1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
|
Metadata-Version: 1.1
Name: schema-salad
Version: 3.0.20181206233650
Summary: Schema Annotations for Linked Avro Data (SALAD)
Home-page: https://github.com/common-workflow-language/schema_salad
Author: Common workflow language working group
Author-email: common-workflow-language@googlegroups.com
License: Apache 2.0
Download-URL: https://github.com/common-workflow-language/schema_salad/releases
Description: |Build Status| |Build status|
.. |Build Status| image:: https://img.shields.io/travis/common-workflow-language/schema_salad/master.svg?label=unix%20build
:target: https://travis-ci.org/common-workflow-language/schema_salad
.. |Build status| image:: https://img.shields.io/appveyor/ci/mr-c/schema-salad/master.svg?label=windows%20build
:target: https://ci.appveyor.com/project/mr-c/schema-salad/branch/master
.. |Code coverage| image:: https://codecov.io/gh/common-workflow-language/schema_salad/branch/master/graph/badge.svg
:target: https://codecov.io/gh/common-workflow-language/schema_salad
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.
.. _JSON-LD: http://json-ld.org
.. _Avro: http://avro.apache.org
.. _metaschema: https://github.com/common-workflow-language/schema_salad/blob/master/schema_salad/metaschema/metaschema.yml
.. _specification: http://www.commonwl.org/v1.0/SchemaSalad.html
.. _Language: https://github.com/common-workflow-language/common-workflow-language/blob/master/v1.0/CommandLineTool.yml
.. _RDF: https://www.w3.org/RDF/
Platform: UNKNOWN
Classifier: Environment :: Console
Classifier: Intended Audience :: Science/Research
Classifier: License :: OSI Approved :: Apache Software License
Classifier: Operating System :: POSIX
Classifier: Operating System :: MacOS :: MacOS X
Classifier: Operating System :: Microsoft :: Windows
Classifier: Development Status :: 5 - Production/Stable
Classifier: Programming Language :: Python :: 2.7
Classifier: Programming Language :: Python :: 3.4
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
|
