sensor-things.js

import config from 'ui/config';



/**
 * Returns the sensor things datastream URL used to fetch the datastream. Add the filter for parameter code if not the null string
 * @param {String} agencySiteNumberCode - combines the Agency Code with the Site Number for example USGS-01646500
 * @param {String} parameterCode - five digit code that uniquely identifies the observed property (parameter)
 * @return {String} Sensor Things datastream URL for the site with parameter code.
 */
const getSiteDatastreamURL = function(agencySiteNumberCode, parameterCode) {
    const parameterQuery = parameterCode ? `ParameterCode eq '${parameterCode}'` : '';
    const queryString = parameterQuery ? `?$filter=properties/${encodeURIComponent(parameterQuery)}` : '';
    return `${config.SENSOR_THINGS_ENDPOINT}Things('${agencySiteNumberCode}')/Datastreams${queryString}`;
};

/**
 * Does the work of contacting the Sensor Things API and returning the datastream
 * @param {String} agencySiteNumberCode - combines the Agency Code with the Site Number for example USGS-01646500
 * @param {String} parameterCode - five digit code that uniquely identifies the observed property
 * @return {Promise} resolves to an empty object or one containing threshold information (and other secondary information)
 */
export const fetchSiteDatastream = async function(agencySiteNumberCode, parameterCode) {
    const url = getSiteDatastreamURL(agencySiteNumberCode, parameterCode);
    try {
        const response = await fetch(url, {
            method: 'GET'
        });
        if (response.status === 200) {
            return await response.json();

        } else {
            console.error(`Received bad status, ${response.status} at ${url}`);
            return {};
        }
    } catch (error) {
        console.error(`Failed fetch for ${url}`);
        return {};
    }
};

/**
 * Fetch the sites that are within the polygon and return the geojson.
 * @param {String} - Well Known Text Polygon string, for example 'Polygon((-92 44, -89 44, -89 43, -92 43, -92 44))'
 * @returns {Promise} - resolves to a json object. If the call fails or returns an unexpected status the json object
 *      will be empty
 */
export const fetchSitesGeoJson = async function(wktPolygon) {
    const expandQuery = encodeURIComponent('Locations($select=id,location)');
    const locationQuery = encodeURIComponent(`st_within(Location/location, geography'${wktPolygon}')`);
    const url =
        `${config.SENSOR_THINGS_ENDPOINT}/Things?$expand=${expandQuery}&$filter=${locationQuery}&$resultFormat=GeoJSON&$top=1000`;

    try {
        const response = await fetch(url, {
            method: 'GET'
        });
        if (response.status === 200) {
            return await response.json();

        } else {
            console.error(`Received bad status, ${response.status} at ${url}`);
            return {};
        }
    } catch (error) {
        console.error(`Failed fetch for ${url}`);
        return {};
    }
};