Sails JS: Validating model with embedded JSON property

Question

How does one validate a model with a property, of type object in Sails JS?

I know that attributes with a simple value (e.g. string), is acceptable, however how does this work for nested JSONs?

Like the following:

{
    name: 'John',
    location: {
        x: 23,
        y: 15,
        z: 50
    }
}

So would it be of the form:

{
    name: {
        type: 'string',
        required: true,
    },
    location: {
        x: {
            type: 'number',
            required: true
        },
        y: {
            type: 'number',
            required: true
        },
        z: {
            type: 'number',
            required: true
        }
    }
}

Answer 1

I have made a structure comparison function to handle such cases, i'd like to share with you, hope it inspires & help:

assuming you are using sails v1

Create a file in ./api/services called ModelService.js with the below code:

module.exports = {
  invalidStructure(schema, input) {
    try {
      if (schema.type === 'array') {
        // Invalid: if input is not array
        //  OR some of input[items] doesn't match schema.item
        return !_.isArray(input) ||
          _.some(input, item => this.invalidStructure(schema.item, item));
      }
      else if (schema.type === 'object') {
        // Invalid if input is not an object
        //  OR if input.keys doesn't match schema.struct.keys
        //  OR if typeof input[key] doesn't match schema.struct[key]
        return !_.isObjectLike(input) ||
          !_.isEqual(_.keys(schema.struct), _.keys(input)) ||
          _.some(_.keys(input), key => this.invalidStructure(schema.struct[key], input[key]));
      }
      else { // verifying field value vs schema.type
        // TODO: Add other field validations here (i.e. isEmail, required,...etc.)
        return typeof input !== schema.type;
      }
    }
    catch (err) {
      sails.log.error('Exception in [invalidStructure] : ', err);
      return true;
    }
  }
}

and use it like this in your model:

const address = {
  type: 'object',
  struct: {
    name: { type: 'string' },
    location: {
      type: 'object',
      struct: {
        x: { type: 'string' },
        y: { type: 'string' },
        z: { type: 'string' },
      }
    }
  }
}
module.exports = {
  attributes: {
    address: {
      type: 'json',
      custom: value => !ModelService.invalidStructure(address, value)
    }
  }
}

Now i know that this doesn't handle or the cases (i.e. required: false)

But it should get you going with matching json structure and value types

Note: This is the source file. Feel free to use, or enhance with a PR

Answer 2

The most elegant solution I have found so far is to using the "machine" library (which powers the actions in sailsjs, built by sailsjs people) to define type validation "machines".

First you need a type define helper:

$ cat api/types/define.js 
const buildWithCustomUsage = require("machine").buildWithCustomUsage;

function validateWith(machine, inputs) {
    machine(inputs).now();
    return true;
}

module.exports = function (def) {
    const machine = buildWithCustomUsage({
        def,
        extraArginsTactic: "doNotCheck"
    });
    return {
        machine,
        validate: validateWith.bind(null, machine)
    };
};

Then you can define a type like this:

$ cat api/types/QuoteRequest.js 
module.exports = require("./define")({

    description: "Quote request type definition",

    inputs: {
        input_currency_type: {
            description: "Input currency type",
            type: "string",
            required: true
        },
        amount_requested: {
            description: "Requested amount in input currency",
            type: "string",
            required: true
        }
    },

    sync: true,

    fn: function (inputs, exits) {
        // your other validation logics
        return exits.success();
    }
});

You need to make sure you set sync: true.

To use it in your controllers, do like this:

inputs: {
    request: {
        type: "json",
        required: true,
        custom: require("../../types/QuoteRequest").validate
    }
},

Hope it helps!

Answer 3

Waterline (the Sails ORM) doesn't directly support nested schemas. You can use a custom validation rule to validate the attribute instead:

module.exports = {

  types: {
    location: function(val) {
      // Make sure that x, y and z are present and are numbers.
      // This won't allow numeric strings, but you can adjust to fit your needs.
      return (_.isNumber(val.x) && _.isNumber(val.y) && _.isNumber(val.z));
    }
  },

  attributes: {

    location: {
      type: 'json',
      required: true, // If you want the whole attribute to be required
      location: true  // Validate that the attribute has the schema you want
    }

    ...more attributes...

  }

};