vector layer loading issue in openlayers 3 - openlayers-3

Question

I have an issue regarding vector loading in ol3.
I am using a geoserver which doesn't handle js callback
In order to have my features loaded, I have to add them in the loader's ajax done function :
var buildLoader = function(vectorSource, $vector) {
return function(extent, resolution, projection) {
extent = ol.extent.applyTransform(extent, ol.proj.getTransform("EPSG:3857", "EPSG:4326"));
var url = 'https://myurl/' + $vector.attr("url") +
'?service=WFS' +
'&version=' + $vector.attr("version") +
'&request=GetFeature' +
'&typename=' + $vector.attr("typename") +
'&srs=' + $vector.attr("projection") +
'&bbox=' + extent +
'&outputFormat=json';
$.ajax({
url: url,
dataType: 'json',
xhrFields: {
withCredentials: true
}
})
.done(function(response) {
vectorSource.addFeatures(vectorSource.readFeatures(response));
});
}
}
I then build an array of vectors to be added on my map.
for (index=0; index < vectors.length; index++) {
var $vector = $(vectors[index]);
var vectorSource = new ol.source.ServerVector({
format: new ol.format.GeoJSON(),
loader: buildLoader(vectorSource, $vector),
projection: 'EPSG:3857'
});
// ... //
datas[index] = new ol.layer.Vector({
source: vectorSource,
visible: 'false',
style: iconStyle
});
}
The problem here is that the vectorSource used by the loader is always [index - 1]
I have found an Hack, by defining the loader function after the instantiation:
var vectorSource = new ol.source.ServerVector({
format: new ol.format.GeoJSON(),
projection: 'EPSG:3857'
});
vectorSource.loader_ = buildLoader(vectorSource, $vector);
I find this ugly enough, but there is no setLoader() available for the ServerVector type. Do you know if there is anoter solution which does not involve using another geoserver?

Answer 1

I save a reference to the VectorSource object instance in the buildLoader function (instead of argument).
vectorSource = this;
Then I use that reference in the done() function:
vectorSource.addFeatures(vectorSource.readFeatures(response));
Full source:
var buildLoader = function($vector) {
return function(extent, resolution, projection) {
vectorSource = this;
extent = ol.extent.applyTransform(extent, ol.proj.getTransform("EPSG:3857", "EPSG:4326"));
var url = 'https://myurl/' + $vector.attr("url") +
'?service=WFS' +
'&version=' + $vector.attr("version") +
'&request=GetFeature' +
'&typename=' + $vector.attr("typename") +
'&srs=' + $vector.attr("projection") +
'&bbox=' + extent +
'&outputFormat=json';
$.ajax({
url: url,
dataType: 'json',
xhrFields: {
withCredentials: true
}
})
.done(function(response) {
vectorSource.addFeatures(vectorSource.readFeatures(response));
});
}
}