GeoStore Data Stores

Data stores are the foundation of the GeoStore. They are key/value storage devices that allow for creating entries, updating, deleting, and retrieving single Feature objects in GeoJSON.

Data Stores are designed to be asyncronous, using Node.js style callbacks. In syncronough stores, like Terraformer.Store.Memory and Terraformer.Store.LocalStorage callbacks are executed immediately, but in truly asyncronous stores they behave as expected.

Existing Data Stores

There are a couple of existing Data Stores that help you get started storing data immediately.

• LocalStorage - works in the browser only
• Memory - works in both the browser and Node.js
• LevelDB - works in Node.js

Writing a DataStore

Since Data Stores are simply key/value stores, it is very easy to write additional Data Stores as long as the method signatures are correct.

Methods

new DataStore()

Instantiating a DataStore should return a new object containing method signatures conforming to the DataStore interface.

You can pass any needed arguments while instantiating.

Example:

var ds = new DataStore({
  path: "some_path",
  username: "me",
  password: "mypass",
});

DataStore.add(geostore, callback)

Add a geojson object to a DataStore. In the case of a Feature, the id should be used as the primary key for storage and retrieval:

// get the id
var id = geojson.id;

// store the data
this.magicdb.put(geojson.id, JSON.stringify(geojson));

If a FeatureCollection is passed in instead, each Feature inside of the FeatureCollection needs to be added before the callback is called.

Option	Value	Description
GeoJSON	object	Must be either a Feature or FeatureCollection and contain an id
callback	function	Callback to be fired when the add has been completed

Example:

ds.add(geojson, function (err, res) {
  // Node.js style callback
});

DataStore.update(geostore, callback)

Update a geojson object already in a DataStore. Only a Feature should be able to be updated, the id should be used as the primary key for update:

Option	Value	Description
GeoJSON	object	Must be a Feature and contain an id
callback	function	Callback to be fired when the update has been completed

Example:

ds.update(geojson, function (err, res) {
  // Node.js style callback
});

DataStore.remove(id, callback)

Remove a geojson object from the DataStore by id.

Option	Value	Description
id	String or Number	The id of the Feature to be removed
callback	function	Callback to be fired when the remove has been completed

Example:

ds.remove(id, function (err, res) {
  // Node.js style callback
});

DataStore.get(id, callback)

Retrieves a geojson object from the DataStore by id.

Option	Value	Description
id	String or Number	The id of the Feature to be retrieved
callback	function	Callback to be fired when the remove has been completed

Example:

ds.get(id, function (err, res) {
  // Node.js style callback
});