I was also trying to use a dynamicMapLayer yesterday with esri-leaflet and couldn't make it work. After digging in the esri-leaflet code I found the function that makes the export request:
_requestExport: function (params, bounds) {
if (this.options.f === 'json') {
this.service.request('export', params, function (error, response) {
if (error) { return; } // we really can't do anything here but authenticate or requesterror will fire
this._renderImage(response.href, bounds);
}, this);
} else {
params.f = 'image';
this._renderImage(this.options.url + 'export' + L.Util.getParamString(params), bounds);
}
}By default, if not specified, esri-leaflet will make the export request with the json format option. As you can see in this code, it will then expect the response to have the href property that points to the image URL. However right now it seems the export response sends the image directly encoded in base64 in the imageData property.
Until this is sorted out, a work-around I found is to tell leaflet to make the request with a non json format. It doesn't matter really, any other format. This will make the export request return the image directly and the leaflet function will load it directly, as seen in the code above.
