Example of using JSON-schema validator (https://github.com/java-json-tools/json-schema-validator)

JsonSchemaValidatorExplorationTest.scala

package com.github.fge.jsonschema

import com.fasterxml.jackson.databind.{JsonNode, ObjectMapper}
import com.github.fge.jsonschema.main.{JsonSchema, JsonSchemaFactory}
import org.scalatest.FunSuite

// Example of using JSON-schema validator
// https://github.com/java-json-tools/json-schema-validator
//
// Code Samples - Example 1 - translated to a Scala test:
// http://java-json-tools.github.io/json-schema-validator/2.2.x/index.html?com/github/fge/jsonschema/examples/package-summary.html
class JsonSchemaValidatorExplorationTest extends FunSuite {
  test("foo") {
    val objectMapper = new ObjectMapper

    val fstabSchema: JsonNode = objectMapper.readTree(
      """{
        |    "$schema": "http://json-schema.org/draft-04/schema#",
        |    "title": "/etc/fstab",
        |    "description": "JSON representation of /etc/fstab",
        |    "type": "object",
        |    "properties": {
        |        "swap": {
        |            "$ref": "#/definitions/mntent"
        |        }
        |    },
        |    "patternProperties": {
        |        "^/([^/]+(/[^/]+)*)?$": {
        |            "$ref": "#/definitions/mntent"
        |        }
        |    },
        |    "required": [ "/", "swap" ],
        |    "additionalProperties": false,
        |    "definitions": {
        |        "mntent": {
        |            "title": "mntent",
        |            "description": "An fstab entry",
        |            "type": "object",
        |            "properties": {
        |                "device": {
        |                    "type": "string"
        |                },
        |                "fstype": {
        |                    "type": "string"
        |                },
        |                "options": {
        |                    "type": "array",
        |                    "minItems": 1,
        |                    "items": { "type": "string" }
        |                },
        |                "dump": {
        |                    "type": "integer",
        |                    "minimum": 0
        |                },
        |                "fsck": {
        |                    "type": "integer",
        |                    "minimum": 0
        |                }
        |            },
        |            "required": [ "device", "fstype" ],
        |            "additionalItems": false
        |        }
        |    }
        |}
      """.stripMargin)

    // valid
    val good: JsonNode = objectMapper.readTree(
      """{
        |    "/": {
        |        "device": "/dev/sda1",
        |        "fstype": "btrfs",
        |        "options": [ "ssd" ]
        |    },
        |    "swap": {
        |        "device": "/dev/sda2",
        |        "fstype": "swap"
        |    },
        |    "/tmp": {
        |        "device": "tmpfs",
        |        "fstype": "tmpfs",
        |        "options": [ "size=64M" ]
        |    },
        |    "/var/lib/mysql": {
        |        "device": "/dev/data/mysql",
        |        "fstype": "btrfs"
        |    }
        |}
      """.stripMargin)
    //    Please note that the failure occurs at the structural level (required entry swap is missing). Validation therefore stops here, and does not attempt to validate the / member of the instance, which is itself invalid.
    val bad: JsonNode = objectMapper.readTree(
      """{
        |    "/": {
        |        "fstype": "btrfs",
        |        "options": [ "ssd" ]
        |    },
        |    "/tmp": {
        |        "device": "tmpfs",
        |        "fstype": "tmpfs",
        |        "options": [ "size=64M" ]
        |    },
        |    "/var/lib/mysql": {
        |        "device": "/dev/data/mysql",
        |        "fstype": "btrfs"
        |    }
        |}""".stripMargin)
    //    problem is with the member values:
    //
    //      the options member of /tmp is a string, but an array is expected;
    //    the / member is missing the required fstype member.
    val bad2: JsonNode = objectMapper.readTree(
      """{
        |    "/": {
        |        "device": "/dev/sda1",
        |        "options": [ "ssd" ]
        |    },
        |    "swap": {
        |        "device": "/dev/sda2",
        |        "fstype": "swap"
        |    },
        |    "/tmp": {
        |        "device": "tmpfs",
        |        "fstype": "tmpfs",
        |        "options": "size=64M"
        |    },
        |    "/var/lib/mysql": {
        |        "device": "/dev/data/mysql",
        |        "fstype": "btrfs"
        |    }
        |}
        |
      """.stripMargin)

    val factory: JsonSchemaFactory = JsonSchemaFactory.byDefault()

    val schema: JsonSchema = factory.getJsonSchema(fstabSchema)

    println(schema.validate(good))
    println(schema.validate(bad))
    println(schema.validate(bad2))
  }

}