Writing Domain Specific Languages with JSON Schema

In this talk, learn how you can use JSON Schema to write a specification language. You will learn about what Domain Specific Languages are, how the WAML web automation language was developed using JSON Schema, and the far-reaching applications of JSON Schema in other domains such as Headless CMSes.

Transcript

2. Writing Domain Specific Languages with JSON Schema Yos Riady yos.io bit.ly/2JbMTrn
3. Weak types in JSON What is JSON Schema? Introduction Schema Uses DSL Conclusion JSON Schema use cases Summary and further learning Writing a DSL with JSON Schema
5. JSON is weakly typed { “userName”: “Yos”, “favouriteNumber”: 42, “interests”: [“programming”, “swimming”] }
7. message Person { required string user_name = 1 optional int64 favourite_number = 2 repeated string interests = 3 } Protocol Buffers are strongly typed
9. How can we validate JSON data with types?
10. Enter JSON Schema { “userName”: { “type”: “string” }, “favouriteNumber”: { “type”: “integer” }, “interests”: { “type”: “array”, “items”: { “type”: “string”} } }
11. JSON Schema helps you validate JSON data.
12. jsonschemalint.com
13. JSON Schema 101 { "type": "string" } Valid Invalid “foo” 123 false
14. JSON Schema Basic Types • string • Numeric types • object • array • boolean • null
15. { "type": "object", "properties": { "userName": { "type": "string" } }, "required": ["userName"], "additionalProperties": false, } JSON Schema 101 Valid Invalid { “userName”: “foo” } { “userName”: 1 } { “name”: “foo” } {}
16. JSON Schema 101 Invalid Validation Message { “userName”: 1 } Field .userName should be a string { “name”: “foo” } Should NOT have additional properties {} Should have required property ‘userName’
17. Additional JSON Schema Validations { "type": "number", "minimum": 0, "maximum": 100, "exclusiveMaximum": true } { "type": "string", "pattern": "^(\\([0-9]{3}\\))?[0-9]{3}-[0-9]{4}$" }
18. Combining JSON Schemas • AnyOf • AllOf • OneOf • not { "anyOf": [ { "type": "string" }, { "type": "number" } ] }
19. Structuring Complex Schemas { "definitions": { "person": { ... } }, "type": "object", "properties": { "user": { "$ref": "#/definitions/person" } } }
21. jsonschemalint.com
22. Use Cases for JSON Schema • Message / data validation ◦ Object Relational Mappers (ORMs) • Schemaless objects in Web Applications • Content Management in Headless CMSes • Writing Specification Languages ◦ OpenAPI / Swagger ◦ AWS States Language ◦ WAML
23. Hapi.js object validation
24. Dynamic forms
25. Content Modeling in Headless CMSes
26. Content Modeling in Headless CMSes
27. Writing Specification Languages
28. Weak types in JSON What is JSON Schema? Introduction Schema Uses DSL Conclusion JSON Schema use cases Summary and further learning Writing a DSL with JSON Schema
29. Writing a DSL with JSON Schema
30. Domain Specific Languages • Computer language specialized to a particular application domain ◦ In contrast to General Purpose Languages (GPLs)
31. OpenAPI / Swagger
32. Web Automation Markup Language (waml.io)
33. waml.io/editor
34. Writing a DSL with JSON Schema "waml": { "description": "WAML Specification semantic version number.", "type": "string", "pattern": "^([0-9]{1,}.[0-9]{1,}.[0-9]{1,})$", "enum": ["0.1.0"] }
35. Writing a DSL with JSON Schema "steps": { "type": "array", "minItems": 1, "items": { "$ref": "#/definitions/Step" } }
36. Writing a DSL with JSON Schema "Step": { "type": "object", "description": "A step represents a single user interaction.", "oneOf": [ { "$ref": "#/definitions/VisitStep" }, { "$ref": "#/definitions/ClickStep" } ] }
37. "ClickStep": { "type": "object", "properties": { "click": { "oneOf": [ { "type": "string" }, { "type": "object", "properties": { "selector": { "type": "string" }, "index": { "type": "integer", "minimum": 0 } } } ] }, }, }
38. github.com/waml-lang/waml
39. Weak types in JSON What is JSON Schema? Introduction Schema Uses DSL Conclusion JSON Schema use cases Summary and further learning Writing a DSL with JSON Schema
40. • JSON is weakly typed • JSON Schema ◦ What is JSON Schema? ◦ JSON validation with JSON Schema ◦ Use cases • Domain Specific Languages ◦ What are DSLs? ◦ Writing a DSL with JSON Schema In Closing
42. Writing Domain Specific Languages with JSON Schema Yos Riady yos.io bit.ly/2JbMTrn
43. Q&A