IDL Syntax for POST Command
oURL = obj_new('IDLnetURL')
oURL->SetProperty, header = 'referer:https://myurl.com',$
url_scheme='https', $
url_host = 'myhosturl.com',$
url_path = 'proxy/myhosturl.com/ags/rest/services/MyMapService/FeatureServer/1/query?f=json'
data = 'geometry='+geom+'&geometryType=esriGeometryPolygon&spatialRel=esriSpatialRelIntersects&outFields=*'
JSON = oURL->Put(data, /POST, /BUFFER, /String)