Edit Page

.leaseConnection()

Lease a new connection from the datastore for use in running multiple queries on the same connection (i.e. so that the logic provided in during can reuse the db connection).

await datastore.leaseConnection(during);

var result = await datastore.leaseConnection(during);

Usage

	Argument	Type	Details
1	during		A procedural parameter which Sails will call automatically when a connection has been obtained and made ready for you. It will receive the arguments specified in the "During" usage table below.

During

	Argument	Type	Details
1	db		Your newly-leased database connection. (See `.usingConnection()` for more information on what to do with this.)
2	proceed		Call this function when your `during` code is finished, or if a fatal error occurs. Usage: • `return proceed();` • `proceed(new Error('Oops))` • `proceed(undefined, { some: 'arbitrary result'} )` Like any Node callback, if you call `proceed(new Error('Oops'))` (i.e. with a truthy first argument; conventionally an Error instance), then Sails understands that to mean a fatal error occurred. Otherwise, it is assumed that everything went according to plan. In any case, when your code calls `proceed()`, the connection is automatically released back to the pool before calling the final callback.

Result

Type	Details
	The optional result data sent back from `during`. In other words, if, in your `during` function, you called `proceed(undefined, 'foo')`, then this will be `'foo'`.

Errors

Name	Type	When?
UsageError		Thrown if something invalid was passed in.
AdapterError		Thrown if something went wrong in the database adapter.
Error		Thrown if anything else unexpected happens.

See Concepts > Models and ORM > Errors for examples of negotiating errors in Sails and Waterline.

Example

Lease a database connection from the default datastore, then use it to send two queries before releasing it back to the pool.

var inventory = await sails.getDatastore()
.leaseConnection(async (db, proceed)=> {

  var location = await Location.findOne({ id: req.param('locationId') })
  .usingConnection(db);

  if (!location) {
    err = new Error('Cannot find location with that id (`'+req.param('locationId')+'`)');
    err.code = 'E_NO_SUCH_LOCATION';
    return proceed(err);
  }

  // Get all products at the location
  var productOfferings = await ProductOffering.find({ location: req.param('locationId') })
  .populate('productType')
  .usingConnection(db);

  var inventory = _.indexBy(productOfferings, 'id');
  return proceed(undefined, inventory);
})
.intercept('E_NO_SUCH_LOCATION', ()=> {
  return res.notFound();
});

// All done!  Whatever we were doing with that connection worked.
// Now we can proceed with our business.
return res.json(inventory);

Is something missing?

If you notice something we've missed or could be improved on, please follow this link and submit a pull request to the sails-docs repo. Once we merge it, the changes will be reflected on the website the next time it is deployed.

Documentation

Reference

Built with Love

The Sails framework is built by a web & mobile shop in Austin, TX, with the help of our contributors. We created Sails in 2012 to assist us on Node.js projects. Naturally we open-sourced it. We hope it makes your life a little bit easier!