62 lines
2.4 KiB
TypeScript
62 lines
2.4 KiB
TypeScript
import { Schema, Validator, ValidatorResult } from 'jsonschema';
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import values = require('lodash.values');
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import { schemas } from './schemas';
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/**
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* A validator for [JSON-schemas](http://json-schema.org/)
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*/
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export class SchemaValidator {
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private readonly _validator: Validator;
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private static _assertSchemaDefined(schema: Schema): void {
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if (schema === undefined) {
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throw new Error(`Cannot add undefined schema`);
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}
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}
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/**
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* Instantiates a SchemaValidator instance
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*/
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constructor() {
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this._validator = new Validator();
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for (const schema of values(schemas)) {
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SchemaValidator._assertSchemaDefined(schema);
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this._validator.addSchema(schema, schema.id);
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}
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}
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/**
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* Add a schema to the validator. All schemas and sub-schemas must be added to
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* the validator before the `validate` and `isValid` methods can be called with
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* instances of that schema.
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* @param schema The schema to add
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*/
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public addSchema(schema: Schema): void {
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SchemaValidator._assertSchemaDefined(schema);
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this._validator.addSchema(schema, schema.id);
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}
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// In order to validate a complex JS object using jsonschema, we must replace any complex
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// sub-types (e.g BigNumber) with a simpler string representation. Since BigNumber and other
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// complex types implement the `toString` method, we can stringify the object and
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// then parse it. The resultant object can then be checked using jsonschema.
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/**
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* Validate the JS object conforms to a specific JSON schema
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* @param instance JS object in question
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* @param schema Schema to check against
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* @returns The results of the validation
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*/
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public validate(instance: any, schema: Schema): ValidatorResult {
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SchemaValidator._assertSchemaDefined(schema);
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const jsonSchemaCompatibleObject = JSON.parse(JSON.stringify(instance));
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return this._validator.validate(jsonSchemaCompatibleObject, schema);
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}
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/**
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* Check whether an instance properly adheres to a JSON schema
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* @param instance JS object in question
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* @param schema Schema to check against
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* @returns Whether or not the instance adheres to the schema
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*/
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public isValid(instance: any, schema: Schema): boolean {
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const isValid = this.validate(instance, schema).errors.length === 0;
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return isValid;
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}
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}
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