transport

#Transport

A hub for centralizing all your request handlers within your application. Implements the disposable pattern.

#Installation

``bash
npm install transport
`

#How to use

Require and initialize transport:

`js
var Transport = require("transport"),
transport = new Transport();
`

Requests

Define a simpleHandler to handle a request and send the result back:

`js
// Object with all the request handlers
var handlers = {
simpleHandler: function (payload, callback) {
// do something with the payload
var result = doSomethingWithPayload(payload);

// send the result back
callback(result);
}
};
`

Add the handler to Transport. The handlers have to be stored in an observable-store. This allows for sharing the same handlers between several implementations of Transport and react accordingly when handlers are added and removed.

`js
var Store = require("observable-store");

transport.setReqHandlers(new Store(handlers));
`

Make the request to simpleHandler:

`js
transport.request("simpleHandler", "payload", function callback(result) {
// do something with result
});
`

Open a channel

Let's define a handler that will publish several updates.

`js
var handlers = {
simpleChannel: function (payload, onEnd, onData) {
var stream = getStream(payload);

stream.on('data', onData);
stream.on('end', onEnd);
}
};
`

Now we can open the channel and receive updates:

`js
transport.listen("simpleChannel", "filename", function onEnd(data) {
// Will be called when stream closes
console.log("END OF FILE", data);
}, function onData(data) {
// Will be called everytime some data is pushed
console.log("MORE DATA", data);
});
`

Close/dispose an open channel

transport.listen returns a function. When the handler also returns a function, it will be called by executing the one returned by transport.listen. It can be used to stop whatever the handler started and do some cleanup too.

`js
var handlers = {
closableChannel: function (payload, onEnd, onData) {
var stream = getStream(payload);

stream.on("data", onData);
stream.on("end", onEnd);

return function stop() {
stream.removeListener("data", onData);
stream.removeListener("end", onEnd);
}
}
};
`

Now, when calling transport.listen, we can call the stop() function returned by the handler.

`js
var stop = transport.listen("closableChannel", "filename", function onEnd() { ... }, function onData() { ... });

// When calling stop, the stop() function returned by the handler will be executed.
stop();
`

Managing errors

A convenient way to bubble up errors is to follow the error first convention:

`js
var handlers = {
closableChannel: function (payload, onEnd, onData) {
var stream = getStream(payload);

stream.on("data", onData);
stream.on("end", function (data) {
onEnd(null, data);
});
stream.on("error", function (error) {
onEnd(error);
});
}
};
``

And now we can handle the errors in the onEnd callback.

`js
transport.listen("closableChannel", "filename", function onEnd(error, data) {
if (error) {
throw new Error(error);
}

// do something with data
}, function onData() {
// ...
});
``

LICENSE
=======

MIT