Hooks

As mentioned before feathers-import-export relies on feathers-s3, particularly on the methods getObjectCommand and uploadFile which are used respectively by the import and export methods. Consequently, you have the flexibility to register hooks on these methods to incorporate additional processing steps. For instance, it might be practical to include a before hook on the uploadFile method to execute preprocessing on the entire file before transferring it to the storage, such as converting it to another file format.

Registering hooks

Hooks can be registered by accessing the internal S3 service, as demonstrated below:

app.use('path-to-service', new Service(Object.assign(options, { app })))
service = app.service('path-to-service')
service.s3Service.hooks({
  before: {
    uploadFile: [myHook]
  }
})

Predefined hooks

convertGeoJson

This hook converts exported GeoJSON data to any format using ogr2ogr.

To trigger this hook,you must declare the convertGeoJson object in the export method with the following properties:

• ogrDriver: any Vector driver, e.g. KML,
• contentType: file mime type; e.g. application/vnd.google-earth.kml+xml

For instance:

convertGeoJson: {
  ogrDriver: 'ESRI Shapefile',
  contentType: 'application/zip'
}

NOTE

In case of ESRI Shapefile format, you must specify a filename with the extension shp.zip to force the creation of a compressed archive containing .shp, .shx, .dbf and other side-car files of one or more layers.

WARNING

This hook cannot be applied to archived data.

reprojectGeoJson

This hook allows to reproject the exported GeoJSON data to any Coordinate Reference System using ogr2ogr.

To trigger this hook, you must declare the reprojectGeoJson object in the export method with the following properties:

• srs: any coordinate reference systems, e.g. EPSG:3857

For instance:

reprojectGeoJson: {
  srs: `EPSG:2154`
}

NOTE

The coordinate reference systems that can be passed are anything supported by the OGRSpatialReference::SetFromUserInput() call, which includes EPSG Projected, Geographic or Compound CRS (i.e. EPSG:4296), a well known text (WKT) CRS definition, PROJ.4 declarations, or the name of a .prj file containing a WKT CRS definition.

WARNING

This hook cannot be applied to archived data.