prometheus

Simple ODM for Node.js with pluggable adapters

Prometheus

Prometheus is a simple ORM for Node.js with adapter for MongoDB.

Because of async nature of database calls, Prometheus' model constructor always returns a promise (we prefer Deferred library), not a model. This promise resolves with model once it is created (e.g. for a blank model, var user = new UserModel()), or once it is loaded from database (e.g. if you provide model id, var user = new UserModel(123)) or null if model was not found.

You define model by passing model-specific options to ModelFactory, which returns a model constructor.

  • name — Name of your model, e.g. UserModel
  • schema — Description of model attributes
  • mixins — An array with mixins that will be applied to constructor's prototype
  • prototype_methods — Model-specific methods that will be added to constructor's prototype
  • static_methods — Model-specific static methods that will be added to constructor
  • hooks — Model-specific hooks (callbacks) that will be called during model lifecycle, e.g. afterInitialize, beforeSave etc.
var prometheus    = require('prometheus'),
    ModelFactory  = prometheus.factory,
    MongodbStore  = prometheus.stores.mongodb,
    Validators    = prometheus.validators,
    MD5           = prometheus.MD5,
    UserModel,
    model_options;
 
model_options = {
 
    name: 'ExampleModel',
 
    store: new MongodbStore({
        collection: 'example'
    }),
 
    schema: {
        name: {
            name: 'Name',
            default: '',
            type: ModelFactory.types.STRING
        },
        email: {
            name: 'Email',
            default: '',
            type: ModelFactory.types.STRING,
            validate: Validators.isEmail,
            unique: true
        },
        password: {
            name: 'Password',
            default: '',
            type: ModelFactory.types.STRING,
            hidden: true
        }
    },
 
    mixins: [],
 
    prototype_methods: {},
 
    static_methods: {
        loginfunction(reqoptions) {
            // your login logic 
        },
 
        logoutfunction(req) {
            // your logout logic 
        }
    },
 
    hooks: {
        beforeSavefunction() {
            var password = this.get('password');
 
            if (password.length !== 32) {
                this.set('password', MD5(password));
            }
 
            this.set('updated_at', utils.now());
        }
    }
}
 
UserModel = module.exports = ModelFactory(model_options);

Blank model is instantiated by calling a model constructor without arguments:

var user = new UserModel();
 
user(function(model) {
    model.set({
        name: 'Shubik',
        email: 'farennikov@gmail.com',
        password: 'password'
    });
 
    model.save()(function(model) {
        // model successfully saved 
    }, function(err) {
        // handle error 
    });
}, function(err) {
    // handle error 
});

Existing model is instantiated with model id as argument:

var user = new UserModel(123);
 
user(function(model) {
    if (model === null) {
        // model with id 123 was not found 
    } else {
        var new_name = model.get('name') + ' updated';
        model.set('name', new_name);
        model.save();
    }
}, function(err) {
    // handle error 
});

Note that if model with such id is not found, promise will resolve with null.

Instance methods

get(attr) retrieves an attribute of the model, or an entire model if attribute name is not provided.

set(attr, [value]) sssigns new value to an attribute or a number of attributes of the model. If given only 1 param which is an Object, method will use keys of the object as attributes.

save() saves a new model or model that has been changed by set(). Returns a promise which is resolved with model if model was successfully saved or error if saving model failed. If model was initialized without an id, new model will be attempted to be created.

destroy() deletes model from a store. Returns a promise which is resolved with this model once model is deleted from database.

keys() returns attribute names of this model.

toJSON() returns all attributes of the model (key-value pairs).

validate() validates model attributes according to the model's schema. Returns true or false.

toForm() returns an object that can be used to create HTML form for this model.

parseForm(req) populates a model by values from a request.

toTable() returns an object that can be used to show this model in table form.

You can add model-specific instance methods by adding them to prototype_methods param of the options you pass to ModelFactory.

Static methods

Model constructors can have static methods which you can use without instantiating a model. By default there are two static methods: find() and count():

find(query, offset, limit, sort) returns a promise which is resolved with an array of models found in database using provided arguments. Example:

UserModel.find({ name: 'Shubik' })(function(results) {
    // do somethig with `results` 
});

count() returns a promise which is resolved with number of all models in the database. Example:

UserModel.count()(function(num) {
    // do somethig with `num` 
});

You can add more model-specific static methods to static_methods param of the options you pass to ModelFactory.