CODEWITHSUNDEEP
javascriptexceptionsails.js
Slava Fomin II
Slava Fomin II

Reputation: 28611

Handling exceptions in Sails.js

I'm using Sails.js to develop a REST API server.

For ease of use and for abstraction sake I would like to throw exceptions inside of my controllers, e.g.:

// api/controllers/TempController.js

module.exports = {
  index: function(request, response) {

    throw new NotFoundException('Specific user is not found.');

    throw new AccessDeniedException('You have no permissions to access this resource.');

    throw new SomeOtherException('Something went wrong.');

  }
};

How do I catch those exceptions automatically (on a global level) and transform them into a valid JSON response? e.g.: 

{
  "success": false,
  "exception": {
    "type": "NotFoundException",
    "message": "Specific user is not found."
  }
}

Is it the best possible approach to use built-in serverError response in order to handle such exceptions? Or is it better to create some custom middleware? If so, could you provide a simple example?

Upvotes: 2

Views: 1985

Answers (1)

Slava Fomin II
Slava Fomin II

Reputation: 28611

The unhandled exceptions are passed to the default response in the api/responses/serverError.js as a first argument data.

Here's an example of how such exceptions can be handled:

var Exception = require('../exceptions/Exception.js');

module.exports = function serverError (data, options) {

  var request = this.req;
  var response = this.res;
  var sails = request._sails;

  // Logging error to the console.
  if (data !== undefined) {
    sails.log.error('Sending 500 ("Server Error") response: \n', String(data));
  }  else {
    sails.log.error('Sending empty 500 ("Server Error") response');
  }

  response.status(500);

  if (data instanceof Exception) {
    return response.json({
      success: false,
      exception: {
        type: data.constructor.name,
        message: data.message
      }
    });
  } else {
    return response.json(data);
  }
};

When exception is thrown in the controller:

// api/controllers/TempController.js

var NotFoundException = require('../exceptions/NotFoundException.js');

module.exports = {
  index: function(request, response) {

    throw new NotFoundException('Specific user is not found.');   

  }
};

This will output the following JSON:

{
    "success": false,
    "exception": {
        "type": "NotFoundException",
        "message": "Specific user is not found."
    }
}

Upvotes: 2

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