CRUDr
Open source module for socket-enabled CRUD operations in Node.js
Features
- Authentication compatible with OAuth2 (using middleware)
Install
npm install crudr
Usage
On the server:
var http = require('http'),
crudr = require('crudr'),
app = http.createServer(),
app.listen(80);
crudr.listen(options);
On the client:
<script src="/crudr/client.js"></script>
<script>
crudr.connect( options, function(){
// .. initiate app
});
</script>
Dependencies
- Socket.io
- Express (only for uri routes)
- Underscore
Events
When a model is synced with a particular backend, the backend will trigger events on the object (across multiple clients) that share the backend.
To initialize the binding logic we create a backend key on the object of specific Model we are interested in
For example,
var Model;
...
Model.backend = "{{name}}";
Model.backend = buildBackend( Model );
We can keep data synced in realtime with the following event bindings:
var self = this;
element.addEventListener('{{name}}:create', function(e) {
var data = e.response;
}, false);
element.addEventListener('{{name}}:update', function(e) {
var data = e.response;
}, false);
element.addEventListener('{{name}}:delete', function(e) {
var data = e.response;
}, false);
In addition to {{name}}:create
, {{name}}:read
, {{name}}:update
, and {{name}}:delete
events, a generic {{name}}
event is also triggered when a model is synced.
element.addEventListener('{{name}}', function(e) {
// Method will be one of create, read, update, or delete
var method = e.method;
var data = e.response;
});
The event prefix backend
is used by default but this can be customized by setting the
event name on the server.
options.event = '{{name}}';
crudr.listen(options);
More information on the initialization options is available at the wiki
Backends
Backends are stacks of composable middleware (inspired by Connect) that are responsible
for handling sync requests and responding appropriately. Each middleware is a function
that accepts request and response objects (and optionally a function that can be called
to continue down the stack). A middleware will generally either return a result by
calling end
on the response object or pass control downward. For example, to add a
logger to our backend:
var backend = crudr.createBackend();
backend.use(function(req, res, next) {
console.log(req.backend);
console.log(req.method);
console.log(JSON.stringify(req.model));
next();
});
backend.use(crudr.helpers.memoryStore());
A request object will contain the following objects (in addition to those set by the various middleware):
method
: the sync method (create
,read
,update
, ordelete
)model
: the model object to by syncedoptions
: any options set by the client (except success and error callbacks)backend
: name of the backend responsible for handling the requestsocket
: the client socket that initiated the request
We can also target only particular types of requests by passing the desired contexts to use
:
backend.use('create', 'update', 'delete', function(req, res, next) {
if (isAuthorized(req)) {
next();
} else {
next(new Error('Unauthorized'));
}
});
Or alternatively by using one of the four helper methods (create
, read
, update
, delete
):
backend.read(function(req, res) {
if (req.model.id) {
req.end(mymodels[req.model.id]);
} else {
req.end(mymodels);
}
});
If the bottom of the middleware stack is reached before a result is returned then the requested
model is returned by default: res.end(req.model)
.
Clients are automatically notified of events triggered by other clients, however, there may be cases where other server-side code needs to make updates to a model outside of a backend handler. In such a case, one can notify clients by emitting events directly on the backend. For example:
var backend = crudr.createBackend();
backend.use(crudr.helpers.memoryStore());
// Clients will receive 'backend:create', 'backend:update',
// and 'backend:delete' events respectively.
backend.emit('created', { id: 'myid', foo: 'bar' });
backend.emit('updated', { id: 'myid', foo: 'baz' });
backend.emit('deleted', { id: 'myid' });
Customizing
In addition to middleware, the behavior of CRUDr can be customized via standard Socket.IO
mechanisms. The object returned from the call to listen
is the Socket.IO object and can be
manipulated further. See http://socket.io for more details.
Tests
Install development dependencies:
npm install
Run the test suite:
make test
Constributors
Credits
Distributed by Makesites.org
Released under the Apache License, Version 2.0