datahub/wherehows-web/app/utils/api/datasets/dataset.ts

import Ember from 'ember';
import { IDataset, IDatasetGetResponse } from 'wherehows-web/typings/api/datasets/dataset';
import { getHeaders, getJSON } from 'wherehows-web/utils/api/fetcher';
import { datasetsUrlRoot, datasetUrlById } from 'wherehows-web/utils/api/datasets/shared';
import { ApiStatus } from 'wherehows-web/utils/api';

const { Logger: { warn } } = Ember;
// TODO:  DSS-6122 Create and move to Error module
const datasetApiException = 'An error occurred with the dataset api';
const datasetIdException = 'Could not find a dataset with a matching id / urn';

/**
 * Reads the dataset object from the get endpoint for the given dataset id
 * @param {number} id the id of the dataset
 * @return {Promise<IDataset>}
 */
const readDataset = async (id: number = 0): Promise<IDataset> => {
  // if id is less than or equal 0, throw illegal dataset error
  if (id <= 0) {
    throw new Error(datasetIdException);
  }

  const { status, dataset } = await getJSON<IDatasetGetResponse>({ url: datasetUrlById(id) });

  if (status === ApiStatus.OK && dataset) {
    return dataset;
  }

  throw new Error(datasetApiException);
};

/**
 * Constructs a url to get a dataset id given a dataset urn
 * @param {string} urn
 * @return {string}
 */
const datasetIdTranslationUrlByUrn = (urn: string): string => {
  return `${datasetsUrlRoot}/urntoid/${encodeURIComponent(urn)}`;
};

/**
 * Translates a dataset urn string to a dataset id, using the endpoint at datasetIdTranslationUrlByUrn()
 * if a dataset id is not found
 * or an exception occurs, the value returned is zero, which is an illegal dataset id
 * and should be treated as an exception.
 * @param {string} urn
 * @return {Promise<number>}
 */
const datasetUrnToId = async (urn: string): Promise<number> => {
  let datasetId = 0;

  try {
    // The headers object is an iterable iterator,
    // convert to a map and return the DatasetId header
    const headers = await getHeaders({ url: datasetIdTranslationUrlByUrn(urn) });
    const stringId = new Map(...headers).get('DatasetId');

    // If stringId is not falsey, parse as int and return, otherwise use default
    if (stringId) {
      datasetId = parseInt(stringId, 10);
    }
  } catch (e) {
    warn(`Exception occurred translating datasetUrn: ${e.message}`);
  }

  return datasetId;
};

export { readDataset, datasetUrnToId };