| /* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for | |
| * full list of contributors). Published under the Clear BSD license. | |
| * See http://svn.openlayers.org/trunk/openlayers/license.txt for the | |
| * full text of the license. */ | |
| /** | |
| * @requires OpenLayers/Layer.js | |
| */ | |
| /** | |
| * Class: OpenLayers.Layer.HTTPRequest | |
| * | |
| * Inherits from: | |
| * - <OpenLayers.Layer> | |
| */ | |
| OpenLayers.Layer.HTTPRequest = OpenLayers.Class(OpenLayers.Layer, { | |
| /** | |
| * Constant: URL_HASH_FACTOR | |
| * {Float} Used to hash URL param strings for multi-WMS server selection. | |
| * Set to the Golden Ratio per Knuth's recommendation. | |
| */ | |
| URL_HASH_FACTOR: (Math.sqrt(5) - 1) / 2, | |
| /** | |
| * Property: url | |
| * {Array(String) or String} This is either an array of url strings or | |
| * a single url string. | |
| */ | |
| url: null, | |
| /** | |
| * Property: params | |
| * {Object} Hashtable of key/value parameters | |
| */ | |
| params: null, | |
| /** | |
| * APIProperty: reproject | |
| * *Deprecated*. See http://trac.openlayers.org/wiki/SpatialMercator | |
| * for information on the replacement for this functionality. | |
| * {Boolean} Whether layer should reproject itself based on base layer | |
| * locations. This allows reprojection onto commercial layers. | |
| * Default is false: Most layers can't reproject, but layers | |
| * which can create non-square geographic pixels can, like WMS. | |
| * | |
| */ | |
| reproject: false, | |
| /** | |
| * Constructor: OpenLayers.Layer.HTTPRequest | |
| * | |
| * Parameters: | |
| * name - {String} | |
| * url - {Array(String) or String} | |
| * params - {Object} | |
| * options - {Object} Hashtable of extra options to tag onto the layer | |
| */ | |
| initialize: function(name, url, params, options) { | |
| var newArguments = arguments; | |
| newArguments = [name, options]; | |
| OpenLayers.Layer.prototype.initialize.apply(this, newArguments); | |
| this.url = url; | |
| this.params = OpenLayers.Util.extend( {}, params); | |
| }, | |
| /** | |
| * APIMethod: destroy | |
| */ | |
| destroy: function() { | |
| this.url = null; | |
| this.params = null; | |
| OpenLayers.Layer.prototype.destroy.apply(this, arguments); | |
| }, | |
| /** | |
| * APIMethod: clone | |
| * | |
| * Parameters: | |
| * obj - {Object} | |
| * | |
| * Returns: | |
| * {<OpenLayers.Layer.HTTPRequest>} An exact clone of this | |
| * <OpenLayers.Layer.HTTPRequest> | |
| */ | |
| clone: function (obj) { | |
| if (obj == null) { | |
| obj = new OpenLayers.Layer.HTTPRequest(this.name, | |
| this.url, | |
| this.params, | |
| this.getOptions()); | |
| } | |
| //get all additions from superclasses | |
| obj = OpenLayers.Layer.prototype.clone.apply(this, [obj]); | |
| // copy/set any non-init, non-simple values here | |
| return obj; | |
| }, | |
| /** | |
| * APIMethod: setUrl | |
| * | |
| * Parameters: | |
| * newUrl - {String} | |
| */ | |
| setUrl: function(newUrl) { | |
| this.url = newUrl; | |
| }, | |
| /** | |
| * APIMethod: mergeNewParams | |
| * | |
| * Parameters: | |
| * newParams - {Object} | |
| * | |
| * Returns: | |
| * redrawn: {Boolean} whether the layer was actually redrawn. | |
| */ | |
| mergeNewParams:function(newParams) { | |
| this.params = OpenLayers.Util.extend(this.params, newParams); | |
| var ret = this.redraw(); | |
| if(this.map != null) { | |
| this.map.events.triggerEvent("changelayer", { | |
| layer: this, | |
| property: "params" | |
| }); | |
| } | |
| return ret; | |
| }, | |
| /** | |
| * APIMethod: redraw | |
| * Redraws the layer. Returns true if the layer was redrawn, false if not. | |
| * | |
| * Parameters: | |
| * force - {Boolean} Force redraw by adding random parameter. | |
| * | |
| * Returns: | |
| * {Boolean} The layer was redrawn. | |
| */ | |
| redraw: function(force) { | |
| if (force) { | |
| return this.mergeNewParams({"_olSalt": Math.random()}); | |
| } else { | |
| return OpenLayers.Layer.prototype.redraw.apply(this, []); | |
| } | |
| }, | |
| /** | |
| * Method: selectUrl | |
| * selectUrl() implements the standard floating-point multiplicative | |
| * hash function described by Knuth, and hashes the contents of the | |
| * given param string into a float between 0 and 1. This float is then | |
| * scaled to the size of the provided urls array, and used to select | |
| * a URL. | |
| * | |
| * Parameters: | |
| * paramString - {String} | |
| * urls - {Array(String)} | |
| * | |
| * Returns: | |
| * {String} An entry from the urls array, deterministically selected based | |
| * on the paramString. | |
| */ | |
| selectUrl: function(paramString, urls) { | |
| var product = 1; | |
| for (var i=0, len=paramString.length; i<len; i++) { | |
| product *= paramString.charCodeAt(i) * this.URL_HASH_FACTOR; | |
| product -= Math.floor(product); | |
| } | |
| return urls[Math.floor(product * urls.length)]; | |
| }, | |
| /** | |
| * Method: getFullRequestString | |
| * Combine url with layer's params and these newParams. | |
| * | |
| * does checking on the serverPath variable, allowing for cases when it | |
| * is supplied with trailing ? or &, as well as cases where not. | |
| * | |
| * return in formatted string like this: | |
| * "server?key1=value1&key2=value2&key3=value3" | |
| * | |
| * WARNING: The altUrl parameter is deprecated and will be removed in 3.0. | |
| * | |
| * Parameters: | |
| * newParams - {Object} | |
| * altUrl - {String} Use this as the url instead of the layer's url | |
| * | |
| * Returns: | |
| * {String} | |
| */ | |
| getFullRequestString:function(newParams, altUrl) { | |
| // if not altUrl passed in, use layer's url | |
| var url = altUrl || this.url; | |
| // create a new params hashtable with all the layer params and the | |
| // new params together. then convert to string | |
| var allParams = OpenLayers.Util.extend({}, this.params); | |
| allParams = OpenLayers.Util.extend(allParams, newParams); | |
| var paramsString = OpenLayers.Util.getParameterString(allParams); | |
| // if url is not a string, it should be an array of strings, | |
| // in which case we will deterministically select one of them in | |
| // order to evenly distribute requests to different urls. | |
| // | |
| if (url instanceof Array) { | |
| url = this.selectUrl(paramsString, url); | |
| } | |
| // ignore parameters that are already in the url search string | |
| var urlParams = | |
| OpenLayers.Util.upperCaseObject(OpenLayers.Util.getParameters(url)); | |
| for(var key in allParams) { | |
| if(key.toUpperCase() in urlParams) { | |
| delete allParams[key]; | |
| } | |
| } | |
| paramsString = OpenLayers.Util.getParameterString(allParams); | |
| return OpenLayers.Util.urlAppend(url, paramsString); | |
| }, | |
| CLASS_NAME: "OpenLayers.Layer.HTTPRequest" | |
| }); | |