WebMapServiceImageryProvider.js

define([
        '../Core/defaultValue',
        '../Core/defined',
        '../Core/defineProperties',
        '../Core/DeveloperError',
        '../Core/freezeObject',
        '../Core/GeographicTilingScheme',
        '../Core/Resource',
        '../Core/WebMercatorProjection',
        './GetFeatureInfoFormat',
        './TimeDynamicImagery',
        './UrlTemplateImageryProvider'
    ], function(
        defaultValue,
        defined,
        defineProperties,
        DeveloperError,
        freezeObject,
        GeographicTilingScheme,
        Resource,
        WebMercatorProjection,
        GetFeatureInfoFormat,
        TimeDynamicImagery,
        UrlTemplateImageryProvider) {
    'use strict';

    /**
     * Provides tiled imagery hosted by a Web Map Service (WMS) server.
     *
     * @alias WebMapServiceImageryProvider
     * @constructor
     *
     * @param {Object} options Object with the following properties:
     * @param {Resource|String} options.url The URL of the WMS service. The URL supports the same keywords as the {@link UrlTemplateImageryProvider}.
     * @param {String} options.layers The layers to include, separated by commas.
     * @param {Object} [options.parameters=WebMapServiceImageryProvider.DefaultParameters] Additional parameters to pass to the WMS server in the GetMap URL.
     * @param {Object} [options.getFeatureInfoParameters=WebMapServiceImageryProvider.GetFeatureInfoDefaultParameters] Additional parameters to pass to the WMS server in the GetFeatureInfo URL.
     * @param {Boolean} [options.enablePickFeatures=true] If true, {@link WebMapServiceImageryProvider#pickFeatures} will invoke
     *        the GetFeatureInfo operation on the WMS server and return the features included in the response.  If false,
     *        {@link WebMapServiceImageryProvider#pickFeatures} will immediately return undefined (indicating no pickable features)
     *        without communicating with the server.  Set this property to false if you know your WMS server does not support
     *        GetFeatureInfo or if you don't want this provider's features to be pickable. Note that this can be dynamically
     *        overridden by modifying the WebMapServiceImageryProvider#enablePickFeatures property.
     * @param {GetFeatureInfoFormat[]} [options.getFeatureInfoFormats=WebMapServiceImageryProvider.DefaultGetFeatureInfoFormats] The formats
     *        in which to try WMS GetFeatureInfo requests.
     * @param {Rectangle} [options.rectangle=Rectangle.MAX_VALUE] The rectangle of the layer.
     * @param {TilingScheme} [options.tilingScheme=new GeographicTilingScheme()] The tiling scheme to use to divide the world into tiles.
     * @param {Ellipsoid} [options.ellipsoid] The ellipsoid.  If the tilingScheme is specified,
     *        this parameter is ignored and the tiling scheme's ellipsoid is used instead. If neither
     *        parameter is specified, the WGS84 ellipsoid is used.
     * @param {Number} [options.tileWidth=256] The width of each tile in pixels.
     * @param {Number} [options.tileHeight=256] The height of each tile in pixels.
     * @param {Number} [options.minimumLevel=0] The minimum level-of-detail supported by the imagery provider.  Take care when
     *        specifying this that the number of tiles at the minimum level is small, such as four or less.  A larger number is
     *        likely to result in rendering problems.
     * @param {Number} [options.maximumLevel] The maximum level-of-detail supported by the imagery provider, or undefined if there is no limit.
     *        If not specified, there is no limit.
     * @param {String} [options.crs] CRS specification, for use with WMS specification >= 1.3.0.
     * @param {String} [options.srs] SRS specification, for use with WMS specification 1.1.0 or 1.1.1
     * @param {Credit|String} [options.credit] A credit for the data source, which is displayed on the canvas.
     * @param {String|String[]} [options.subdomains='abc'] The subdomains to use for the <code>{s}</code> placeholder in the URL template.
     *                          If this parameter is a single string, each character in the string is a subdomain.  If it is
     *                          an array, each element in the array is a subdomain.
     * @param {Clock} [options.clock] A Clock instance that is used when determining the value for the time dimension. Required when options.times is specified.
     * @param {TimeIntervalCollection} [options.times] TimeIntervalCollection with its data property being an object containing time dynamic dimension and their values.
     *
     * @see ArcGisMapServerImageryProvider
     * @see BingMapsImageryProvider
     * @see GoogleEarthEnterpriseMapsProvider
     * @see createOpenStreetMapImageryProvider
     * @see SingleTileImageryProvider
     * @see createTileMapServiceImageryProvider
     * @see WebMapTileServiceImageryProvider
     * @see UrlTemplateImageryProvider
     *
     * @see {@link http://resources.esri.com/help/9.3/arcgisserver/apis/rest/|ArcGIS Server REST API}
     * @see {@link http://www.w3.org/TR/cors/|Cross-Origin Resource Sharing}
     *
     * @example
     * var provider = new Cesium.WebMapServiceImageryProvider({
     *     url : 'https://sampleserver1.arcgisonline.com/ArcGIS/services/Specialty/ESRI_StatesCitiesRivers_USA/MapServer/WMSServer',
     *     layers : '0',
     *     proxy: new Cesium.DefaultProxy('/proxy/')
     * });
     *
     * viewer.imageryLayers.addImageryProvider(provider);
     */
    function WebMapServiceImageryProvider(options) {
        options = defaultValue(options, defaultValue.EMPTY_OBJECT);

        //>>includeStart('debug', pragmas.debug);
        if (!defined(options.url)) {
            throw new DeveloperError('options.url is required.');
        }
        if (!defined(options.layers)) {
            throw new DeveloperError('options.layers is required.');
        }
        //>>includeEnd('debug');

        if (defined(options.times) && !defined(options.clock)) {
            throw new DeveloperError('options.times was specified, so options.clock is required.');
        }

        var resource = Resource.createIfNeeded(options.url);

        var pickFeatureResource = resource.clone();

        resource.setQueryParameters(WebMapServiceImageryProvider.DefaultParameters, true);
        pickFeatureResource.setQueryParameters(WebMapServiceImageryProvider.GetFeatureInfoDefaultParameters, true);

        if (defined(options.parameters)) {
            resource.setQueryParameters(objectToLowercase(options.parameters));
        }

        if (defined(options.getFeatureInfoParameters)) {
            pickFeatureResource.setQueryParameters(objectToLowercase(options.getFeatureInfoParameters));
        }

        var that = this;
        this._reload = undefined;
        if (defined(options.times)) {
            this._timeDynamicImagery = new TimeDynamicImagery({
                clock : options.clock,
                times : options.times,
                requestImageFunction : function(x, y, level, request, interval) {
                    return requestImage(that, x, y, level, request, interval);
                },
                reloadFunction : function() {
                    if (defined(that._reload)) {
                        that._reload();
                    }
                }
            });
        }

        var parameters = {};
        parameters.layers = options.layers;
        parameters.bbox = '{westProjected},{southProjected},{eastProjected},{northProjected}';
        parameters.width = '{width}';
        parameters.height = '{height}';

        // Use SRS or CRS based on the WMS version.
        if (parseFloat(resource.queryParameters.version) >= 1.3) {
            // Use CRS with 1.3.0 and going forward.
            // For GeographicTilingScheme, use CRS:84 vice EPSG:4326 to specify lon, lat (x, y) ordering for
            // bbox requests.
            parameters.crs = defaultValue(options.crs, options.tilingScheme && options.tilingScheme.projection instanceof WebMercatorProjection ? 'EPSG:3857' : 'CRS:84');
        } else {
            // SRS for WMS 1.1.0 or 1.1.1.
            parameters.srs = defaultValue(options.srs, options.tilingScheme && options.tilingScheme.projection instanceof WebMercatorProjection ? 'EPSG:3857' : 'EPSG:4326');
        }

        resource.setQueryParameters(parameters, true);
        pickFeatureResource.setQueryParameters(parameters, true);

        var pickFeatureParams = {
            query_layers: options.layers,
            x: '{i}',
            y: '{j}',
            info_format: '{format}'
        };
        pickFeatureResource.setQueryParameters(pickFeatureParams, true);

        this._resource = resource;
        this._pickFeaturesResource = pickFeatureResource;
        this._layers = options.layers;

        // Let UrlTemplateImageryProvider do the actual URL building.
        this._tileProvider = new UrlTemplateImageryProvider({
            url : resource,
            pickFeaturesUrl : pickFeatureResource,
            tilingScheme : defaultValue(options.tilingScheme, new GeographicTilingScheme({ ellipsoid : options.ellipsoid})),
            rectangle : options.rectangle,
            tileWidth : options.tileWidth,
            tileHeight : options.tileHeight,
            minimumLevel : options.minimumLevel,
            maximumLevel : options.maximumLevel,
            subdomains: options.subdomains,
            tileDiscardPolicy : options.tileDiscardPolicy,
            credit : options.credit,
            getFeatureInfoFormats : defaultValue(options.getFeatureInfoFormats, WebMapServiceImageryProvider.DefaultGetFeatureInfoFormats),
            enablePickFeatures: options.enablePickFeatures
        });
    }

    function requestImage(imageryProvider, col, row, level, request, interval) {
        var dynamicIntervalData = defined(interval) ? interval.data : undefined;
        var tileProvider = imageryProvider._tileProvider;

        if (defined(dynamicIntervalData)) {
            // We set the query parameters within the tile provider, because it is managing the query.
            tileProvider._resource.setQueryParameters(dynamicIntervalData);
        }
        return tileProvider.requestImage(col, row, level, request);
    }

    function pickFeatures(imageryProvider, x, y, level, longitude, latitude, interval) {
        var dynamicIntervalData = defined(interval) ? interval.data : undefined;
        var tileProvider = imageryProvider._tileProvider;

        if (defined(dynamicIntervalData)) {
            // We set the query parameters within the tile provider, because it is managing the query.
            tileProvider._pickFeaturesResource.setQueryParameters(dynamicIntervalData);
        }
        return tileProvider.pickFeatures(x, y, level, longitude, latitude);
    }

    defineProperties(WebMapServiceImageryProvider.prototype, {
        /**
         * Gets the URL of the WMS server.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {String}
         * @readonly
         */
        url : {
            get : function() {
                return this._resource._url;
            }
        },

        /**
         * Gets the proxy used by this provider.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Proxy}
         * @readonly
         */
        proxy : {
            get : function() {
                return this._resource.proxy;
            }
        },

        /**
         * Gets the names of the WMS layers, separated by commas.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {String}
         * @readonly
         */
        layers : {
            get : function() {
                return this._layers;
            }
        },

        /**
         * Gets the width of each tile, in pixels. This function should
         * not be called before {@link WebMapServiceImageryProvider#ready} returns true.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Number}
         * @readonly
         */
        tileWidth : {
            get : function() {
                return this._tileProvider.tileWidth;
            }
        },

        /**
         * Gets the height of each tile, in pixels.  This function should
         * not be called before {@link WebMapServiceImageryProvider#ready} returns true.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Number}
         * @readonly
         */
        tileHeight : {
            get : function() {
                return this._tileProvider.tileHeight;
            }
        },

        /**
         * Gets the maximum level-of-detail that can be requested.  This function should
         * not be called before {@link WebMapServiceImageryProvider#ready} returns true.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Number}
         * @readonly
         */
        maximumLevel : {
            get : function() {
                return this._tileProvider.maximumLevel;
            }
        },

        /**
         * Gets the minimum level-of-detail that can be requested.  This function should
         * not be called before {@link WebMapServiceImageryProvider#ready} returns true.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Number}
         * @readonly
         */
        minimumLevel : {
            get : function() {
                return this._tileProvider.minimumLevel;
            }
        },

        /**
         * Gets the tiling scheme used by this provider.  This function should
         * not be called before {@link WebMapServiceImageryProvider#ready} returns true.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {TilingScheme}
         * @readonly
         */
        tilingScheme : {
            get : function() {
                return this._tileProvider.tilingScheme;
            }
        },

        /**
         * Gets the rectangle, in radians, of the imagery provided by this instance.  This function should
         * not be called before {@link WebMapServiceImageryProvider#ready} returns true.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Rectangle}
         * @readonly
         */
        rectangle : {
            get : function() {
                return this._tileProvider.rectangle;
            }
        },

        /**
         * Gets the tile discard policy.  If not undefined, the discard policy is responsible
         * for filtering out "missing" tiles via its shouldDiscardImage function.  If this function
         * returns undefined, no tiles are filtered.  This function should
         * not be called before {@link WebMapServiceImageryProvider#ready} returns true.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {TileDiscardPolicy}
         * @readonly
         */
        tileDiscardPolicy : {
            get : function() {
                return this._tileProvider.tileDiscardPolicy;
            }
        },

        /**
         * Gets an event that is raised when the imagery provider encounters an asynchronous error.  By subscribing
         * to the event, you will be notified of the error and can potentially recover from it.  Event listeners
         * are passed an instance of {@link TileProviderError}.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Event}
         * @readonly
         */
        errorEvent : {
            get : function() {
                return this._tileProvider.errorEvent;
            }
        },

        /**
         * Gets a value indicating whether or not the provider is ready for use.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Boolean}
         * @readonly
         */
        ready : {
            get : function() {
                return this._tileProvider.ready;
            }
        },

        /**
         * Gets a promise that resolves to true when the provider is ready for use.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Promise.<Boolean>}
         * @readonly
         */
        readyPromise : {
            get : function() {
                return this._tileProvider.readyPromise;
            }
        },

        /**
         * Gets the credit to display when this imagery provider is active.  Typically this is used to credit
         * the source of the imagery.  This function should not be called before {@link WebMapServiceImageryProvider#ready} returns true.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Credit}
         * @readonly
         */
        credit : {
            get : function() {
                return this._tileProvider.credit;
            }
        },

        /**
         * Gets a value indicating whether or not the images provided by this imagery provider
         * include an alpha channel.  If this property is false, an alpha channel, if present, will
         * be ignored.  If this property is true, any images without an alpha channel will be treated
         * as if their alpha is 1.0 everywhere.  When this property is false, memory usage
         * and texture upload time are reduced.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Boolean}
         * @readonly
         */
        hasAlphaChannel : {
            get : function() {
                return this._tileProvider.hasAlphaChannel;
            }
        },

        /**
         * Gets or sets a value indicating whether feature picking is enabled.  If true, {@link WebMapServiceImageryProvider#pickFeatures} will
         * invoke the <code>GetFeatureInfo</code> service on the WMS server and attempt to interpret the features included in the response.  If false,
         * {@link WebMapServiceImageryProvider#pickFeatures} will immediately return undefined (indicating no pickable
         * features) without communicating with the server.  Set this property to false if you know your data
         * source does not support picking features or if you don't want this provider's features to be pickable.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Boolean}
         * @default true
         */
        enablePickFeatures : {
            get : function() {
                return this._tileProvider.enablePickFeatures;
            },
            set : function(enablePickFeatures)  {
                this._tileProvider.enablePickFeatures = enablePickFeatures;
            }
        },

        /**
         * Gets or sets a clock that is used to get keep the time used for time dynamic parameters.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {Clock}
         */
        clock : {
            get : function() {
                return this._timeDynamicImagery.clock;
            },
            set : function(value) {
                this._timeDynamicImagery.clock = value;
            }
        },
        /**
         * Gets or sets a time interval collection that is used to get time dynamic parameters. The data of each
         * TimeInterval is an object containing the keys and values of the properties that are used during
         * tile requests.
         * @memberof WebMapServiceImageryProvider.prototype
         * @type {TimeIntervalCollection}
         */
        times : {
            get : function() {
                return this._timeDynamicImagery.times;
            },
            set : function(value) {
                this._timeDynamicImagery.times = value;
            }
        }
    });

    /**
     * Gets the credits to be displayed when a given tile is displayed.
     *
     * @param {Number} x The tile X coordinate.
     * @param {Number} y The tile Y coordinate.
     * @param {Number} level The tile level;
     * @returns {Credit[]} The credits to be displayed when the tile is displayed.
     *
     * @exception {DeveloperError} <code>getTileCredits</code> must not be called before the imagery provider is ready.
     */
    WebMapServiceImageryProvider.prototype.getTileCredits = function(x, y, level) {
        return this._tileProvider.getTileCredits(x, y, level);
    };

    /**
     * Requests the image for a given tile.  This function should
     * not be called before {@link WebMapServiceImageryProvider#ready} returns true.
     *
     * @param {Number} x The tile X coordinate.
     * @param {Number} y The tile Y coordinate.
     * @param {Number} level The tile level.
     * @param {Request} [request] The request object. Intended for internal use only.
     * @returns {Promise.<Image|Canvas>|undefined} A promise for the image that will resolve when the image is available, or
     *          undefined if there are too many active requests to the server, and the request
     *          should be retried later.  The resolved image may be either an
     *          Image or a Canvas DOM object.
     *
     * @exception {DeveloperError} <code>requestImage</code> must not be called before the imagery provider is ready.
     */
    WebMapServiceImageryProvider.prototype.requestImage = function(x, y, level, request) {
        var result;
        var timeDynamicImagery = this._timeDynamicImagery;
        var currentInterval;

        // Try and load from cache
        if (defined(timeDynamicImagery)) {
            currentInterval = timeDynamicImagery.currentInterval;
            result = timeDynamicImagery.getFromCache(x, y, level, request);
        }

        // Couldn't load from cache
        if (!defined(result)) {
            result = requestImage(this, x, y, level, request, currentInterval);
        }

        // If we are approaching an interval, preload this tile in the next interval
        if (defined(result) && defined(timeDynamicImagery)) {
            timeDynamicImagery.checkApproachingInterval(x, y, level, request);
        }

        return result;

    };

    /**
     * Asynchronously determines what features, if any, are located at a given longitude and latitude within
     * a tile.  This function should not be called before {@link ImageryProvider#ready} returns true.
     *
     * @param {Number} x The tile X coordinate.
     * @param {Number} y The tile Y coordinate.
     * @param {Number} level The tile level.
     * @param {Number} longitude The longitude at which to pick features.
     * @param {Number} latitude  The latitude at which to pick features.
     * @return {Promise.<ImageryLayerFeatureInfo[]>|undefined} A promise for the picked features that will resolve when the asynchronous
     *                   picking completes.  The resolved value is an array of {@link ImageryLayerFeatureInfo}
     *                   instances.  The array may be empty if no features are found at the given location.
     *
     * @exception {DeveloperError} <code>pickFeatures</code> must not be called before the imagery provider is ready.
     */
    WebMapServiceImageryProvider.prototype.pickFeatures = function(x, y, level, longitude, latitude) {
        var timeDynamicImagery = this._timeDynamicImagery;
        var currentInterval = defined(timeDynamicImagery) ? timeDynamicImagery.currentInterval : undefined;

        return pickFeatures(this, x, y, level, longitude, latitude, currentInterval);
    };

    /**
     * The default parameters to include in the WMS URL to obtain images.  The values are as follows:
     *    service=WMS
     *    version=1.1.1
     *    request=GetMap
     *    styles=
     *    format=image/jpeg
     *
     * @constant
     * @type {Object}
     */
    WebMapServiceImageryProvider.DefaultParameters = freezeObject({
        service : 'WMS',
        version : '1.1.1',
        request : 'GetMap',
        styles : '',
        format : 'image/jpeg'
    });

    /**
     * The default parameters to include in the WMS URL to get feature information.  The values are as follows:
     *     service=WMS
     *     version=1.1.1
     *     request=GetFeatureInfo
     *
     * @constant
     * @type {Object}
     */
    WebMapServiceImageryProvider.GetFeatureInfoDefaultParameters = freezeObject({
        service : 'WMS',
        version : '1.1.1',
        request : 'GetFeatureInfo'
    });

    WebMapServiceImageryProvider.DefaultGetFeatureInfoFormats = freezeObject([
        freezeObject(new GetFeatureInfoFormat('json', 'application/json')),
        freezeObject(new GetFeatureInfoFormat('xml', 'text/xml')),
        freezeObject(new GetFeatureInfoFormat('text', 'text/html'))
    ]);

    function objectToLowercase(obj) {
        var result = {};
        for ( var key in obj) {
            if (obj.hasOwnProperty(key)) {
                result[key.toLowerCase()] = obj[key];
            }
        }
        return result;
    }

    return WebMapServiceImageryProvider;
});