Skip to main content

Schema Annotations for Linked Avro Data (SALAD)

Project description

Build Status Build status

Schema Salad

Salad is a schema language for describing JSON or YAML structured linked data documents. Salad schema describes rules for preprocessing, structural validation, and hyperlink checking for documents described by a Salad schema. Salad supports rich data modeling with inheritance, template specialization, object identifiers, object references, documentation generation, code generation, and transformation to RDF. Salad provides a bridge between document and record oriented data modeling and the Semantic Web.

Usage

$ pip install schema_salad

To install from source:

git clone https://github.com/common-workflow-language/schema_salad
cd schema_salad
python setup.py install

Commands

Schema salad can be used as a command line tool or imported as a Python module:

$ schema-salad-tool
usage: schema-salad-tool [-h] [--rdf-serializer RDF_SERIALIZER]
                      [--print-jsonld-context | --print-rdfs | --print-avro | --print-rdf | --print-pre | --print-index | --print-metadata | --print-inheritance-dot | --print-fieldrefs-dot | --codegen language | --print-oneline]
                      [--strict | --non-strict] [--verbose | --quiet | --debug] [--version]
                      [schema] [document]

$ python
>>> import schema_salad

Validate a schema:

$ schema-salad-tool myschema.yml

Validate a document using a schema:

$ schema-salad-tool myschema.yml mydocument.yml

Get JSON-LD context:

$ schema-salad-tool --print-jsonld-context myschema.yml mydocument.yml

Convert a document to JSON-LD:

$ schema-salad-tool --print-pre myschema.yml mydocument.yml > mydocument.jsonld

Generate Python classes for loading/generating documents described by the schema:

$ schema-salad-tool --codegen=python myschema.yml > myschema.py

Display inheritance relationship between classes as a graphviz ‘dot’ file and render as SVG:

$ schema-salad-tool --print-inheritance-dot myschema.yml | dot -Tsvg > myschema.svg

Documentation

See the specification and the metaschema (salad schema for itself). For an example application of Schema Salad see the Common Workflow Language.

Rationale

The JSON data model is an popular way to represent structured data. It is attractive because of it’s relative simplicity and is a natural fit with the standard types of many programming languages. However, this simplicity comes at the cost that basic JSON lacks expressive features useful for working with complex data structures and document formats, such as schemas, object references, and namespaces.

JSON-LD is a W3C standard providing a way to describe how to interpret a JSON document as Linked Data by means of a “context”. JSON-LD provides a powerful solution for representing object references and namespaces in JSON based on standard web URIs, but is not itself a schema language. Without a schema providing a well defined structure, it is difficult to process an arbitrary JSON-LD document as idiomatic JSON because there are many ways to express the same data that are logically equivalent but structurally distinct.

Several schema languages exist for describing and validating JSON data, such as JSON Schema and Apache Avro data serialization system, however none understand linked data. As a result, to fully take advantage of JSON-LD to build the next generation of linked data applications, one must maintain separate JSON schema, JSON-LD context, RDF schema, and human documentation, despite significant overlap of content and obvious need for these documents to stay synchronized.

Schema Salad is designed to address this gap. It provides a schema language and processing rules for describing structured JSON content permitting URI resolution and strict document validation. The schema language supports linked data through annotations that describe the linked data interpretation of the content, enables generation of JSON-LD context and RDF schema, and production of RDF triples by applying the JSON-LD context. The schema language also provides for robust support of inline documentation.

Project details


Release history Release notifications | RSS feed

Download files

Download the file for your platform. If you're not sure which to choose, learn more about installing packages.

Source Distribution

schema-salad-2.7.20180719125426.tar.gz (350.1 kB view details)

Uploaded Source

Built Distribution

schema_salad-2.7.20180719125426-py2.py3-none-any.whl (382.1 kB view details)

Uploaded Python 2 Python 3

File details

Details for the file schema-salad-2.7.20180719125426.tar.gz.

File metadata

File hashes

Hashes for schema-salad-2.7.20180719125426.tar.gz
Algorithm Hash digest
SHA256 905551d7e7e0db66eeebba20edde67afa31b9feb019a42d16a71a10f53bb5407
MD5 dce9d8f7d0073ca16ff0712698ca7034
BLAKE2b-256 8d9fca8a766bf0f9dc7500a81758d49180a2a78649330bc1e9db72fc5c249e09

See more details on using hashes here.

Provenance

File details

Details for the file schema_salad-2.7.20180719125426-py2.py3-none-any.whl.

File metadata

File hashes

Hashes for schema_salad-2.7.20180719125426-py2.py3-none-any.whl
Algorithm Hash digest
SHA256 1db38851292fde76ce7700f2e47037b37912485c623d9fdf60b47cdfcdf90935
MD5 8e327934559b3f1ec1d4a113c6ceb93b
BLAKE2b-256 a3a9809fc5e8683c7fa88feb56e9bf7fdc704d2cc6c4c116b3ef393ab7f171cf

See more details on using hashes here.

Provenance

Supported by

AWS AWS Cloud computing and Security Sponsor Datadog Datadog Monitoring Fastly Fastly CDN Google Google Download Analytics Microsoft Microsoft PSF Sponsor Pingdom Pingdom Monitoring Sentry Sentry Error logging StatusPage StatusPage Status page