⚠️ IMPORTANT NEWS! 📰

I’ve been dealing with CQRS, event-sourcing and DDD long enough now that I don’t need working with it anymore unfortunately, so at least for now this my formal farewell!

I want to thank everyone who has contributed in one way or another. Especially...

Jan, who introduced me to this topic.
Dimitar, one of the last bigger contributors and maintainer.
My last employer, who gave me the possibility to use all these CQRS modules in a big Cloud-System.
My family and friends, who very often came up short.

Finally, I would like to thank Golo Roden, who was there very early at the beginning of my CQRS/ES/DDD journey and is now here again to take over these modules.

Golo Roden is the founder, CTO and managing director of the native web, a company specializing in native web technologies. Among other things, he also teaches CQRS/ES/DDD etc. and based on his vast knowledge, he brought wolkenkit to life. wolkenkit is a CQRS and event-sourcing framework based on Node.js. It empowers you to build and run scalable distributed web and cloud services that process and store streams of domain events.

With this step, I can focus more on i18next, locize and localistars. I'm happy about that. 😊

So, there is no end, but the start of a new phase for my CQRS modules. 😉

I wish you all good luck on your journey.

Who knows, maybe we'll meet again in a github issue or PR at i18next 😉

Adriano Raiano

Introduction

Node-viewmodel is a node.js module for multiple databases. It can be very useful if you work with (d)ddd, cqrs, eventdenormalizer, host, etc.

Installation

$ npm install viewmodel

Usage

Connecting to an in-memory repository in read mode

var viewmodel = require('viewmodel');

viewmodel.read(function(err, repository) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }
});

Connecting to any repository (mongodb in the example / mode=write)

Make shure you have installed the required driver, in this example run: 'npm install mongodb'.

var viewmodel = require('viewmodel');

viewmodel.write(
    {
        type: 'mongodb',
        host: 'localhost',      // optional
        port: 27017,            // optional
        dbName: 'viewmodel',    // optional
        timeout: 10000          // optional
        // authSource: 'authedicationDatabase',        // optional
  	    // username: 'technicalDbUser',                // optional
  	    // password: 'secret'                          // optional
        // url: 'mongodb://user:pass@host:port/db?opts // optional
    },
    function(err, repository) {
        if(err) {
            console.log('ohhh :-(');
            return;
        }
    }
);

Catch connect ad disconnect events

var repository = viewmodel.write({ type: 'mongodb' });
repository.on('connect', function() {
    console.log('hello from event');
});
repository.on('disconnect', function() {
    console.log('bye');
});
repository.connect();

Define a collection...

var dummyRepo = repository.extend({
    collectionName: 'dummy'
});

Create a new viewmodel (only in write mode)

dummyRepo.get(function(err, vm) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    vm.set('myProp', 'myValue');
    vm.set('myProp.deep', 'myValueDeep');

    console.log(vm.toJSON());

    console.log(vm.has('myProp.deep'));

    dummyRepo.commit(vm, function(err) {
    });
    // or you can call commit directly on vm...
    vm.commit(function(err) {
    });
});

Find...

// the query object ist like in mongoDb...
dummyRepo.find({ color: 'green' }, function(err, vms) {
// or
//dummyRepo.find({ 'deep.prop': 'dark' }, function(err, vms) {
// or
//dummyRepo.find({ age: { $gte: 10, $lte: 20 } }, function(err, vms) {
// or
//dummyRepo.find({ $or: [{age: 18}, {special: true}] }, function(err, vms) {
// or
//dummyRepo.find({ age: { $in: [1, 2, 3, 6] } }, function(err, vms) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    // vms is an array of all what is in the repository
    var firstItem = vms[0];
    console.log('the id: ' + firstItem.id);
    console.log('the saved value: ' + firstItem.get('color'));
});

Find with query options

// the query object ist like in mongoDb...
dummyRepo.find({ color: 'green' }, { limit: 2, skip: 1, sort: { age: 1 } }, function(err, vms) {
// or
//dummyRepo.find({ color: 'green' }, { limit: 2, skip: 1, sort: [['age', 'desc']] }, function(err, vms) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    // vms is an array of all what is in the repository
    var firstItem = vms[0];
    console.log('the id: ' + firstItem.id);
    console.log('the saved value: ' + firstItem.get('color'));
});

FindOne

// the query object ist like in mongoDb...
dummyRepo.findOne({ color: 'green' }, function(err, vm) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    console.log('the id: ' + vm.id);
    if (vm.has('color')) {
        console.log('the saved value: ' + vm.get('color'));
    }
});

Find by id...

// the query object ist like in mongoDb...
dummyRepo.get('myId', function(err, vm) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    console.log('the id: ' + vm.id);
    console.log('the saved value: ' + vm.get('color'));
});

Delete a viewmodel (only in write mode)

dummyRepo.get('myId', function(err, vm) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    vm.destroy();

    dummyRepo.commit(vm, function(err) {
    });
    // or you can call commit directly on vm...
    vm.commit(function(err) {
    });
});

Obtain a new id

myQueue.getNewId(function(err, newId) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }

    console.log('the new id is: ' + newId);
});

Clear a "collection" (only in write mode)

dummyRepo.clear(function(err) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }
});

Catch before and after database events

var repository = viewmodel.write({ type: 'mongodb' });
repository.on('before-database-get', function(ms, id) { console.log(ms, id); });
repository.on('after-database-get', function(ms, id) { console.log(ms, id); });
repository.on('before-database-find', function(ms, query, queryOptions) { console.log(ms, query, queryOptions); });
repository.on('after-database-find', function(ms, query, queryOptions) { console.log(ms, query, queryOptions); });
repository.on('before-database-findOne', function(ms, query, queryOptions) { console.log(ms, query, queryOptions); });
repository.on('after-database-findOne', function(ms, query, queryOptions) { console.log(ms, query, queryOptions); });
repository.on('before-database-commit', function(ms, vm) { console.log(ms, vm); });
repository.on('after-database-commit', function(ms, vm) { console.log(ms, vm); });

Implementation differences

Some implementations support bulkCommit

dummyRepo.bulkCommit([vm1, vm2, vm3], function(err) {
    if(err) {
        console.log('ohhh :-(');
        return;
    }
});

currently supported by:

inmemory
mongodb
elasticsearch6

mongodb

For mongodb you can define indexes for performance boosts in find function.

var dummyRepo = repository.extend({
    collectionName: 'dummy',
    // like that
    indexes: [
        'profileId',
        // or:
        { profileId: 1 },
        // or:
        { index: {profileId: 1}, options: {} }
    ]
    // or like that
    repositorySettings : {
        mongodb: {
            indexes: [ // same as above
                'profileId',
                // or:
                { profileId: 1 },
                // or:
                { index: {profileId: 1}, options: {} }
            ]
        }
    }
});

redis

The find function does ignore the query argument and always fetches all items in the collection.

Elasticsearch >= 5.X

Use the 'elasticsearch6' type for Elasticsearch versions 5.X and 6.X.

The find queries are not mongoDb compatible as the rest of the implementations due to the uneeded overhead and complexity of converting between both formats.

For find queries with elasticsearch6 use elasticsearch native elastic Query DSL;

repository.find( onlyTheQueryClause, otherBodyOptions, callback);

    repository.find(
        {
            range : {
                age : {
                    gte : 10,
                    lte : 20
                }
            }
        ),
        {
            from: 0,
            size: 10,
            sort: { age: 'asc' }
        },
        function(error, results) {
        });

Additionaly for elasticsearch6 the number of shards, number of replicas, the refresh behaivour on index and the mappings on index create can be addtionaly defined to optimize performace.

    var dummyRepo = repository.extend({
        collectionName: 'dummy',
        repositorySettings: {
            elasticsearch6: {
                refresh: 'wait_for', // optional, refresh behaviour on index, default is true ( ie. force index refresh ) https://www.elastic.co/guide/en/elasticsearch/reference/current/docs-refresh.html                
                waitForActiveShards: 2 // optional, defaults to 1 ( ie. wait only for primary ) https://www.elastic.co/guide/en/elasticsearch/reference/current/indices-create-index.html#create-index-wait-for-active-shards
                index: { // optional applied on index create, https://www.elastic.co/guide/en/elasticsearch/reference/6.x/indices-create-index.html
                    settings : { // will be merged with the default ones,
                        number_of_shards: 3, // optional defaults to 1,
                        number_of_replicas: 1 // optional defaults to 0,
                    },
                    mappings : { // optiona will be merged with the default ones,
                        properties: { // specific properties to not be handled by dynamic mapper
                            title: {
                                type: "text"
                            }
                        }                    
                    }
                }
            }
        }
    });

Release notes

Database Support

Currently these databases are supported:

inmemory
mongodb ([node-mongodb-native] (https://github.com/mongodb/node-mongodb-native))
couchdb ([cradle] (https://github.com/cloudhead/cradle))
tingodb ([tingodb] (https://github.com/sergeyksv/tingodb))
redis ([redis] (https://github.com/mranney/node_redis))
azuretable (azure-storage)
documentdb (documentdb, doqmentdb)
elasticsearch ([elasticsearch] (https://github.com/elastic/elasticsearch-js))
elasticsearch6 ([elasticsearch] (https://github.com/elastic/elasticsearch-js)) - for Elasticsearch 5.x and 6.x
dynamodb ([aws-sdk] (https://github.com/aws/aws-sdk-js))

own db implementation

You can use your own db implementation by extending this...

var Repository = require('viewmodel').Repository,
util = require('util'),
    _ = require('lodash');

function MyDB(options) {
  Repository.call(this, options);
}

util.inherits(MyDB, Repository);

_.extend(MyDB.prototype, {

  ...

});

module.exports = MyDB;

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

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