LD and performs an RFC7386 merge patch against the persisted resource, in compact form.

Configuration

Logging

System properties or environment variables that start with LOG can be used to adjust logging levels, with the form LOG.logger.name=LEVEL, e.g. LOG.org.dataconservancy=DEBUG

1. You may define an environment variable for a logger of your choice (e.g. org.dataconservancy.jsonld). Underscores may be used in place of periods

   export LOG_ORG_DATACONSERVANCY_JSONLD=DEBUG
   

2. You may define a system property that does the same

   -Dlog.org.dataconservancy.jsonld=DEBUG
   

Static Loaded Contexts

Context URIs can be mapped to a files to pre-load contexts so that they can be used/cached without requiring resolution on the internet. As many contexts as desired can be loaded using the following pattern for a given arbitrary context name NAME. Define system properties or environment varlables as follows:

1. Define environment variables COMPACTION_PRELOAD_URI_NAME and COMPACTION_PRELOAD_FILE_NAME

   export COMPACTION_PRELOAD_URI_MY_CONTEXT_1=http://example.org/context.jsonld
   export COMPACTION_PRELOAD_FILE_MY_CONTEXT_1=/path/to/file
   

2. Define system properties compaction.preload.uri.NAME and compaction.preload.file.NAME

   -Dcompaction.preload.uri.my.context.1=http://example.org/context.jsonld
   -Dcompaction.preload.file.my.context.1=/path/to/file
   

Compaction

A context can be provided such that json-ld responses are compacted with respect to the given context by default. Use one of the following three methods:

1. Define an environment variable COMPACTION_URI

   export COMPACTION_URI=http://example.org/context.jsonld
   

2. Define a system property compaction.uri

   -Dcompaction.uri=http://example.org/context.jsonld
   

Strict JSON-LD

When deserializing json-ld, normally unknown JSON attributes are ignored. This can be problematic if json-ld from users is known/assumed/required to be in a compact form such that every attribute is presumed to have a definition. In this scenario, an undefined attribute is an error. Strict jsonld processing will throw a bad request error (400) if user-submitted jsonld contaiins any content that isn't defined in a context.

1. Define an environment variable JSONLD_STRICT

   export JSONLD_STRICT=true
   

2. Define a system property jsonld.strict

   -Djsonld.strict=true
   

Minimal JSON-LD

When returning json-ld in compact form, when this is set the server will omit any properties that aren't mapped to anything in the context.

1. Define an environment variable JSONLD_CONTEXT_MINIMAL

   export JSONLD_CONTEXT_MINIMAL=true
   

2. Define a system property jsonld.context.minimal

   -Djsonld.context.minimal=true
   

Persisted contexts

This will cause the original jsonld context URI to be persisted in the repository, so that subsequent requests are compacted with respect to this context upon retrieval.

1. Define an environment variable JSONLD_CONTEXT_PERSIST

   export JSONLD_CONTEXT_PERSIST=true
   

2. Define a system property jsonld.context.persist

   -Djsonld.context.persist=true