terriajs/lib/Models/ArcGisFeatureServerCatalogGroup.js

Geospatial data visualization platform.

'use strict';

/*global require*/
var URI = require('urijs');

var clone = require('terriajs-cesium/Source/Core/clone');
var defined = require('terriajs-cesium/Source/Core/defined');
var defineProperties = require('terriajs-cesium/Source/Core/defineProperties');
var freezeObject = require('terriajs-cesium/Source/Core/freezeObject');
var knockout = require('terriajs-cesium/Source/ThirdParty/knockout');
var loadJson = require('../Core/loadJson');
var when = require('terriajs-cesium/Source/ThirdParty/when');

var TerriaError = require('../Core/TerriaError');
var CatalogGroup = require('./CatalogGroup');
var inherit = require('../Core/inherit');
var proxyCatalogItemUrl = require('./proxyCatalogItemUrl');
var replaceUnderscores = require('../Core/replaceUnderscores');
var ArcGisFeatureServerCatalogItem = require('./ArcGisFeatureServerCatalogItem');

/**
 * A {@link CatalogGroup} representing a collection of layers from an ArcGIS Feature Service.
 * Eg. https://sampleserver6.arcgisonline.com/arcgis/rest/services/Wildfire/FeatureServer
 *
 * @alias ArcGisFeatureServerCatalogGroup
 * @constructor
 * @extends CatalogGroup
 *
 * @param {Terria} terria The Terria instance.
 */
var ArcGisFeatureServerCatalogGroup = function(terria) {
    CatalogGroup.call(this, terria, 'esri-featureServer-group');

    /**
     * Gets or sets the URL of the Feature Server.  This property is observable.
     * @type {String}
     */
    this.url = '';

    /**
     * Gets or sets a description of the custodian of the data sources in this group.
     * This property is an HTML string that must be sanitized before display to the user.
     * This property is observable.
     * @type {String}
     */
    this.dataCustodian = undefined;

    /**
     * Gets or sets a hash of names of blacklisted data layers.  A layer that appears in this hash
     * will not be shown to the user.  In this hash, the keys should be the Title of the layers to blacklist,
     * and the values should be "true".  This property is observable.
     * @type {Object}
     */
    this.blacklist = undefined;

    /**
     * Gets or sets a hash of properties that will be set on each child item.
     * For example, { 'treat404AsError': false }
     */
    this.itemProperties = undefined;

    knockout.track(this, ['url', 'dataCustodian', 'blacklist', 'itemProperties']);
};

inherit(CatalogGroup, ArcGisFeatureServerCatalogGroup);

defineProperties(ArcGisFeatureServerCatalogGroup.prototype, {
    /**
     * Gets the type of data member represented by this instance.
     * @memberOf ArcGisFeatureServerCatalogGroup.prototype
     * @type {String}
     */
    type : {
        get : function() {
            return 'esri-featureServer-group';
        }
    },

    /**
     * Gets a human-readable name for this type of data source, such as 'Web Map Service (WMS)'.
     * @memberOf ArcGisFeatureServerCatalogGroup.prototype
     * @type {String}
     */
    typeName : {
        get : function() {
            return 'ArcGIS Feature Server Group';
        }
    },

    /**
     * Gets the set of functions used to serialize individual properties in {@link CatalogMember#serializeToJson}.
     * When a property name on the model matches the name of a property in the serializers object lieral,
     * the value will be called as a function and passed a reference to the model, a reference to the destination
     * JSON object literal, and the name of the property.
     * @memberOf ArcGisFeatureServerCatalogGroup.prototype
     * @type {Object}
     */
    serializers : {
        get : function() {
            return ArcGisFeatureServerCatalogGroup.defaultSerializers;
        }
    }
});

/**
 * Gets or sets the set of default serializer functions to use in {@link CatalogMember#serializeToJson}.  Types derived from this type
 * should expose this instance - cloned and modified if necesary - through their {@link CatalogMember#serializers} property.
 * @type {Object}
 */
ArcGisFeatureServerCatalogGroup.defaultSerializers = clone(CatalogGroup.defaultSerializers);

ArcGisFeatureServerCatalogGroup.defaultSerializers.items = CatalogGroup.enabledShareableItemsSerializer;

ArcGisFeatureServerCatalogGroup.defaultSerializers.isLoading = function(wmsGroup, json, propertyName, options) {};

freezeObject(ArcGisFeatureServerCatalogGroup.defaultSerializers);

ArcGisFeatureServerCatalogGroup.prototype._getValuesThatInfluenceLoad = function() {
    return [this.url, this.blacklist];
};

ArcGisFeatureServerCatalogGroup.prototype._load = function() {
    return loadFeatureServer(this);
};

// loadFeatureServer is exposed so that ArcGisCatalogGroup can call it,
// to load a MapServer as if it were an ArcGisFeatureServerCatalogGroup.
ArcGisFeatureServerCatalogGroup.loadFeatureServer = function(catalogGroup) {
    return loadFeatureServer(catalogGroup);
};

function loadFeatureServer(catalogGroup) {
    var terria = catalogGroup.terria;
    var uri = new URI(catalogGroup.url).addQuery('f', 'json');
    return when(loadJson(proxyCatalogItemUrl(catalogGroup, uri.toString(), '1d'))).then(function(result) {
        // Is this really a FeatureServer REST response?
        if (!result || !result.layers) {
            throw new TerriaError({
                title: 'Invalid ArcGIS Feature Service',
                message: '\
An error occurred while invoking the ArcGIS Feature Service.  The server\'s response does not appear to be a valid Feature Service document.  \
<p>If you entered the link manually, please verify that the link is correct.</p>\
<p>If you did not enter this link manually, this error may indicate that the group you opened is temporarily unavailable or there is a \
problem with your internet connection.  Try opening the group again, and if the problem persists, please report it by \
sending an email to <a href="mailto:'+terria.supportEmail+'">'+terria.supportEmail+'</a>.</p>'
            });
        }

        if (defined(result.documentInfo)) {
            var dataCustodian = catalogGroup.dataCustodian;
            if (!defined(dataCustodian) && defined(result.documentInfo.Author)) {
                dataCustodian = result.documentInfo.Author;
            }
            if (catalogGroup.name === 'Unnamed Item' && defined(result.documentInfo.Title) && (result.documentInfo.Title.length > 0)) {
                catalogGroup.name = result.documentInfo.Title;
            }
        }
        addLayers(catalogGroup, -1, result.layers, catalogGroup, dataCustodian);
    }).otherwise(function(e) {
        throw new TerriaError({
            sender: catalogGroup,
            title: 'Group is not available',
            message: '\
An error occurred while invoking the ArcGIS Feature Service. \
<p>If you entered the link manually, please verify that the link is correct.</p>\
<p>This error may also indicate that the server does not support <a href="http://enable-cors.org/" target="_blank">CORS</a>.  If this is your \
server, verify that CORS is enabled and enable it if it is not.  If you do not control the server, \
please contact the administrator of the server and ask them to enable CORS.  Or, contact the '+terria.appName+' \
team by emailing <a href="mailto:'+terria.supportEmail+'">'+terria.supportEmail+'</a> \
and ask us to add this server to the list of non-CORS-supporting servers that may be proxied by '+terria.appName+' \
itself.</p>\
<p>If you did not enter this link manually, this error may indicate that the group you opened is temporarily unavailable or there is a \
problem with your internet connection.  Try opening the group again, and if the problem persists, please report it by \
sending an email to <a href="mailto:'+terria.supportEmail+'">'+terria.supportEmail+'</a>.</p>'
        });
    });
}

function addLayers(featureServerGroup, parentID, layers, thisGroup, dataCustodian) {
    if (!(layers instanceof Array)) {
        layers = [layers];
    }

    for (var i = 0; i < layers.length; ++i) {
        var layer = layers[i];

        if (parentID === -1 && layer.parentLayer !== null && defined(layer.parentLayer)) {
            continue;
        } else if (parentID !== -1 && (!layer.parentLayer || layer.parentLayer.id !== parentID)) {
            continue;
        }

        if (featureServerGroup.blacklist && featureServerGroup.blacklist[layer.name]) {
            console.log('Provider Feedback: Filtering out ' + layer.name + ' (' + layer.id + ') because it is blacklisted.');
            continue;
        }

        thisGroup.add(createDataSource(featureServerGroup, layer, dataCustodian));
    }
}

function createDataSource(featureServerGroup, layer, dataCustodian) {
    var item = new ArcGisFeatureServerCatalogItem(featureServerGroup.terria);

    item.name = replaceUnderscores(layer.name);
    item.dataCustodian = dataCustodian;
    var uri = new URI(featureServerGroup.url).segment(layer.id + '');  // Convert layer id to string as segment(0) means sthg different.
    item.url = uri.toString();
    item.layers = layer.id.toString();
    item.maximumScale = layer.maxScale;

    if (typeof(featureServerGroup.itemProperties) === 'object') {
        item.updateFromJson(featureServerGroup.itemProperties);
    }

    return item;
}

module.exports = ArcGisFeatureServerCatalogGroup;