Vanilla Primus

Primus works very similar to Socket.io but supports a number of different real-time libraries. Once configured on the server service methods and events will be available through a Primus socket connection.

Establishing the connection

In the browser, the connection can be established by loading the client from primus/primus.js and instantiating a new Primus instance. Unlike HTTP calls, websockets do not have a cross-origin restriction in the browser so it is possible to connect to any Feathers server.

See the Primus docs for more details.

ProTip: The socket connection URL has to point to the server root which is where Feathers will set up Primus.

Calling service methods

Service methods can be called by emitting a <servicepath>::<methodname> event with the method parameters. servicepath is the name the service has been registered with (in app.use) without leading or trailing slashes. An optional callback following the function(error, data) Node convention will be called with the result of the method call or any errors that might have occurred.

params will be set as params.query in the service method call. Other service parameters can be set through a Primus middleware.

`find`

Retrieves a list of all matching resources from the service

primus.send('messages::find', { status: 'read', user: 10 }, (error, data) => {
  console.log('Found all messages', data);
});

Will call messages.find({ query: { status: 'read', user: 10 } }) on the server.

`get`

Retrieve a single resource from the service.

primus.send('messages::get', 1, (error, message) => {
  console.log('Found message', message);
});

Will call messages.get(1, {}) on the server.

primus.send('messages::get', 1, { fetch: 'all' }, (error, message) => {
  console.log('Found message', message);
});

Will call messages.get(1, { query: { fetch: 'all' } }) on the server.

`create`

Create a new resource with data which may also be an array.

primus.send('messages::create', {
  "text": "I really have to iron"
}, (error, message) => {
  console.log('Message created', message);
});

Will call messages.create({ "text": "I really have to iron" }, {}) on the server.

primus.send('messages::create', [
  { "text": "I really have to iron" },
  { "text": "Do laundry" }
]);

Will call messages.create on the server with the array.

`update`

Completely replace a single or multiple resources.

primus.send('messages::update', 2, {
  "text": "I really have to do laundry"
}, (error, message) => {
  console.log('Message updated', message);
});

Will call messages.update(2, { "text": "I really have to do laundry" }, {}) on the server. The id can also be null to update multiple resources:

primus.send('messages::update', null, {
  complete: true
}, { complete: false });

Will call messages.update(null, { "complete": true }, { query: { complete: 'false' } }) on the server.

ProTip: update is normally expected to replace an entire resource which is why the database adapters only support patch for multiple records.

`patch`

Merge the existing data of a single or multiple resources with the new data.

primus.send('messages::patch', 2, {
  read: true
}, (error, message) => {
  console.log('Patched message', message);
});

Will call messages.patch(2, { "read": true }, {}) on the server. The id can also be null to update multiple resources:

primus.send('messages::patch', null, {
  complete: true
}, {
  complete: false
}, (error, message) => {
  console.log('Patched message', message);
});

Will call messages.patch(null, { complete: true }, { query: { complete: false } }) on the server to change the status for all read messages.

This is supported out of the box by the Feathers database adapters

`remove`

Remove a single or multiple resources:

primus.send('messages::remove', 2, { cascade: true }, (error, message) => {
  console.log('Removed a message', message);
});

Will call messages.remove(2, { query: { cascade: true } }) on the server. The id can also be null to remove multiple resources:

primus.send('messages::remove', null, { read: true });

Will call messages.remove(null, { query: { read: 'true' } }) on the server to delete all read messages.

Listening to events

Listening to service events allows real-time behaviour in an application. Service events are sent to the socket in the form of servicepath eventname.

created

The created event will be published with the callback data when a service create returns successfully.

<script>
  primus.on('messages created', function(message) {
    console.log('Got a new Message!', message);
  });
</script>

updated, patched

The updated and patched events will be published with the callback data when a service update or patch method calls back successfully.

<script>
  primus.on('my/messages updated', function(message) {
    console.log('Got an updated Message!', message);
  });

  primus.send('my/messages::update', 1, {
    text: 'Updated text'
  }, {}, function(error, callback) {
   // Do something here
  });
</script>

removed

The removed event will be published with the callback data when a service remove calls back successfully.

<script>
  primus.on('messages removed', function(message) {
    // Remove element showing the Message from the page
    $('#message-' + message.id).remove();
  });
</script>

Primus