How to exchange data between FeatureStore and AJAX backend?

Question

I'm new to Extjs4.2/OL/Geoext2 developing, and I'm confused about how it should work.

--- edit ---

I'm trying to write a small app to read GeoJSON, place read features on the map, let the user to edit them / draw new ones, and finally save them back to GeoJSON.

My current approach: OpenLayers.Layer.Vector is bound to Geoext.data.FeatureStore. Layer reads GeoJSON, and FeatureStore is populated.

And now my question - how to save the modified by user data to GeoJSON? I can save the data as JSON by FeatureStore, but I don't see an easy way to make FetureStore save GeoJSON. Should I use vector layer to save GeoJSON, or try to add some type of conversion to add geometry attributes of the features to FeatureStore, and then sync() the store?

--- edit ---

Already done this by inserting another attribute to the model:

{
  name: 'geom',
  convert: function(value, record) {
    return record.raw.geometry.toString();
  }
}

Now my FeatureStore saves GeoJSON-like output with geometry, which is ok for me.

Question: Is it the right way to do this?

Regards, Pawel

I didn't post any code, since I'm looking for an answer to a generic problem. I'll try to rephrase my question... — Paweł Kowalski, Sep 05 '14 at 10:41

score 1 · Answer 1 · answered Sep 16 '14 at 12:46

I'm not an expert, but I think GeoExt.data.FeatureStore was created to be synchronized with the layer. So, if you do a store.sync() no update request will be sent to your remote GeoJSON data source. GeoExt.data.FeatureStore constructor starts by creating a proxy: { type: 'memory', ... and thus your original proxy will be replaced by this one. To use the GeoExt.data.FeatureStore you have to rewrite it.

So, I think the best way to do this is to use a OpenLayers.Protocol.Script source, which is quite flexible, configured to use your remote GeoJSON source. Using the layer's save strategy, all updates will be sent to the remote source.

Regards!

How to exchange data between FeatureStore and AJAX backend?

1 Answers1