bd262fce41
Now the application no longer needs to care about the tile origin, because the CacheWrite control modifies the url if the CORS image loading is disabled and it is from a different origin. This only requires OpenLayers.ProxyHost to be properly configured. Also local storage keys use the original url instead of the proxied url, to make the CacheRead control work without proxy settings. No deferred exceptions are thrown any more. Instead, OpenLayers.Console is used to show an error message for security exceptions. We now check for OpenLayers.Tile.Image, because other tile types (e.g. UTFGrid) are not supported (yet). To make the same origin handling in the CacheWrite control easier, OpenLayers.Request now exposes the same origin logic from request.issue as a separate function, so it can also be used by other components.
157 lines
4.9 KiB
JavaScript
157 lines
4.9 KiB
JavaScript
/* Copyright (c) 2006-2012 by OpenLayers Contributors (see authors.txt for
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* full list of contributors). Published under the Clear BSD license.
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* See http://svn.openlayers.org/trunk/openlayers/license.txt for the
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* full text of the license. */
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/**
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* @requires OpenLayers/Control.js
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*/
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/**
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* Class: OpenLayers.Control.CacheRead
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* A control for using image tiles cached with <OpenLayers.Control.CacheWrite>
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* from the browser's local storage.
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*
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* Inherits from:
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* - <OpenLayers.Control>
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*/
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OpenLayers.Control.CacheRead = OpenLayers.Class(OpenLayers.Control, {
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/**
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* APIProperty: fetchEvent
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* {String} The layer event to listen to for replacing remote resource tile
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* URLs with cached data URIs. Supported values are "tileerror" (try
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* remote first, fall back to cached) and "tileloadstart" (try cache
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* first, fall back to remote). Default is "tileloadstart".
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*
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* Note that "tileerror" will not work for CORS enabled images (see
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* https://developer.mozilla.org/en/CORS_Enabled_Image), i.e. layers
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* configured with a <OpenLayers.Tile.Image.crossOriginKeyword> in
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* <OpenLayers.Layer.Grid.tileOptions>.
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*/
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fetchEvent: "tileloadstart",
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/**
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* APIProperty: layers
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* {Array(<OpenLayers.Layer.Grid>)}. Optional. If provided, only these
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* layers will receive tiles from the cache.
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*/
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layers: null,
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/**
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* APIProperty: autoActivate
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* {Boolean} Activate the control when it is added to a map. Default is
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* true.
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*/
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autoActivate: true,
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/**
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* Constructor: OpenLayers.Control.CacheRead
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*
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* Parameters:
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* options - {Object} Object with API properties for this control
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*/
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/**
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* Method: setMap
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* Set the map property for the control.
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*
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* Parameters:
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* map - {<OpenLayers.Map>}
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*/
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setMap: function(map) {
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OpenLayers.Control.prototype.setMap.apply(this, arguments);
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var i, layers = this.layers || map.layers;
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for (i=layers.length-1; i>=0; --i) {
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this.addLayer({layer: layers[i]});
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}
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if (!this.layers) {
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map.events.on({
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addlayer: this.addLayer,
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removeLayer: this.removeLayer,
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scope: this
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});
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}
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},
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/**
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* Method: addLayer
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* Adds a layer to the control. Once added, tiles requested for this layer
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* will be cached.
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*
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* Parameters:
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* evt - {Object} Object with a layer property referencing an
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* <OpenLayers.Layer> instance
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*/
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addLayer: function(evt) {
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evt.layer.events.register(this.fetchEvent, this, this.fetch);
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},
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/**
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* Method: removeLayer
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* Removes a layer from the control. Once removed, tiles requested for this
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* layer will no longer be cached.
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*
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* Parameters:
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* evt - {Object} Object with a layer property referencing an
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* <OpenLayers.Layer> instance
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*/
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removeLayer: function(evt) {
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evt.layer.events.unregister(this.fetchEvent, this, this.fetch);
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},
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/**
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* Method: fetch
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* Listener to the <fetchEvent> event. Replaces a tile's url with a data
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* URI from the cache.
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*
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* Parameters:
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* evt - {Object} Event object with a tile property.
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*/
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fetch: function(evt) {
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if (this.active && window.localStorage &&
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evt.tile instanceof OpenLayers.Tile.Image) {
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var tile = evt.tile,
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url = tile.url;
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// deal with modified tile urls when both CacheWrite and CacheRead
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// are active
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if (!tile.layer.crossOriginKeyword && OpenLayers.ProxyHost &&
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url.indexOf(OpenLayers.ProxyHost) === 0) {
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url = OpenLayers.Control.CacheWrite.urlMap[url];
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}
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var dataURI = window.localStorage.getItem("olCache_" + tile.url);
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if (dataURI) {
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tile.url = dataURI;
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if (evt.type === "tileerror") {
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tile.setImgSrc(dataURI);
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}
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}
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}
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},
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/**
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* Method: destroy
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* The destroy method is used to perform any clean up before the control
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* is dereferenced. Typically this is where event listeners are removed
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* to prevent memory leaks.
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*/
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destroy: function() {
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if (this.layers || this.map) {
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var i, layers = this.layers || this.map.layers;
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for (i=layers.length-1; i>=0; --i) {
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this.removeLayer({layer: layers[i]});
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}
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}
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if (this.map) {
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this.map.events.un({
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addlayer: this.addLayer,
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removeLayer: this.removeLayer,
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scope: this
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});
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}
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OpenLayers.Control.prototype.destroy.apply(this, arguments);
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},
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CLASS_NAME: "OpenLayers.Control.CacheRead"
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});
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