Koop Provider Hub Search OGC

This is a Koop provider that extracts datasets from the ArcGIS Hub Search OGC API.

Use - Streaming All Datasets

This provider plugin currently only supports streaming ALL datasets matching a given search query.

Define Search Parameters

To perform a search from an output plugin, attach onto the response.

req.res.locals.siteIdentifier = 'https://my-site.hub.arcgis.com'

Pull the Readable Stream

Then pass the request object to this.model.pullStream.

const docStream = await this.model.pullStream(req);

Full Example

What you have now is a Node.js Readable stream. You can pipe the datasets from the readable through a transform stream in order to format them into some other type of output before sending them back to the browser by piping them to the Express.js response. The following simple example also uses the through2 library to conveniently define a transform stream.

async handleRequest (req, res) {
  req.res.locals.siteIdentifier = 'my-site.hub.arcgis.com'

  const docStream = await this.model.pullStream(req);

  docStream
    .pipe(through2.obj(function (dataset, enc, callback) {
      const transformed = someTranformFunc(dataset);

      // the Express.js "res" Writable only accepts strings or Buffers
      this.push(JSON.stringify(transformed));
      callback();
    }))
    .pipe(res);
}

Develop

# clone and install dependencies
git clone https://github.com/koopjs/koop-provider-hub-search-ogc 
cd koop-provider-hub-search-ogc 
npm i

# starts the example Koop app found in ./example-app.
npm run dev

Test

Run the npm t commmand to spin up the automated tests.