Merge pull request #342 from bbinet/wmts

Add WMTS support.

src/ol/source/wmtssource.exports

@@ -0,0 +1,2 @@
+@exportClass ol.source.WMTS ol.source.WMTSOptions
+@exportSymbol ol.source.WMTS.optionsFromCapabilities

src/ol/source/wmtssource.js

@@ -0,0 +1,260 @@
+goog.provide('ol.source.WMTS');
+goog.provide('ol.source.WMTSRequestEncoding');
+
+goog.require('ol.Attribution');
+goog.require('ol.Extent');
+goog.require('ol.Projection');
+goog.require('ol.TileCoord');
+goog.require('ol.TileUrlFunction');
+goog.require('ol.TileUrlFunctionType');
+goog.require('ol.projection');
+goog.require('ol.source.ImageTileSource');
+goog.require('ol.tilegrid.WMTS');
+
+
+/**
+ * @enum {string}
+ */
+ol.source.WMTSRequestEncoding = {
+  KVP: 'KVP',  // see spec §8
+  REST: 'REST' // see spec §10
+};
+
+
+
+/**
+ * @constructor
+ * @extends {ol.source.ImageTileSource}
+ * @param {ol.source.WMTSOptions} wmtsOptions WMTS options.
+ */
+ol.source.WMTS = function(wmtsOptions) {
+
+  // TODO: add support for TileMatrixLimits
+
+  var version = goog.isDef(wmtsOptions.version) ?
+      wmtsOptions.version : '1.0.0';
+  var format = goog.isDef(wmtsOptions.format) ?
+      wmtsOptions.format : 'image/jpeg';
+  var dimensions = wmtsOptions.dimensions || {};
+
+  // FIXME: should we guess this requestEncoding from wmtsOptions.url(s)
+  //        structure? that would mean KVP only if a template is not provided.
+  var requestEncoding = goog.isDef(wmtsOptions.requestEncoding) ?
+      wmtsOptions.requestEncoding : ol.source.WMTSRequestEncoding.KVP;
+
+  // FIXME: should we create a default tileGrid?
+  // we could issue a getCapabilities xhr to retrieve missing configuration
+  var tileGrid = wmtsOptions.tileGrid;
+
+  var context = {
+    'Layer': wmtsOptions.layer,
+    'style': wmtsOptions.style,
+    'TileMatrixSet': wmtsOptions.matrixSet
+  };
+  goog.object.extend(context, dimensions);
+  var kvpParams;
+  if (requestEncoding == ol.source.WMTSRequestEncoding.KVP) {
+    kvpParams = {
+      'Service': 'WMTS',
+      'Request': 'GetTile',
+      'Version': version,
+      'Format': format,
+      'TileMatrix': '{TileMatrix}',
+      'TileRow': '{TileRow}',
+      'TileCol': '{TileCol}'
+    };
+    goog.object.extend(kvpParams, context);
+  }
+
+  // TODO: factorize the code below so that it is usable by all sources
+  var urls = wmtsOptions.urls;
+  if (!goog.isDef(urls)) {
+    urls = [];
+    var url = wmtsOptions.url;
+    goog.asserts.assert(goog.isDef(url));
+    var match = /\{(\d)-(\d)\}/.exec(url) || /\{([a-z])-([a-z])\}/.exec(url);
+    if (match) {
+      var startCharCode = match[1].charCodeAt(0);
+      var stopCharCode = match[2].charCodeAt(0);
+      var charCode;
+      for (charCode = startCharCode; charCode <= stopCharCode; ++charCode) {
+        urls.push(url.replace(match[0], String.fromCharCode(charCode)));
+      }
+    } else {
+      urls.push(url);
+    }
+  }
+
+  /**
+   * @param {string} template Template.
+   * @return {ol.TileUrlFunctionType} Tile URL function.
+   */
+  function createFromWMTSTemplate(template) {
+    return function(tileCoord) {
+      if (goog.isNull(tileCoord)) {
+        return undefined;
+      } else {
+        var localContext = {
+          'TileMatrix': tileGrid.getMatrixId(tileCoord.z),
+          'TileCol': tileCoord.x,
+          'TileRow': tileCoord.y
+        };
+        if (requestEncoding != ol.source.WMTSRequestEncoding.KVP) {
+          goog.object.extend(localContext, context);
+        }
+        var url = template;
+        for (var key in localContext) {
+          // FIXME: should we filter properties with hasOwnProperty?
+          url = url.replace('{' + key + '}', localContext[key])
+              .replace('%7B' + key + '%7D', localContext[key]);
+        }
+        return url;
+      }
+    };
+  }
+
+  var tileUrlFunction = ol.TileUrlFunction.createFromTileUrlFunctions(
+      goog.array.map(urls, function(url) {
+        if (goog.isDef(kvpParams)) {
+          // TODO: we may want to create our own appendParams function
+          // so that params order conforms to wmts spec guidance,
+          // and so that we can avoid to escape special template params
+          url = goog.uri.utils.appendParamsFromMap(url, kvpParams);
+        }
+        return createFromWMTSTemplate(url);
+      }));
+
+  tileUrlFunction = ol.TileUrlFunction.withTileCoordTransform(
+      function(tileCoord, tileGrid, projection) {
+        if (tileGrid.getResolutions().length <= tileCoord.z) {
+          return null;
+        }
+        var x = tileCoord.x;
+        var y = -tileCoord.y - 1;
+        var tileExtent = tileGrid.getTileCoordExtent(tileCoord);
+        var projectionExtent = projection.getExtent();
+        var extent = goog.isDef(wmtsOptions.extent) ?
+            wmtsOptions.extent : projectionExtent;
+
+        if (!goog.isNull(extent) && projection.isGlobal() &&
+            extent.minX === projectionExtent.minX &&
+            extent.maxX === projectionExtent.maxX) {
+          var numCols = Math.ceil(
+              (extent.maxX - extent.minX) /
+              (tileExtent.maxX - tileExtent.minX));
+          x = goog.math.modulo(x, numCols);
+          tileExtent = tileGrid.getTileCoordExtent(
+              new ol.TileCoord(tileCoord.z, x, tileCoord.y));
+        }
+        if (!tileExtent.intersects(extent)) {
+          return null;
+        }
+        return new ol.TileCoord(tileCoord.z, x, y);
+      },
+      tileUrlFunction);
+
+  goog.base(this, {
+    attributions: wmtsOptions.attributions,
+    crossOrigin: wmtsOptions.crossOrigin,
+    extent: wmtsOptions.extent,
+    projection: wmtsOptions.projection,
+    tileGrid: tileGrid,
+    tileUrlFunction: tileUrlFunction
+  });
+
+};
+goog.inherits(ol.source.WMTS, ol.source.ImageTileSource);
+
+
+/**
+ * @param {Object} wmtsCap An object representing the capabilities document.
+ * @param {string} layer The layer identifier.
+ * @return {ol.source.WMTSOptions} WMTS source options object.
+ */
+ol.source.WMTS.optionsFromCapabilities = function(wmtsCap, layer) {
+
+  // TODO: add support for TileMatrixLimits
+
+  var layers = wmtsCap['contents']['layers'];
+  var l = goog.array.find(layers, function(elt, index, array) {
+    return elt['identifier'] == layer;
+  });
+  goog.asserts.assert(!goog.isNull(l));
+  goog.asserts.assert(l['tileMatrixSetLinks'].length > 0);
+  var matrixSet = /** @type {string} */
+      (l['tileMatrixSetLinks'][0]['tileMatrixSet']);
+  var format = /** @type {string} */ (l['formats'][0]);
+  var idx = goog.array.findIndex(l['styles'], function(elt, index, array) {
+    return elt['isDefault'];
+  });
+  if (idx < 0) {
+    idx = 0;
+  }
+  var style = /** @type {string} */ (l['styles'][idx]['identifier']);
+
+  var dimensions = {};
+  goog.array.forEach(l['dimensions'], function(elt, index, array) {
+    var key = elt['identifier'];
+    var value = elt['default'];
+    if (goog.isDef(value)) {
+      goog.asserts.assert(goog.array.indexOf(elt['values'], value) >= 0);
+    } else {
+      value = elt['values'][0];
+    }
+    goog.asserts.assert(goog.isDef(value));
+    dimensions[key] = value;
+  });
+
+  var matrixSets = wmtsCap['contents']['tileMatrixSets'];
+  goog.asserts.assert(matrixSet in matrixSets);
+  var matrixSetObj = matrixSets[matrixSet];
+
+  var tileGrid = ol.tilegrid.WMTS.createFromCapabilitiesMatrixSet(
+      matrixSetObj);
+
+  var projection = ol.projection.get(matrixSetObj['supportedCRS']);
+
+  var gets = wmtsCap['operationsMetadata']['GetTile']['dcp']['http']['get'];
+  var encodings = goog.object.getKeys(
+      gets[0]['constraints']['GetEncoding']['allowedValues']);
+  goog.asserts.assert(encodings.length > 0);
+  var requestEncoding = /** @type {ol.source.WMTSRequestEncoding} */
+      (encodings[0]);
+  // TODO: arcgis support, quote from ol2:
+  // The OGC documentation is not clear if we should use REST or RESTful,
+  // ArcGis use RESTful, and OpenLayers use REST.
+
+  var urls;
+  switch (requestEncoding) {
+    case ol.source.WMTSRequestEncoding.REST:
+      goog.asserts.assert(l['resourceUrls'].hasOwnProperty('tile'));
+      goog.asserts.assert(l['resourceUrls']['tile'].hasOwnProperty(format));
+      urls = /** @type {Array.<string>} */
+          (l['resourceUrls']['tile'][format]);
+      break;
+    case ol.source.WMTSRequestEncoding.KVP:
+      urls = [];
+      goog.array.forEach(gets, function(elt, index, array) {
+        if (elt['constraints']['GetEncoding']['allowedValues'].hasOwnProperty(
+            ol.source.WMTSRequestEncoding.KVP)) {
+          urls.push(/** @type {string} */ (elt['url']));
+        }
+      });
+      goog.asserts.assert(urls.length > 0);
+      break;
+    default:
+      goog.asserts.assert(false);
+  }
+
+  return {
+    urls: urls,
+    layer: layer,
+    matrixSet: matrixSet,
+    format: format,
+    projection: projection,
+    requestEncoding: requestEncoding,
+    tileGrid: tileGrid,
+    style: style,
+    dimensions: dimensions
+  };
+};