specs.js

/*
 * The MIT License (MIT)
 *
 * Copyright (c) 2014 Apigee Corporation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 */

'use strict';

// Done this way to make the Browserify build smaller
var _ = {
  cloneDeep: require('lodash-compat/lang/cloneDeep'),
  difference: require('lodash-compat/array/difference'),
  each: require('lodash-compat/collection/each'),
  find: require('lodash-compat/collection/find'),
  has: require('lodash-compat/object/has'),
  isArray: require('lodash-compat/lang/isArray'),
  isFunction: require('lodash-compat/lang/isFunction'),
  isPlainObject: require('lodash-compat/lang/isPlainObject'),
  isString: require('lodash-compat/lang/isString'),
  isUndefined: require('lodash-compat/lang/isUndefined'),
  map: require('lodash-compat/collection/map'),
  reduce: require('lodash-compat/collection/reduce'),
  set: require('lodash-compat/object/set'),
  union: require('lodash-compat/array/union')
};
var async = require('async');
var helpers = require('./helpers');
var JsonRefs = require('json-refs');
var SparkMD5 = require('spark-md5');
var swaggerConverter = require('swagger-converter');
var traverse = require('traverse');
var validators = require('./validators');
var YAML = require('js-yaml');

// Work around swagger-converter packaging issue (Browser builds only)
if (_.isPlainObject(swaggerConverter)) {
  swaggerConverter = global.SwaggerConverter.convert;
}

var documentCache = {};

var sanitizeRef = function (version, ref) {
  return version !== '1.2' ? ref : ref.replace('#/models/', '');
};

var swagger1RefPreProcesor = function (obj) {
  var pObj = _.cloneDeep(obj);

  pObj.$ref = '#/models/' + obj.$ref;

  return pObj;
};
var validOptionNames = _.map(helpers.swaggerOperationMethods, function (method) {
  return method.toLowerCase();
});

var isRemotePtr = function (refDetails) {
  return ['relative', 'remote'].indexOf(refDetails.type) > -1;
};

var createErrorOrWarning = function (code, message, path, dest) {
  dest.push({
    code: code,
    message: message,
    path: path
  });
};

var addReference = function (cacheEntry, defPathOrPtr, refPathOrPtr, results, omitError) {
  var result = true;
  var swaggerVersion = helpers.getSwaggerVersion(cacheEntry.resolved);
  var defPath = _.isArray(defPathOrPtr) ? defPathOrPtr : JsonRefs.pathFromPtr(defPathOrPtr);
  var defPtr = _.isArray(defPathOrPtr) ? JsonRefs.pathToPtr(defPathOrPtr) : defPathOrPtr;
  var refPath = _.isArray(refPathOrPtr) ? refPathOrPtr : JsonRefs.pathFromPtr(refPathOrPtr);
  var refPtr = _.isArray(refPathOrPtr) ? JsonRefs.pathToPtr(refPathOrPtr) : refPathOrPtr;
  var code;
  var def;
  var displayId;
  var i;
  var msgPrefix;
  var type;

  def = cacheEntry.definitions[defPtr];
  type = defPath[0];
  code = type === 'securityDefinitions' ?
    'SECURITY_DEFINITION' :
    type.substring(0, type.length - 1).toUpperCase();
  displayId = swaggerVersion === '1.2' ? defPath[defPath.length - 1] : defPtr;
  msgPrefix = type === 'securityDefinitions' ?
    'Security definition' :
    code.charAt(0) + code.substring(1).toLowerCase();

  // This is an authorization scope reference
  if (['authorizations', 'securityDefinitions'].indexOf(defPath[0]) > -1 && defPath[2] === 'scopes') {
    code += '_SCOPE';
    msgPrefix += ' scope';
  }

  // If the reference was not found and this is not an authorization/security scope reference, attempt to find a
  // parent object to add the reference too.  (Issue 176)
  if (_.isUndefined(def) && ['AUTHORIZATION_SCOPE', 'SECURITY_DEFINITION_SCOPE'].indexOf(code) === -1) {
    // Attempt to find the definition in case the reference is to a path within a definition`
    for (i = 1; i < defPath.length; i++) {
      var pPath = defPath.slice(0, defPath.length - i);
      var pPtr = JsonRefs.pathToPtr(pPath);
      var pDef = cacheEntry.definitions[pPtr];

      if (!_.isUndefined(pDef)) {
        def = pDef;

        break;
      }
    }
  }

  if (_.isUndefined(def)) {
    if (!omitError) {
      if (cacheEntry.swaggerVersion !== '1.2' && ['SECURITY_DEFINITION', 'SECURITY_DEFINITION_SCOPE'].indexOf(code) === -1) {
        refPath.push('$ref');
      }

      createErrorOrWarning('UNRESOLVABLE_' + code, msgPrefix + ' could not be resolved: ' + displayId, refPath,
                           results.errors);
    }

    result = false;
  } else {
    if (_.isUndefined(def.references)) {
      def.references = [];
    }

    def.references.push(refPtr);
  }

  return result;
};

var getOrComposeSchema = function (documentMetadata, modelId) {
  var title = 'Composed ' + (documentMetadata.swaggerVersion === '1.2' ?
                               JsonRefs.pathFromPtr(modelId).pop() :
                               modelId);
  var metadata = documentMetadata.definitions[modelId];
  var originalT = traverse(documentMetadata.original);
  var resolvedT = traverse(documentMetadata.resolved);
  var composed;
  var original;

  if (!metadata) {
    return undefined;
  }

  original = _.cloneDeep(originalT.get(JsonRefs.pathFromPtr(modelId)));
  composed = _.cloneDeep(resolvedT.get(JsonRefs.pathFromPtr(modelId)));

  // Convert the Swagger 1.2 document to a valid JSON Schema file
  if (documentMetadata.swaggerVersion === '1.2') {
    // Create inheritance model
    if (metadata.lineage.length > 0) {
      composed.allOf = [];

      _.each(metadata.lineage, function (modelId) {
        composed.allOf.push(getOrComposeSchema(documentMetadata, modelId));
      });
    }

    // Remove the subTypes property
    delete composed.subTypes;

    _.each(composed.properties, function (property, name) {
      var oProp = original.properties[name];

      // Convert the string values to numerical values
      _.each(['maximum', 'minimum'], function (prop) {
        if (_.isString(property[prop])) {
          property[prop] = parseFloat(property[prop]);
        }
      });

      _.each(JsonRefs.findRefs(oProp, {
        includeInvalid: true,
        refPreProcessor: swagger1RefPreProcesor
      }), function (refDetails, refPtr) {
        var dMetadata = documentMetadata.definitions[refDetails.uri];
        var path = JsonRefs.pathFromPtr(refPtr);

        if (dMetadata.lineage.length > 0) {
          traverse(property).set(path, getOrComposeSchema(documentMetadata, refDetails.uri));
        } else {
          traverse(property).set(path.concat('title'), 'Composed ' + sanitizeRef(documentMetadata.swaggerVersion,
                                                                                 refDetails.uri));
        }
      });
    });
  }

  // Scrub id properties
  composed = traverse(composed).map(function (val) {
    if (this.key === 'id' && _.isString(val)) {
      this.remove();
    }
  });

  composed.title = title;

  return composed;
};

var createUnusedErrorOrWarning = function (val, codeSuffix, msgPrefix, path, dest) {
  createErrorOrWarning('UNUSED_' + codeSuffix, msgPrefix + ' is defined but is not used: ' + val, path, dest);
};

var getDocumentCache = function (apiDOrSO) {
  var key = SparkMD5.hash(JSON.stringify(apiDOrSO));
  var cacheEntry = documentCache[key] || _.find(documentCache, function (cacheEntry) {
    return cacheEntry.resolvedId === key;
  });

  if (!cacheEntry) {
    cacheEntry = documentCache[key] = {
      definitions: {},
      original: apiDOrSO,
      resolved: undefined,
      swaggerVersion: helpers.getSwaggerVersion(apiDOrSO)
    };
  }

  return cacheEntry;
};

var handleValidationError = function (results, callback) {
  var err = new Error('The Swagger document(s) are invalid');

  err.errors = results.errors;
  err.failedValidation = true;
  err.warnings = results.warnings;

  if (results.apiDeclarations) {
    err.apiDeclarations = results.apiDeclarations;
  }

  callback(err);
};

var normalizePath = function (path) {
  var matches = path.match(/\{(.*?)\}/g);
  var argNames = [];
  var normPath = path;

  if (matches) {
    _.each(matches, function (match, index) {
      normPath = normPath.replace(match, '{' + index + '}');
      argNames.push(match.replace(/[{}]/g, ''));
    });
  }

  return {
    path: normPath,
    args: argNames
  };
};

var removeCirculars = function (obj) {
  function walk (ancestors, node, path) {
    function walkItem (item, segment) {
      path.push(segment);
      walk(ancestors, item, path);
      path.pop();
    }

    // We do not process circular objects again
    if (ancestors.indexOf(node) === -1) {
      ancestors.push(node);

      if (_.isArray(node) || _.isPlainObject(node)) {
        _.each(node, function (member, indexOrKey) {
          walkItem(member, indexOrKey.toString());
        });
      }
    } else {
      _.set(obj, path, {});
    }

    ancestors.pop();
  }

  walk([], obj, []);
};


var validateNoExist = function (data, val, codeSuffix, msgPrefix, path, dest) {
  if (!_.isUndefined(data) && data.indexOf(val) > -1) {
    createErrorOrWarning('DUPLICATE_' + codeSuffix, msgPrefix + ' already defined: ' + val, path, dest);
  }
};

var validateSchemaConstraints = function (documentMetadata, schema, path, results, skip) {
  try {
    validators.validateSchemaConstraints(documentMetadata.swaggerVersion, schema, path, undefined);
  } catch (err) {
    if (!skip) {
      createErrorOrWarning(err.code, err.message, err.path, results.errors);
    }
  }
};

var processDocument = function (documentMetadata, results) {
  var swaggerVersion = documentMetadata.swaggerVersion;
  var getDefinitionMetadata = function (defPath, inline) {
    var defPtr = JsonRefs.pathToPtr(defPath);
    var metadata = documentMetadata.definitions[defPtr];

    if (!metadata) {
      metadata = documentMetadata.definitions[defPtr] = {
        inline: inline || false,
        references: []
      };

      // For model definitions, add the inheritance properties
      if (['definitions', 'models'].indexOf(JsonRefs.pathFromPtr(defPtr)[0]) > -1) {
        metadata.cyclical = false;
        metadata.lineage = undefined;
        metadata.parents = [];
      }
    }

    return metadata;
  };
  var getDisplayId = function (id) {
    return swaggerVersion === '1.2' ? JsonRefs.pathFromPtr(id).pop() : id;
  };
  var jsonRefsOptions = {
    filter: 'local',
    includeInvalid: true
  };
  var walk = function (root, id, lineage) {
    var definition = documentMetadata.definitions[id || root];

    if (definition) {
      _.each(definition.parents, function (parent) {
        lineage.push(parent);

        if (root !== parent) {
          walk(root, parent, lineage);
        }
      });
    }
  };
  var authDefsProp = swaggerVersion === '1.2' ? 'authorizations' : 'securityDefinitions';
  var modelDefsProp = swaggerVersion === '1.2' ? 'models' : 'definitions';

  // Process authorization definitions
  _.each(documentMetadata.resolved[authDefsProp], function (authorization, name) {
    var securityDefPath = [authDefsProp, name];

    // Swagger 1.2 only has authorization definitions in the Resource Listing
    if (swaggerVersion === '1.2' && !authorization.type) {
      return;
    }

    // Create the authorization definition metadata
    getDefinitionMetadata(securityDefPath);

    _.reduce(authorization.scopes, function (seenScopes, scope, indexOrName) {
      var scopeName = swaggerVersion === '1.2' ? scope.scope : indexOrName;
      var scopeDefPath = securityDefPath.concat(['scopes', indexOrName.toString()]);
      var scopeMetadata = getDefinitionMetadata(securityDefPath.concat(['scopes', scopeName]));

      scopeMetadata.scopePath = scopeDefPath;

      // Identify duplicate authorization scope defined in the Resource Listing
      validateNoExist(seenScopes, scopeName, 'AUTHORIZATION_SCOPE_DEFINITION', 'Authorization scope definition',
                      swaggerVersion === '1.2' ? scopeDefPath.concat('scope') : scopeDefPath, results.warnings);

      seenScopes.push(scopeName);

      return seenScopes;
    }, []);
  });

  // Process model definitions
  _.each(documentMetadata.resolved[modelDefsProp], function (model, modelId) {
    var modelDefPath = [modelDefsProp, modelId];
    var modelMetadata = getDefinitionMetadata(modelDefPath);

    // Identify model id mismatch (Id in models object is not the same as the model's id in the models object)
    if (swaggerVersion === '1.2' && modelId !== model.id) {
      createErrorOrWarning('MODEL_ID_MISMATCH', 'Model id does not match id in models object: ' + model.id,
                           modelDefPath.concat('id'), results.errors);
    }

    // Do not reprocess parents/references if already processed
    if (_.isUndefined(modelMetadata.lineage)) {
      // Handle inheritance references
      switch (swaggerVersion) {
      case '1.2':
        _.each(model.subTypes, function (subType, index) {
          var subPath = ['models', subType];
          var subPtr = JsonRefs.pathToPtr(subPath);
          var subMetadata = documentMetadata.definitions[subPtr];
          var refPath = modelDefPath.concat(['subTypes', index.toString()]);

          // If the metadata does not yet exist, create it
          if (!subMetadata && documentMetadata.resolved[modelDefsProp][subType]) {
            subMetadata = getDefinitionMetadata(subPath);
          }

          // If the reference is valid, add the parent
          if (addReference(documentMetadata, subPath, refPath, results)) {
            subMetadata.parents.push(JsonRefs.pathToPtr(modelDefPath));
          }
        });

        break;

      default:
        _.each(documentMetadata.original[modelDefsProp][modelId].allOf, function (schema, index) {
          var isInline = false;
          var parentPath;

          if (_.isUndefined(schema.$ref) || isRemotePtr(JsonRefs.getRefDetails(schema))) {
            isInline = true;
            parentPath = modelDefPath.concat(['allOf', index.toString()]);
          } else {
            parentPath = JsonRefs.pathFromPtr(schema.$ref);
          }

          // If the parent model does not exist, do not create its metadata
          if (!_.isUndefined(traverse(documentMetadata.resolved).get(parentPath))) {
            // Create metadata for parent
            getDefinitionMetadata(parentPath, isInline);

            modelMetadata.parents.push(JsonRefs.pathToPtr(parentPath));
          }
        });

        break;
      }
    }
  });

  switch (swaggerVersion) {
  case '2.0':
    // Process parameter definitions
    _.each(documentMetadata.resolved.parameters, function (parameter, name) {
      var path = ['parameters', name];

      getDefinitionMetadata(path);

      validateSchemaConstraints(documentMetadata, parameter, path, results);
    });

    // Process response definitions
    _.each(documentMetadata.resolved.responses, function (response, name) {
      var path = ['responses', name];

      getDefinitionMetadata(path);

      validateSchemaConstraints(documentMetadata, response, path, results);
    });

    break;
  }

  // Validate definition/models (Inheritance, property definitions, ...)
  _.each(documentMetadata.definitions, function (metadata, id) {
    var defPath = JsonRefs.pathFromPtr(id);
    var definition = traverse(documentMetadata.original).get(defPath);
    var defProp = defPath[0];
    var code = defProp.substring(0, defProp.length - 1).toUpperCase();
    var msgPrefix = code.charAt(0) + code.substring(1).toLowerCase();
    var dProperties;
    var iProperties;
    var lineage;

    // The only checks we perform below are inheritance checks so skip all non-model definitions
    if (['definitions', 'models'].indexOf(defProp) === -1) {
      return;
    }

    dProperties = [];
    iProperties = [];
    lineage = metadata.lineage;

    // Do not reprocess lineage if already processed
    if (_.isUndefined(lineage)) {
      lineage = [];

      walk(id, undefined, lineage);

      // Root > next > ...
      lineage.reverse();

      metadata.lineage = _.cloneDeep(lineage);

      metadata.cyclical = lineage.length > 1 && lineage[0] === id;
    }

    // Swagger 1.2 does not allow multiple inheritance while Swagger 2.0+ does
    if (metadata.parents.length > 1 && swaggerVersion === '1.2') {
      createErrorOrWarning('MULTIPLE_' + code + '_INHERITANCE',
                           'Child ' + code.toLowerCase() + ' is sub type of multiple models: ' +
                           _.map(metadata.parents, function (parent) {
                             return getDisplayId(parent);
                           }).join(' && '), defPath, results.errors);
    }

    if (metadata.cyclical) {
      createErrorOrWarning('CYCLICAL_' + code + '_INHERITANCE',
                           msgPrefix + ' has a circular inheritance: ' +
                             _.map(lineage, function (dep) {
                               return getDisplayId(dep);
                             }).join(' -> ') + ' -> ' + getDisplayId(id),
                            defPath.concat(swaggerVersion === '1.2' ? 'subTypes' : 'allOf'), results.errors);
    }

    // Remove self reference from the end of the lineage (Front too if cyclical)
    _.each(lineage.slice(metadata.cyclical ? 1 : 0), function (id) {
      var pModel = traverse(documentMetadata.resolved).get(JsonRefs.pathFromPtr(id));

      _.each(Object.keys(pModel.properties || {}), function (name) {
        if (iProperties.indexOf(name) === -1) {
          iProperties.push(name);
        }
      });
    });

    // Validate simple definitions
    validateSchemaConstraints(documentMetadata, definition, defPath, results);

    // Identify redeclared properties
    _.each(definition.properties, function (property, name) {
      var pPath = defPath.concat(['properties', name]);

      // Do not process unresolved properties
      if (!_.isUndefined(property)) {
        validateSchemaConstraints(documentMetadata, property, pPath, results);
        dProperties.push(name);
      }
    });

    // Identify missing required properties
    _.each(definition.required || [], function (name, index) {
      var type = swaggerVersion === '1.2' ? 'Model' : 'Definition';

      if (iProperties.indexOf(name) === -1 && dProperties.indexOf(name) === -1) {
        createErrorOrWarning('MISSING_REQUIRED_' + type.toUpperCase() + '_PROPERTY',
                             type + ' requires property but it is not defined: ' + name,
                             defPath.concat(['required', index.toString()]), results.errors);
      }
    });
  });

  if (documentMetadata.swaggerVersion === '1.2') {
    jsonRefsOptions.refPreProcessor = swagger1RefPreProcesor;
  }

  // Process local references
  _.each(JsonRefs.findRefs(documentMetadata.original, jsonRefsOptions), function (refDetails, refPtr) {
    addReference(documentMetadata, refDetails.uri, refPtr, results);
  });

  // Process invalid references
  _.each(documentMetadata.referencesMetadata, function (refDetails, refPtr) {
    if (isRemotePtr(refDetails) && refDetails.missing === true) {
      results.errors.push({
        code: 'UNRESOLVABLE_REFERENCE',
        message: 'Reference could not be resolved: ' + sanitizeRef(documentMetadata.swaggerVersion, refDetails.uri),
        path: JsonRefs.pathFromPtr(refPtr).concat('$ref')
      });
    }
  });
};

var validateExist = function (data, val, codeSuffix, msgPrefix, path, dest) {
  if (!_.isUndefined(data) && data.indexOf(val) === -1) {
    createErrorOrWarning('UNRESOLVABLE_' + codeSuffix, msgPrefix + ' could not be resolved: ' + val, path, dest);
  }
};

var processAuthRefs = function (documentMetadata, authRefs, path, results) {
  var code = documentMetadata.swaggerVersion === '1.2' ? 'AUTHORIZATION' : 'SECURITY_DEFINITION';
  var msgPrefix = code === 'AUTHORIZATION' ? 'Authorization' : 'Security definition';

  if (documentMetadata.swaggerVersion === '1.2') {
    _.reduce(authRefs, function (seenNames, scopes, name) {
      var authPtr = ['authorizations', name];
      var aPath = path.concat([name]);

      // Add reference or record unresolved authorization
      if (addReference(documentMetadata, authPtr, aPath, results)) {
        _.reduce(scopes, function (seenScopes, scope, index) {
          var sPath = aPath.concat(index.toString(), 'scope');
          var sPtr = authPtr.concat(['scopes', scope.scope]);

          validateNoExist(seenScopes, scope.scope, code + '_SCOPE_REFERENCE', msgPrefix + ' scope reference', sPath,
                          results.warnings);

          // Add reference or record unresolved authorization scope
          addReference(documentMetadata, sPtr, sPath, results);

          return seenScopes.concat(scope.scope);
        }, []);
      }

      return seenNames.concat(name);
    }, []);
  } else {
    _.reduce(authRefs, function (seenNames, scopes, index) {
      _.each(scopes, function (scopes, name) {
        var authPtr = ['securityDefinitions', name];
        var authRefPath = path.concat(index.toString(), name);

        // Ensure the security definition isn't referenced more than once (Swagger 2.0+)
        validateNoExist(seenNames, name, code + '_REFERENCE', msgPrefix + ' reference', authRefPath,
                        results.warnings);

        seenNames.push(name);

        // Add reference or record unresolved authorization
        if (addReference(documentMetadata, authPtr, authRefPath, results)) {
          _.each(scopes, function (scope, index) {
            // Add reference or record unresolved authorization scope
            var sPtr = authPtr.concat(['scopes', scope]);
            addReference(documentMetadata, sPtr, authRefPath.concat(index.toString()),
                         results);
          });
        }
      });

      return seenNames;
    }, []);
  }
};

var resolveRefs = function (apiDOrSO, callback) {
  var cacheEntry = getDocumentCache(apiDOrSO);
  var swaggerVersion = helpers.getSwaggerVersion(apiDOrSO);
  var jsonRefsOptions = {
    includeInvalid: true,
    loaderOptions: {
      processContent: function (res, callback) {
        callback(undefined, YAML.safeLoad(res.text));
      }
    }
  };

  if (!cacheEntry.resolved) {
    // For Swagger 1.2, we have to create real JSON References
    if (swaggerVersion === '1.2') {
      jsonRefsOptions.refPreProcessor = swagger1RefPreProcesor;
    }

    // Resolve references
    JsonRefs.resolveRefs(apiDOrSO, jsonRefsOptions)
      .then(function (results) {
        removeCirculars(results.resolved);

        // Fix circular references
        _.each(results.refs, function (refDetails, refPtr) {
          if (refDetails.circular) {
            _.set(results.resolved, JsonRefs.pathFromPtr(refPtr), {});
          }
        });

        cacheEntry.referencesMetadata = results.refs;
        cacheEntry.resolved = results.resolved;
        cacheEntry.resolvedId = SparkMD5.hash(JSON.stringify(results.resolved));

        callback();
      })
      .catch(callback);
  } else {
    callback();
  }
};

var validateAgainstSchema = function (spec, schemaOrName, data, callback) {
  var validator = _.isString(schemaOrName) ? spec.validators[schemaOrName] : helpers.createJsonValidator();

  helpers.registerCustomFormats(data);

  try {
    validators.validateAgainstSchema(schemaOrName, data, validator);
  } catch (err) {
    if (err.failedValidation) {
      return callback(undefined, err.results);
    } else {
      return callback(err);
    }
  }

  resolveRefs(data, function (err) {
    return callback(err);
  });
};

var validateDefinitions = function (documentMetadata, results) {
  // Validate unused definitions
  _.each(documentMetadata.definitions, function (metadata, id) {
    var defPath = JsonRefs.pathFromPtr(id);
    var defType = defPath[0].substring(0, defPath[0].length - 1);
    var displayId = documentMetadata.swaggerVersion === '1.2' ? defPath[defPath.length - 1] : id;
    var code = defType === 'securityDefinition' ? 'SECURITY_DEFINITION' : defType.toUpperCase();
    var msgPrefix = defType === 'securityDefinition' ?
                             'Security definition' :
                             defType.charAt(0).toUpperCase() + defType.substring(1);

    if (metadata.references.length === 0 && !metadata.inline) {
      // Swagger 1.2 authorization scope
      if (metadata.scopePath) {
        code += '_SCOPE';
        msgPrefix += ' scope';
        defPath = metadata.scopePath;
      }

      createUnusedErrorOrWarning(displayId, code, msgPrefix, defPath, results.warnings);
    }
  });
};

var validateParameters = function (spec, documentMetadata, nPath, parameters, path, results,
                                   skipMissing) {
  var createParameterComboError = function (path) {
    createErrorOrWarning('INVALID_PARAMETER_COMBINATION',
                         'API cannot have a a body parameter and a ' +
                           (spec.version === '1.2' ? 'form' : 'formData') + ' parameter',
                         path, results.errors);
  };
  var pathParams = [];
  var seenBodyParam = false;
  var seenFormParam = false;

  _.reduce(parameters, function (seenParameters, parameter, index) {
    var pPath = path.concat(['parameters', index.toString()]);

    // Unresolved parameter
    if (_.isUndefined(parameter)) {
      return;
    }

    // Identify duplicate parameter names
    validateNoExist(seenParameters, parameter.name, 'PARAMETER', 'Parameter', pPath.concat('name'),
                    results.errors);

    // Keep track of body and path parameters
    if (parameter.paramType === 'body' || parameter.in === 'body') {
      if (seenBodyParam === true) {
        createErrorOrWarning('DUPLICATE_API_BODY_PARAMETER', 'API has more than one body parameter', pPath,
                             results.errors);
      } else if (seenFormParam === true) {
        createParameterComboError(pPath);
      }

      seenBodyParam = true;
    } else if (parameter.paramType === 'form' || parameter.in === 'formData') {
      if (seenBodyParam === true) {
        createParameterComboError(pPath);
      }

      seenFormParam = true;
    } else if (parameter.paramType === 'path' || parameter.in === 'path') {
      if (nPath.args.indexOf(parameter.name) === -1) {
        createErrorOrWarning('UNRESOLVABLE_API_PATH_PARAMETER',
                             'API path parameter could not be resolved: ' + parameter.name, pPath.concat('name'),
                             results.errors);
      }

      pathParams.push(parameter.name);
    }

    if (spec.primitives.indexOf(parameter.type) === -1 && spec.version === '1.2') {
      addReference(documentMetadata, '#/models/' + parameter.type, pPath.concat('type'), results);
    }

    // Validate parameter constraints
    validateSchemaConstraints(documentMetadata, parameter, pPath, results, parameter.skipErrors);

    return seenParameters.concat(parameter.name);
  }, []);

  // Validate missing path parameters (in path but not in operation.parameters)
  if (_.isUndefined(skipMissing) || skipMissing === false) {
    _.each(_.difference(nPath.args, pathParams), function (unused) {
      createErrorOrWarning('MISSING_API_PATH_PARAMETER', 'API requires path parameter but it is not defined: ' + unused,
                           documentMetadata.swaggerVersion === '1.2' ? path.slice(0, 2).concat('path') : path,
                           results.errors);
    });
  }
};

var validateSwagger1_2 = function (spec, resourceListing, apiDeclarations, callback) { // jshint ignore:line
  var adResourcePaths = [];
  var rlDocumentMetadata = getDocumentCache(resourceListing);
  var rlResourcePaths = [];
  var results = {
    errors: [],
    warnings: [],
    apiDeclarations: []
  };

  // Process Resource Listing resource definitions
  rlResourcePaths = _.reduce(resourceListing.apis, function (seenPaths, api, index) {
    // Identify duplicate resource paths defined in the Resource Listing
    validateNoExist(seenPaths, api.path, 'RESOURCE_PATH', 'Resource path', ['apis', index.toString(), 'path'],
                    results.errors);

    seenPaths.push(api.path);

    return seenPaths;
  }, []);

  // Process Resource Listing definitions (authorizations)
  processDocument(rlDocumentMetadata, results);


  // Process each API Declaration
  adResourcePaths = _.reduce(apiDeclarations, function (seenResourcePaths, apiDeclaration, index) {
    var aResults = results.apiDeclarations[index] = {
      errors: [],
      warnings: []
    };
    var adDocumentMetadata = getDocumentCache(apiDeclaration);

    // Identify duplicate resource paths defined in the API Declarations
    validateNoExist(seenResourcePaths, apiDeclaration.resourcePath, 'RESOURCE_PATH', 'Resource path',
                    ['resourcePath'], aResults.errors);

    if (adResourcePaths.indexOf(apiDeclaration.resourcePath) === -1) {
      // Identify unused resource paths defined in the API Declarations
      validateExist(rlResourcePaths, apiDeclaration.resourcePath, 'RESOURCE_PATH', 'Resource path',
                    ['resourcePath'], aResults.errors);

      seenResourcePaths.push(apiDeclaration.resourcePath);
    }

    // TODO: Process authorization references
    // Not possible due to https://github.com/swagger-api/swagger-spec/issues/159

    // Process models
    processDocument(adDocumentMetadata, aResults);

    // Process the API definitions
    _.reduce(apiDeclaration.apis, function (seenPaths, api, index) {
      var aPath = ['apis', index.toString()];
      var nPath = normalizePath(api.path);

      // Validate duplicate resource path
      if (seenPaths.indexOf(nPath.path) > -1) {
        createErrorOrWarning('DUPLICATE_API_PATH', 'API path (or equivalent) already defined: ' + api.path,
                             aPath.concat('path'), aResults.errors);
      } else {
        seenPaths.push(nPath.path);
      }

      // Process the API operations
      _.reduce(api.operations, function (seenMethods, operation, index) {
        var oPath = aPath.concat(['operations', index.toString()]);

        // Validate duplicate operation method
        validateNoExist(seenMethods, operation.method, 'OPERATION_METHOD', 'Operation method', oPath.concat('method'),
                        aResults.errors);

        // Keep track of the seen methods
        seenMethods.push(operation.method);

        // Keep track of operation types
        if (spec.primitives.indexOf(operation.type) === -1 && spec.version === '1.2') {
          addReference(adDocumentMetadata, '#/models/' + operation.type, oPath.concat('type'), aResults);
        }

        // Process authorization references
        processAuthRefs(rlDocumentMetadata, operation.authorizations, oPath.concat('authorizations'), aResults);

        // Validate validate inline constraints
        validateSchemaConstraints(adDocumentMetadata, operation, oPath, aResults);

        // Validate parameters
        validateParameters(spec, adDocumentMetadata, nPath, operation.parameters, oPath, aResults);

        // Validate unique response code
        _.reduce(operation.responseMessages, function (seenResponseCodes, responseMessage, index) {
          var rmPath = oPath.concat(['responseMessages', index.toString()]);

          validateNoExist(seenResponseCodes, responseMessage.code, 'RESPONSE_MESSAGE_CODE', 'Response message code',
                          rmPath.concat(['code']), aResults.errors);

          // Validate missing model
          if (responseMessage.responseModel) {
            addReference(adDocumentMetadata, '#/models/' + responseMessage.responseModel,
                         rmPath.concat('responseModel'), aResults);
          }

          return seenResponseCodes.concat(responseMessage.code);
        }, []);

        return seenMethods;
      }, []);

      return seenPaths;
    }, []);

    // Validate API Declaration definitions
    validateDefinitions(adDocumentMetadata, aResults);

    return seenResourcePaths;
  }, []);

  // Validate API Declaration definitions
  validateDefinitions(rlDocumentMetadata, results);

  // Identify unused resource paths defined in the Resource Listing
  _.each(_.difference(rlResourcePaths, adResourcePaths), function (unused) {
    var index = rlResourcePaths.indexOf(unused);

    createUnusedErrorOrWarning(resourceListing.apis[index].path, 'RESOURCE_PATH', 'Resource path',
                               ['apis', index.toString(), 'path'], results.errors);
  });

  callback(undefined, results);
};

var validateSwagger2_0 = function (spec, swaggerObject, callback) { // jshint ignore:line
  var documentMetadata = getDocumentCache(swaggerObject);
  var results = {
    errors: [],
    warnings: []
  };

  // Process definitions
  processDocument(documentMetadata, results);

  // Process security references
  processAuthRefs(documentMetadata, swaggerObject.security, ['security'], results);

  _.reduce(documentMetadata.resolved.paths, function (seenPaths, path, name) {
    var pPath = ['paths', name];
    var nPath = normalizePath(name);

    // Validate duplicate resource path
    if (seenPaths.indexOf(nPath.path) > -1) {
      createErrorOrWarning('DUPLICATE_API_PATH', 'API path (or equivalent) already defined: ' + name, pPath,
                           results.errors);
    }

    // Validate parameters
    validateParameters(spec, documentMetadata, nPath, path.parameters, pPath, results, true);

    // Validate the Operations
    _.each(path, function (operation, method) {
      var cParams = [];
      var oPath = pPath.concat(method);
      var seenParams = [];

      if (validOptionNames.indexOf(method) === -1) {
        return;
      }

      // Process security references
      processAuthRefs(documentMetadata, operation.security, oPath.concat('security'), results);

      // Compose parameters from path global parameters and operation parameters
      _.each(operation.parameters, function (parameter) {
        // Can happen with invalid references
        if (_.isUndefined(parameter)) {
          return;
        }

        cParams.push(parameter);

        seenParams.push(parameter.name + ':' + parameter.in);
      });

      _.each(path.parameters, function (parameter) {
        var cloned = _.cloneDeep(parameter);

        // The only errors that can occur here are schema constraint validation errors which are already reported above
        // so do not report them again.
        cloned.skipErrors = true;

        if (seenParams.indexOf(parameter.name + ':' + parameter.in) === -1) {
          cParams.push(cloned);
        }
      });

      // Validate parameters
      validateParameters(spec, documentMetadata, nPath, cParams, oPath, results);

      // Validate responses
      _.each(operation.responses, function (response, responseCode) {
        // Do not process references to missing responses
        if (!_.isUndefined(response)) {
          // Validate validate inline constraints
          validateSchemaConstraints(documentMetadata, response, oPath.concat('responses', responseCode), results);
        }
      });
    });

    return seenPaths.concat(nPath.path);
  }, []);

  // Validate definitions
  validateDefinitions(documentMetadata, results);

  callback(undefined, results);
};

var validateSemantically = function (spec, rlOrSO, apiDeclarations, callback) {
  var cbWrapper = function (err, results) {
    callback(err, helpers.formatResults(results));
  };
  if (spec.version === '1.2') {
    validateSwagger1_2(spec, rlOrSO, apiDeclarations, cbWrapper); // jshint ignore:line
  } else {
    validateSwagger2_0(spec, rlOrSO, cbWrapper); // jshint ignore:line
  }
};

var validateStructurally = function (spec, rlOrSO, apiDeclarations, callback) {
  validateAgainstSchema(spec, spec.version === '1.2' ? 'resourceListing.json' : 'schema.json', rlOrSO,
                        function (err, results) {
                          if (err) {
                            return callback(err);
                          }

                          // Only validate the API Declarations if the API is 1.2 and the Resource Listing was valid
                          if (!results && spec.version === '1.2') {
                            results = {
                              errors: [],
                              warnings: [],
                              apiDeclarations: []
                            };

                            async.map(apiDeclarations, function (apiDeclaration, callback2) {
                              validateAgainstSchema(spec, 'apiDeclaration.json', apiDeclaration, callback2);
                            }, function (err, allResults) {
                              if (err) {
                                return callback(err);
                              }

                              _.each(allResults, function (result, index) {
                                results.apiDeclarations[index] = result;
                              });

                              callback(undefined, results);
                            });
                          } else {
                            callback(undefined, results);
                          }
                        });
};

/**
 * Creates a new Swagger specification object.
 *
 * @param {string} version - The Swagger version
 *
 * @constructor
 */
var Specification = function (version) {
  var that = this;
  var createValidators = function (spec, validatorsMap) {
    return _.reduce(validatorsMap, function (result, schemas, schemaName) {
      result[schemaName] = helpers.createJsonValidator(schemas);

      return result;
    }, {});
  };
  var fixSchemaId = function (schemaName) {
    // Swagger 1.2 schema files use one id but use a different id when referencing schema files.  We also use the schema
    // file name to reference the schema in ZSchema.  To fix this so that the JSON Schema validator works properly, we
    // need to set the id to be the name of the schema file.
    var fixed = _.cloneDeep(that.schemas[schemaName]);

    fixed.id = schemaName;

    return fixed;
  };
  var primitives = ['string', 'number', 'boolean', 'integer', 'array'];

  switch (version) {
  case '1.2':
    this.docsUrl = 'https://github.com/swagger-api/swagger-spec/blob/master/versions/1.2.md';
    this.primitives = _.union(primitives, ['void', 'File']);
    this.schemasUrl = 'https://github.com/swagger-api/swagger-spec/tree/master/schemas/v1.2';

    // Here explicitly to allow browserify to work
    this.schemas = {
      'apiDeclaration.json': require('../schemas/1.2/apiDeclaration.json'),
      'authorizationObject.json': require('../schemas/1.2/authorizationObject.json'),
      'dataType.json': require('../schemas/1.2/dataType.json'),
      'dataTypeBase.json': require('../schemas/1.2/dataTypeBase.json'),
      'infoObject.json': require('../schemas/1.2/infoObject.json'),
      'modelsObject.json': require('../schemas/1.2/modelsObject.json'),
      'oauth2GrantType.json': require('../schemas/1.2/oauth2GrantType.json'),
      'operationObject.json': require('../schemas/1.2/operationObject.json'),
      'parameterObject.json': require('../schemas/1.2/parameterObject.json'),
      'resourceListing.json': require('../schemas/1.2/resourceListing.json'),
      'resourceObject.json': require('../schemas/1.2/resourceObject.json')
    };

    this.validators = createValidators(this, {
      'apiDeclaration.json': _.map([
        'dataTypeBase.json',
        'modelsObject.json',
        'oauth2GrantType.json',
        'authorizationObject.json',
        'parameterObject.json',
        'operationObject.json',
        'apiDeclaration.json'
      ], fixSchemaId),
      'resourceListing.json': _.map([
        'resourceObject.json',
        'infoObject.json',
        'oauth2GrantType.json',
        'authorizationObject.json',
        'resourceListing.json'
      ], fixSchemaId)
    });

    break;

  case '2.0':
    this.docsUrl = 'https://github.com/swagger-api/swagger-spec/blob/master/versions/2.0.md';
    this.primitives = _.union(primitives, ['file']);
    this.schemasUrl = 'https://github.com/swagger-api/swagger-spec/tree/master/schemas/v2.0';

    // Here explicitly to allow browserify to work
    this.schemas = {
      'schema.json': require('../schemas/2.0/schema.json')
    };

    this.validators = createValidators(this, {
      'schema.json': [fixSchemaId('schema.json')]
    });

    break;

  default:
    throw new Error(version + ' is an unsupported Swagger specification version');
  }

  this.version = version;
};

/**
 * Returns the result of the validation of the Swagger document(s).
 *
 * @param {object} rlOrSO - The Swagger Resource Listing (1.2) or Swagger Object (2.0)
 * @param {object[]} [apiDeclarations] - The array of Swagger API Declarations (1.2)
 * @param {resultCallback} callback - The result callback
 *
 * @returns undefined if validation passes or an object containing errors and/or warnings
 * @throws Error if the arguments provided are not valid
 */
Specification.prototype.validate = function (rlOrSO, apiDeclarations, callback) {
  // Validate arguments
  switch (this.version) {
  case '1.2':
    // Validate arguments
    if (_.isUndefined(rlOrSO)) {
      throw new Error('resourceListing is required');
    } else if (!_.isPlainObject(rlOrSO)) {
      throw new TypeError('resourceListing must be an object');
    }

    if (_.isUndefined(apiDeclarations)) {
      throw new Error('apiDeclarations is required');
    } else if (!_.isArray(apiDeclarations)) {
      throw new TypeError('apiDeclarations must be an array');
    }

    break;

  case '2.0':
    // Validate arguments
    if (_.isUndefined(rlOrSO)) {
      throw new Error('swaggerObject is required');
    } else if (!_.isPlainObject(rlOrSO)) {
      throw new TypeError('swaggerObject must be an object');
    }

    break;
  }

  if (this.version === '2.0') {
    callback = arguments[1];
  }

  if (_.isUndefined(callback)) {
    throw new Error('callback is required');
  } else if (!_.isFunction(callback)) {
    throw new TypeError('callback must be a function');
  }

  // For Swagger 2.0, make sure apiDeclarations is an empty array
  if (this.version === '2.0') {
    apiDeclarations = [];
  }

  var that = this;

  // Perform the validation
  validateStructurally(this, rlOrSO, apiDeclarations, function (err, result) {
    if (err || helpers.formatResults(result)) {
      callback(err, result);
    } else {
      validateSemantically(that, rlOrSO, apiDeclarations, callback);
    }
  });
};

/**
 * Returns a JSON Schema representation of a composed model based on its id or reference.
 *
 * Note: For Swagger 1.2, we only perform structural validation prior to composing the model.
 *
 * @param {object} apiDOrSO - The Swagger Resource API Declaration (1.2) or the Swagger Object (2.0)
 * @param {string} modelIdOrRef - The model id (1.2) or the reference to the model (1.2 or 2.0)
 * @param {resultCallback} callback - The result callback
 *
 * @returns the object representing a composed object
 *
 * @throws Error if there are validation errors while creating
 */
Specification.prototype.composeModel = function (apiDOrSO, modelIdOrRef, callback) {
  var swaggerVersion = helpers.getSwaggerVersion(apiDOrSO);
  var doComposition = function (err, results) {
    var documentMetadata;

    if (err) {
      return callback(err);
    } else if (helpers.getErrorCount(results) > 0) {
      return handleValidationError(results, callback);
    }

    documentMetadata = getDocumentCache(apiDOrSO);
    results = {
      errors: [],
      warnings: []
    };

    processDocument(documentMetadata, results);

    if (!documentMetadata.definitions[modelIdOrRef]) {
      return callback();
    }

    if (helpers.getErrorCount(results) > 0) {
      return handleValidationError(results, callback);
    }

    callback(undefined, getOrComposeSchema(documentMetadata, modelIdOrRef));
  };

  switch (this.version) {
  case '1.2':
    // Validate arguments
    if (_.isUndefined(apiDOrSO)) {
      throw new Error('apiDeclaration is required');
    } else if (!_.isPlainObject(apiDOrSO)) {
      throw new TypeError('apiDeclaration must be an object');
    }

    if (_.isUndefined(modelIdOrRef)) {
      throw new Error('modelId is required');
    }

    break;

  case '2.0':
    // Validate arguments
    if (_.isUndefined(apiDOrSO)) {
      throw new Error('swaggerObject is required');
    } else if (!_.isPlainObject(apiDOrSO)) {
      throw new TypeError('swaggerObject must be an object');
    }

    if (_.isUndefined(modelIdOrRef)) {
      throw new Error('modelRef is required');
    }

    break;
  }

  if (_.isUndefined(callback)) {
    throw new Error('callback is required');
  } else if (!_.isFunction(callback)) {
    throw new TypeError('callback must be a function');
  }

  if (modelIdOrRef.charAt(0) !== '#') {
    if (this.version === '1.2') {
      modelIdOrRef = '#/models/' + modelIdOrRef;
    } else {
      throw new Error('modelRef must be a JSON Pointer');
    }
  }

  // Ensure the document is valid first
  if (swaggerVersion === '1.2') {
    validateAgainstSchema(this, 'apiDeclaration.json', apiDOrSO, doComposition);
  } else {
    this.validate(apiDOrSO, doComposition);
  }
};

/**
 * Validates a model based on its id.
 *
 * Note: For Swagger 1.2, we only perform structural validation prior to composing the model.
 *
 * @param {object} apiDOrSO - The Swagger Resource API Declaration (1.2) or the Swagger Object (2.0)
 * @param {string} modelIdOrRef - The model id (1.2) or the reference to the model (1.2 or 2.0)
 * @param {*} data - The model to validate
 * @param {resultCallback} callback - The result callback
 *
 * @returns undefined if validation passes or an object containing errors and/or warnings
 *
 * @throws Error if there are validation errors while creating
 */
Specification.prototype.validateModel = function (apiDOrSO, modelIdOrRef, data, callback) {
  switch (this.version) {
  case '1.2':
    // Validate arguments
    if (_.isUndefined(apiDOrSO)) {
      throw new Error('apiDeclaration is required');
    } else if (!_.isPlainObject(apiDOrSO)) {
      throw new TypeError('apiDeclaration must be an object');
    }

    if (_.isUndefined(modelIdOrRef)) {
      throw new Error('modelId is required');
    }

    break;

  case '2.0':
    // Validate arguments
    if (_.isUndefined(apiDOrSO)) {
      throw new Error('swaggerObject is required');
    } else if (!_.isPlainObject(apiDOrSO)) {
      throw new TypeError('swaggerObject must be an object');
    }

    if (_.isUndefined(modelIdOrRef)) {
      throw new Error('modelRef is required');
    }

    break;
  }

  if (_.isUndefined(data)) {
    throw new Error('data is required');
  }

  if (_.isUndefined(callback)) {
    throw new Error('callback is required');
  } else if (!_.isFunction(callback)) {
    throw new TypeError('callback must be a function');
  }

  var that = this;

  this.composeModel(apiDOrSO, modelIdOrRef, function (err, result) {
    if (err) {
      return callback(err);
    }

    validateAgainstSchema(that, result, data, callback);
  });
};

/**
 * Returns a fully resolved document or document fragment.  (Does not perform validation as this is typically called
 * after validation occurs.))
 *
 * @param {object} document - The document to resolve or the document containing the reference to resolve
 * @param {string} [ptr] - The JSON Pointer or undefined to return the whole document
 * @param {resultCallback} callback - The result callback
 *
 * @returns the fully resolved document or fragment
 *
 * @throws Error if there are upstream errors
 */
Specification.prototype.resolve = function (document, ptr, callback) {
  var documentMetadata;
  var respond = function (document) {
    if (_.isString(ptr)) {
      return callback(undefined, traverse(document).get(JsonRefs.pathFromPtr(ptr)));
    } else {
      return callback(undefined, document);
    }
  };

  // Validate arguments
  if (_.isUndefined(document)) {
    throw new Error('document is required');
  } else if (!_.isPlainObject(document)) {
    throw new TypeError('document must be an object');
  }

  if (arguments.length === 2) {
    callback = arguments[1];
    ptr = undefined;
  }

  if (!_.isUndefined(ptr) && !_.isString(ptr)) {
    throw new TypeError('ptr must be a JSON Pointer string');
  }

  if (_.isUndefined(callback)) {
    throw new Error('callback is required');
  } else if (!_.isFunction(callback)) {
    throw new TypeError('callback must be a function');
  }

  documentMetadata = getDocumentCache(document);

  // Swagger 1.2 is not supported due to invalid JSON References being used.  Even if the JSON References were valid,
  // the JSON Schema for Swagger 1.2 do not allow JavaScript objects in all places where the resoution would occur.
  if (documentMetadata.swaggerVersion === '1.2') {
    throw new Error('Swagger 1.2 is not supported');
  }

  if (!documentMetadata.resolved) {
    // Ensure the document is valid first
    this.validate(document, function (err, results) {
      if (err) {
        return callback(err);
      } else if (helpers.getErrorCount(results) > 0) {
        return handleValidationError(results, callback);
      }

      return respond(documentMetadata.resolved);
    });
  } else {
    return respond(documentMetadata.resolved);
  }
};

/**
 * Converts the Swagger 1.2 documents to a Swagger 2.0 document.
 *
 * @param {object} resourceListing - The Swagger Resource Listing
 * @param {object[]} [apiDeclarations] - The array of Swagger API Declarations
 * @param {boolean=false} [skipValidation] - Whether or not to skip validation
 * @param {resultCallback} callback - The result callback
 *
 * @returns the converted Swagger document
 *
 * @throws Error if the arguments provided are not valid
 */
Specification.prototype.convert = function (resourceListing, apiDeclarations, skipValidation, callback) {
  var doConvert = function (resourceListing, apiDeclarations) {
    callback(undefined, swaggerConverter(resourceListing, apiDeclarations));
  };

  if (this.version !== '1.2') {
    throw new Error('Specification#convert only works for Swagger 1.2');
  }

  // Validate arguments
  if (_.isUndefined(resourceListing)) {
    throw new Error('resourceListing is required');
  } else if (!_.isPlainObject(resourceListing)) {
    throw new TypeError('resourceListing must be an object');
  }

  // API Declarations are optional because swagger-converter was written to support it
  if (_.isUndefined(apiDeclarations)) {
    apiDeclarations = [];
  }

  if (!_.isArray(apiDeclarations)) {
    throw new TypeError('apiDeclarations must be an array');
  }

  if (arguments.length < 4) {
    callback = arguments[arguments.length - 1];
  }

  if (_.isUndefined(callback)) {
    throw new Error('callback is required');
  } else if (!_.isFunction(callback)) {
    throw new TypeError('callback must be a function');
  }

  if (skipValidation === true) {
    doConvert(resourceListing, apiDeclarations);
  } else {
    this.validate(resourceListing, apiDeclarations, function (err, results) {
      if (err) {
        return callback(err);
      } else if (helpers.getErrorCount(results) > 0) {
        return handleValidationError(results, callback);
      }

      doConvert(resourceListing, apiDeclarations);
    });
  }
};

module.exports.v1 = module.exports.v1_2 = new Specification('1.2'); // jshint ignore:line
module.exports.v2 = module.exports.v2_0 = new Specification('2.0'); // jshint ignore:line