vsivsi/node-ddp-client

Node DDP Client

A callback style DDP (Meteor's Distributed Data Protocol) node client, originally based alansikora's node-js_ddp-client and Meteor's python client. Uses a more callback style approach.

The client implements the pre1 and pre2 versions of DDP.

Installation

  npm install ddp

Example

Please see the example in examples/example.js. Or here for reference:

var DDPClient = require("ddp");

var ddpclient = new DDPClient({
  host: "localhost",
  port: 3000,
  /* optional: */
  auto_reconnect: true,
  auto_reconnect_timer: 500,
  use_ejson: true,           // Use Meteor's EJSON to preserve certain data types.
  use_ssl: false,
  maintain_collections: true // Set to false to maintain your own collections.
});

/*
 * Connect to the Meteor Server
 */
ddpclient.connect(function(error) {
  if (error) {
    console.log('DDP connection error!');
    return;
  }

  console.log('connected!');

  /*
   * Uncomment to log in with username/password
   */
  // ddpclient.loginWithUsername("username", "password", function (err, result) {
    // result contains your auth token

    setTimeout(function () {
      /*
       * Call a Meteor Method
       */
      ddpclient.call(
        'deletePosts',             // name of Meteor Method being called
        ['foo', 'bar'],            // parameters to send to Meteor Method
        function (err, result) {   // callback which returns the method call results
          console.log('called function, result: ' + result);
        },
        function () {              // callback which fires when server has finished
          console.log('updated');  // sending any updated documents as a result of
          console.log(ddpclient.collections.posts);  // calling this method
        }
      );
    }, 3000);

    /*
     * Call a Meteor Method while passing in a random seed. 
     * Added in DDP pre2, the random seed will be used on the server to generate
     * repeatable IDs. This allows the same id to be generated on the client and server
     */
    var Random = require("ddp-random"),
        random = Random.createWithSeeds("randomSeed");  // seed an id generator

    ddpclient.callWithRandomSeed(
      'createPost',              // name of Meteor Method being called
      [{ _id : random.id(),      // generate the id on the client 
        body : "asdf" }],            
      "randomSeed",              // pass the same seed to the server
      function (err, result) {   // callback which returns the method call results
        console.log('called function, result: ' + result);
      },
      function () {              // callback which fires when server has finished 
        console.log('updated');  // sending any updated documents as a result of
        console.log(ddpclient.collections.posts);  // calling this method 
      }                          
    );

    /*
     * Subscribe to a Meteor Collection
     */
    ddpclient.subscribe(
      'posts',                  // name of Meteor Publish function to subscribe to
      [],                       // any parameters used by the Publish function
      function () {             // callback when the subscription is complete
        console.log('posts complete:');
        console.log(ddpclient.collections.posts);
      }
    );
  // });
});

/*
 * Useful for debugging and learning the ddp protocol
 */
ddpclient.on('message', function (msg) {
  console.log("ddp message: " + msg);
});

/*
 * If you need to do something specific on close or errors.
 * You can also disable auto_reconnect and
 * call ddpclient.connect() when you are ready to re-connect.
*/
ddpclient.on('socket-close', function(code, message) {
  console.log("Close: %s %s", code, message);
});

ddpclient.on('socket-error', function(error) {
  console.log("Error: %j", error);
});

/*
 * If use_ejson is true, you can access the EJSON object used by ddp.
 */
var oid = new ddpclient.EJSON.ObjectID();

Unimplemented Features

The node DDP client does not implement ordered collections, something that while in the DDP spec has not been implemented in Meteor yet.

Thanks

Many thanks to Alan Sikora for the ddp-client which formed the inspiration for this code.

Contributions:

• Tom Coleman (@tmeasday)
• Thomas Sarlandie (@sarfata)
• Mason Gravitt (@emgee3)
• Mike Bannister (@possiblities)
• Chris Mather (@eventedmind)
• James Gill (@jagill)
• Vaughn Iverson