[76] | 1 | /* Copyright (c) 2006-2010 by OpenLayers Contributors (see authors.txt for |
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| 2 | * full list of contributors). Published under the Clear BSD license. |
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| 3 | * See http://svn.openlayers.org/trunk/openlayers/license.txt for the |
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| 4 | * full text of the license. */ |
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| 5 | |
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| 6 | |
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| 7 | /** |
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| 8 | * @requires OpenLayers/Layer.js |
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| 9 | */ |
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| 10 | |
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| 11 | /** |
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| 12 | * Class: OpenLayers.Layer.HTTPRequest |
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| 13 | * |
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| 14 | * Inherits from: |
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| 15 | * - <OpenLayers.Layer> |
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| 16 | */ |
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| 17 | OpenLayers.Layer.HTTPRequest = OpenLayers.Class(OpenLayers.Layer, { |
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| 18 | |
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| 19 | /** |
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| 20 | * Constant: URL_HASH_FACTOR |
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| 21 | * {Float} Used to hash URL param strings for multi-WMS server selection. |
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| 22 | * Set to the Golden Ratio per Knuth's recommendation. |
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| 23 | */ |
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| 24 | URL_HASH_FACTOR: (Math.sqrt(5) - 1) / 2, |
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| 25 | |
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| 26 | /** |
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| 27 | * Property: url |
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| 28 | * {Array(String) or String} This is either an array of url strings or |
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| 29 | * a single url string. |
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| 30 | */ |
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| 31 | url: null, |
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| 32 | |
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| 33 | /** |
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| 34 | * Property: params |
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| 35 | * {Object} Hashtable of key/value parameters |
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| 36 | */ |
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| 37 | params: null, |
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| 38 | |
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| 39 | /** |
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| 40 | * APIProperty: reproject |
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| 41 | * *Deprecated*. See http://trac.openlayers.org/wiki/SpatialMercator |
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| 42 | * for information on the replacement for this functionality. |
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| 43 | * {Boolean} Whether layer should reproject itself based on base layer |
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| 44 | * locations. This allows reprojection onto commercial layers. |
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| 45 | * Default is false: Most layers can't reproject, but layers |
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| 46 | * which can create non-square geographic pixels can, like WMS. |
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| 47 | * |
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| 48 | */ |
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| 49 | reproject: false, |
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| 50 | |
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| 51 | /** |
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| 52 | * Constructor: OpenLayers.Layer.HTTPRequest |
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| 53 | * |
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| 54 | * Parameters: |
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| 55 | * name - {String} |
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| 56 | * url - {Array(String) or String} |
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| 57 | * params - {Object} |
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| 58 | * options - {Object} Hashtable of extra options to tag onto the layer |
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| 59 | */ |
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| 60 | initialize: function(name, url, params, options) { |
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| 61 | var newArguments = arguments; |
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| 62 | newArguments = [name, options]; |
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| 63 | OpenLayers.Layer.prototype.initialize.apply(this, newArguments); |
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| 64 | this.url = url; |
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| 65 | this.params = OpenLayers.Util.extend( {}, params); |
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| 66 | }, |
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| 67 | |
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| 68 | /** |
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| 69 | * APIMethod: destroy |
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| 70 | */ |
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| 71 | destroy: function() { |
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| 72 | this.url = null; |
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| 73 | this.params = null; |
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| 74 | OpenLayers.Layer.prototype.destroy.apply(this, arguments); |
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| 75 | }, |
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| 76 | |
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| 77 | /** |
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| 78 | * APIMethod: clone |
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| 79 | * |
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| 80 | * Parameters: |
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| 81 | * obj - {Object} |
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| 82 | * |
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| 83 | * Returns: |
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| 84 | * {<OpenLayers.Layer.HTTPRequest>} An exact clone of this |
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| 85 | * <OpenLayers.Layer.HTTPRequest> |
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| 86 | */ |
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| 87 | clone: function (obj) { |
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| 88 | |
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| 89 | if (obj == null) { |
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| 90 | obj = new OpenLayers.Layer.HTTPRequest(this.name, |
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| 91 | this.url, |
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| 92 | this.params, |
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| 93 | this.getOptions()); |
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| 94 | } |
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| 95 | |
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| 96 | //get all additions from superclasses |
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| 97 | obj = OpenLayers.Layer.prototype.clone.apply(this, [obj]); |
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| 98 | |
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| 99 | // copy/set any non-init, non-simple values here |
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| 100 | |
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| 101 | return obj; |
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| 102 | }, |
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| 103 | |
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| 104 | /** |
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| 105 | * APIMethod: setUrl |
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| 106 | * |
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| 107 | * Parameters: |
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| 108 | * newUrl - {String} |
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| 109 | */ |
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| 110 | setUrl: function(newUrl) { |
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| 111 | this.url = newUrl; |
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| 112 | }, |
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| 113 | |
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| 114 | /** |
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| 115 | * APIMethod: mergeNewParams |
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| 116 | * |
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| 117 | * Parameters: |
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| 118 | * newParams - {Object} |
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| 119 | * |
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| 120 | * Returns: |
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| 121 | * redrawn: {Boolean} whether the layer was actually redrawn. |
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| 122 | */ |
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| 123 | mergeNewParams:function(newParams) { |
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| 124 | this.params = OpenLayers.Util.extend(this.params, newParams); |
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| 125 | var ret = this.redraw(); |
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| 126 | if(this.map != null) { |
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| 127 | this.map.events.triggerEvent("changelayer", { |
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| 128 | layer: this, |
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| 129 | property: "params" |
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| 130 | }); |
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| 131 | } |
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| 132 | return ret; |
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| 133 | }, |
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| 134 | |
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| 135 | /** |
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| 136 | * APIMethod: redraw |
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| 137 | * Redraws the layer. Returns true if the layer was redrawn, false if not. |
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| 138 | * |
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| 139 | * Parameters: |
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| 140 | * force - {Boolean} Force redraw by adding random parameter. |
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| 141 | * |
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| 142 | * Returns: |
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| 143 | * {Boolean} The layer was redrawn. |
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| 144 | */ |
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| 145 | redraw: function(force) { |
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| 146 | if (force) { |
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| 147 | return this.mergeNewParams({"_olSalt": Math.random()}); |
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| 148 | } else { |
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| 149 | return OpenLayers.Layer.prototype.redraw.apply(this, []); |
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| 150 | } |
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| 151 | }, |
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| 152 | |
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| 153 | /** |
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| 154 | * Method: selectUrl |
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| 155 | * selectUrl() implements the standard floating-point multiplicative |
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| 156 | * hash function described by Knuth, and hashes the contents of the |
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| 157 | * given param string into a float between 0 and 1. This float is then |
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| 158 | * scaled to the size of the provided urls array, and used to select |
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| 159 | * a URL. |
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| 160 | * |
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| 161 | * Parameters: |
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| 162 | * paramString - {String} |
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| 163 | * urls - {Array(String)} |
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| 164 | * |
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| 165 | * Returns: |
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| 166 | * {String} An entry from the urls array, deterministically selected based |
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| 167 | * on the paramString. |
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| 168 | */ |
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| 169 | selectUrl: function(paramString, urls) { |
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| 170 | var product = 1; |
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| 171 | for (var i=0, len=paramString.length; i<len; i++) { |
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| 172 | product *= paramString.charCodeAt(i) * this.URL_HASH_FACTOR; |
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| 173 | product -= Math.floor(product); |
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| 174 | } |
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| 175 | return urls[Math.floor(product * urls.length)]; |
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| 176 | }, |
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| 177 | |
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| 178 | /** |
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| 179 | * Method: getFullRequestString |
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| 180 | * Combine url with layer's params and these newParams. |
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| 181 | * |
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| 182 | * does checking on the serverPath variable, allowing for cases when it |
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| 183 | * is supplied with trailing ? or &, as well as cases where not. |
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| 184 | * |
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| 185 | * return in formatted string like this: |
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| 186 | * "server?key1=value1&key2=value2&key3=value3" |
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| 187 | * |
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| 188 | * WARNING: The altUrl parameter is deprecated and will be removed in 3.0. |
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| 189 | * |
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| 190 | * Parameters: |
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| 191 | * newParams - {Object} |
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| 192 | * altUrl - {String} Use this as the url instead of the layer's url |
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| 193 | * |
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| 194 | * Returns: |
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| 195 | * {String} |
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| 196 | */ |
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| 197 | getFullRequestString:function(newParams, altUrl) { |
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| 198 | |
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| 199 | // if not altUrl passed in, use layer's url |
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| 200 | var url = altUrl || this.url; |
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| 201 | |
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| 202 | // create a new params hashtable with all the layer params and the |
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| 203 | // new params together. then convert to string |
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| 204 | var allParams = OpenLayers.Util.extend({}, this.params); |
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| 205 | allParams = OpenLayers.Util.extend(allParams, newParams); |
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| 206 | var paramsString = OpenLayers.Util.getParameterString(allParams); |
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| 207 | |
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| 208 | // if url is not a string, it should be an array of strings, |
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| 209 | // in which case we will deterministically select one of them in |
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| 210 | // order to evenly distribute requests to different urls. |
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| 211 | // |
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| 212 | if (url instanceof Array) { |
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| 213 | url = this.selectUrl(paramsString, url); |
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| 214 | } |
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| 215 | |
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| 216 | // ignore parameters that are already in the url search string |
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| 217 | var urlParams = |
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| 218 | OpenLayers.Util.upperCaseObject(OpenLayers.Util.getParameters(url)); |
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| 219 | for(var key in allParams) { |
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| 220 | if(key.toUpperCase() in urlParams) { |
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| 221 | delete allParams[key]; |
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| 222 | } |
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| 223 | } |
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| 224 | paramsString = OpenLayers.Util.getParameterString(allParams); |
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| 225 | |
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| 226 | return OpenLayers.Util.urlAppend(url, paramsString); |
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| 227 | }, |
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| 228 | |
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| 229 | CLASS_NAME: "OpenLayers.Layer.HTTPRequest" |
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| 230 | }); |
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