Adds JSON Schema Draft 6/7 support

lib/errors.js

@@ -7,6 +7,7 @@ class UnknownValidatorError extends Error {}
 class NotValidatableError extends Error {}
 class NotEnoughDataError extends Error {}
 class JsonSchemaNotValid extends Error {}
+class JsonSchemaNotSupported extends Error {}
 
 module.exports = {
   DataNotJsonParsableError,
@@ -18,4 +19,5 @@ module.exports = {
   NotValidatableError,
   NotEnoughDataError,
   JsonSchemaNotValid,
-}
+  JsonSchemaNotSupported
+};

lib/validators/json-schema-legacy.js

@@ -0,0 +1,182 @@
+const amanda = require('amanda');
+const tv4 = require('tv4');
+const jsonPointer = require('json-pointer');
+
+const { JsonSchemaValidator, META_SCHEMA } = require('./json-schema-next');
+const { ValidationErrors } = require('./validation-errors');
+
+/**
+ * Returns a proper article for a given string.
+ * @param {string} str
+ * @returns {string}
+ */
+function getArticle(str) {
+  return ['a', 'e', 'i', 'o', 'u'].includes(str.toLowerCase()) ? 'an' : 'a';
+}
+
+const jsonSchemaOptions = {
+  singleError: false,
+  messages: {
+    minLength: (prop, val, validator) =>
+      `The ${prop} property must be at least ${validator} characters long (currently ${val.length} characters long).`,
+    maxLength: (prop, val, validator) =>
+      `The ${prop} property must not exceed ${validator} characters (currently${val.length} characters long).`,
+    length: (prop, val, validator) =>
+      `The ${prop} property must be exactly ${validator} characters long (currently ${val.length} characters long).`,
+    format: (prop, val, validator) =>
+      `The ${prop} property must be ${getArticle(
+        validator[0]
+      )} ${validator} (current value is ${JSON.stringify(val)}).`,
+    type: (prop, val, validator) =>
+      `The ${prop} property must be ${getArticle(
+        validator[0]
+      )} ${validator} (current value is ${JSON.stringify(val)})."`,
+    except: (prop, val) => `The ${prop} property must not be ${val}.`,
+    minimum: (prop, val, validator) =>
+      `The minimum value of the ${prop} must be ${validator} (current value is ${JSON.stringify(
+        val
+      )}).`,
+    maximum: (prop, val, validator) =>
+      `The maximum value of the ${prop} must be ${validator} (current value is ${JSON.stringify(
+        val
+      )}).`,
+    pattern: (prop, val, validator) =>
+      `The ${prop} value (${val}) does not match the ${validator} pattern.`,
+    maxItems: (prop, val, validator) =>
+      `The ${prop} property must not contain more than ${validator} items (currently contains ${val.length} items).`,
+    minItems: (prop, val, validator) =>
+      `The ${prop} property must contain at least ${validator} items (currently contains ${val.length} items).`,
+    divisibleBy: (prop, val, validator) =>
+      `The ${prop} property is not divisible by ${validator} (current value is ${JSON.stringify(
+        val
+      )}).`,
+    uniqueItems: (prop) => `All items in the ${prop} property must be unique.`
+  }
+};
+
+class JsonSchemaLegacy extends JsonSchemaValidator {
+  validateSchema() {
+    const { jsonSchema, jsonMetaSchema } = this;
+    const metaSchema = jsonMetaSchema || META_SCHEMA.v3;
+
+    tv4.reset();
+    tv4.addSchema('', metaSchema);
+    tv4.addSchema(metaSchema.$schema, metaSchema);
+    const validationResult = tv4.validateResult(jsonSchema, metaSchema);
+
+    return validationResult.valid;
+  }
+
+  validate(data) {
+    switch (this.jsonSchemaVersion) {
+      case 'v3':
+        return this.validateUsingAmanda(data);
+      case 'v4':
+        return this.validateUsingTV4(data);
+      default:
+        throw new Error(
+          'Attempted to use JsonSchemaLegacy on non-legacy JSON Schema!'
+        );
+    }
+  }
+
+  validateUsingAmanda(data) {
+    let errors = {
+      length: 0,
+      errorMessages: {}
+    };
+
+    try {
+      amanda.validate(data, this.jsonSchema, jsonSchemaOptions, (error) => {
+        if (error && error.length > 0) {
+          for (let i = 0; i < error.length; i++) {
+            if (error[i].property === '') {
+              error[i].property = [];
+            }
+          }
+
+          errors = new ValidationErrors(error);
+        }
+      });
+    } catch (error) {
+      errors = new ValidationErrors({
+        '0': {
+          property: [],
+          attributeValue: true,
+          message: `Validator internal error: ${error.message}`,
+          validatorName: 'error'
+        },
+        length: 1,
+        errorMessages: {}
+      });
+    }
+
+    return this.toGavelResult(errors);
+  }
+
+  validateUsingTV4(data) {
+    const result = tv4.validateMultiple(data, this.jsonSchema);
+    const validationErrors = result.errors.concat(result.missing);
+
+    const amandaCompatibleError = {
+      length: validationErrors.length,
+      errorMessages: {}
+    };
+
+    for (let index = 0; index < validationErrors.length; index++) {
+      const validationError = validationErrors[index];
+      let error;
+
+      if (validationError instanceof Error) {
+        error = validationError;
+      } else {
+        error = new Error('Missing schema');
+        error.params = { key: validationError };
+        error.dataPath = '';
+      }
+
+      const pathArray = jsonPointer
+        .parse(error.dataPath)
+        .concat(error.params.key || []);
+      const pointer = jsonPointer.compile(pathArray);
+
+      amandaCompatibleError[index] = {
+        message: `At '${pointer}' ${error.message}`,
+        property: pathArray,
+        attributeValue: true,
+        validatorName: 'error'
+      };
+    }
+
+    const errors = new ValidationErrors(amandaCompatibleError);
+    return this.toGavelResult(errors);
+  }
+
+  /**
+   * Converts Amanda-like validation result to the
+   * unified Gavel public validation result.
+   */
+  toGavelResult(amandaLikeResult) {
+    const results = Array.from(
+      { length: amandaLikeResult.length },
+      (_, index) => {
+        const item = amandaLikeResult[index];
+        const { property, message } = item;
+        const pathArray = [].concat(property).filter(Boolean);
+        const pointer = jsonPointer.compile(pathArray);
+
+        return {
+          message,
+          location: {
+            pointer,
+            property
+          }
+        };
+      }
+    );
+
+    return results;
+  }
+}
+
+module.exports = { JsonSchemaLegacy };

lib/validators/json-schema-next.js

@@ -0,0 +1,129 @@
+const Ajv = require('ajv');
+const metaSchemaV6 = require('ajv/lib/refs/json-schema-draft-06.json');
+const metaSchemaV7 = require('ajv/lib/refs/json-schema-draft-07.json');
+
+const metaSchemaV4 = require('../meta-schema-v4');
+const metaSchemaV3 = require('../meta-schema-v3');
+const errors = require('../errors');
+
+const SCHEMA_VERSIONS = {
+  v3: 'http://json-schema.org/draft-03/schema',
+  v4: 'http://json-schema.org/draft-04/schema',
+  v6: 'http://json-schema.org/draft-06/schema',
+  v7: 'http://json-schema.org/draft-07/schema'
+};
+
+const META_SCHEMA = {
+  v3: metaSchemaV3,
+  v4: metaSchemaV4,
+  v6: metaSchemaV6,
+  v7: metaSchemaV7
+};
+
+/**
+ * Returns a JSON Schema Draft version of the given JSON Schema.
+ */
+const getSchemaVersion = (jsonSchema) => {
+  const jsonSchemaVersion = Object.keys(SCHEMA_VERSIONS).find((version) => {
+    const jsonSchemaAnnotation = SCHEMA_VERSIONS[version];
+    return (
+      jsonSchema.$schema && jsonSchema.$schema.includes(jsonSchemaAnnotation)
+    );
+  });
+
+  if (jsonSchemaVersion == null) {
+    throw new errors.JsonSchemaNotSupported(
+      `Provided JSON Schema version is missing, or not supported. Please provide a JSON Schema Draft ${Object.keys(
+        SCHEMA_VERSIONS
+      ).join('/')}.`
+    );
+  }
+
+  return jsonSchemaVersion;
+};
+
+class JsonSchemaValidator {
+  constructor(jsonSchema) {
+    this.jsonSchema = jsonSchema;
+    this.jsonSchemaVersion = getSchemaVersion(jsonSchema);
+    this.jsonMetaSchema = this.getMetaSchema();
+
+    const isSchemaValid = this.validateSchema();
+    if (!isSchemaValid) {
+      throw new errors.JsonSchemaNotValid(
+        `Provided JSON Schema is not a valid JSON Schema Draft ${this.jsonSchemaVersion}.`
+      );
+    }
+  }
+
+  /**
+   * Returns a meta schema for the provided JSON Schema.
+   */
+  getMetaSchema() {
+    return META_SCHEMA[this.jsonSchemaVersion];
+  }
+
+  /**
+   * Validates the schema against its version specification.
+   * @return {boolean}
+   */
+  validateSchema() {
+    const { jsonSchemaVersion, jsonSchema } = this;
+    let isSchemaValid = true;
+
+    // use AJV to validate modern schema (6/7)
+    const ajv = new Ajv();
+
+    const metaSchema = META_SCHEMA[jsonSchemaVersion];
+    ajv.addMetaSchema(metaSchema, 'meta');
+
+    isSchemaValid = ajv.validateSchema(jsonSchema);
+
+    // Clean up the added meta schema
+    ajv.removeSchema('meta');
+
+    return isSchemaValid;
+  }
+
+  /**
+   * Validates the given data.
+   */
+  validate(data) {
+    const ajv = new Ajv({
+      // Disable adding JSON Schema Draft 7 meta schema by default.
+      // Allows to always add a meta schema depending on the schema version.
+      meta: false,
+      // No need to validate schema again, already validated
+      // in "validateSchema()" method.
+      validateSchema: false,
+      // Make AJV point to the property in "error.dataPath",
+      // so it could be used as a complete pointer.
+      // errorDataPath: 'property',
+      jsonPointers: true
+    });
+
+    ajv.validate(this.jsonSchema, data);
+
+    // Convert AJV validation errors to the Gavel public validation errors.
+    return (ajv.errors || []).map((ajvError) => {
+      const errorMessage = ajv.errorsText([ajvError]);
+      const { dataPath: pointer } = ajvError;
+      const property =
+        ajvError.params.missingProperty || pointer.split('/').filter(Boolean);
+
+      return {
+        message: errorMessage,
+        location: {
+          pointer,
+          property
+        }
+      };
+    });
+  }
+}
+
+module.exports = {
+  JsonSchemaValidator,
+  getSchemaVersion,
+  META_SCHEMA
+};