--- a/labs/openlayers/lib/OpenLayers/Layer/HTTPRequest.js +++ b/labs/openlayers/lib/OpenLayers/Layer/HTTPRequest.js @@ -1,1 +1,231 @@ - +/* 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" +}); +