Package: schema-salad
Schema SaladSalad 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 toRDF. Salad provides a bridge
between document and record oriented data modeling and the Semantic
Web.The Schema Salad library is Python 3.8+ only.Installationpip3 install schema_saladIf you intend to use theschema-salad-tool –codegen=pythonfeature, please
include the[pycodegen]extra:pip3 install schema_salad[pycodegen]To install from source:git clone https://github.com/common-workflow-language/schema_salad
cd schema_salad
pip3 install .
# or pip3 install .[pycodegen] if neededCommandsSchema 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] [--skip-schemas]
                      [--strict-foreign-properties] [--print-jsonld-context]
                      [--print-rdfs] [--print-avro] [--print-rdf] [--print-pre]
                      [--print-index] [--print-metadata] [--print-inheritance-dot]
                      [--print-fieldrefs-dot] [--codegen language] [--codegen-target CODEGEN_TARGET]
                      [--codegen-examples directory] [--codegen-package dotted.package]
                      [--codegen-copyright copyright_string] [--print-oneline]
                      [--print-doc] [--strict | --non-strict]
                      [--verbose | --quiet | --debug] [--only ONLY] [--redirect REDIRECT]
                      [--brand BRAND] [--brandlink BRANDLINK] [--brandstyle BRANDSTYLE]
                      [--brandinverse] [--primtype PRIMTYPE] [--version]
                      [schema] [document]

$ python
>>> import schema_saladValidate a schema:$ schema-salad-tool myschema.ymlValidate a document using a schema:$ schema-salad-tool myschema.yml mydocument.ymlGenerate HTML documentation:$ schema-salad-tool --print-doc myschema.yml > myschema.html
$ # or
$ schema-salad-doc myschema.yml > myschema.htmlGet JSON-LD context:$ schema-salad-tool --print-jsonld-context myschema.yml mydocument.ymlConvert a document to JSON-LD:$ schema-salad-tool --print-pre myschema.yml mydocument.yml > mydocument.jsonldGenerate Python classes for loading/generating documents described by the schema
(Requires the[pycodegen]extra):$ schema-salad-tool --codegen=python myschema.yml > myschema.pyDisplay inheritance relationship between classes as a graphviz ‘dot’ file and
render as SVG:$ schema-salad-tool --print-inheritance-dot myschema.yml | dot -Tsvg > myschema.svgCodegen ExamplesThe examples in the tables below are helpful to see how to use the output ofschema-salad-tool –codegenin different languages for loading and/or creating/editing/saving objects.First set of examples is using theCWL v1.2 schema:LanguageRepositorySerialization Example                                                                                                                                 | Deserialization ExamplePythonhttps://github.com/common-workflow-language/cwl-utils/create_cwl_from_objects.pyload_document()Javahttps://github.com/common-workflow-language/cwljava/(Not yet implemented)PackedWorkflowClassTest.javaTypeScripthttps://github.com/common-workflow-lab/cwl-ts-autoCreating, editing, and saving CWL docs with TypeScriptLoading CWL documents with TypeScript.Nethttps://github.com/common-workflow-lab/CWLDotNetCreating, editing, and saving CWL docs with .NetLoading CWL documents with .NetC++https://github.com/common-workflow-lab/cwl-cpp-autocwl_output_example.cppcwl_input_example.cppDhttps://github.com/common-workflow-lab/cwl-d-autoHow to useHow to useSecond set of examples is for theGalaxy Workflow Format 2schema:LanguagePathPythonhttps://github.com/galaxyproject/gxformat2/blob/master/gxformat2/schema/v19_09.pyJavahttps://github.com/galaxyproject/gxformat2/tree/master/javaTypeScripthttps://github.com/galaxyproject/gxformat2/tree/master/typescriptQuick StartLet’s say you have a ‘basket’ record that can contain items measured either by
weight or by count.  Here’s an example:basket:
  - product: bananas
    price: 0.39
    per: pound
    weight: 1
  - product: cucumbers
    price: 0.79
    per: item
    count: 3We want to validate that all the expected fields are present, the
measurement is known, and that “count” cannot be a fractional value.
Here is an example schema to do that:- name: Product
  doc: |
    The base type for a product.  This is an abstract type, so it
    can't be used directly, but can be used to define other types.
  type: record
  abstract: true
  fields:
    product: string
    price: float

- name: ByWeight
  doc: |
    A product, sold by weight.  Products may be sold by pound or by
    kilogram.  Weights may be fractional.
  type: record
  extends: Product
  fields:
    per:
      type:
        type: enum
        symbols:
          - pound
          - kilogram
      jsonldPredicate: '#per'
    weight: float

- name: ByCount
  doc: |
    A product, sold by count.  The count must be a integer value.
  type: record
  extends: Product
  fields:
    per:
      type:
        type: enum
        symbols:
          - item
      jsonldPredicate: '#per'
    count: int

- name: Basket
  doc: |
    A basket of products.  The 'documentRoot' field indicates it is a
    valid starting point for a document.  The 'basket' field will
    validate subtypes of 'Product' (ByWeight and ByCount).
  type: record
  documentRoot: true
  fields:
    basket:
      type:
        type: array
        items: ProductYou can check the schema and document in schema_salad/tests/basket_schema.yml
and schema_salad/tests/basket.yml:$ schema-salad-tool basket_schema.yml basket.yml
Document `basket.yml` is validDocumentationSee thespecificationand themetaschema(salad schema for itself).  For an
example application of Schema Salad see the Common WorkflowLanguage.RationaleThe 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.