Node simple OData server

Super simple implementation of OData server running on Node.js with easy adapters for mongodb and lowdb. Just define an OData model, provide a mongo or lowdb database, hook into node.js http server and run.

It supports basic operations you would expect like providing $metadata, filtering and also operations for insert, update and delete. On the other hand it suppose to be really simple so you don't get support for entity links, batch operations, atom feeds and many others.

The implementation is tested with .net OData client and it should fulfill basic protocol requirements.

Get started

This is how you can create an OData server with node.js http module and lowdb.

var http = require('http');
var { Low, Memory } = require('lowdb');
var memoryDB = new Memory();
var db = new Low(memoryDB);
var ODataServer = require('simple-odata-server');
var Adapter = require('simple-odata-server-lowdb');

if (!db.data) {
  db.data = {}
  db.write()
}

var model = {
    namespace: "jsreport",
    entityTypes: {
        "UserType": {
            "_id": {"type": "Edm.String", key: true},
            "test": {"type": "Edm.String"},            
        }
    },   
    entitySets: {
        "users": {
            entityType: "jsreport.UserType"
        }
    }
};

var odataServer = ODataServer("http://localhost:1337")
    .model(model)
    .adapter(Adapter(function(es, cb) { cb(null, db)}));


http.createServer(odataServer.handle.bind(odataServer)).listen(1337);

Now you can try requests like:
GET http://localhost:1337/$metadata
GET http://localhost:1337/users?$filter=test eq 'a' or test eq 'b'&$skip=1&$take=5
GET http://localhost:1337/users('aaaa')
GET http://localhost:1337/users?$orderby=test desc
GET http://localhost:1337/users/$count
POST, PATCH, DELETE

Adapters

There are currently two adapters implemented.

• mongodb - ranawaysuccessfully/node-simple-odata-server-mongodb
• lowdb - ranawaysuccessfully/node-simple-odata-server-lowdb

The mongo adapter can be used as

var Adapter = require('simple-odata-server-mongodb')
MongoClient.connect(url, function(err, db) {
	odataServer.adapter(Adapter(function(cb) { 
		cb(err, db.db('myodatadb')); 
	})); 
});

express.js

It works well also with the express.js. You even don't need to provide service uri in the ODataServer constructor because it is taken from the express.js request.

app.use("/odata", function (req, res) {
        odataServer.handle(req, res);
});

cors

You can quickly set up cors without using express and middlewares using this call

odataServer.cors('*')

Configurations

Using existing adapter is just a simple way for initializing ODataServer. You can implement your own data layer or override default behavior using following methods:

odataServer
	.query(fn(setName, query, req, cb))
	.update(fn(setName, query, update, req, cb))
	.insert(fn(setName, doc, req, cb))
	.remove(fn(setName, query, req, cb))
	.beforeQuery(fn(setName, query, req, cb))
	.beforeUpdate(fn(setName, query, req, update))
	.beforeInsert(fn(setName, doc, req, cb))
	.beforeRemove(fn(setName, query, req, cb))
	.afterRead(fn(setName, result));
	//add hook to error which you can handle or pass to default
	.error(fn(req, res, error, default))

Contributions

You are more than welcome to contribute with pull requests and add other basic operations you require.

Limitations

• document ids must have name _id
• no entity links
• no validations
• ... this would be a very long list, so rather check yourself

License

See license